workshop

Transcription

workshop

Epitome 2007 - Geoitalia 2007
WORKSHOP
3
4
WORKSHOP W01
Dalla definizione della pericolosità alla gestione delle emergenze
idrogeologiche: metodologie, strumenti e tecniche di studio.
WORKSHOP W02
Dalle dinamiche profonde ai processi superficiali: è possibile un
linguaggio comune?
WORKSHOP W03
Evoluzione petrologica del mantello litosferico europeo dall'Archeano
al presente.
W03-1 Orale
Armienti, Pietro
10.1474/Epitome.02.0001.Geoitalia2007
ISOTOPIC EVIDENCE FOR CHAOTIC IMPRINT IN UPPER MANTLE
HETEROGENEITY
ARMIENTI Pietro 1, GASPERINI Daniela 1
1 - DST - Pisa University
Presenter e-mail: [email protected]
Key terms: Mantle heterogeneity; Mantle convection; Scale invariance
A systematic check of the structure of the data set of geochemical composition
of samples from the Mid-Atlantic Ridge (MAR) and East Pacific Rise (EPR)
reveals an isomorphism between geometric structures and chemical features.
We observe that the distribution of isotopic heterogeneity in lavas sampled at
these ridge crests, believed to represent the isotopic composition of their
mantle source, is self-similar in the range of about 7000 km. Self-similarity is
the imprint of chaotic mantle processes, induced by recursion and favored by
"high-turbulent" behavior of the mantle. The size of the identified fractal region
reflects the large length scale of upper mantle chemical variability, and it is
likely frozen since the Early Proterozoic. The geochemical heterogeneity of the
asthenosphere along the ridges would record a fundamental transition in the
thermal conditions of the Earth's mantle, marking the shift towards a
"soft-turbulent" regime.
W03-2 Orale
Bali, Eniko
A QUARTZ-BEARING ORTHOPYROXENE-RICH WEBSTERITE XENOLITH
FROM THE PANNONIAN BASIN, WESTERN HUNGARY: EVIDENCE FOR
RELEASE OF SI-OVERSATURATED MELTS FROM THE SUBDUCTED SLAB
BALI Eniko 1, ZAJACZ Zoltan 2, KOVACS Istvan 3, SZABO Csaba 4, HALTER Werner 2,
VASELLI Orlando 5, TOROK Kalman 6, BODNAR Robert 7
1 - BAYERISCHES GEOINSTITUT, BAYREUTH
2 - INSTITUTE OF ISOTOPE CHEMISTRY AND MINERAL RESOURCES, ETH,
ZURICH
3 - RESEARCH SCHOOL OF EARTH SCIENCES, ANU, CANBERRA
4 - LITHOSPHERE FLUID RESEARCH GROUP, INSTITUTE OF GEOLOGY AND
GEOGRAPHY, EOTVOS UNIVERSITY, BUDAPEST
5 - DEPARTMENT OF EARTH SCIENCES, UNIVERSITY OF FLORENCE
6 - EOTVOS LORAND GEOPHYSICAL INSTITUTE, BUDAPEST
7 - DEPARTMENT OF EARTH SCIENCES, VIRGINIA TECH, BLACKSBURG
Key terms: quartz-bearing websterite; silicate melt inclusion; subduction;
Carpathian Pannonian Region
A quartz (qz)-bearing orthopyroxene(opx)-rich websterite xenolith was found in
Pliocene alkali basaltic tuff of Szigliget, Bakony-Balaton Highland Volcanic Field
(western Hungary). The xenolith has cumulate texture and is composed of opx
and subordinate interstitial clinopyroxene (cpx). Both cpx and opx contain
primary silicate melt inclusions (smi), although only opx contains large (up to 1
mm) rounded or needle shaped qz inclusions. Smi in both pyroxenes is
composed of silicate glass and CO2-fluid phase. Smi is large (up to 100 mm),
rounded or negative crystal shaped occurring as single inclusions or forming
clusters in cores of both host minerals. The glass-fluid ratio is 10:1 - 20:1.
Smi in opx was reheated. At 1 atmosphere the complete dissolution of the CO2
did not happen before decrepitation, thus only the beginning (average: 863°C)
and the termination (average: 958°C) of glass melting was observed. The
equilibrium temperature of the xenolith is 954ºC, in agreement with the entire
melting of glass. The crystallization pressure was calculated from the density of
the CO2 inclusions, giving the minimum pressure of 1.1 GPa corresponding to
the present day uppermost mantle.
Silicate glass in smi is SiO2- and alkali-rich MgO-, FeO- and CaO-poor.
Reheated smi displays lower SiO2 and higher MgO contents as a consequence
of remelting of the opx crystallized on the smi walls. The studied smi is richer
in SiO2, poorer in Al2O3 and strongly depleted in CaO, MgO and FeO relative
either to the high P/T partial melts of peridotite or to those olivine hosted smi
that represent partial melts of metasomatized mantle wedge. In contrast, slab
derived silicate melts show a similar composition to the studied smi suggesting
common origin.
Cpx is strongly enriched in LREE and MREE compared to HREE, with significant
negative anomalies of Pb, Sr, Hf, Zr and Ti on PM-normalized trace element
diagrams. These cpxs are enriched in LREE and MREE, but depleted in Sr
compared to the cpx in local peridotite and pyroxenite and granulite xenoliths.
Opx is depleted in LREE and MREE compared to HREE, however shows the
same degree of enrichment in incompatible elements compared to opx from
5
BBHVF peridotites that is shown by the coexisting cpx. Both cpx and opx have
high concentrations of Cr (4200 and 1770 ppm, respectively) and Ni (855 and
1550 ppm, respectively) the latter being significantly higher than that in the
pyroxenes of local peridotite xenoliths.
Trace element composition of smi covers a narrow range independently of the
host mineral. They are strongly enriched in incompatible elements displaying
negative anomalies of Nb, Ta, and Sr and slight positive anomaly of Pb. The
trace element composition of the smi also resembles silicate melts released
from subducted slab, but with low Sr-contents compared to those typical for
slab melts.
The incompatible element characteristics of both the smi and their host
minerals (cpx and opx) and the presence of qz-inclusions in opx suggest a
slab-derived origin, whereas the high Ni- and Cr-contents suggest the
involvement of peridotite component in the genesis of the studied rock. Model
calculations suggest, that:
1) Similar qz-bearing orthopyroxene-rich rocks might form from a hybrid melt
developed on the interface between peridotite and a Si-oversaturated slab-melt
in case of a high silicate melt/wall-rock ratio (>5:1).
2) The reaction and fractional crystallization from the hybrid melt did not
change significantly the composition of the original slab-melt, giving a
possibility to estimate the source and P/T conditions of slab melt formation.
Thus we can conclude that the Si-oversaturated melt was released from the
subducted slab at
1.5-2.0 GPa and <1000 °C, leaving behind a restite of
cpx+amp+gt+ru+pl/ap(?). The trace element composition of MI in both opx
and cpx suggest the involvement of a metasedimentary component during slab
melting.
W03-3 Poster
Bali, Eniko
SIGNIFICANT WATER SOLUBILITY REDUCTION IN FORSTERITE DUE TO
THE VARIATION OF WATER ACTIVITY IN THE EARTH'S MANTLE
BALI Eniko 1, BOLFAN-CASANOVA Nathalie 2, KOGA Kenneth 2
1 - BAYERISCHES GEOINSTITUT, BAYREUTH
2 - LABORATOIRE MAGMAS ET VOLCANS, CNRS, UNIVERSITÉ BLAISE PASCAL,
CLERMONT-FERRAND
Key terms: Water solubility in forsterite; mantle; FTIR
The storage capacity of water in the upper mantle largely depends on water
solubility in mantle olivine, and provides a fundamental information required
for petrological, geophysical and geochemical models of the mantle. An
accurate assessment of water storage capacity of minerals of the upper mantle
must account for simultaneous effects of variables such as pressure,
temperature, iron content and silica activity. Previous experimental studies
have shown that the water solubility in olivine increases with increasing water
fugacity up to 12 GPa at 1100°C (Kohsltedt et al., 1996). Water incorporation
in olivine was also observed to increase with increasing temperature (from
1000°C to 1300°C) at 0.3 GPa (Zhao et al., 2004). This contrasts with the
incorporation of water in transition zone phases such as wadsleyite and
ringwoodite for which water solubility decreases with increasing temperature.
We performed experiments at 2.5, 6 and 9 GPa, and temperatures ranging
from 1000 to 1400°C in the MgO-SiO2-H2O system using a multi-anvil
apparatus. The starting material consisted of forsterite and enstatite in the 1:1
molar ratio with 1 to 5 wt% H2O. The samples were analysed using scanning
electron microscopy, electron microprobe and polarized Fourier transform
infrared spectroscopy.
We report the dependence of water maximum concentration on temperature at
pressures higher than 0.3 GPa. The results show that water solubility in olivine
increases with temperature only at 2.5 GPa. At 6 and 9 GPa, the water
solubility reaches a maximum at temperatures of 1175 to 1250°C, depending
on pressure, then decreases at higher temperatures. These results agree with
recent observations at 12 GPa in the MgO-SiO2-H2O system (Smyth et al.,
2006).
Such behaviour is explained by the change in water fugacity due to dissolution
of silicate component in the fluid. Coincidentally, these drastic reductions of
water activities are observed at the conditions above the second critical point
of silicate-water system. The solubilities determined in this study allow
estimating the water storage capacity in the mantle. Furthermore, because of
the variation of the geothermal gradient, the continental lithosphere is
expected to have higher water storage capacity than oceanic mantle at depths
ranging from 100 to 400 km.
References
Kohlstedt, D.L., Keppler, H. & Rubie, D.C. (1996): Solubility of water in the
,
and phases of (Mg,Fe)2SiO4. Contributions to Mineralogy and Petrology,
123, 345-357
Smyth, J.R., Frost, D.J., Nestola, F., Holl, M., Bromiley, G. (2006): Olivine
hydration in the deep upper mantle: effects of temperature and silica activity.
Zhao, Y.H., Ginsberg, S.B. & Kohlstedt, D.L. (2004): Solubility of hydrogen in
olivine: dependence on temperature and iron content. Contributions to
Mineralogy and Petrology, 147, 155-161.
W03-4 Orale
Beccaluva, Luigi
PETROGENESIS OF THE ETHIOPIAN PLATEAU BASALTS AND THEIR
BEARING ON MANTLE PLUME COMPONENTS
BECCALUVA Luigi 1, BIANCHINI Gianluca 1, NATALI Claudio 1, SIENA Franca 1
1 - Dipartimento di Scienze della Terra - Università di Ferrara
Key terms: Ethiopia; flood basalts; mantle sources; mantle components;
metasomatism
The Ethiopian-Yemen continental flood basalts represent an Oligocene Large
Igneous Province where some typical features of deep mantle plume, including
high 3He/4He ratios, have been documented (Afar plume; Courtillot et al.,
WORKSHOP W03
6
2003). In the Ethiopian plateau large volumes (ca. 250000 Km3) of tholeiitic
magmas, erupted in a short time span (31-28 Ma), appear to be zonally
arranged with low-Ti basalts in the NW part of the province, and high-Ti basalts
(and picrites) in the eastern sector neighbouring the Afar-Red Sea region (Pik
et al. 1998)
An integrated petrogenetic model based on major element mass balance
calculations, phase equilibria, and thermo-barometric evaluations indicates that
primary basaltic magmas were generated by ca. 15-20% melting of mantle
lherzolite at ca. 1250-1300 °C / 13-16 Kb and ca. 1300-1350 C° / 14-19 Kb for
low-Ti and high-Ti tholeiites, respectively; high-Ti picrites by ca. 30% melting
at ca. 1400-1450 °C / 20-30 Kb.
The calculated mantle sources invariably require hydrated lherzolite
composition with up to 5% and 10% of amphibole for low-Ti and high-Ti
magmas respectively, and a parallel increase of 2 - 17 times incompatible
element abundances with respect to those observed in the Ethiopian mantle
xenoliths. Further Ti-rich metasomatic phases (e.g. rutile, ilmenite, armalcolite)
are required in the mantle sources, particularly for the generation of extremely
high-Ti magmas (TiO2 up to 5-6%). Therefore, low-Ti basalts may have been
generated in the outer zone of the Afar-plume by partial melting of moderately
metasomatized lithospheric mantle sources, in connection with the activation of
the hotspot and related crustal bulging. High-Ti basalts/picrites could in turn be
generated in the inner part of the Afar buoyancy flux from mantle sources
significantly more enriched by plume components. These metasomatizing
components may correspond to Na-alkali silicate mafic melts enriched in Ba,
Th, Nb, Ti, Zr as well as light REE and show compositional analogies with the
Ti-rich alkali silicate metasomatism documented in some mantle xenoliths from
Kerguelen Islands (Grégoire et al., 2000).
References
Courtillot et al., 2003. Earth Planet. Sci. Lett. 205, 295-308.
Grégoire et al., 2000. Geochim. Cosmochim Acta 64, 673-694.
Pik et al., 1998. J. Volc. Geoth. Res. 81, 91-111.
W03-5 Poster
Berkesi, Marta
PRESSURE PRESERVED BY CO2-RICH FLUID INCLUSIONS: A CASE
STUDY FROM TIHANY PERIDOTITES, WESTERN HUNGARY
BERKESI Marta 1, HIDAS Karoly 1, SZABÓ Csaba 1
1 - Lithosphere Fluid Research Lab, Eötvös University, Budapest, Hungary
Key terms: CO2-rich fluid inclusions; upper mantle peridotite xenoliths;
minimum trapping pressure; Pannonian Basin
Detailed fluid inclusion study hosted in upper mantle peridotite xenoliths from
Tihany (western Hungary, central part of the Pannonian Basin) were carried out
in this work. The peridotite xenoliths were brought to the surface by
post-extension-related alkali basalt 8 million years ago (Balogh & Németh,
2005), which is the oldest volcano of the Bakony-Balaton Highland Volcanic
Field hosting subcontinental upper mantle xenoliths (Szabó et al., 2004; Falus
& Szabó, 2004).
In previously study, using geothermometer based on the
orthopyroxene/clinopyroxene equilibrium in the host xenoliths by Brey and
Köhler (1990), two domains in the mantle lithosphere beneath Tihany have
been distinguished (Hidas, 2006). We applied the given temperature values to
be able to estimate pressure, whilst the individual CO2-rich fluid inclusions,
occurring particularly in orthopyroxene and clinopyroxene, have preserved their
high density representing minimum trapping conditions in the upper mantle.
This is because the fluid inclusions, in equilibrium with their host minerals, can
be defined by the intersection of the geotherm with the density of the trapped
fluid. Since a precise geobarometer for the spinel peridotites is not available
yet, the minimum trapping pressure estimation from CO2 fluid inclusion
densities provides the best method available for pressure estimation for these
mantle rocks.
The Tihany orthopyroxene-rich spinel peridotite xenoliths (lherzolites and
harzburgites) contain abundant CO2-rich inclusions. The inclusions are mostly
hosted in orthopyroxenes showing two well-defined types: type-1
orthopyroxene-hosted negative crystal shaped inclusions with size up to 70
m containing one phase (liquid) at ambient conditions, and type-2:
orthopyroxene- and olivine-hosted elongated or irregular shaped inclusions
with a size varying between 5 and 20
m. Latter ones contain one (liquid) or two (liquid and vapor) phases at ambient
conditions.
The CO2 fluid inclusions have been studied using heating and cooling stage and
Raman microspectroscopy. The microthermometric data suggests that in most
cases the fluid phase of the inclusions is pure CO2 (melting temperature /Tm/ =
-56,6 - -56,9 °C). Furthermore, type-1 inclusions have higher densities
(0.89-1.12 g/cm3) than type-2 ones (0.5-0.9 g/cm3) in all xenoliths. Results
from microthermometry suggest presence of further fluid phase(s) in those
xenoliths, which show values of Tm lower than pure CO2 (<-56,9 °C). Raman
microspectroscopy confirms that these fluid inclusions also contain H2S besides
CO2.
The geothermobarometric calculations and CO2-density values suggest that the
studied peridotite xenoliths represent two, physically distinct, a shallower and a
deeper domains in the lithosphere beneath the studied area. Minimum trapping
pressure estimations of CO2 fluid inclusions support this idea and provide
12 °C/km temperature gradient for the upper mantle beneath Tihany 8 million
years ago.
W03-6 Orale
Bianchini, Gianluca
MANTLE XENOLITHS FROM THE IBERIAN PENINSULA - 20 YEARS LATER
BIANCHINI
Gianluca 1, BECCALUVA Luigi 1, BONADIMAN Costanza 1, SIENA Franca
1
Key terms: Iberian lithosphere; mantle xenoliths; metasomatism
After the pioneeristic study of mantle xenoliths from the Neogene volcanic
districts of the Iberian Peninsula by Ancochea and Nixon (1987; in P.H. Nixon
ed "Mantle xenoliths", John Wiley and Sons Ltd) extensive sampling of these
rocks has been carried out at Olot (north-east Spain), Cofrentes (near
Valencia), Calatrava (central Spain) and Tallante (Betic Cordillera).
Mantle xenoliths and host lavas from these localities were systematically
investigated for bulk rock major and trace element (XRF, ICP-MS), "in situ"
microanalyses of constituent phases (EMPA, LA-ICP-MS), as well as Sr-Nd (Hf)
isotopic analyses on mineral separates.
Mantle xenoliths from the OLOT volcanic field comprise a bi-modal suite of
protogranular spinel lherzolites (sometimes with pargasitic amphibole), and
coarse-grained granular - highly refractory -spinel harzburgites. In these
xenoliths distinctive REE patterns and isotopic systematics of clinopyroxenes
suggest interaction with metasomatic agents corresponding to a) tholeiitic
melts with DM isotopic signature for lherzolites and b) highly alkaline melts
with EM1 isotopic signature for harzburgites. Olot lherzolites possibly represent
asthenosphere mantle material up-lifted, juxtaposed and accreted to the older
subcontinental lithospheric mantle (harzburgites), during the post-Variscan
rifting of the Iberian margin. These genetically different, but adjoining, mantle
domains intimately mingled along the northern Iberian margin during
subsequent plate convergence processes (Bianchini et al., 2007; Lithos 94,
25-45).
Mantle xenoliths from the single volcanic centre of COFRENTES are mainly
lherzolitic in composition and characterized by clinopyroxene REE patterns
closely resembling those of the Olot lherzolites. This suggests also for this
mantle section the upraise/protrusion of asthenospheric mantle material to
shallow levels in the Iberian lithospheric margin, as also indicated by extremely
low re-equilibration nominal temperatures (down to 700 °C).
Mantle xenoliths from the TALLANTE volcanic centre in the Betic Cordillera
show a more complicated petrogenetic history, which can be attributed to
diverse metasomatic events: a) impregnation of lherzolitic domains by tholeitiic
melts (up to 5% of modal plagioclase, flat REE patterns of both bulk rocks and
clinopyroxene, DM isotopic signature); b) interactions with alkali-silicate basic
melts particularly evident in cpx-poor lherzolites and harzburgites
(LREE-enriched patterns in both bulk rocks and clinopyroxene, EM1 isotopic
signature); c) percolation of silicic melts in the peridotite matrix with formation
of veins made up of plagioclase, orthopyroxene, amphibole and phlogopite.
This veining appears to be related to silica-oversaturated/alkali-rich hydrous
metasomatic melts, inducing progressive conversion of olivine in orthopyroxene
or, in extreme cases, crystallization of quartz; particularly high 87Sr/86Sr and
low 143Nd/144Nd ratios, coupled with strong negative Sr and Eu anomalies in
both bulk-rocks and constituent minerals, indicate a significant contribution of
continental crust components in the mantle sources, plausibly related to the
Cenozoic subduction processes that ultimately led to the Betic orogeny
(Beccaluva et al., 2004; Lithos 75, 67-87).
Mantle xenoliths from the CALATRAVA volcanic district are protogranular
lherzolites (and wehrlites) widely overprinted by pyrometamorphic textures,
with spongy clinopyroxene and reaction rims around orthopyroxene and spinel
with secondary parageneses including feldspars, phlogopite, apatite, carbonate
as well as interstitial glassy blebs. Bulk rock and clinopyroxene trace element
and isotopic analyses suggest that the sub-lithospheric metasomatic agents
were highly-alkaline carbonated basic melts characterized by HIMU isotopic
affinity, that seems to be an ubiquitous isotopic fingerprint throughout the
European-Mediterranean regions.
W03-7 Orale
Bodinier, Jean-Louis
CHEMICAL VARIATIONS IN TECTONICALLY-EMPLACED MANTLE ROCKS:
SUPERIMPOSED EFFECTS OF PARTIAL MELTING, MELT
REDISTRIBUTION AND IGNEOUS REFERTILIZATION
BODINIER Jean-Louis 1, LE ROUX Véronique 1, SOUSTELLE Vincent 1, TOMMASI
Andréa 1, GARRIDO Carlos 2
1 - GÉOSCIENCES MONTPELLIER
2 - UNIVERSIDAD DE GRANADA
Key terms: Tectonically-emplaced mantle rocks; Orogenic peridotites; Igneous
refertilization; Rejuvenation of lithospheric mantle
There is a growing body of evidence indicating that chemical variations in
tectonically-emplaced mantle rocks mostly reflect melt redistribution and
near-solidus reactions at decreasing melt mass superimposed onto previous
depletion events. The convergence of the most fertile lherzolite compositions at
around 4% Al2O3 in peridotite massifs is not an indication of their pristine
origin. This composition rather coincides with a threshold for melt segregation
and formation of pyroxenite-peridotite "veined" mantle.
Recent studies also tend to converge on the idea that the orogenic peridotites
represent thinned and/or rejuvenated lithospheric mantle, thermally eroded by
asthenospheric mantle during continental rifting or early ocean initiation.
Lithospheric rejuvenation is marked by annealing of deformation
microstructures, overgrowth of mineral grains and km-scale modal/chemical
variations resulting from partial melt redistribution. From top to base of eroded
lithosphere, melt processes vary from refertilization of aged, refractory
(harzburgite) lithosphere to partial melting of previously refertilized material
(lherzolite and websterite). In the Ronda and Lherz massifs, both processes are
associated with narrow fronts where major microstructural, modal and
chemical variations occur within a few meters to tens of meters. Melting and
refertilization fronts display striking resemblances (e.g., annealing of textures
and small-scale chemical heterogeneities) as well as significant differences. The
melting front observed in Ronda is a clear-cut structure that can be followed
over > 10 km in the massif, suggesting that its formation was
thermally-controlled at regional scale. In contrast, the refertilization front of
Lherz is extremely convoluted, suggesting its formation by coalescence of
relatively narrow ( 10 m) melt infiltration channels. Refertilization and melting
fonts are considered as the upper and lower boundaries of transient, moving
asthenosphere-lithosphere transition zones during thermo-mechanical erosion
of the lithospheric mantle by upwelling asthenosphere. Further complexity
arises during the waning stages of lithospheric erosion - upon conductive
cooling - when partially molten lithosphere is traversed by the receding
melting/refertilization fronts.
An important implication of the origin of fertile orogenic lherzolites by
WORKSHOP W03
refertilization is that these rocks cannot be straightforwardly used to infer
primitive mantle compositions. It is thus logic to wonder whether fertile mantle
xenoliths with similar compositions represent refertilized or pristine mantle.
Several authors have ascribed the chemical stratification of cratonic lithosphere
and/or its temporal evolution to metasomatic refertilization. In this scheme,
fertile (predominantly lherzolitic), off-craton lithosphere may be viewed as the
ultimate transformation of cratonic lithosphere after one or several cycles of
igneous refertilization. Extensive refertilization in the Western Alps (Lanzo) and
Betic peridotites (Ronda) is intrinsically related to the lithospheric thinning
processes that led to mantle exhumation, which might suggest that large-scale
refertilization is specific of tectonically-emplaced, orogenic peridotites.
However, the Lherz massif illustrates a situation where refertilization and
exhumation are related to distinct events, separated in time by thermal
relaxation of subcontinental lithosphere. Several suites of spinel peridotite
xenoliths compositionally comparable to the Lherz peridotites (e.g. formed of
LREE-depleted lherzolites associated with subordinate, LREE-enriched
harzburgites) might also record magmatic refertilization of a previously
depleted lithospheric mantle.
W03-8 Orale
Bogdanova, Svetlana V.
HETEROGENEITY OF THE SUBCONTINENTAL MANTLE BENEATH THE
UKRAINIAN SHIELD
BOGDANOVA Svetlana V. 1, TSYMBAL Stepan N. 2, SHUMLYANSKYY Leonid V. 2,
BILLSTROEM Kjell 3, PASHKEVICH Inna K. 4, TSYMBAL Yury S. 2
1 - LUND UNIVERSITY SWEDEN
2 - INSTITUTE OF GEOCHEMISTRY, MINERALOGY & ORE FORMATIONS, KIEV,
UKRAINE
3 - LABORATORY FOR ISOTOPE GEOLOGY, SWEDISH MUSEUM OF NATURAL
HISTORY, STOCKHOLM
4 - INSTITUTE OF GEOPHYSICS, KIEV, UKRAINE
Key terms: East European Craton; Ukrainian Shield; Subcontinental mantle
The Ukrainian Shield (UkS) comprises the Meso- to Palaeoarchaean (2.8 to 3.7
Ga) Podolian, Bug, Middle Dniepr and Azov crustal blocks of different
evolutions. These are separated by Palaeoproterozoic, 2.3-2.1 Ga orogenic
belts. All the different units were welded together at ca. 2.1-2.0 Ga.
Subsequently, tectonic and/or magmatic reworking occurred at 1.79-1.75 Ga,
at the end of Precambrian at ca. 550 Ma, and in the Devonian when the
Pripyat-Dniepr-Donets Aulacogen (PDDA) was formed. Accordingly, the
subcontinental mantle was developed during several major events, and lateral
as well as vertical compositional variation resulted from the degrees of mantle
differentiation and depletion during recurrent magmatism and due to
metasomatic enrichment of the depleted mantle during its fluidization.
Juxtaposition of tectonic terranes of different ages also contributed to mantle
heterogeneity.
Geophysically, the lithosphere of the UkS features two large resistant, stable
regions corresponding to the principal Archaean crustal blocks. A zone of highly
conductive lithosphere and elevated heat flow (more than 40 mWt/m2)
coincides, in general, with the main Paleoproterozoic suture zones, where the
Moho boundary shows complicated steep offsets. The Vp and densities of the
uppermost mantle range from 8.4-8.6 km/s and 3400-3450 kg/m3 along the
suture zones to 7.8-8.1 km/s and 3000-3200 kg/m3. A characteristic
high-velocity lower crust underlies the 1.79-1.74 Ga
gabbro-anorthosite-mangerite-rapakivi plutons.
Mantle-derived alkaline-ultramafic rocks of Palaeoproterozoic and Devonian
ages occur in the different blocks of the UkS. They are: Palaeoproterozoic
(Kirovograd) and Devonian (Azov and NW Volyn) basaltoid and mica-rich
kimberlites, (2) Palaeoproterozoic lamproites (Azov and Kirovograd), (3)
Palaeoproterozoic carbonatites, ijolites and other alkaline ultramafic rocks (the
Azov, Podolian blocks and Volyn). Numerous placers of minerals (pyrope,
Cr-diopside, picroilmenite, Cr-spinels) including diamond are known in the
sedimentary cover.
Reconstructions of the compositional variation of the upper mantle with depth
by employing xenolith and mineral compositions indicate significant diversity.
Garnet-spinel ± phlogopite bearing harzburgites, lherzolites, pyroxenites,
dunites and eclogites occur in various proportions. However, without precise
rock ages it is difficult to use these data to compare the structure of the mantle
at different times.
Isotopic (Nd-Sr-Pb) analyses of mantle-derived rocks in the different crustal
blocks are still relatively few and occasionally the isotopic compositions have
been modified by post-magmatic processes. Nd-isotope data typically show
mildly depleted to slightly enriched compositions for almost all the rocks
studied, which range age span from the Archean to the Devonian. Sr isotope
data are quite variable, comprising both unrealistically low and very radiogenic
ratios when calculated to the times of rock crystallization. Post-magmatic
open-system behaviour and crustal assimilation during magma generation may
therefore have played a role.
However, a majority of the Sr isotope data appear to yield consistent and
reasonable initial 87Sr/86Sr ratios, e.g. between 0.702 and 0.703 for 2.1-1.8
Ga rocks. The Pb isotope data suggest that at least some parts of the mantle
were enriched in uranium already in the Archean as evidenced by highly
radiogenic Pb compositions for rocks of different ages. Moreover, many
whole-rock analyses suggest elevated 207Pb contents, consistent with an
enriched source of the protoliths.
In summary, the geophysical, mineralogical and isotopic data demonstrate the
mantle heterogeneity beneath the UkS. The most pronounced structural and
compositional changes probably occurred at ca. 2.1-2.0, 1.8 and 0.4 Ga.
W03-9 Orale
Bonadiman, Costanza
PRE-MESOZOIC LITHOSPHERIC MANTLE BENEATH SCOTLAND
TERRAINS
BONADIMAN Costanza 1, COLTORTI Massimo 1, DUGGEN Svend 2, PALUDETTI
Laura 1, SIENA Franca 1, THIRWALL Matthew 3, UPTON Brian B.G. 4
1 - Dip. Scienze Terra, Università di Ferrara, Italy
2 - IFM-GEOMAR, Kiel, Germany
7
3 - Dept. of Geology, Royal Holloway University of London, U.K
4 - School of GeoSciences, The University of Edinburgh, U.K.
Key terms: mantle xenoliths; pre-mesozoic; mantle metasomatsm; intraplate
and subduction metasomatism; Scotland
Mantle xenoliths entrained in late Carboniferous to mid-Permian silica-poor
basic magmas from northern Scotland were investigated using major and trace
elements of minerals and isotopic compositions of whole-rock and
clinopyroxenes. The work concerns peridotites from two localities in the ENE
and WSW of the Scottish Northern Highlands Terrane, namely Rinibar (Orkney)
and Streap Com'laidh, (near Glenfinnan), but a geochemical comparison with
Scottish mantle xenoliths of the same age has been made in order to
characterize the Pre-mesozoic lithospheric mantle beneath Scotland terrains.
Northern Highland Terrane is one of the five main terranes which constitute
Scotland. From South to North, these are: 1) Southern Uplands, 2) Midland
Valley, 3) Grampian Highland, 4) Northern Highland and 5) Hebridean to the
north-west of the Moine Thrust Zone. The terranes are believed to have been
amalgamated into their present relationships by 400 Ma at the latest.
Uncertainty exists as to where the Northern Highland Terrane lay in earlier
times, but magnetic studies suggest that by around 1.2 Ga ago, it was an
integral part of a supercontinent Rodinia located in the southern hemisphere.
Break-up of Rodinia led at ~ 600 Ma to the opening of the Iapetus Ocean. This
subsequently underwent complex closure resulting in the Caledonian Orogeny.
The final 'docking' of the Northern Highland Terrane with respect to its
neighbouring Grampian and Hebridean Terranes appears to have been effected
during the (Silurian) Scandian phase of the orogeny. On the basis of different
trace element contents and isotopic ratios clinopyroxenes from Rinibar
identified two different metasomatic styles, one carbonatitic and one
kimberlite-like, probably derived from the same source for variable degree of
partial melting. This is also supported by the similarity of Sr and Nd isotopic
ratios at 550+50Ma. This age is crucial for Scotland and for global tectonics. It
corresponds to the opening of Iapetus Ocean. At about the same time (550Ma)
the Canadian and Finnish Shields were also affected by kimberlitic and
carbonatitic magmatism. Late Proterozoic-Early Phanerozoic carbonatite
magmatism is also recognized within Scotland (Loch Borralan, Northern
Highland Terrane)as also testified by the coherent suites of cpx, amph and
exotic megacrysts in the Carbo-Permian basanites & melanephelinites across
Scotland from the Hebridean Terrane (Loch Roag) to the Southern Uplands
(Burn-Between-the-Laws).At 500 Ma the tectonic regime changed from
divergent to convergent as Iapetus began to close and the Baltica continent
start approaching Laurentia. It may have been during this convergent stage
(~400Ma) that the metasomatism affecting the sub-Streap lithospheric mantle
occurred. Clinopyroxenes from this locality show in fact trace element and
isotopic features that can be explained by metasomatic fluids coming off a
subducted slab. The various terranes that now constitute Scotland came into
conjunction at the end of Caledonian Orogeny, and were certainly contiguous
by 416 Ma. By comparison, the Rinibar clinopyroxenes record no
subduction-related imprinting. This could imply that i) the north easternmost
portion of the Highland Terrain lithospheric mantle was unaffected by the
subduction or, alternatively, ii) the subduction-related metasomatism recorded
in the Streap mantle may be older, when the two lithospheric blocks were far
apart.
A detailed analyses of the elemental and isotopic data of the xenoliths from the
other Scottish blocks reveal a possible regional distribution of the intraplate
metasomatic enrichment from SE (Midland Valley) to NW (Hebridean Craton),
whereas subduction-relatated mtasomatism have been clearly detected only in
the mantle xenoliths of Northern Terrane (Streap) and Hebridean Terrane
(Loch Roag).
W03-10 Poster
Bonelli, Rossana
METASOMATIC PROCESSES IN THE MANTLE BENEATH THE VENETO
VOLCANIC PROVINCE (NORTHERN ITALY): FLUID AND MELT
INCLUSIONS EVIDENCE
BONELLI Rossana 1, FREZZOTTI Maria Luce 1
1 - Dipartimento di Scienze della Terra, Università degli Studi di Siena, Siena,
53100 Italy
Key terms: peridotites; fluid inclusions; melt inclusions; metasomatism
Tertiary alkali-basalts of the Veneto Volcanic Province (VVP,SE Alps) contain
abundant peridotite xenoliths, representing one of the few localities where to
study the lithosphere mantle beneath Italy.
Previous studies showed that peridotites are depleted harzburgites and
lherzolites, re-equilibrated under spinel-facies conditions. Beccaluva et al.
(2001) described a pervasive metasomatism characterised by variable
LREE-enrichment patterns, due to infiltration of alkali silicate basic melts
related to the Tertiary volcanism, forming glass pockets and veins
(pyrometamorphic textures). More recently, Gasperini et al. (2006) suggested
two metasomatc events: 1) an older one induced by slab-derived material and
characterised by crystallisation of amphibole and mica; and 2) a more recent
alkaline metasomatic event consistent with the Tertiary volcanism of the area.
We have investigated petrography, mineral chemistry, fluid and melt inclusions
of 17 peridotites from VVP in order to constrain P-T conditions of mantle
events, to determine the style of the metasomatic reactions, and the
compositions of the metasomatic agents. Studied rocks show dominant
protogranular and transitional (intermediate between protogranular and
porphyroclastic) textures; only one sample shows pyrometamorphic features.
They consist of a four-phase assemblage: clear olivine (43-70 % vol.), light
brown orthopyroxene (20-42 % vol.), green clinopyroxene (5-15 % vol.) and
brown spinel (2-8 % vol.). Clinopyroxenes in protogranular lherzolites show
depleted LREE patterns, while those of transitional rocks are characterised by
spoon-shaped REE patterns (La up to 60 times chondrite), and variable
enrichments in LILE.
Two generations of fluid inclusions (1-30 µm) are recognised: 1) Type A
(CO2-rich fluid), commonly present in orthopyroxene, while seldom observed in
clinopyroxene and olivine; 2) Type B (CO2 and CO2-CO fluids) present only in
orthopyroxene. Type B inclusions may contain very small amphibole (~10 µm)
as trapped mineral, indicating a presence of an aqueous component in the
fluid. Most of inclusions homogenise to the liquid, with ThL ranging between
WORKSHOP W03
8
-44 and 24°C. The densest CO2 fluid inclusions (d = 1.13 g/cm3) indicate a
trapping pressure of ~ 1 GPa at 900°C.
Melt/glass in studied xenoliths occur with different textures: 1) Type A clear
glass occurs as microveins, melt inclusions (~50 µm), and pockets (e.g. in
pyrometamorphic xenolith), and shows high SiO2 and alkali contents; 2) Type
B melt is represented by colourless micro-channels of glass (~100 µm) around
the porous rims of clinopyroxene (i.e. dendrites) and by melt inclusions (~50
µm), consisting of glass and a CO2 bubble. Type B glass shows lower SiO2 and
alkali contents than Type A glass.
Mantle equilibration temperatures were calculated from mineral pairs in spinel
peridotites, and range between 680 and 992°C for protogranular and
transitional textured xenoliths, and between 941 and 1171°C for the
pyrometamorphic sample.
We propose that the mantle beneath the VVP equilibrated at pressures >1 GPa,
in a temperature range of 680-992°C. A major metasomatic event was induced
by Type A melts with alkaline affinity, probably originating from the Tertiary
alkali basalts of the VVP. Type A melts were responsible for the observed
pyrometamorphic textures in the rocks, for a substantial enrichment in LREE in
clinopyroxene, and for a 100-200°C temperature increase, similarly to what
described by Beccaluva et al. (2001). Traces of an aqueous fluid (CO2 +
brines) preserved as fluid inclusions in orthopyroxene suggest the existence of
an older subduction related metasomatic event, confirming the hypothesis of a
two stage metasomatism in the lithosphere beneath the SE Alps (Gasperini et
al.,2006).
REFERENCES
Beccaluva L., Bonadiman C., Coltorti M., Salvini L. & Siena F. (2001) J.
Petrology. 42: 173-187.
Gasperini D, Bosch D., Braga R., Bondi M., Macera P. & Morten L. (2006) J.
Geochemical. 40: 377-404.
W03-11 Poster
Carraro, Anna
HYDROGEN CONTENT IN PYROXENES FROM MANTLE XENOLITHS IN
THE TRIASSIC MAGMATIC COMPLEX OF PREDAZZO (DOLOMITES, NE
ITALY)
CARRARO Anna 1, RAEPSAET Caroline 2, BUREAU Hélène 2, VISONÀ Dario 1, FUCHS
Yves 3, KHODJA Hicham 2
1 - Dipartimento di Geoscienze, Università di Padova, Italy
2 - Laboratoire Pierre Süe, CEA Saclay, Gif-sur-Yvette, France
3 - Laboratoire G2I, Université Paris Est, Marne la Vallée, France
Key terms: Mantle xenoliths; Nominally Anhydrous Minerals; Hydrogen
concentration; Dolomites, NE Italy
The amount of hydrogen dissolved in nominally anhydrous silicates from the
upper mantle has been quantified using a nuclear microprobe. Studied samples
are clinopyroxene (cpx) and orthopyroxene (opx) grains, which, together with
olivine and spinel, form lherzolite xenoliths contained in Triassic dykes of the
Predazzo Magmatic Complex (Dolomites, NE Italy). The xenoliths here
considered have protogranular texture and no evidence of additional hydrous
phases or melt was observed. Both clino- and orthopyroxene can be considered
as host minerals for the largest concentrations of hydrogen among Nominally
Anhydrous Minerals (Peslier et al., 2002); for this reason, their role in providing
a repository of water in the upper mantle and in mantle water recycling
processes is coming of crucial interest. An absolute analytical method, a
combination of ERDA (Elastic Recoil Detection Analysis) and RBS (Rutherford
Backscattering Spectroscopy), was used for H measurements. During the last
years, the ERDA method was improved in the nuclear microprobe at the
Laboratoire Pierre Süe (Saclay, France) and the detection limit of 130 wt ppm
H2O has been now obtained for dehydrated San Carlos olivine (Bureau et al.,
2007). Samples were prepared for analyses following a specific protocol, in
order to decrease the effect of H absorbed at the surface of the mineral grains.
The analytical conditions were: 4He + energy = 3.0 MeV, beam spot size = 4x4
µm 2, 4x16 µm 2 for ERDA, scattering angle = 170°, recoil angle = 30°. The
maps were processed using a specific software (Daudin et al., 2003): from RBS
and ERDA maps, chemically homogeneous areas were selected and results are
referred only to H depleted zones. Homogeneity of the selected zones was
confirmed by electron microprobe analyses (CAMECA SX50, CNR - University of
Padova).
H amounts in cpx vary from 716 to 1094 wt ppm H2O, whereas opx shows H
concentrations from 378 to 456 wt ppm H2O. Total relative uncertainty is about
13 wt ppm H2O for all the samples. These values are slightly higher than those
reported for pyroxenes (e.g., 450 wt ppm H2O for cpx) in spinel peridotite
xenoliths from the Tertiary Veneto Volcanic Province (NE Italy; Carraro et al.,
2007) and obtained with the same method. However, H concentrations in the
Predazzo samples are in the ranges for mantle pyroxenes reported in the
literature but higher than values usually found for diopside and enstatite
forming spinel lherzolite xenoliths (Skogby, 2006). On one hand, an increasing
trend in water concentration for cpx was observed when going from spinel
lherzolite to garnet lherzolite stability field (Demouchy, 2004). In our case, the
provenance of the xenoliths from higher pressure conditions is supported by
clusters of opx-cpx-spinel (i.e., garnet peridotite precursor) observed in the
texture of the Predazzo samples (Carraro & Visonà, 2003). On the other hand,
the highest concentrations for opx may be attributed either to higher pressure
environment or to metasomatic reactions at mantle level (Bell & Rossman,
1992).
REFERENCES
Bell D.R., Rossman G.R. (1992): Science 255, 1391-1397.
Bureau H., Raepsaet C., Khodja H., Carraro A., Aubaud C. (2007):
Goldschmidt2007 (submitted).
Carraro A., Visonà D. (2003): Eur. J. Mineral., 15, 103-115.
Carraro A., Bureau H., Visonà D., Raepsaet C., Fuchs Y, Khodja H. (2007):
Goldschmidt2007 (submitted).
Daudin L., Khodja H., Gallien L.P. (2003): Nucl. Instr. and Meth. in Phys. Res.
B, 210, 153-158.
Demouchy S. (2004): PhD Dissertation, Univ. Bayreuth, Germany.
Peslier A.H., Luhr J.F., Post J. (2002): Earth. Planet. Sci. Lett., 201, 69-86.
Skogby H. (2006): Rev. Mineral. Geochem., MSA, 62, 155-167.
W03-12 Orale
Conticelli, Sandro
POTASSIC AND ULTRAPOTASSIC MAGMATISM IN THE WESTERN
MEDITERRANEAN BASIN AND INSIGHTS ON ITS GEODYNAMIC
SIGNIFICANCE -1: EVIDENCE FROM PB, ND, AND SR ISOTOPES AND
TRACE ELEMENTS DATA ON LAMPROITE, SHOSHONITES AND
CALC-ALKALIC ASSOCIATIONS FROM TUSCANY, MURCIA-ALMERIA,
CORSICA, AND WESTERN ALPS
CONTICELLI Sandro 1, GUARNIERI Luisa 1, MATTEI Massimo 2, FARINELLI Alice 1,
BIANCHINI Gianluca 3, BOARI Elena 1, AVANZINELLI Riccardo 4, TIEPOLO Massimo
5
, TOMMASINI Simone 1, VENTURELLI Giampiero 6
1 - Dipartimento di Scienze della Terra, Università degli Studi di Firenze,
Firenze, Italy
2 - Dipartimento Scienze Geologiche, Università Roma III, Roma, Italy
3 - Dipartimento di Scienze della Terra, Università degli Studi di Ferrara,
Ferrara, Italy
4 - Department of Earth Sciences, University of Bristol, Bristol, U.K.
5 - C.N.R. - Istituto di Geoscienze e Georisorse - Sezione di Pavia, Campus
Universitario, Pavia, Italy
6 - Dipartimento di Scienze della Terra, Università degli Studi di Parma,
Campus Universitario, Parma, Italy
Key terms: ultrapotassic rocks; lamproites; western mediterranean; Sr, Nd, Pb
isotopes
Lamproitic rocks associated to shoshonitic and calc-alkalic ones are found
around the Western Mediterranean. The oldest ones were intruded as dykes
into the metamorphic rocks of the Western Alps during the Oligocene. The
youngest ones were intruded and poured out in Southern Tuscany from
Pliocene to Pleistocene. The most important lamproitic magmatic event is found
in South-Eastern Spain, with several dikes, plugs, and lava flows emplaced
during the Late Miocene. The smallest lamproitic outcrop is found in Corsica, in
the form of dike during the Middle Miocene. Shoshonitic and calc-alkalic rocks
are invariably timely and spacely associated to lamproites.
Western Mediterranean lamproites are peculiar ultrapotassic rocks, ranging
from slightly silica undersaturated to silica over-saturated, they are extremely
enriched in MgO, but low Al2O3, CaO, and Na2O. They are plagioclase-free
rocks, but K-feldspar is abundant beside other K-bearing phases.
Lamproite-like rocks are also characterised by a strong enrichment in
incompatible elements, which sometimes prevent further enrichment due to
crustal contamination during ascent to surface.
New trace element beside new and original Sr, Nd and Pb isotopic data are
reported. All the sample studied are characterised by strong fractionation of
High Field Strength elements with respect to Large Ion Lithophile elements.
Extreme enrichment in Th, U, and Pb with respect to Ba, Nb, Ta, Sr, P, and Ti is
a common characteristic observed. Shoshonitic, high-K calc-alkalic, and
calc-alkalic rocks show similar trace element distribution patterns and
elemental fractionation but less enriched then in lamproitic rocks.
Sr isotopic data of lamproite are extremely enriched in radiogenic compositions
with initial 87Sr/86Sr in the ranges between 0.716350 and 0.717652 for
Western Alps lamproites, between 0.716415 and 0.723595 for Spanish
lamproites and between 0.71579 and 0.71672 for Tuscany lamproites. The
Corsica lamproite shows the lowest values of initial 87Sr/86Sr (0.71229).
Conversely Nd isotopes are extremely low with initial values in the ranges
between 0.511990 and 0.512009 for Western Alps lamproites, between
0.511190 and 0.512140 for Spanish lamproites, and between 0.512086 and
0.512123 for Tuscany lamproites. Also in this case Corsica lamproite
distinguishes clearly from others Western Mediterranean lamproites showing
the highest value of initial 143Nd/144Nd (0.512148). Regarding lead isotopes,
no large differences are observed among the 207Pb/204Pb values of lamproites
(15.629-15.715) from the different provinces, whereas significant differences
are observed in the 206Pb/204Pb and 208Pb/204Pb values, with Tuscan
Lamproites showing the lowest values (206Pb/204Pb = 18.653-18.677,
208Pb/204Pb = 38.855-39.026) and Western Alps the highest values
(206Pb/204Pb = 18.684-18.904, 208Pb/204Pb = 39.029-39.485). Shoshonitic
to calc-alkalic rocks display significantly different isotopic values with dilution of
the radiogenic components for Sr and Nd and of the un-radiogenic one for Nd
with decreasing alkali contents.
Several evidences indicate that magmas of the different provinces have been
generated by a depleted upper mantle subsequently modified by
metasomatism. The metasomatic agents were originated by recycling of upper
crustal material into the mantle before magma generation. Metasomatism was
not patently and not homogeneous, but concentrated in a vein network. Pure
vein partial melting produced lamproitic-like magmas, increasing melting of
surrounding upper mantle source produced the spectra of magma observed.
Deviation from this hypothesis is shown by Murcia-Almeria and Corsica regions.
Corsica lamproite bear a consistent withinplate component that indicate a
different process of generation and complicate the general geodynamic setting
for these rocks. A geodynamic model for the evolution of the Western
Mediterranean basin from Miocene is also provided.
W03-13 Orale
Cottin, Jean-Yves
MANTLE XENOLITHS EVOLUTION DURING NEOGENE
POST-COLLISIONAL TRANSITION FROM CALC-ALKALINE TO ALKALINE
VOLCANISME IN ORANIE : A SLAB BREAKOFF
COTTIN Jean-Yves 1, DELPECH Guillame 2, ZERKA M. 3, O'REILLY Suzanne Y. 4,
LOUNI A. 4, GREGOIRE Michel 5, LORAND Jean-Pierre 6
1 - Department of Geology-UMR 6524 "Magmas et Volcans", University of Jean
Monnet, Saint-Etienne Cedex, France
2 - "Interactions et Dynamique des Environnements de Surface"
3 - IST, Université d'Oran Es Senia, Oran, Algérie
4 - GEMOC ARC National Key Centre, Earth and Planetary Sciences, Macquarie
University, Australia
5 - "Dynamique Terrestre et Planétaire", Observatoire Midi-Pyrénées, Toulouse,
France
6 - LAB. Minéralogie, Muséum Paris, France
Key terms: Mantle xenoliths; Slab breakoff; Calc-alkaline and alkaline
volcanism
WORKSHOP W03
The western Oranie, located at the northern margin of the African plate, is
characterized by important plio-quaternary alkali volcanic extrusions. This
volcanism shows a change in composition during the Neogene from calco-alkali
at the Miocène to alkali at the Plio-Quaternary. These xenoliths are subdivided
in three groups : (1) Type I mantle tectonites (porphyroclastic and
equigranular lherzolites and protogranular harzburgites) reequilibrated in the
spinel and/or plagioclase stability field. (2) type II basaltic cumulates
(wehrlites, pyroxenites and hornblendites) and (3) rare composite xenoliths.
On the basis of trace element compositions determined by LAM-ICP-MS, three
groups of clinopyroxene can be subdivided. (1) Clinopyroxenes with trace
element signature depleted in LREE ((La/Yb)N=0.21-0.33) belong to
protogranular Sp-bearing harzburgites or Cpx-rich Sp-bearing lherzolite. They
show evidence of small degrees of partial melting that affected only LREE. (2)
Clinopyroxenes associated with composite xenoliths have the same shape of
patterns (enrichments in MREE relative to LREE) but show different level of
enrichment in trace elements characteristic of a nearly complete reequilibration
with deep alkali segregates. This difference in trace element enrichments is
related to the Mg# of the cpx and probably to the depth of crystallisation of the
cpx in an alkaline melt. (3) Clinopyroxenes associated with harzburgites or
lherzolites showing various degrees of enrichments in LREE are directly related
to different stages of incomplete reequilibration during melt-rock reaction
processes. Some of these peridotites are enriched in metasomatized cpx and
can evolve to a werhlitic composition. Moreover, some of these peridotites are
strongly metasomatized and show occurrences of glass in foliation plans
underlined by spinel alignements. The trace element composition of the glass
has been determined and shows enrichments in LREE (La/YbN=22.4-23.6) but
positive anomalies in Nb, Ta ((Nb/La)N=1.82-2.17) without significant other
enrichment or depletion in other HFSE. The glass trace element composition is
either distinct from the trace element composition of the alkaline host lava nor
with the trace element composition of calco-alkaline lavas in the area. The
composition of the glass probably results from complex
infiltration-reaction-crystallisation processes. The calc- alkaline volcanic
products of Oranie would derived from melting of a mantle having preserved an
orogenic geochemical, probably inherited of a previous subduction episode.
This signature would have dimmed progressively during the time, what would
reflect a change of geodynamical context bordering to a contribution more and
more marked of the process of partial melt of a subcontinental sheared and
more fertile mantle.
W03-14 Orale
Cvetkovic, Vladica
INSIGHT INTO THE LITHOSPHERIC MANTLE BENEATH BALKAN
PENINSULA: EVIDENCE FROM STUDY OF MANTLE XENOLITHS AND
THEIR HOST BASALTS
CVETKOVIC Vladica 1, DOWNES Hilary 2, PRELEVIC Dejan 3, LAZAROV Marina 4
1 - UNIVERSITY OF BELGRADE, FACULTY OF MINING AND GEOLOGY, SERBIA
2 - BIRKBECK COLLEGE, LONDON, UK
3 - UNIVERSITY OF MAINZ, GERMANY
4 - UNIVERSITY OF FRANKFURT, GERMANY
Key terms: Geochemistry; Mineralogy; Alkaline basalts; Dinarides
Mantle xenoliths occurring in 40-60 Ma old basanites in East Serbia can be
roughly distinguished as (i) depleted, (ii) orthopyroxene-rich, and (iii)
fertile/metasomatized xenoliths. Their study provides important conclusions
about the composition and geodynamics of mantle underneath East Serbia.
(i) The first sub-group predominates; it consists of harzburgite,
clinopyroxene-poor lherzolite and rare dunite xenoliths. They contain mostly <5
vol% of modal clinopyroxene and are characterized by high Mg# in silicates
(>91), high Cr# in spinel (mostly 0.5-0.7), and by distinctively low Al2O3
contents in orthopyroxene (1-2 wt.%). Non-modal batch and fractional melting
models for REE contents in orthopyroxene revealed the extent of depletion of
>>30% and 20-22% of melting, respectively.
(ii) Orthopyroxene-rich xenoliths are composed of tabular low-Al orthopyroxene
(~70vol.%, Mg# 85-87) containing tiny inclusions of very Cr-rich spinels.
Orthopyroxene shows a slightly U-shaped primitive mantle-normalized trace
element pattern with strong peaks at U and Pb, similar to that of
orthopyroxene from normal regional peridotitic mantle. These xenoliths are
interpreted as having originally been hydrous olivine-bearing orthopyroxenites
that crystallised from subduction-related SiO2-saturated, boninite-like
magmas.
(iii) Fertile/metsomatized lithologies include (a) Fe-rich dunite xenoliths and
clinopyroxene megacrysts, (b) lherzolite xenoliths with metasomatic
spongy-rimmed Ti-Al-rich clinopyroxene, and (c) tiny discrete metasomatic
assemblages in veinlets and pockets in the highly depleted xenoliths. The
fertile lithologies have low Mg#s in their silicates (ca. 88), low Cr#s in spinels
(<0.4), and high Al2O3 in orthopyroxene (2-6 wt%). Trace element patterns of
metasomatic clinopyroxene indicate that the inferred metasomatic melts are
genetically related to the host basanites.
The most abundant East Serbian mantle xenoliths are more depleted than most
non-cratonic sub-continental mantle xenolith suites, as well as orogenic
peridotites and abyssal peridotites. Geological and compositional evidence
suggests that the xenoliths do not represent Archean mantle. The existence of
Proterozoic mantle cannot be entirely excluded, although it is in disagreement
with geological evidence. On the other hand, the studied xenoliths are
compositionally very similar to peridotites of modern oceanic sub-arc settings.
The existence of such a depleted lithospheric mantle segment is also inferred
from the presence of rare orthopyroxene-rich xenoliths in the same suite.
These are interpreted to have originated as lithospheric precipitates of high-Mg,
SiO2-saturated magmas that require a highly depleted mantle source. Such
source is typically required by boninitic-like magmas of intraoceanic
suprasubduction settings. A proposed geodynamic model to explain these
observations involves accretion or underplating of the lower parts of the
Tethyan oceanic lithosphere during the Upper Jurassic closure of the eastern
branch of the Vardar ocean.
Fertile lithology can be explained as addition of 5-20 wt% of a basanitic-like
melt to a refractory mantle. The inversion modeling, performed on least
contaminated and most isotopically uniform host basanites, implies a source
which is enriched in highly and moderately incompatible elements
(~35-40xchondrite for U-Th-Nb-Ta) suggesting that the primary magma of the
host basanites was not derived by melting of a homogeneous asthenospheric
9
source. D0 values of the calculated basanitic source are similar to D0 values of
anhydrous metasomatized mantle with small additions of metasomatic
clinopyroxene and carbonate (~5 %) and with traces of ilmenite (~1 %) and
apatite (~0.05 %). A schematic two-phase model involves percolation of
CO2-and H2O-rich fluids, precipitation of metasomatic hydrous minerals and
their subsequent breakdown due to the further uplift of hot asthenospheric
mantle.
W03-15 Orale
Downes, Hilary
MANTLE XENOLITHS IN SPACE AND TIME IN EUROPE
DOWNES Hilary 1
1 - BIRKBECK UNIVERSITY OF LONDON
Key terms: xenolith; mantle; Europe
The European continent is particularly rich in localities in which mantle
xenoliths have been brought to the surface, representing lithosphere from
beneath regions of crust of Archaean to Phanerozoic age. Cratonic lithosphere
is represented by rare xenoliths from a few scattered localities in the
Fennnoscandian shield (Finland, Arkhangelsk, Kola) and the East European
platform (Belarus, Ukraine), where depleted garnet and spinel peridotites are
brought to the surface mostly in kimberlites. More studies need to be
undertaken concerning the nature of the lithosphere beneath the cratonic
terranes of Europe (Fennoscandia, Ukraine, NW Scotland) and the processes
that have formed it. Alkali basalts in Scotland and southern Scandinavia
provide samples of somewhat younger (Proterozoic-early Palaeozoic)
lithosphere.
In the Tertiary and Quaternary alkaline volcanics erupted in the Hercynian and
Alpine regions of western and central Europe, mantle xenoliths are abundant,
but the processes that have affected the mantle in these areas are very
diverse. Extreme depletion in Zr and Hf in clinopyroxenes associated with
unusually high Hf-isotope ratios in mantle xenoliths from the Massif Central
indicate that some regions of the lithospheric mantle have been extremely
depleted by melting in Hercynian times. More constraints are needed on the
age of depletion across different regions of Europe. Enrichment due to
subduction-derived fluids has been suggested by various workers for regions of
the mantle beneath the Pannonian-Carpathian region, the Dinarides, Spain and
central Italy. Carbonatite metasomatism has been detected in xenoliths from
the Pannonian-Carpathian region, NE Spain, central Italy, Poland and France.
We need to have an agreed methodology to determine the degree of depletion
of the mantle in different regions and an agreed set of criteria to distinguish
between different types of metasomatism. Silicate melt metasomatism is
common beneath most regions, often giving rise to composite
peridotite-pyroxenite or peridotite-hornblendite xenoliths. Metasomatising
melts appear to be ubiquitously related to the host Neogene alkali basalt
magmas. There are still some fundamental questions about how enrichment
really occurs within xenoliths (i.e. to what extent interaction with magma prior
to entrainment overprints many samples), and the extent to which the
subcontinental lithospheric mantle participates in magmagenesis.
W03-16 Orale
Faccini, Barbara
PETROLOGICAL FEATURES OF MANTLE XENOLITHS FROM EASTERN
TRANSYLVANIAN BASIN: A VERY FERTILE MANTLE OR
RE-FERTILISATION PROCESSESCOLTORTI Massimo 1, BONADIMAN Costanza 1, FACCINI Barbara 1, HARANGI
Szabolcs 2, NTAFLOS Theodoros 3, SEGHEDI Ioan 4
1 - Earth Science Department, Ferrara University, Italy
2 - ELTE Department of Petrology and Geochemistry, Hungary
3 - Department of Lithospheric Sciences, University of Vienna, Austria
4 - Institute of Geodynamics, Bucharest, Romania
Key terms: Transylvanian basin; Mantle metasomatism; Amphibole
Mantle xenoliths from Eastern Transylvanian Basin have been collected in the
Persani Mts. area from tuff cones and a basaltic quarry. The rocks are mainly
amphibole-bearing lherzolites with subordinate ol-websterites and anhydrous
lherzolites. Most peridotites have porphyroclastic textures with aligned spinels
and variable grain size of olivine and orthopyroxene (opx) porphyroclasts (5-2
mm and 1 cm-3 mm, respectively). Amphibole can be found mostly as
disseminated crystals around spinel (sp), usually associated with opx and
clinopyroxene (cpx), and/or as selvages at the contact with peridotite, and/or
as discontinuous veinlets intruding the peridotite matrix. Glassy patches and
veinlets, not related to host basalt infiltration, occur close to amphibole (amph)
and cpx; secondary olivine, cpx and sp are found in the glassy pools. Xenoliths
present cpx modal content varying between 6.5 and 27%, together with high
opx and sp modal content (up to 33% and 12% respectively).
Primary olivine (Ol1) have mg# and CaO varying from 88.9 to 91.8 and 0.02 to
0.13 respectively, whereas secondary idiomorphic crystals (Ol2) reach higher
values, from 90.7 to 94.1. In Ol2 CaO content ranges between 0.10 and 0.29.
Orthopyroxenes mg#, SiO2 and Al2O3 vary from 89.14 to 92.12, from 53.10 to
55.88 and from 2.84 to 5.90, respectively. Primary clinopyroxenes (Cpx1) have
mg# going from 89.01 to 92.99, SiO2 from 49.92 to 52.23, TiO2 from 0.11 to
0.71, Al2O3 from 3.45 to 8.16, CaO from 19.52 to 23.25, Na2O from 0.49 to
1.80 and Cr2O3 from 0.47 to 1.37. Cpx1 rims and secondary crystals have
variable mg#, 85.40-94.51, probably in relation with the presence of
amphibole. On the whole they show an increase of TiO2, Al2O3 and Cr2O3 and
a decrease of SiO2 and Na2O. Primary spinels are alumina-rich, whith cr#
varying between 6.64 and 34.60. Secondary tiny spinels in reaction zones tend
to increase their Cr2O3 content. Amphiboles major element contents are: mg#
(86.55-89.50), SiO2 (41.59-43.99), TiO2 (0.64-2.34), Al2O3 (14.61-16.28),
CaO (10.37-12.06), Na2O (2.91-3.81), K2O (0.01-1.34), Cr2O3 (0.73-1.57).
Glasses in anhydrous samples are SiO2-richer and FeO-, MgO-, CaO- and
Na2O-poorer than those in amphibole-bearing xenoliths. All glasses are quite
rich in Al2O3 (20.70-26.65).
Based on trace element contents three different groups of cpx1 can be
recognized. The first group is characterized by slight depletion in LREE
WORKSHOP W03
10
[(La/Yb)N, 0.42-1.03] with HREE at 6-9 x Ch, a negative Zr-Hf anomaly, a
diffuse Sr positive anomaly (Sr/Sr*, 0.91-2.00) and a highly variable Th and U
contents. The second group is equally depleted in LREE [(La/Yb)N, 0.34-1.37]
but at higher HREE content (11-13 x Ch). It has negative to positive Hf and Sr
anomalies, and less variable Th and U contents. The third group is LREE
enriched [(La/Yb)N, 1.36-5.45] with HREE at 9-11 x Ch and a Sr negative
anomaly (Sr/Sr*, 0.65-0.96). All cpx1 share a slight but peculiar Eu positive
anomaly. Amphiboles have patterns identical to their associated cpx except for
those elements which are better partitioned into amphibole, such as Nb, Ta, Sr
and Ti.
Accurate measurements of Ca contents in Ol1 allowed the application of the
Ca-exchange barometer coupled with the two-pyroxene thermomether, which
revealed equilibrium temperatures and pressures of 920-1010°C and
13.0-17.7 Kbar, consistent with the presence of amphiboles. The high modal
percentage of opx, cpx and spinel, coupled with their high Al2O3 content, the
high HREE and the positive anomalies in Sr and Eu in cpx trace element
patterns seem to rule out that we are simply facing a very fertile mantle
portion, but point toward a re-fertilisation process involving an hydrate
LREE-poor, HREE-rich, silica-saturated melt with high Sr contents.
W03-17 Poster
Facer, John
METASOMATISM IN SPINEL DUNITE XENOLITHS FROM THE BEARPAW
MOUNTAINS, MONTANA, USA
FACER John 1, DOWNES Hilary 1, BEARD Andy 1
1 - SCHOOL OF EARTH SCIENCES, BIRKBECK, UNIVERSITY OF LONDON,
MALET STREET, LONDON WC1E 7HX, UK
Key terms: ultramafic xenoliths; metasomatism; Montana
The Bearpaw Mountains are located on the northern margin of the Archean
Wyoming craton and form part of an extensive Eocene high-K alkaline
magmatic province. Ultramafic xenoliths hosted by this magmatism include
highly depleted spinel peridotites (the tectonite suite) and chromite spinel
dunites with iron-rich olivine (the Fe-rich dunites). Presented here are the
initial results of a petrological and geochemical study of the unusual and
previously unreported Fe-rich dunites.
The Fe-rich dunites have an olivine forsterite content in the range Fo83-87
which indicates that they are not the refractory end-members of a
lherzolite-harzburgite-dunite mantle melt-depletion trend. Whether they are
cumulates or the products of melt-rock reaction is at present unclear but their
microstructure indicates high temperature grain boundary migration and
dynamic recrystallization which are processes not usually associated with
cumulates.
In the Fe-rich dunites, fluid films along olivine grain boundaries connect with a
network of grain-penetrating veinlets and small (0.5 to 3.0 mm) "reaction
pockets". These pockets typically contain grains of spinel and/or diopside (and,
less commonly, enstatite or pargasite) undergoing breakdown reactions. This is
evidenced in the spinel by embayments, striations and scalloped margins and,
in the pyroxenes and amphibole, by fragmentation into numerous small
patches. Some of the spinel show zoning with Mg, Al-rich cores and Al-poor,
Fe, Ti and Cr-rich rims. The reaction pockets also commonly include fragments
of olivine derived from the primary olivine surrounding the pocket as well as
newly precipitated olivine grains and minute grains of spinel. The grains
undergoing breakdown are surrounded by a groundmass of Mg-rich, Al-poor
chlorite and/or an Mg and Mn-rich calcite. The interconnecting veinlets and
films along grain boundaries appear to contain mainly chlorite with some
patches of calcite. In a few xenoliths, the calcitic groundmass of reaction
pockets appears to have been replaced by phlogopite.
Some of the Fe-rich dunite xenoliths also contain veins of Al-poor
orthopyroxene. In one sample, the orthopyroxene forms fibrous to elongate
grains: radiating clusters of fibrous grains form at intervals along the vein and
elongated grains with length/width ratios as high as 140 grow out from the
vein into the host olivine. Some of the radiating clusters have at their hub
vesicles (now filled with chlorite) suggesting that nucleation may have been
triggered by a release of volatiles. Small patches of calcite occur within the
orthopyroxene veins and intergrowths of orthopyroxene and clinopyroxene
(diopside or Mg-rich augite) also occur. Low-Al orthopyroxene veins also occur
in some of the harzburgites of the tectonite suite and it is clear that several
generations of such veins exist.
The modal metasomatism evidenced in the Fe-rich dunites by the reaction
pockets and orthopyroxenite veins may both be explained by the migration of
an H2O + CO2 fluid, rich in silica but poor in alumina, which reacted with the
dunites. The origin of this hydrous fluid may be connected with the steepening
subduction of the originally shallow-dipping Farallon plate under North America
during the Eocene.
W03-18 Orale
Falus, György
STRUCTURE AND DEFORMATION OF THE SHALLOW LITHOSPHERIC
MANTLE IN SUPRA SUBDUCTION (-) SETTING: A XENOLITH STUDY
FROM THE EASTERN TRANSYLVANIAN BASIN.
FALUS György 1, TOMMASI Andrea 2, INGRIN Jannick 3, SZABÓ Csaba 4
1 - UM2, ELGI
2 - CNRS, UM2
3 - UPS
4 - ELTE
Key terms: upper mantle; deformation; crystal preferred orientation;
subduction
Peridotite mantle xenoliths, with broad textural variation, representing the
35-55 km depth range of the lower lithosphere, provide evidence for consistent
microstructural evolution beneath the Eastern Transylvanian Basin,
Southeastern Carpathians, Romania, related to ongoing plate convergence in
the Carpathian Arc nearby. Recrystallized grain size (indicative of stress), fabric
strength and resulting anisotropy and equilibrium temperatures vary
continuously from depth to the shallowermost upper mantle. Replacive
orthopyroxene structures, mostly consuming olivine, associated with
H2O-saturated concentrations and relatively low Al2O3 compositions, are
observed in a few of the xenoliths indicating (extremely) limited percolation of
subduction-related fluids/melts in the represented upper mantle
However, despite high stress deformation and high H2O content in some of the
studied mantle nodules, fabric analysis in olivine shows the exclusivity of the
[100] slip systems and absence of [001] slip, which is attributed to low H2O
solubility in olivine at spinel peridotite facies conditions, and questions the
overall existence of 'wet' deformation of olivine at shallow depths. Seismic
anisotropy values, estimated from fabric strength, are in agreement with
seismologic measurements in the region. We interpret that strike-parallel fast
directions, observed in the region are not the result of 'wet' olivine fabrics, but
are more likely the consequence of plate convergence-driven mountain-parallel
creep of the upper mantle.
W03-19 Orale
Gréau, Yoann
EVIDENCE OF MELT STAGE REFERTILIZATION AND METASOMATISM IN
ABYSSAL PERIDOTITES FROM HESS DEEP (ODP LEG 147)
GRÉAU Yoann 1, GODARD Marguerite 2, ALARD Olivier 2
1 - GEMOC/GÉOSCIENCES MONTPELLIER
Key terms: Abyssal peridotites; Mantle metasomatism; Mantle clinopyroxene;
Clinopyroxene rare-earth elements
It is commonly accepted that abyssal peridotites (AP) are simple residue of
recent partial-melting due to the upwelling of convective and fertile mantle
under mid oceanic ridges. Numerous authors have argued that given this
straightforward history and their short residence time into the lithosphere, AP
should be representative of the Earth's fertile mantle. This study examines
samples from the Hess Deep, the triple junction between the East-Pacific Rise
and Cocos-Nazca propagator (ODP Leg 147). Despite extensive alteration
(80%) due to serpentinisation and seafloor alteration (a common feature in
AP), two assemblages can be recognised in samples from this locality: (1) a
primary relict assemblage with large porphyroclasts of orthopyroxene (Opx1)
and olivine (Ol1); (2) a secondary assemblage formed of interstitial and
vermicular clinopyroxene (Cpx2), which may also occur in symplectitic
association with spinel (spl) and sulfide. The textural occurrence of this
assemblage 2 suggests that it represents the crystallization of an infiltrated
melt Abyssal peridotites from this leg are harzburgites with the average modal
composition: 80% Ol, 15% Opx, 3% Cpx and 2% Spl. Major element analyses
of primary phases show that they are residual after extensive degrees of fusion
and that a chemical disequilibrium between Cpx2 and Ol1-Opx1 has been
preserved. Inductively coupled plasma-mass spectrometer (ICP-MS) analyses
on whole rocks and Laser Ablation ICP-MS analyses of Cpx2 and Opx1 show
that trace-elements concentrations are among the most depleted observed so
far in abyssal peridotites. Rare-earth element (REE) patterns of Cpx2 are very
depleted in comparison with those from the literature. Moreover, Cpx2 are not
in equilibrium with Opx1 concentrations. Enrichment in light rare-earth
elements and in large ion lithophile elements (LILE, e.g., U, Th, Pb and Sr),
both in Opx1 and Cpx2 indicates a late stage metasomatic event. It is worth
noting that U, Pb, Sr enrichments in whole-rock are commonly ascribed to
seawater alteration. Here the fact that fresh Cpx2 and Opx1 core show such
enrichment, coupled with enrichment in Th and LREE (not affected by alteration
processes) suggesting a magmatic rather than an alteration origin.
So we can conclude that:
- Abyssal peridotites from Hess Deep have experienced a primary episode of
melting of about 15%, as calculated from the heavy and medium REE
composition of Opx1.
- Textures of Cpx2 and disequilibrium between Cpx2 and Opx1 suggest that
Cpx2 has crystallised from a percolating melt. The Spl-Cpx2 clusters are
reminiscent of a quenching texture and indicate that part of this melt has
crystallised under lithospheric (cold) conditions.
- Such high depletion of REE in clinopyroxene indicates that this melt is derived
from a very depleted mantle source. Calculated melt in equilibrium with Cpx2
is similar to the ultra depleted melt (UDM) evidenced as melt-inclusion in
olivine phenocryst in MORBs by [Sobolev et al., 1993]. This suggests a
widespread occurrence of those UDM.
Thus APs are not simple residues of partial melting but record a complex and
protracted history of multiple events of melt extraction and
percolation-reaction. This recall what have been observed in the
sub-continental lithospheric mantle and suggest that the mantle section
sampled by APs is not as young as one could expect. UDM giving the Cpx2 are
clearly derived from an old and extremely depleted mantle reservoir. The
occurrence of such mantle volume/component in such geodynamic setting is at
odd with the assumed young and convective nature of the oceanic mantle.
However, the occurrence of old and depleted mantle component within the
oceanic convective mantle is also suggested by other studies of AP [Seyler et
al., 2004] on a worldwide basis and especially by recent Re-Os isotopic
investigations [e.g. Alard et al., 2005; Author's unpub data].
W03-20 Orale
Griffin, William L.
TRACE-ELEMENT PATTERNS OF DIAMOND: CLUES TO MANTLE
PROCESSES
GRIFFIN William L. 1, REGE Sonal 1, ARAUJO Debora 1, JACKSON Simon 1,
PEARSON Norman 1
1 - GEMOC ARC National Key Centre, Dept. Earth and Planetary Sciences,
Macquarie University, Sydney, NSW 2109, Australia
Key terms: Mantle processes; Diamond trace elements; Mantle metasomatism;
Lithosphere geochemical signatures; Diamond genesis
Quantitative trace-element analyses of > 40 elements in diamonds have been
carried out by LAM-ICPMS, using a multi-element doped-cellulose standard;
detection limits range to low-ppb levels for many elements [1]. This new type
of data offers new insights into metasomatic processes in the SCLM.
WORKSHOP W03
The trace-element patterns of polycrystalline (framesite, diamondite) and
fibrous diamonds are consistent with crystallisation from
kimberlitic-carbonatitic melts. However, some fibrous diamonds show an
abrupt change in trace-element patterns as crystallisation proceeds. Contents
of LREE, Sr and Ba decrease sharply, accompanied by decreases in Nb/Ta and
Zr/Hf from chondritic to 0.1-0.01 x Chondrites. The fractionation of these pairs
of geochemically similar elements is hard to explain by fractional
crystallisation, because D(solid/melt) for these elements are very similar.
However, such fractionations can be the result of liquid immiscibility: a
separation into broadly (?hydrous)-silicate and carbonatite fluids. The
ubiquitous development of pronounced negative Y anomalies (relative to
Ho-Dy) during the crystallisation of some fibrous diamonds may reflect the
separation of fluoride phases or immiscible fluoride melts; microinclusions with
positive Y (±Yb) anomalies are observed during ablation of diamondites.
Nearly all monocrystalline diamonds show low LREE/HREE, Ba/MREE and
Sr/MREE, as well as low Nb/Ta and Zr/Hf, suggesting that they have
crystallised from the hydrous-silicate member of the proposed immiscible-liquid
couple. Oscillatory zoning of composition in some diamonds suggests that both
fluids were circulating in the system. Preliminary studies show little difference
in the trace-element patterns of peridotitic and eclogitic diamonds from single
localities. This implies limited interaction between the fluid(s) and wall rocks,
which in turn suggests high fluid/rock ratios during diamond crystallisation.
Further work is required to reconcile the model described here with the data
from single-inclusion studies of fibrous diamonds, which suggest immiscibility
between a hydrous fluid (brine) and a continuum of carbonatite-silicate melts.
However, it is consistent with observations of carbonate-silicate immiscibility in
melt inclusions trapped in Cr-diopside derived from ca 180 km beneath the
Slave craton [2].
Modelling of the Mg-rich carbonatitic fluid that develops in the diamond-forming
system shows it would have extremely high LREE/HREE, Ba and Sr; similar
patterns are observed in secondary coats on monocrystalline diamonds from
some localities. The reaction of this fractionated carbonatitic fluid with chromite
+ olivine + opx can produce subcalcic Cr-pyrope garnets with "sinuous" REE
patterns and high Sr contents, which are a characteristic inclusion in diamonds
of the peridotitic paragenesis [3]. We therefore suggest that the development
of immiscibility during the evolution of methane-rich low-volume melts of the
kimberlite-carbonatite spectrum produces conjugate fluids, one of which
crystallises most monocrystalline diamonds, and the other of which interacts
with mantle harzburgites to produce the most ubiquitous inclusions in
peridotitic diamonds. This model provides a genetic link between the diamonds
and their most distinctive indicator minerals.
[1] Rege, S., Jackson, S.J., Griffin, W.L., Davies, R.M., Pearson, N.J. and
O'Reilly, S.Y. 2005. Quantitative trace element analysis of diamond by laser
ablation inductively coupled plasma mass spectrometry. Journal Analytical
Atomic Spectroscopy 20, 601-610.
[2] van Achterbergh, E., Griffin, W.L., Ryan, C.G., O'Reilly, S.Y., Pearson, N.J.,
Kivi, K. and Doyle, B.J. 2002. A subduction signature for quenched
carbonatites from the deep lithosphere. Geology 30, 743-746
[3] Malkovets, V., Griffin, W.L., O'Reilly, S.Y. and Wood, B.J. 2007. Diamond,
subcalcic garnet and mantle metasomatism: Kimberlite sampling patterns
define the link. Geology 35, 339-342.
W03-21 Orale
Guzmics, Tibor
LA-ICPMS STUDY OF CLINOPYROXENE-APATITE-K
FELDSPAR-PHLOGOPITE METASOMATIC MANTLE XENOLITHS FROM
HUNGARIAN LAMPROPHYRES AND THEIR PRIMARY CARBONATITE
MELT INCLUSIONS: IMPLICATIONS FOR CARBONATITE MELT
METASOMATISM IN THE EARTH'S UPPER MANTLE
GUZMICS Tibor 1, ZAJACZ Zoltán 2, SZABÓ Csaba 1, HALTER Werner 2
1 - Lithosphere Fluid Research Lab, Eötvös University, Budapest, Hungary
2 - Department of Earth Sciences, Institute of Isotope Geochemistry and
Mineral Resources, ETH, Switzerland
Key terms: carbonatite melt inclusions; carbonatite metasomatism; trace
element geochemistry; Hungarian lamprophyres
We studied rare metasomatic mantle xenoliths consisting of clinopyroxene
(Cpx), apatite (Ap), K feldspar (Kfs) and phlogopite (phl) from the
Alcsútdoboz-2 lamprophyre dikes, Hungary (Szabó et al., 1993). Ap and Kfs
contain numerous primary, negative crystal shaped carbonatite melt inclusions
(CMI) that were analyzed by LA-ICPMS. Cpx and Phl are barren. The CMI have
a phosphorous dolomitic character in Ap and an alkaline-aluminosiliceous
dolomitic character in Kfs. Both Ap- and Kfs-hosted CMI show post entrapment
crystallization onto the wall of the melt inclusions. The amount of apatite
crystallized onto the wall in Ap-hosted CMI and the bulk composition of these
CMI show entrapment temperature range of 1090 - 1180 oC, based on the
Baker-Wyllie equation (1992). Primitive mantle normalized (PM) trace element
distributions of the Ap- and Kfs-hosted CMI (n=60 and 20, respectively) reveal
a strong negative Ti anomaly, and an extreme enrichment in the incompatible
LILE and LREE relative to HREE and the compatible elements (Sc, V, Ni and
Cr). The relative La/Lu to PM is in the range of 107-147, furthermore,
PM-normalized U, Th, Sr show ~one million times higher value than those of Ni
and Cr. This indicates that the initial melt of the CMI was formed with a very
low degree partial melting of a carbonated source. We suggest that the CMI in
Ap and in Kfs cannot be differentiation product or residuum of each other
because the Kfs-hosted CMI contain small amount of P and most of Ap-hosted
CMI contain small amount of K, Al and Si. Therefore, they are more likely to
have been formed by liquid-liquid separation, which requires their common
origin. This is supported by PM-normalized REE composition of CMI in Ap
showing highly similar distribution to that of CMI in Kfs. Addition, apatites
rarely enclose unique CMI that show major- and trace-element signature
similar to K feldspar-hosted CMI. This confirms that there was a liquid-liquid
separation between a P-bearing carbonatite melt and a carbonate-bearing
silicate melt before crystallization of their host phases (namely Ap and Kfs).
Trace element distributions of the CMI reveal that U, Th, Ba, Pb, Nb, Ta, P, Sr,
Y and REE are partitioned into P-bearing carbonatite melt whereas; Cs, Rb, Na,
K, Al, Zr and Hf prefer silicate-bearing one.
PM-normalized patterns of the Cpx compositions indicate enrichment in LREE
relative to HREE and compatible elements such as Sc, V, Ni and Cr.
Furthermore, they show strong negative Ti anomaly. Thus, chemical
11
characteristics of the CMI are clearly reflected in the clinopyroxene
compositions. This indicates that formation of the clinopyroxenes was linked to
the metasomatic carbonatite melt trapped as CMI in the studied apatite and K
feldspar. The studied xenoliths also reveal that modal metasomatism
happened, however; clinopyroxenes which occur in the studied xenoliths with
high modal proportion of Ap, contain Ti, Sc, Ni, V and especially Cr in much
lower concentration than those clinopyroxenes wich occur with low modal
proportion of Ap. Coincidentally, distributions of Zr and Hf in Cpx show an
opposite pattern. All of the studied CMI reveal that Ti, Sc, V, Cr and Ni were in
much lower concentration in the "initial" carbonatite melt than that in PM;
contrarily, Zr and Hf were in higher concentration in it than in PM.
Consequently, a continuously migrating "initial" carbonatite melt, which
crystallized Ap and Kfs, increased Zr and Hf concentration, whereas, decreased
amount of Ti, Sc, V, Ni and Cr in the clinopyroxenes. All of these supports that
the studied CAKP rocks were formed by carbonatite melt metasomatism, which
occurred in an open system in peridotitic environment.
References:
Baker & Wyllie (1992): Geochim Cosmochim Acta, 56, 3409-3422.
Szabó et al. (1993): Miner. Petrol., 47, 127-148.
W03-22 Poster
Hara, Kaori
PETROLOGICAL INVESTIGATIONS ON DEEP-SEATED ROCKS
(HARZBURGITE, DUNITE AND GABBROS) AROUND THE KAIREI
HYDROTHERMAL FIELD IN THE CENTRAL INDIAN RIDGE
HARA Kaori 1, KUMAGAI Hidenori 2, OKINO Kyoko 3, MORISHITA Tomoaki 1,
SAWAGUCHI Takashi 4, JOSHIMA Masato 5, NAKAMURA Kentaro 6, NEO Natsuki 7,
SHIBUYA Takazo 8, SATO Taichi 3
1 - KANAZAWA UNIVERSITY
2 - JAMSTEC
3 - TOKYO UNIVERSITY
4 - SHOUHOKU COLLEGE
5 - AIST
6 - JSPS, JAMSTEC
7 - NIIGATA UNIVERSITY
8 - TOKYO INSTITUTE OF TECHNOLOGY
Key terms: peridotite; Ocean core complex; Kairei hydrothermal field; Central
Indian Ridge
We investigated petrological characteristics of deep-seated rocks, such as
harzburgite, dunite and gabbros, collected from an oceanic core complex and
two topographic highs (the so-called 25°S OCC and Uraniwa-hills, respectively)
around the Kairei hydrothermal filed, which is characterized by a high
concentration of H2 in the vent fluid (Takai et al., 2004), in the Central Indian
Ridge.
The 25°S OCC is a dome-like shape dipping shallowly toward the axis near the
ridge. It is also characterized by continuous surfaces on which prominent
striations parallel the spreading direction. Gabbros are recovered and are
massive with variations both in composition (gabbro, gabbro norite, oxide-rich
gabbro) and grain size at the scale of individual samples. Some gabbros are
amphibolitized and are further locally altered under green schist facies
conditions. Microstructures show magmatic textures, usually with no or very
minor plastic deformation except for very localized mm-scale shear zones in
altered gabbros. Two serpentinized peridotites are recovered along the
ridge-facing slope. These peridotites have been statically serpentinized and
show the typical serpentine mesh texture replacing olivine crystals, serpentine
pyroxene pseudomorphs. Modal amount of clinopyroxene is low in the both
samples. These peridotites were intruded by highly altered gabbroic veins now
consisting of tremolitic amphibole, chlorite and saussurite with small amount of
ilmenite (partly replaced by titanite), apatite and zircon. Plagioclase
pseudomorph is frequently observed in a sample abundant in the gabbroic
veins. On the other hand, we collected olivine-rich gabbroic rocks (troctolite
including one plagioclase-bearing dunite) with small amount of olivine gabbros
from the Uraniwa hills. These oceanic highs are interpreted to be exhumed
footwall consisting of oceanic lower crust and upper mantle along low-angle
detachment faults. Hydrogen can be produced by a reaction for the
serpentinization of these olivine-dominate rocks due to sea water circulations
related to the formation of the detachment fault.
Chemical compositions of chromian spinel without chemical modification due to
formation of plagioclase (now saussuritized) and the gabbroic veins from
recovered serpentinized samples in the 25°OCC shows Cr/(Cr+ Al) atomic ratio
= 0.3-0.45. This combined with clinopyroxene-poor lithologies indicates that
degree of partial melting of peridotite samples from the 25°S OCC is higher
than typical peridotites recovered from slow-spreading ocean floor (Dick,
1989), although the 25°S Megamullion is located at a segment end of the ridge
where generally smaller degrees of melting in the mantle are expected, the
so-called transform fault effect (Ghose et al., 1996). Petrological and
geochemical characteristics of serpentinites from the OCC show that the degree
of partial melting is higher in the studied samples than in slow-spreading
ridges. On the other hand, it is interesting to note that the
dunite-troctolite-olivine gabbros in the Uraniwa hills were similar to those found
from the first-spreading East Pacific Rise (e.g., Arai & Matsukage., 1996),
where magmatic activity is expected to be high. We will also discuss the
process of serpentinization in these samples.
W03-23 Orale
Harangi, Szabolcs
THE NATURE OF THE SUB-LITHOSPHERIC MANTLE BENEATH THE
PANNONIAN BASIN, EASTERN-CENTRAL EUROPE, AS INFERRED FROM
THE GEOCHEMISTRY OF THE NEOGENE TO QUATERNARY ALKALINE
MAFIC ROCKS
HARANGI Szabolcs 1, NTAFLOS Theodoros 2, DOWNES Hilary 3, LENKEY László 4
1 - EOTVOS UNIVERSITY, DEPARTMENT OF PETROLOGY AND GEOCHEMISTRY,
BUDAPEST, HUNGARY
2 - DEPARTMENT OF LITHOSPHERIC SCIENCES, UNIVERSITY OF VIENNA,
VIENNA, AUSTRIA
3 - SCHOOL OF EARTH SCIENCES, BIRKBECK UNIVERSITY OF LONDON,
WORKSHOP W03
12
LONDON, U.K.
4 - HUNGARIAN ACADEMY OF SCIENCES, RESEARCH GROUP OF GEOPHYSICS
AND ENVIRONMENTAL PHYSICS, BUDAPEST, HUNGARY
Key terms: Pannonian basin; Petrogenetic modelling; Asthenosphere; Melt
generation; Geochemistry
The petrology and geochemistry of mafic lavas could provide important
information about the thermal state and the composition of the mantle where
their parental magmas formed. One of the recent challenging approaches is to
constrain the existence or absence of anomalously hot sub-lithospheric mantle,
i.e. mantle plumes. This is commonly inferred either by the isotopic
composition of mafic lavas (e.g., Pb-isotope values close to the HIMU
component) or by the calculated mantle potential temperature (i.e., about
200-300oC higher than MORB-mantle). A strongly heterogeneous mantle
model is an alternative explanation of the plume hypothesis.
In Europe, alkaline mafic magmatism has been taking place mostly at the
periphery of the Mediterranean region since the Palaeogene. The last eruptions
in these volcanic fields (French Massif Central, Eifel, Bohemian area, Pannonian
basin) occurred only in some tens or hundreds ka. Understanding the magma
generation processes is crucial in order to evaluate the possible continuation of
the volcanic eruptions in these areas. The origin of this magmatism is
commonly regarded as a response of diapiric upwelling of small-scale,
relatively hot upper mantle material ('plume-fingers').
Here, we attempt to have an insight into the state of the sub-lithospheric
mantle beneath the Pannonian basin. Existence of a 'plume-finger' has been
supposed also beneath this area. Indeed, Sr-Nd-Pb isotopic compositions of the
alkaline basaltic rocks are similar with those shown by the mafic rocks in
Europe and the whole area is characterized by high heat flow. However, we
demonstrate here that a mantle plume beneath the Pannonian basin is highly
unlikely. The trace element composition of the most primitive samples suggests
that the primary magmas were formed by different degrees (1-6%) of melting
of a garnet-peridotite source region with a moderately enriched composition
(1.5- to 4-times primitive mantle values). Another constrain on the mineralogy
of the mantle source comes from the presence of negative K-anomaly in the
primitive mantle normalized patterns of most of the samples. This requires a
K-bearing hydrous phase (amphibole or phlogopite) in the source region or an
inherited K-depleted signature of the upper mantle. Trace element modelling
appears to be consistent with the first explanation. At low degree (<5%)
melting, amphibole or phlogopite could remain in the residuum retaining
potassium, whereas they were consumed at higher degree of melting. The
inferred depth of the melt generation is between 60 and 120 km, i.e. mostly in
the asthenosphere. This should mean that these volatile-bearing mantle rocks
could reside in the sub-lithospheric mantle causing mantle heterogeneity in
various scales. The long history of orogenic events (Hercynian and Alpine
orogenesis) in Europe could supply vast amount of crustal material into the
upper mantle resulting in this geochemical heterogeneity. Partial melting of
different parts of the shallow asthenospheric mantle such as metasomatized,
amphibole/phlogopite-bearing enriched sections with HIMU-like composition at
low degree melting and depleted MORB-mantle around them at higher degree
of melting and mixing of these melts could also explain the isotopic variation in
the alkaline mafic magmas of the Pannonian basin. The high heat flow can be
readily explained by the thinning of the lithosphere during the Miocene basin
formation and the still shallow asthenosphere. The temperature could be still
close to the solidus temperature and local perturbance caused by mantle flow
can initiate magma generation. The reason of such a mantle flow is unclear,
although a possible explanation for this could be the large gradient in the depth
of the lithosphere-asthenosphere boundary at the periphery of the Pannonian
basin. This region with an anomalously thin lithosphere could act as a thin spot
and its suction force could generate mantle flow from the surrounding areas.
W03-24 Poster
Hidas, Károly
SILICATE MELT INCLUSIONS IN AMPHIBOLE-BEARING SPINEL
PERIDOTITE XENOLITHS FROM THE BAKONY-BALATON HIGHLAND
VOLCANIC FIELD (WESTERN HUNGARY)
HIDAS Károly 1, SZABÓ Csaba 1, GUZMICS Tibor 1, BALI Eniko 2, ZAJACZ Zoltan 3,
KOVÁCS István 4
1 - Lithosphere Fluid Research Lab, Eötvös University, Hungary
2 - Bayerisches Geoinstitut, Universität Bayreuth, Germany
3 - Department of Earth Sciences, Institute of Isotope Geochemistry and
Mineral Resources, ETH, Switzerland
4 - Research School of Earth Sciences, The Australian National University,
Canberra, Australia
Key terms: spinel peridotite xenoliths; silicate melt inclusions; CO2-bearing
fluid inclusions; Pannonian Basin; Hungary
In this work we present a detailed textural and geochemical study of two
equigranular textured amphibole-bearing spinel lherzolite xenoliths of the
subcontinental lithospheric mantle (Szg07 and Szg08) from Szigliget,
Bakony-Balaton Highland Volcanic Field (Pannonian Basin) containing abundant
primary silicate melt inclusions (SMI) in clinopyroxene rims and secondary SMI
in orthopyroxene (and rarely spinel) along healed fractures. The SMI are
dominantly composed of silicate glass and CO2-bearing fluid phase at room
temperature. Only the primary SMI show evidence for significant
post-entrapment modification as a result of crystallization on the wall of the
host clinopyroxene.
Microprobe study reveals that clinopyroxene and orthopyroxene are zoned in
both studied xenoliths, especially in Fe, Mg, Na and Al contents. Cores of
clinopyroxenes in both xenoliths show trace element distribution close to
primitive mantle. Rims of clinopyroxenes are enriched in Th, U, LREE and
MREE. Amphiboles, particularly in Szg08 xenolith, exhibit elevated Rb, Ba, Nb,
Ta, LREE and MREE content.
The composition of silicate glass in the SMI covers a wide compositional range
from the basaltic trachyandesite and andesite to phonolitic composition through
the most common trachyandesite. The glasses are rich in P2O5 (up to 2.88
wt%). There are no notable differences in glass compositions neither in the
different host minerals nor in the different xenoliths, except the Cl and TiO2
content. The SMI, either primary or secondary ones, are strongly enriched in
incompatible elements (particularly in U, Th, La, Zr), displaying slight negative
Hf anomaly. The SMI in Szg07 show approximately one order higher
enrichment in LILE and LREE compared to those of SMI in xenolith Szg08.
Based on microthermometry of the fluid phase of SMI, melting temperatures
show values below -56.6 °C, which indicate the presence of other fluid
components beside CO2. Furthermore, homogenization of fluids into the liquid
phase at low T (in the range of -40 and -53 °C) suggests extremely high
density for the CO2-rich fluids. Furthermore, numerous opx- and cpx-hosted
SMI reveal various glass-fluid ratios.
During high-temperature experiments of cpx-hosted SMI, the silicate glass
started to melt at 850-900 °C. At 1150 °C the glass was completely melted,
however the fluid phase was not homogenized into the melted glass. The
SMI-cpx boundary at 1150 °C reveals that some cpx from the host dissolved
into the glass in all runs. At 1200 °C the cpx-hosted SMI decrepitated without
complete homogenization. In contrast, the opx-hosted SMI, indicating the
same melting features, were not decrepitated at same temperature.
The development of zoned pyroxenes, as well as the trapping of primary SMI in
the clinopyroxene rims happened after the partial melting and subsequent
crystallization of clinopyroxenes, most probably due to an interaction between
hot volatile-bearing mafic melt and mantle wall-rock. This interaction formed
evolved silicate melts, which filled microfractures in orthopyroxenes (and rarely
spinels), resulting in secondary SMI ranging from the basaltic trachyandesite
and andesite to phonolitic compositions. Their trace element distributions and
high volatile contents also suggest that the studied melt, which were trapped
as SMI, could be the product of fractionation crystallization of a mafic magma
at mantle T-P conditions. The relatively high fluid content permits to assume
the migration of these evolved melts along veins or grain boundaries in the
mantle, causing significant metasomatism on reactive mantle minerals. The
different fluid-glass ratios in the studied SMI indicate a pre-entrapment phase
separation. Besides this, the trace element composition modeling suggest that
melt similar to the host alkali basaltic magma, can be responsible for the
presence of zoned mantle minerals together with SMI, which, therefore, could
act as a metasomatic agent in the upper mantle.
W03-25 Poster
Kovács, István
MIDDLE MIOCENE VOLCANISM IN THE VICINITY OF THE MIDDLE
HUNGARIAN ZONE: EVIDENCE FOR AN INHERITED ENRICHED MANTLE
SOURCE
KOVÁCS István 1, SZABÓ Csaba 2
1 - AUSTRALIAN NATIONAL UNIVERSITY AND EOTVOS UNIVERSITY, (LRG)
2 - EOTVOS UNIVERSITY, (LRG)
Key terms: geodynamics; xenoliths; subduction; volcanism;
Carpathian-Pannonian region
Middle Miocene igneous rocks in the vicinity of the Middle Hungarian zone
(MHZ) show subduction-related geochemical characteristics of which strength
faded away with time. In contrast to previous models, which suggest that
southward-dipping subduction of the European lithosphere beneath the Alcapa
microplate along the Western Carpathians was responsible for the source
enrichment of middle Miocene volcanics, we propose that source enrichment
happened along the subduction of either the Budva-Pindos or Vardar Oceans.
Recent seismic studies have revealed that the proposed southward-dipping
subduction had not developed beneath the entire Western Carpathians or even
if it had, it was overprinted after the collision between the European plate and
the Alcapa unit at 16 Ma. This subduction is thought to have started 30 Ma
ago, therefore the time between the onset of subduction and collision cannot
account for extensive source enrichment in the overlying mantle wedge.
Furthermore, the middle Miocene volcanics along the MHZ in their
reconstructed position are not parallel to the supposed suture, as would be
expected for subduction-related arc volcanoes.
We propose, alternatively, that the source enrichment was related to the
subduction of either the Budva-Pindos or Vardar Ocean during the
Mesozoic-Paleogene. The Alcapa microplate was transferred from this distant
tectonic setting to its present tectonic position via extrusion and rotations.
Geophysical modeling and mantle xenoliths provide evidence that this process
happened at the scale of the lithospheric mantle, therefore the
subduction-modified lithospheric mantle was not decoupled from the crust.
Melting in the lithospheric mantle of the Alcapa unit was triggered by the
extension during the formation of the Pannonian Basin. The preserved
subduction-related geochemical character of volcanics in intra-plate settings
that are otherwise directly unaffected by subduction can be accounted for by
tectonic transport of metasomatized mantle from a previous
subduction-affected setting. In general this model provides an alternative
approach to understand the geochemical complexity of intra-plate calc-alkaline
volcanics without the involvement of plumes.
W03-26 Poster
Le Roux, Véronique
INSIGHTS INTO REFERTILIZATION PROCESSES IN LITHOSPHERIC
MANTLE FROM INTEGRATED ISOTOPIC STUDIES IN THE LHERZ MASSIF
LE ROUX Véronique 1, BODINIER Jean-Louis 2, ALARD Olivier 1, O'REILLY Suzanne
Y. 3
1 - GÉOSCIENCES MONTPELLIER - GEMOC
3 - GEMOC
Key terms: Lherz; refertilization; erosion of lthosperic mantle
Differentiation of the Earth's mantle occurs principally through partial melting
and extraction of basaltic melt. Among the mantle rocks occurring at the
Earth's surface, harzburgites are widely considered as refractory mantle
residues left after extraction of a basaltic component. In contrast, fertile
lherzolites are generally regarded as pristine mantle, only weakly affected by
partial melting. However in the Lherz Massif (France), structural mapping
shows that the lherzolites are secondary rocks formed at the expense of the
harzburgites. Variations of major, minor and trace elements across the
harzburgite-lherzolite contacts indicate that the lherzolites were formed
WORKSHOP W03
through a refertilization process involving interaction of refractory, lithospheric
mantle with upwelling asthenospheric partial melts. Rare-earth elements (REE)
in clinopyroxenes display variable chondrite-normalized REE patterns. Massive
harzburgite bodies show U-shaped REE patterns whereas lherzolites have
classic N-MORB REE patterns as observed in orogenic lherzolites worldwide.
However at the contact, both lherzolite and harzburgite show more
LREE-enriched clinopyroxenes than their distal counterparts. These REE
enrichments also cannot be explained by partial melting model and provide
further evidence for refertilization.
In order to further constrain the mechanisms involved in the refertilisation
process, we investigated Sr, Nd and Hf isotopic compositions of over 15
samples accross a harburgite-lherzolite contact, as well as "distal" samples. Sr
isotopes were measured in whole-rocks and clinopyroxene separates (TIMS and
MC-ICP-MS), combined with the Sr in-situ method on clinopyroxenes
(LA-MC-ICPMS). Al2O3 is negatively correlated with 87Sr/ 86Sr and positively
correlated with 143Nd/ 144Nd. These correlations are consistent with REE patterns.
Distal harzbugites have 87Sr/ 86Sr = 0.703638(6), while distal lherzolites have 87
Sr/ 86Sr between 0.7020 and 0.7025. Towards the contact, the lherzolites show
a steady increase in 87Sr/ 86Sr up to 0.7032. The harzburgites within the contact
radiogenic compositions up to 0.7055. The highly radiogenic composition of the
contact zone is not compatible with melting models. Further investigations are
in progress to characterise the scale and range of isotopic variations across the
transition from harzburgite and lherzolite.
W03-27 Poster
Matusiak, Magdalena
ORIGIN OF XENOLITHS FROM WINNA GÓRA BASALT (SW POLAND)
MATUSIAK Magdalena 1, PUZIEWICZ Jacek 1
1 - WROCLAW UNIVERSITY
Key terms: Basalt; Xenoliths; Cumulates; SW Poland
The basalt from Winna Góra near Jawor in SW Poland (K-Ar age ~ 22Ma)
belongs to the Tertiary Central European Volcanic Province. Small (<5 cm)
peridotite (dunite, lherzolite, harzburgite), websterite, clinopyroxenite and
gabbro xenoliths occur in the rock.
The xenoliths consist of olivine
clinopyroxene
orthopyroxene
plagioclase. Small (<200 m) pools consisting of younger generation of olivine,
clinopyroxene, spinel and plagioclase occur between primary phases in
peridotite and websterite. Clinopyroxene forming gabbro has spongy structure
due to voids (up to 100 m) filled with plagioclase and olivine.
The main constituent of dunite is olivine (Fo 89-82%, Ca<300 - 1450 ppm, NiO
0.11-0.43 wt.%). In olivine occurring (together with spinel, clino- and
orthopyroxene) in pools the Fo content varies from 82 to 85% (Ca 750-1800
ppm, NiO 0.19-0.35 wt.%), #mg of clinopyroxene (CaO 20-23 wt.%) is 88-82 ,
in orthopyroxene (Al2O3 0.5-0.6 wt.%) is 86-87. The #cr of spinel is 74-78.
Fo content in olivine forming lherzolite varies from 75 to 80 % (Ca< 300-1300
ppm, NiO 0.22-0.37 wt.%), #mg of clinopyroxene is 0.86 (CaO 23 wt.%) and
in orthopyroxene is 0.83 (Al2O3 0.6-0.74 wt.%). Spinel #cr is 0.73-0.76.
Olivine forming harzburgite contains 82-88% of Fo (Ca <300-1700, NiO
0.2-0.5 wt%), the #mg of orthopyroxene is 85-87 (Al2O3 0.9-1.6 wt.%), #cr
of spinel is variable from 0.5 to 0.7. Younger olivine (Fo 80-85, Ca 600-1500
ppm, NiO 0.09-0.3 wt.%) occurs in pools together with clinopyroxene (#mg
0.80-0.91, CaO 18-23 wt.%) and spinel (#cr 0.8-0.86).
Websterite consists of orthopyroxene (#mg 0.74-0.84, Al2O3 1.2-3.9 wt.%)
and clinopyroxene (#mg=0.86, CaO 21-23 wt.%). Clinopyroxene occurring in
pools together with olivine (Fo 71-78, Ca 1400-2300 ppm, NiO 0.01-0.06)
contains from 19 to 21 wt.% of CaO (#mg=0.86).
Clinopyroxene forming clinopyroxenite contains 23-24.5% of CaO, #mg is
variable from 0.71-0.87.
Gabbro consists of clinopyroxene (#mg=68-74, CaO 19-22 wt%) and
plagioclase (An 40- 56%). An content in plagioclase occurring with olivine (Fo
64-70, CaO 1600-2200 ppm, NiO 0.02-0.09 wt%) in voids in clinopyroxene
varies from 0 to 24%.
Temperatures of primary clino- and orthopyroxene equilibration (Brey and
Köhler algorithm) are 850-880°C (lherzolite, dunite) and 960-990°C
(websterite).
Spinel and olivine occurring in xenoliths from Winna Góra do not fall in
Olivine-Spinel Mantle Array of Arai (1994) but are rather similar to those from
volcanic rocks or cumulates. Volcanic chemical composition of spinel is also
suggested by plot of data on Al2O3/TiO2 and Al2O3/(Fe2+/Fe3+) diagrams by
Kamenetsky et al., 2001.
The presented data indicate that the xenoliths from Winna Góra are not of
mantle origin: olivine is too rich in Fe, spinel has compositions which differ
from those of OSMA. The xenoliths may be products of cumulative processes
from host basaltic magma or may come from older, ultramafic intrusion located
at the crust-mantle boundary. Size of the xenoliths suggest rather slow ascent
of magma, which resulted in sinking of larger xenoliths. Small sizes maybe also
due to disintegration of primarily larger xenoliths.
Due to small size of the xenoliths, which precludes determination of whole-rock
geochemistry, mineral chemistry is the only possible source of information
about their origin. Mineral-chemical data supplied from minerals are
unequivocal, but suggest that gabbro and clinopyroxenite are cumulates of
host basaltic magma. Some features (e.g. NiO and Ca contents in olivine) of
phases forming peridotites and websterite suggest their mantle origin, whereas
the other (e.g. Fo contents in olivine) are typical for crystallization as shallow
as mantle/crust boundary. The variation in mineral chemistry is similar to that
of Beaunit layered intrusion (Féménias et al, 2003). Younger generation of
minerals is probably a result of decompressional melting of xenoliths during
magma ascent.
W03-28 Orale
Mazzucchelli, Maurizio
NEW CONSTRAINTS ON THE MESOZOIC EMPLACEMENT OF DIORITIC
DYKES IN THE BALDISSERO MANTLE PERIDOTITE MASSIF
(IVREA-VERBANO ZONE)
13
MAZZUCCHELLI Maurizio 1, ZANETTI Alberto 2, RIVALENTI Giorgio 1, VANNUCCI
Riccardo 3, CORREIA TEIXEIRA Ciro 4, TASSINARI Colombo 4, CELSO Gaeta 4
1 - Dipartimento di Scienze della Terra, Università degli Studi di Modena e
Reggio Emilia, Largo S. Eufemia 19, 41100 Modena, Italy
2 - IGG-CNR, Sezione di Pavia, via Ferrata 1, 27100 Pavia, Italy
3 - Dipartimento di Scienze della Terra, Università di Pavia, via Ferrata 1,
27100 Pavia, Italy
4 - Instituto de Geociências, Universidade de São Paulo, Rua do Lago 563,
Cidade Universitaria, 05508-900 São Paulo, Brazil
Key terms: Mesozoic Magmatism; Diorite Dykes; Baldissero; Ivrea-Verbano
The Baldissero peridotite is the main mantle massif occurring in the
south-western part of the Ivrea-Verbano Zone. It is in contact with the gabbros
of the Ivrea-Verbano Mafic Complex to the East, while it is sheared by the
faults of the Insubric system to the West, being in tectonic contact with the
Canavese terrains of the Austroalpine Domain. To the north-west, another
Alpine shear zone, the Cremosina line, limits the Baldissero terrains from the
rest of the Ivrea-Verbano Mafic Complex. Amphibole-bearing dioritic dykes in
the Baldissero mantle peridotite have variable Mg# value in bulk-rock and
mafic phases, which positively correlates with the incompatible element
concentration. The peridotite at the dyke contact is enriched in modal
orthopyroxene, iron and incompatible trace element with respect to the
LREE-depleted spinel lherzolites typical of the Baldissero massif. The
geochemical characteristics of the diorites are explained by fractional
crystallization of a hydrous silica-saturated melt, accompanied by assimilation
of peridotite olivine. In this frame, the diorites in equilibrium with the least
evolved melts are those with the lowest incompatible trace element
concentration and Mg#. The low Mg# argued for the most primitive parent
melts of the diorites indicate that they experienced a significant fractionation
before the emplacement into the peridotite. New internal Sm-Nd isochrons for
two diorites (198±29, with Ndi = +5.6 and 204±31 Ma with Ndi = +6.0) and
Re-Os data for peridotites at the dyke contact point to late Triassic - early
Jurassic ages. These ages may record subsolidus diffusion on cooling. However,
internal Sm-Nd isochrons for hydrous diorites forming the External Gabbro Unit
of the Finero Mafic Complex ( Ndi from +2.7 to + 5.3; Lu et al., 1997) range
from 223 to 231 Ma, and are only slightly different from U-Pb zircon ages
(232±2 Ma; Peressini et al., 2005). Therefore, even if the Sm-Nd ages
obtained for the Baldissero diorites may be slightly younger with respect to the
age of emplacement, the latter should not be, anyway, older than the late
Triassic. At the estimated age of the diorite intrusion, the Ivrea-Verbano
mantle peridotites were already emplaced in the crust, but the isotopic
composition of the diorites does not show any clear evidence of crustal
contamination.
The late Triassic - early Jurassic hydrous diorites from the Baldissero and
Finero areas represent the first documentation of Mesozoic magmatic activity in
the westernmost sector of the Southern Alps. This activity is also supported by
the late Triassic zircon ages of peridotites and dykes of the Finero ultramafic
mantle sequence, which records a main metasomatic imprint attributed to a
hydrous silica-saturated component of crustal origin, deriving from a
subducting slab (Zanetti et al., 1999).
The hydrous diorites from the Finero Mafic Complex exhibit, besides the ages,
trace element and isotopic compositions similar to those of the Baldissero
diorites. The Mafic Complex in the Finero region is in tectonic contact, marked
by an ENE high-temperature shear-zone, with the relatively-anhydrous
mafic-ultramafic Permian sequences occurring in Val Sesia and Val d'Ossola.
Similar high-temperature shear-zones mark the transition between the
Baldissero region and the "anhydrous" Ivrea Complex, suggesting that the
records of Mesozoic magmatism in the Ivrea-Verbano Zone are presently
confined by tectonic lineaments to the southernmost and northernmost portion,
respectively.
The evidence of a Mesozoic magmatic activity, its particular location within the
Ivrea-Verbano Zone and the hydrous silica-saturated nature of the involved
parent melts introduce new complexities in the geodynamic evolution of the
westernmost sector of the Southern Alps before the opening of the Jurassic
Tethys.
References
Lu et al., 1997. Chem. Geol. 140, 223-235.
Peressini et al., 2005, Epitome, 1, 157.
Zanetti et al., 1999. CMP 58, 345-568.
W03-29 Orale
Montanini, Alessandra
MAGMATIC ACTIVITY DURING CONTINENTAL BREAKUP AND OCEAN
OPENING RECORDED BY THE EXTERNAL LIGURIDE OPHIOLITES
(NORTHERN APENNINES, ITALY): IMPLICATIONS FOR A MIXED
PERIDOTITE-PYROXENITE MANTLE SOURCE
MONTANINI Alessandra 1, TRIBUZIO Riccardo 2
1 - DIPARTIMENTO DI SCIENZE DELLA TERRA UNIVERSITA' DI PARMA
2 - DIPARTIMENTO DI SCIENZE DELLA TERRA UNIVERSITA' DI PAVIA
Key terms: MORB petrogenesis; depleted mantle; pyroxenite
Petrogenesis of igneous rocks formed along non-volcanic margins is of special
interest because it may shed light on the nature of the magma sources
involved during continental break-up and inception of ocean spreading.
Previous works have shown that some basalts from the Jurassic Ligurian
ophiolites, originated in such a transitional setting, were formed by low partial
melting degrees of a MORB-type mantle (e.g. Desmurs et al., 2002). These
rocks may be therefore useful candidates to unravel the presence of a
non-peridotitic component in the MORB mantle source, which becomes
progressively diluted with increasing degree of melting. In particular, remnants
of a fossile continent-ocean transition similar to that of the modern
non-volcanic continental margins are preserved in the External Liguride (EL)
ophiolites, which consist of fertile lherzolites, MOR-type basalts and rare
syn-rift gabbros (Marroni et al., 1998; Tribuzio et al., 2004). The mantle
peridotites preserve a subcontinental lithospheric origin (Rampone et al., 1995)
and are in places characterised by garnet pyroxenite layers (Montanini et al.,
2006).
The EL gabbroic rocks include troctolites, olivine-bearing to olivine-free
WORKSHOP W03
14
gabbros, Fe-Ti oxide-bearing gabbros and diorites. The gabbros have a
cumulus origin and were derived from N-MORB melts, variably evolved through
fractional crystallisation. The EL basalts display nearly flat REE patterns
(LaN/SmN = 0.8-1.1) and a slight LREE/HREE enrichment (LaN/YbN =
1.0-1.7). They also have high Y/Nb (5-14) and Zr/Nb (20-50), La/Nb > 1 and
low Th/Hf (0.05-0.21), as typically observed for N-MORB. Remarkable
geochemical feature is the Zr enrichment over neighbouring REE (Zr/Zr* =
1.1-1.6), coupled with a garnet signature represented by high Sm/Yb values
(SmDM/YbDM = 1.5-1.8). Nd isotope compositions of both gabbroic rocks and
basalts encompass the range of depleted mantle (initial Nd = +7.6 to +10.3).
However, the less radiogenic Nd isotope compositions fall at the low end of
MORB compositions (Salters & Dick, 2002), thus suggesting the involvement of
an enriched component.
Calculations of the aggregated melts formed through low melting degree
(5-8%) fractional melting of a mixed spinel peridotite/garnet pyroxenite
source, with a small melt fraction (10-15 %) derived from the garnet
pyroxenite, are capable to reproduce the trace element fingerprint of EL
basalts. A literature data compilation for the MOR-type basalts from the
Ligurian Tethys ophiolites, including those formed in a intra-oceanic setting,
shows that they are commonly characterised by positive Zr anomaly and high
(Sm/Yb)DM values. As a whole, the data are consistent with low to moderate
degree of melting of a depleted spinel peridotite source, coupled with a residual
garnet signature.
Bodinier & Godard (2003) proposed a mechanism by which relict lithospheric
mantle can be entrained into asthenospheric material during thermomechanical
erosion of the subcontinental lithosphere by the upwelling asthenosphere.
Similarly, recent works on the ophiolitic peridotites from the Alpine-Apennine
system have provided evidence for interaction between old lithospheric mantle
originally characterized by garnet pyroxenite layers (Piccardo et al., 2004;
Tribuzio et al., 2004; Montanini et al., 2006) and the ascending asthenosphere.
We can therefore speculate that such a mechanism may have played a role in
generating the geochemical features of the MOR-type melts formed during the
early phases of ocean opening and subsequent establishment of a
slow-spreading ridge system.
Bodinier & Godard (2003) In: Treatise on Geochemistry, Vol. 2, pp. 103-170
Desmurs et al., 2002. Contrib Mineral Petrol 144: 365-382
Marroni et al., 1998. Tectonophysics 292: 43-66
Montanini et al.,2006. J Petrol 47: 1943-1971
Piccardo et al., 2004. Int Geol Rev 46: 1119-1159
Rampone et al., 1995. J Petrol 36: 81-105
Salters & Dick, 2002. Nature 418: 68-72
Tribuzio et al., 2004. J Petrol 45: 1109-1124
W03-30 Poster
Montanini, Alessandra
A SUBCONTINENTAL MANTLE-LOWER CRUSTAL ASSOCIATION FROM
CENTRAL CORSICA (FRANCE): PRELIMINARY DATA ON THE ST. LUCIA
NAPPE MANTLE SEQUENCE
MONTANINI Alessandra 1, TRIBUZIO Riccardo 2
1 - DIPARTIMENTO DI SCIENZE DELLA TERRA UNIV. DI PARMA
2 - DIPARTIMENTO DI SCIENZE DELLA TERRA UNIV. DI PAVIA
Key terms: Corsica; mantle; lower crust; peridotite; pyroxenite
The Corsica island was linked to the Pyrénées-Provence domain in southern
France until the Early Miocene drifting from the European mainland following
the collision between Europe and Adria. Corsica is divided into two main
geological domains. The northeastern area ("Alpine Corsica") is formed by a
complex stack of nappes derived from the Ligurian Tethys oceanic litosphere
and older continental crust, both commonly displaying HP-LT metamorphism
developed in Late Cretaceous to Eocene times. The S. Lucia nappe belongs to
the Alpine Corsica and consists of a pre-Alpine crystalline basement overlain by
a Middle Cretaceous detritic cover. The S. Lucia basement includes a High
Grade Mafic complex and a Granitoid complex (Libourel, 1985; Zibra, 2006),
which partly escaped the Alpine tectono-metamorphic event. In particular, the
High Grade Mafic complex consists of a layered gabbroic sequence of Early
Permian age (Paquette et al., 2003) which contains lenses of felsic granulites
and displays a pervasive recrystallisation under granulite facies conditions (P
ca. 0.9 GPa, T = 800-900°C, Caby & Jacob, 2000). As a whole, the High Grade
complex shows many similarities to the Ivrea-Verbano lower crustal sequence
from the Western Alps (Libourel, 1985). The base of the mafic sequence is
associated with up to 50-m thick mantle slices. The mantle rocks consist of
spinel-bearing lherzolites (clinopyroxene = 10-15 % vol) with minor, up to
cm-thick pyroxenite layers. The peridotites show a subvertical mylonitic to
ultramylonitic foliation roughly concordant with that of the nearby
metagabbroic rocks. The pyroxenite layers are oriented subparallel to the
peridotite foliation.
The mylonite microstructure in the peridotite is characterised by aligned
porphyroclasts of pyroxene (and rare spinel) in a fine-grained polyphase matrix
composed of olivine (Fo88-89) + pyroxenes + spinel occurring as mm-size
bands, lenses and porphyroclast tails. Orthopyroxene porphyroclasts are
stretched along the mylonitic foliation with high aspect ratio. Both pyroxenes
commonly show evidence for intracrystalline deformation. Relics of an older
low-strain spinel tectonite predating the mylonite deformation are locally
preserved. The composition of clinopyroxene (Al2O3 = 4.5-5.1 wt%, Na2O=
0.70-0.90 wt%) and spinel porphyroclast cores (Cr# 0.14) reveal a rather
fertile character. The pyroxenites are Opx-poor spinel websterites containing
small amounts of Ti-rich amphibole and plagioclase. They have fine-grained
granoblastic texture and may show elonged porphyroclasts of green spinel
(with altered plagioclase rims) and Al-rich clinopyroxene.
Temperature estimates based on clinopyroxene-orthopyroxene equilibria for
both peridotites and websterites (Wells, 1977; Brey & Kohler, 1990) are in the
range 830-890°C, similar to the temperature conditions reported for the
granulite-facies recrystallization of the associated lower crustal rocks. There is
no significant decrease from the porphyroclastic to the neoblastic assemblage
equilibration temperatures of the peridotites. However, the orthopyroxene
porphyroclasts record up to ca. 1000°C values, employing the Ca-in-Opx
geothermometer (Brey & Kohler, 1990). This suggests a former higher-T stage
in the spinel stability field, in agreement with the occurrence of mutual
pyroxene exsolution lamellae and tiny Cr-spinel exsolutions in the pyroxene
porphyroclasts.
Brey and Kohler, 1990. J. Petrol., 31, 1353-1378
Caby and Jacob, 2000. Geol. de la France 1, 21-34.
Libourel, 1995. These doct., Univ. Toulouse, 405 pp.
Paquette et al., 2003. Chem Geol. 148, 1-120
Wells, 1977. Contrib. Mineral. Petrol. 62, 129-139
Zibra, 2006. PhD Thesis, Univ. Pisa, 204 pp.
W03-31 Orale
Morishita, Tomoaki
GEOCHEMICAL CHARACTERISTICS OF APATITE-RICH LAYERS IN THE
FINERO PHLOGOPITE-PERIDOTITE MASSIF
MORISHITA Tomoaki 1, HATTORI Keiko 2, TERADA Kentaro 3, MATSUMOTO Takuya
4
, YAMAMOTO Koshi 5, TAKEBE Masamichi 5, TAMURA Akihiro 1, ARAI Shoji 1
1 - KANAZAWA UNIVERSITY
2 - UNIVERSITY OF OTTAWA
3 - HIROSHIMA UNIVERSITY
4 - OSAKA UNIVERSITY
5 - NAGOYA UNIVERSITY
Key terms: Finero phlogopite-peridotite; Apatite-rich rock; Metasomatism
Mantle metasomatism is caused by infiltration of metasomatising agents (fluids
or melts) in diverse tectonic settings under a wide range of P-T conditions
(e.g., Zinngrebe and Foley 1995; Vannucci et al., 1998; Wulff-Pedersen et al.
1999; Arai et al., 2003, 2004; Morishita et al., 2003a). Apatite in mantle
xenoliths has been reported from intra-plate rifts (e.g., O'Reilly and Griffin,
1988; Yaxley et al., 1991; Hauri et al., 1993; Rudnick et al., 1993; Ionov et
al., 1996) as well as mantle wedges (e.g., McInnes and Cameron, 1994;
Laurora et al., 2001). Apatite can contain high concentrations of rare earth
elements (REE), Cl, F, U, Th, Sr and it would play an important role in the
behavior of these trace-elements in the upper mantle (e.g., Watson, 1980;
Exley and Smith, 1982; O'Reilly and Griffin, 2000). Therefore, the study of
mantle-derived apatite-rich lithology is important in understanding the
behavior of P-rich metasomatising agent locally present in the mantle.
The Finero phlogopite-peridotite massif in the western Italian Alps is
characterized by intense metasomatism forming apatite and carbonate
minerals after partial melting (Exley et al., 1982; Cummings et al., 1987;
Voshage et al., 1987; Hartmann & Wedepohl, 1993; Zanetti et al., 1999;
Grieco et al., 2001, 2004; Prouteau et al., 2001; Morishita et al., 2003b;
Zaccarini et al., 2004; Raffone et al., 2006). The occurrence of apatite- and
carbonate-bearing domains in the area was first documented around
pyroxenite layers by Zanetti et al. (1999). Morishita et al. (2003b) found a
fine-grained apatite-rich peridotite layer (AP-layer hereafter) Metasomatising
agents in the Finero peridotites are, however, still in debate. We present
major-element, trace-element and isotopic compositions of whole-rock and
metasomatic minerals of the AP-layer, and ages of apatite using a sensitive
high-resolution ion microprobe (SHRIMP) and discusses the origin and
evolution of the metasomatising agent responsible for the formation of the
AP-layer in the Finero massif.
Strontium and Nd isotope compositions of the AP-layer and its host peridotite
show the bulk silicate Earth signature which is distinctive from the previous
data obtained from apatite-free peridotites except for one carbonate
aggregate-bearing sample with high 87Sr/86Sr and low Nd. The carbonate
aggregate restrictedly occurs in an altered serpentine-talc vein cutting both the
AP-layer and its host. These data coupled with C-O-isotope compositions from
carbonate in the carbonate aggregate-bearing sample suggest that the some
carbonates were formed or recrystallized by infiltration of fluids with ancient
crust signature after the formation of the apatite-rich layer.
The AP-layer and the host peridotite are geochemically characterized by
extremely high REE and LILE contents with high LREE/HREE ratio, and low
HFSE concentrations compared with other apatite-bearing lithologies in the
Finero massif. Incompatible trace elements in whole rock and amphiboles
increase in concentration toward the apatite-rich peridotite layer. The AP-layer
was formed by infiltration of highly evolved SiO2-CO2-bearing hydrous
metasomatising agents derived from parent metasomatising agents having
carbonatitic geochemical signatures at the late stage of the metasomatism.
Sensitive high-resolution ion microprobe (SHRIMP) analyses of apatite grains
yielded a Tera-Wasserburg concordia three-dimensional isochron age of 215 ±
35 Ma in the 238U/206Pb-207Pb/206Pb-204Pb/207Pb diagram.
W03-32 Poster
Nagashima, Ryoko
CRYSTALLOGRAPHIC ORIENTATION AMONG SYMPLECTITE MINERALS
IN THE HOROMAN PERIDOTITE COMPLEX, JAPAN
NAGASHIMA Ryoko 1, ODAJIMA Norihiro 2, MORISHITA Tomoaki 1, OZAWA
Kazuhito 2
1 - Kanazawa University
2 - Tokyo University
Key terms: Two-pyroxene spinel symplectite; crystallograghic orientation;
Horoman peridotites complex
Symplectites consisting of orthopyroxene, clinopyroxene and spinel•@in the
Horoman Peridotite Complex, Japan, are thought to be the subsolidus reaction
product after garnet with addition of olivine component during decompression
of the complex from the garnet-lherzolite stability conditions. Automated
electron backscattered diffraction (EBSD) analysis using a field-emission gun
SEM was applied for determination of crystallographic orientations of
symplectite minerals. Minerals have similar crystallographic orientations in each
symplectite, although they occur as isolated grains in a two-dimensional plane.
Systematic crystallographic orientations among them are the same among the
studied samples collected from the upper part to the lower part of the complex
and are summarized as follows: 1) the (100) and (010) planes and [001] axis
of orthopyroxene are parallel to the (100) and (010) planes and [001] axis of
clinopyroxene, respectively, and 2) the (100) and (010) planes are parallel to
the {111} and {101} planes of spinel, respectively. 1) the crystallographic
relationships between orthopyroxene and clinopyroxene in the Horoman
WORKSHOP W03
symplectites are the same as those of Bushveld-type exsolution in pyroxenes.
A qualitative model for the formation of symplectitic mineral intergrowth was
proposed. Garnet in peridotites become a thermodynamically unstable high-Cr,
Al orthopyroxene as pressure-temperature conditions were changed from
garnet-lherzolite stability conditions to spinel-lherzolite stability conditions.
Then high-Cr, Al clinopyroxenes were exsolved from the unstable
orthopyroxene following the crystallogaraphic rules of the Bushveld-type
exsolution. The reaction volumes from the precursor garnet to the
orthopyroxene-clinopyroxene intergrowth might be large enough for minerals
to be grown in three-dimensional directions the reaction was caused by
decompression. Finally, spinel was selectively nucleated at grain boundaries
between orthopyroxene and clinopyroxene by the reaction with olivine
components that were introduced by diffusion from the surroundings.
EBSD data also suggest that orientation contrast of symplectite spinel in each
symplectite tends to occur around one of <111> axis of spinel. Furthermore
the <111> axis of spinel, the rotation axis, are orientated the direction parallel
to the foliation and perpendicular to the lineation. Further investigations on
relationships between deformation and crystallographic orientations of
symplectite minerals are needed because rotation of crystallographic
orientations of symplectite minerals might be caused by deformation of the
complex after the formation of symplectite textures.
W03-33 Orale
Nédli, Zsuzsanna
THE MESOZOIC SUBCONTINENTAL LITHOSPHERIC MANTLE BENEATH
THE TISZA UNIT (S HUNGARY): UPPER MANTLE XENOLITHS IN LATE
CRETACEOUS LAMPROPHYRE FROM VILLÁNY MTS
NÉDLI Zsuzsanna 1, M.TÓTH Tivadar 2, SZABÓ Csaba 1
1 - LITHOSPHERE FLUID RESEARCH LAB, DEPARTMENT OF PETROLOGY AND
GEOCHEMISTRY, EOTVOS UNIVERSITY BUDAPEST
2 - DEPARTMENT OF MINERALOGY, GEOCHEMISTRY AND PETROLOGY,
UNIVERSITY OF SZEGED
Key terms: upper mantle xenoliths; Late Cretaceous; lamprophyre; Tisza Unit;
Carpathian-Pannonian Region
The Mesozoic subcontinental lithosphere beneath the Carpathian-Pannonian
Region is poorly known, because upper mantle xenoliths are rare in
pre-Neogene volcanics. In contrast, mantle xenoliths from Neogene volcanics
have been studied in details in the last decades. Moreover, xenolith studies
have been concentrated on localities from the Alcapa Unit (N Hungary),
therefore, the subcontinental mantle beneath the Tisza Unit (S Hungary) is
quite unknown. Poiana Rusca (Romania) alkali basic rocks and their xenoliths
(Downes et al., 1995) held the only direct information about the mantle for the
last decade. Therefore, the spinel peridotite xenoliths settled in Upper
Cretaceous lamprophyre dykes in the Villány Mts (S Hungary), found in the last
decade, offer unique information about the lithospheric subcontinental mantle
beneath the Tisza Unit and also make possible to compare it to the mantle
beneath the Alcapa Unit.
Villàny Mts xenoliths are porphyritic spinel lherzolites with rare OH-bearing
minerals. They display rounded or ovoidal shapes, are of 1 to 5 cm in diameter,
consisting of olivine (often altered), enstatite, Cr-diopside and Cr-spinel. They
show porphyroclastic texture, ortho- and clinopyroxene are bimodal: they occur
as porphyroclasts or fine-grained, equigranular grains. Spherical spinel
inclusions are abundant in silicates. Exsolution features also are abundant in
pyroxene porphyroclasts.
Porphyroclasts and neoblasts show minute but consequent differences in
chemistry indicating that their equilibrium conditions could be different and
that the xenoliths suffered cooling and re-equilibration at lower PT conditions.
Clinopyroxenes are relatively low in Cr, Al and Na. Compositional tendencies
from the porphyroclasts to neoblasts (decrease in Cr, Al, Na and increase of
mg#) coincide with the tendencies in the sheared porphyroclastic xenoliths
from W Eifel (Witt and Seck, 1987). Orthopyroxene also occur bimodally,
porphyroclasts are slightly richer in Cr, Al but lower in Mg, Si and Ti than
neoblasts. Compositionally our pyroxenes are very similar to W Eifel sheared
porphyroclastic xenoliths and also to mosaic and poikilitic textured xenoliths
from the centre of Carpathian-Pannonian Region (Downes et al., 1992;
Embey-Isztin et al., 2001). Spinel have low cr# (0.17-0.24) indicating that the
mantle suffered low degree of melt extraction (approx. 5-10%).
Thermobarometry also suggests that the xenoliths re-equilibrated at lower PT
conditions, probably in the shallower zones of the upper mantle. Porphyroclasts
record original temperatures approx. 1000 °C whereas neoblasts indicate a
re-equilibration at slightly lower temperatures. Extended exsolution features in
porphyroclasts can be explained by the long-time residence and cooling at
ambient conditions after emplacement.
These observations provide further evidence of the previously suggested lower
temperature for the mantle beneath the Tisza block than the Alcapa (Szabó et
al., 1995) moreover hold the first records of metasomatic effects beneath the
Tisza block. Strong textural and chemical similarities of studied xenoliths to
sheared porphyroclastic xenoliths from the W Eifel and mosaic/poikilitic
textured xenoliths from the centre of the Carpathian-Pannonian Region likely
suggest their similar evolution, in relation with a diapiric uplift or tectonic
emplacement of hot mantle material into a colder upper mantle. Our
hypothesis would require to suppose the presence of a mantle upwelling before
the Late Mesozoic beneath the Tisza block, not described before.
References
Downes H, Embey-Isztin A, Thirlwall MF (1992) Contrib Mineral Petrol 109:
340-354
Downes H, Vaselli O, Seghedi I, Ingram G, Rex D, Coradossi N, Pécskay Z,
Pinarelli L (1995) Acta Vulcanol 7: 209-217
Embey-Isztin A, Dobosi G, Altherr R, Meyer HP (2001) Tectonophysics 331:
285-306
Szabó Cs, Harangi Sz, Vaselli O, Downes H (1995) Acta Vulcanol 7: 231-240
Witt G, Seck HA (1987) J Petrol 28: 475-493
W03-34 Poster
Nédli, Zsuzsanna
CRYSTAL CHEMISTRY OF CLINOPYROXENES ENCLOSED IN UPPER
15
MANTLE XENOLITHS FROM THE CARPATHIAN-PANNONIAN REGION
(HUNGARY): CONTRIBUTIONS TO PETROGENESIS AND PRESSURE
ESTIMATION
NÉDLI Zsuzsanna 1, PRINCIVALLE Francesco 2, DOBOSI Gábor 3, EMBEY-ISZTIN
Antal 4, HIDAS Károly 1, BERKESI Márta 5, SZABÓ Csaba 1
1 - LITHOSPHERE FLUID RESEARCH LAB, DEPARTMENT OF PETROLOGY AND
GEOCHEMISTRY, EOTVOS UNIVERSITY BUDAPEST
2 - DEPARTMENT OF EARTH SCIENCES, UNIVERSITY OF TRIESTE
3 - INSTITUTE OF GEOCHEMISTRY, HUNGARIAN ACADEMY OF SCIENCES,
BUDAPEST
4 - NATURAL HISTORY MUSEUM, BUDAPEST
5 - LITHOSPHERE FLUID RESEARCH LAB,
Key terms: upper mantle xenoliths; clinopyroxene; crystal chemistry; pressure
estimation; Carpathian-Pannonian Region
Crystal structural characteristics provide significant information about the
petrogenesis and equilibrium pressure conditions of the mantle xenoliths. Most
of the crystal structural analysis have been carried out on xenoliths showing
undeformed texture until now. We selected a texturally heterogeneous upper
mantle xenolith series from different part of the Carpathian-Pannonian Basin 1)
to reveal crystal structural and chemical variation in xenolith series with
textural and deformation variety, 2) to estimate equilibrium pressure
conditions of different textured mantle xenoliths, and 3) to contribute to
understand the petrogenesis of the special group of poikilitic and mosaic
textured xenoliths.
For analysis we selected a well described, texturally heterogeneous xenolith
series hosted in Plio-Pleistocene alkaline basalts from the Bakony-Balaton
Highland Volcanic Field (central part of the Carpathian-Pannonian Region), in
Late-Cretaceous lamprophyres from Villàny Mts (S Hungary) and in
Late-Cretaceous- Paleogene alkali basalts from Poiana Rusca (Romania,
peripherial part of the region). Clinopyroxenes from xenoliths were studied by
means of single crystal X-ray diffraction and electron microprobe analysis.
Xenoliths studied show wide textural variety: the dominant textural types
(protogranular, porphyroclastic, equigranular) compose the main series,
whereas the rarer poikilitic and mosaic textured samples form a special group.
The main series samples represent common textural evolution of the upper
mantle, governed by polimetamorphic process and increasing deformation in
the progressive protogranular - porphyroclastic - equigranular series. For
mosaic and poikilitic textured xenoliths several authors proposed formation in
relation with mantle derived melts.
Previous crystal chemistry studies on mantle xenolith clinopyroxenes have
shown that crystal structure depends notably on the equilibrium physical
conditions, and relations between cell and site (M1, M2) volumes are indicative
of different equilibrium pressures. These observations allowe us to use
structural parameters as a useful and chemically independent estimation of
equilibrium pressure of mantle xenoliths even for spinel peridotite facies.
Our results suggest that protogranular, porphyroclastic and equigranular
xenoliths define the main trend of chemical, structural and textural changes in
the suites which is characterized by the progressive increase of deformation in
proportion with the decrease of equilibrium pressure. Protogranular xenoliths
record pressure near to garnet stability field, whereas equigranular xenoliths
were equilibrated near to plagioclase stability field. This inverse proportion of
pressure and deformation geodynamically can be explained by the mantle
diapir beneath the Carpathian-Pannonian Region, which could cause significant
deformation and lithosphere thinning in the centre of the basin, in accordance
with the fact that xenoliths from the peripherial parts of the basin record higher
pressures.
Poikilitic and mosaic xenoliths are detached in crystal chemistry from the main
trend, suggesting that their origin and evolution may not be explained by the
continuous deformation/depletion. Despite of their similar texture, poikilitic
xenoliths from different parts of the basin show very different structural
parameters, suggesting that thay likely were formed at different pressure
conditions. Xenoliths deriving from the centre show pressure conditions near to
plagioclase stability field, whereas that ones from the peripherial areas of the
Basin indicate remarkably higher pressure. These observations are in
accordance with works which link them to percolating melts in the lithospheric
mantle indicating that they can be formed by interaction of this melts at
different depths of the subcontinental mantle.
W03-35 Orale
Neumann, Else-Ragnhild
METASOMATISM IN THE LITHOSPHERIC MANTLE BENEATH THE
CANARY ISLANDS: DOES THIS HAVE BEARING ON CENOZOIC
METASOMATISM IN THE CONTINENTAL MANTLE BENEATH WESTERN
AND CENTRAL EUROPENEUMANN Else-Ragnhild 1
1 - UNIVERSITY OF OSLO
Key terms: Canary Islands; Mantle xenoliths; Immiscibility; Carbonaceous
silicate melt
In a Nature paper in 1995 Hoernle et al. proposed, on the basis of tomography
and radiogenic isotope data, that Cenozoic volcanism in central Europe, the
western Mediterranean and eastern Atlantic Ocean is caused by a common,
large region of mantle upwelling (a "mega-plume"). In addition to magmatism,
this mantle upwelling is believed to have caused metasomatism in the
continental lithospheric mantle beneath Europe as well as in the oceanic mantle
lithosphere beneath ocean islands in the eastern Atlantic Ocean, including the
Canary Islands. This presentation focuses on the effects of this plume on the
lithospheric mantle beneath the Canary Islands, hoping that some of the
information from that area will be relevant for the upper mantle beneath
Europe.
Mantle xenoliths from the Canary Islands are well suited to identify the effects
of recent metasomatism. Before metasomatism spinel harzburgite and
lherzolite xenoliths from the Canary Islands belonged to a group of
ultra-refractory spinel harzburgites which are found in many ocean islands (e.g.
Canary Islands, Kerguelen, Cape Verde, Samoa). These rocks are more
refractory than average MOR peridotites; their major element and modal
compositions are relatively uniform and imply that they have been subjected to
a high enough degree of melting to remove clinopyroxene. All cpx presently
WORKSHOP W03
16
found in these rocks is secondary, formed by exsolution from orthopyroxene
and/or metasomatic melts/fluids.
Metasomatism in the upper mantle beneath the Canary Islands includes
formation of minor amounts of phlogopite, melt - wall-rock reactions (e.g.
formation of olivine and clinopyroxene at the expense of orthopyroxene),
addition of incompatible trace elements (e.g. LREE), CaO, and Na2O, and
resetting of the Sr-Nd istopic ratios to values within the range of Canary
Islands basalts. Evidence from fluid inclusions indicate that a range of
metasomatic fluids formed as the results of immiscible separations, melt wall-rock reactions, and chromatographic fractionation, from an initial CO2-rich
basaltic primary melt, or a carbonaceous silicate melt. The main metasomatic
agents appears to be a carbonatitic or carbonaceous melts highly enriched in
light REE relative to heavy REE, and depleted in Zr-Hf and Ti relative to REE.
The metasomatism mainly acted as open-system processes, meaning that
metasomatic melts/fluids ascending through the upper mantle caused reactions
and chemical exchange between fluid and wall-rock, leaving a residual fluid
which moved to shallower levels. Elements compatible with the wall-rock
minerals and/or with phases formed through metasomatic reactions
(clinopyroxene and phlogopite) were "trapped" by these minerals, whereas
elements incompatible with all phases were preferentially transported away by
the residual fluid. A series of Fe-Al-Ti-rich dunites, wehrlites and
clinopyroxenites (and rare Ti-Al-Fe-rich harzburgites/lherzolites) have
compositions that imply formation through interaction between peridotite
wall-rock and significant proportions of mildly alkaline basaltic melts (similar to
Canary Islands magmas); some clinopyroxenites may have formed directly
from mildly alkaline magmas. However, interaction between peridotite
wall-rocks and basaltic fluids appears to be mainly restricted to magma
conduits and the close vicinity of such conduits.
W03-36 Poster
Ntaflos, Theodoros
THE ORIGIN OF THE ALKALINE AND HIGH-K CALC-ALKALINE MAGMAS
ALONG THE SE MARGIN OF THE STYRIAN BASIN, AUSTRIA
NTAFLOS Theodoros 1, KRUMPEL Georg 1, HARANGI Szabolcs 2, TSCHEGG
Cornelius 1
AUSTRIA
2 - EOTVOS UNIVERSITY, DEPARTMENT OF PETROLOGY AND GEOCHEMISTRY,
BUDAPEST, HUNGARY
Key terms: Calc-alkaline rocks; Alkaline rocks; Pre-enriched mantle; Styrian
Basin
The potassic volcanism occurred in the Pannonian-Carpathian area could
provide valuable information about the nature of the lithosphere and the
melting/metasomatic processes that took place beneath this region.
The Styrian basin, the westernmost sub-basin of the Pannonian basin system,
is located as well at the eastern margin of the Eastern Alps. The majority of the
studied samples were revealed by drilling cores in the south-eastern part of the
Styrian Basin. The rest of the samples have been collected from quarries.
The rocks are high-K calc-alkaline (andesites and dacites) and alkaline (latites
and shoshonites). K/Ar-ages range from 16.3 to 13 Ma with high-K
calc-alkaline rocks representing the oldest suite. A striking
petrographicdifference between both groups is that the calc-alkaline rocks are
amphibole bearing and lack clinopyroxene. Alkaline rocks include zoned
clinopyroxenes that have magmatic corroded cores overgrown by more basic
rims suggesting basic magma reflux.
In the spiderdiagrams all the samples show remarkable negative Nb and Ta
troughs and high contents of LILE. Additionally the calc-alkaline rocks have
negative P anomaly. However, the calc-alkaline rocks are characterized by low
contents of LILE and HFSE when compared to the alkaline rocks.
The calc-alkaline rocks from Styria are similar to those from the
Carpathian-Pannonian area that have long been recognized as being typical for
subduction related-magmas (Seghedi et. al. 2004). They can be modelled by
an AFC-process controlling the composition of an IAB-magma with F=0.6 and
r=0.4. The upper continental crust is proposed as contaminant.
While high-K calc alkaline rocks can be explained by an AFC-process the
composition of the alkaline rocks (latites and shoshonites) seems to be a
consequence of batch melting processes of a pre-enriched mantle, which can
be derived by mixing of primitive lithospheric mantle with material from the
continental crust. Harangi et al. 1995 proposed a similar explanation for the
Pannonian alkaline volcanism. Model calculations reveal that the fraction of
continental material in the mixture was 4% and the batch melting process took
place in the stability field of spinel-lherzolite at 5%.
From the geodynamical point of view, the calc-alkaline lavas can be seen as a
consequence of the oceanic subduction, which exhibit the basis of the
Rhenodanubian-flysch or of the West-Carpathian-flysch. This subduction was
related to the N-S convergence of Africa and Europe in the Early Miocene. In
contrast the alkaline magmatism was the result of decompressional melting of
a metasomatic pre-enriched mantle. The process of decompressional melting
may be related to the extension that characterizes the western margin of the
Panonnian Basin during the Middle Miocene.
Literature
Harangi Sz., Wilson M. & Tomarini S. (1995) Petrogenesis of Neogene potassic
volcanic rocks in the Pannonian Basin. Acta Vulcanologica, 7, 125-134.
Seghedi I. Downes H., Szakacs A., Mason P.R.D, Thirwall M.F., Rosu E.,
Pecskay Z., Marton E. & Panaiotu C. (2004) Neogene-Quaternary magmatism
and geodynamics in the Carpathian-Pannonian region: a synthesis. Lithos, 72,
117-146.
W03-37 Orale
Ntaflos, Theodoros
THE SIGNIFICANCE OF THE PHOSPHORAN OLIVINE ON THE
PETROGENESIS OF THE GATAIA LAMPROITE, SW ROMANIA
NTAFLOS Theodoros 1, SEGHEDI Ioan 2
AUSTRIA
2 - INSTITUTE OF GEODYNAMICS, STR. JEAN-LUIS CALDERON 19-21, 70201
BUCHAREST, ROMANIA
Key terms: Pannonian-Carpathian region; Lithosphere; Lamproites; Gataia
The Gataia lamproite is a new occurrence located at the southeastern wedge of
the Pannonian Basin (Romania). The main petrographical characteristics of the
Gataia lamproite are: (1) modal proportions of olivine and leucite are high; (2)
relatively abundant are phlogopite, apatite and armalcolite, whereas minor
phases include diopside, sanidine, richterite and spinel and (3) Zr-rich glass.
Olivines, as phenocrysts or microcrysts, are zoned with Fo up to 93 in the core
and up to 84 in the rim. They have abundant spinel, apatite and melt inclusions
suggesting that they are not xenocrysts and the apatite and olivine crystallized
simultaneously. Olivine X-ray maps show the presence of phosphorus as
fine-scale delicate oscillatory zoning. Occasionally the core is enriched in
phosphorus, providing the highest P concentration (P2O5=0.80 wt %). Along the
oscillations are growing fine-grained apatites.
The incorporation of phosphorus into silicate minerals is not surprising as from
the crystallographic point of view IVP 5+ can replace IVSi 4+ due to the small
differences in their ionic radii. The charge balancing scheme for phosphoran
olivine that has been experimentally determined by Boesenberg et al., 2004
is: 4 VIM +2 + 2Si +4
2P +5+ VI[]. Furthermore they estimated that up to 70%
of the tetrahedral sites can be replaced by P. In our case, the incorporation of
phosphorus into olivine took place prior to saturation of the lamproitic magma
with a phosphate mineral. In addition, compared to other lamproites
worldwide, the Gataia lamproite has the lowest CaO content (CaO=3.43 wt %)
and is one of the most rich in P2O5 (2.13 wt %). Consequently, the lamproitic
magma was oversaturated in P and depleted in Ca preventing the
crystallization of apatite and providing the conditions for crystallization of P-rich
olivine. The P-oversaturation is continuous up to the groundmass glass
generation, which has up to 0.30 wt % P2O5 and only 0.07 wt % CaO.
Whole rock contains 1230 ppm Zr that is concentrated in the glass (ZrO2= 0.26
wt %) explaining the absence of Zr-bearing phases. Zircon has not been
observed in lamproites and Zr-bearing minerals as wadeite and/or daylite are
recognized as late stage crystallization minerals; their absence in our case
suggests a very fast transport to the surface. Such Zr-rich melts can be
considered as the metasomatic agent causing anomalous Zr-enrichments in
mantle diopsides.
Gataia is located far from the Carpathian subduction system, excluding any
relationship to that system. As well, a plume origin for the Gataia lamproite can
also be excluded as none of the isotopic compositions shows affinity to HIMU
mantle component. The Gataia lamproite appears to be of lithospheric origin
related to the extensional processes at the margin of the Pannonian basin. The
question whether the source of the potassic volcanism that is common in the
Carpathian-Pannonian area could be considered as similar of that of the Gataia
lamproite and the Bar leucitite is still open.
Literature
Boesenberg et al., 2004, Lunar and Planetary Science XXV, 1366.pdf
W03-38 Orale
O'Reilly, Suzanne Y.
ARCHEAN LITHOSPHERIC MANTLE: THE REFERTILISED REMAINS
O'REILLY Suzanne Y. 1, GRIFFIN William L. 1, BEGG Graham 2
1 - GEMOC, Dept of Earth and Planetary Sciences, Macquarie University, NSW
2109, Australia
2 - GEMOC, Dept of Earth and Planetary Sciences, Macquarie University, NSW
2109, Australia and BHP Billiton, Level 34 Central Park, 152-158 St Georges
Tce, Perth, WA 6000, Australia
Key terms: Archean lithosphere; Lithosphere refertilisation; Mantle
tomography; Mantle composition; Crustal growth rates
The composition of subcontinental lithospheric mantle (SCLM) varies broadly
with the age of the last major tectonothermal event in the overlying crust.
Archean SCLM is highly depleted, commonly is strongly stratified, and contains
rock types absent in younger SCLM. Phanerozoic terrains are generally
underlain by fertile mantle, and most Proterozoic SCLM is intermediate between
these two extremes. This secular evolution in SCLM composition implies
quasi-contemporaneous formation (or modification) of the crust and its
underlying mantle root. The "typical" Archean mantle composition used in
geochemical/geophysical modelling is a depleted garnet lherzolite. This
composition is derived from peridotite xenoliths in kimberlites, mainly from the
SW Kaapvaal Craton, and a few from Siberia. However, most such "typical"
Archean xenoliths have experienced repeated metasomatism, leading to a
progression from dunite/harzburgite through "depleted" lherzolite to "fertile"
lherzolite, mirroring the secular evolution of the SCLM as a whole. Similar
refertilisation processes can be studied in situ in peridotite massifs (eg Western
Norway, Lherz), showing the lherzolites to be the product of melt infiltration
into magnesian dunite/harzburgite protoliths. These rocks are poorly
represented in the published xenolith record; the bias partly reflects the
collecting of rocks useful for P-T studies, but also has a geological basis.
High-resolution seismic tomography of Archean cratons shows high-Vs volumes
surrounded and dissected by zones of lower Vs. The low-Vs parts can be
modelled using the "typical" garnet lherzolite compositions, while the higher-Vs
volumes require much more depleted rocks. In detail, kimberlites avoid the
high-Vs volumes to preferentially follow older zones of fluid passage and
metasomatism, hence biasing our "mantle sample" toward the metasomatic
products. A revised estimate of the composition of "original" Archean SCLM
yields a dunite/harzburgite with 49% MgO, 6.6% FeO, 0.4% Al2O3, 0.34%
Cr2O3 and 0.2% CaO. Seismic tomography suggests that this material still
underlies the bulk of Archean cratons to depths of 150-200 km, but is poorly
sampled by kimberlites. Relict Archean mantle is also imaged as buoyant high
Vp blobs in oceanic regions, a likely source for reported "recycled" geochemical
signatures in some ocean island basalts, and providing evidence of mechanisms
of continental breakup Hf-isotope data on zircons show that much Proterozoic
crust, especially in cratonic areas, has Archean protoliths, suggesting that the
underlying SCLM also was originally Archean. Seismic tomography shows
high-Vs roots, requiring depleted compositions and low geotherms, under many
of these areas; clearly juvenile Proterozoic belts (eg SW Scandinavia) do not
have such roots. Re-Os isotopic data for the underlying mantle record similar
events, indicating a linked tectonic history. These observations suggest that
WORKSHOP W03
much of the observed secular evolution in SCLM composition reflects
progressive reworking of buoyant Archean SCLM, rather than secular changes
in the mechanisms of SCLM production. Seismic tomography suggests that
50% of existing continental crust is underlain by relict Archean SCLM, modified
to varying degrees. This implies a much larger volume of originally Archean
crust than currently accepted, and hence very high early crustal growth rates.
Melt-modelling exercises that treat "typical" Archean peridotites as simple
residues are invalid, and cannot be used to support "lithosphere stacking"
models for SCLM formation. The "primitive" Archean dunites/harzburgites are
best modelled as restites/cumulates from high-degree melting at 3-6 GPa, in
ascending plumes/mantle overturns. This uniquely Archean regime may have
coexisted with a more modern plate-tectonic regime, which produced weakly
depleted residues similar to Phanerozoic SCLM. This "modern" SCLM would be
inherently unstable, easily recycled and lost to the modern record.
W03-39 Orale
Pearson, Norman
LINKING CRUSTAL AND MANTLE EVENTS USING IN-SITU U-PB, LU-HF
AND RE-OS ISOTOPE ANALYSIS
PEARSON Norman 1, O'REILLY Suzanne Y. 1, GRIFFIN William L. 1, ALARD Olivier 1,
BELOUSOVA Elena 1
1 - Macquarie University
Key terms: geochronolgy; Multi-collector ICP-MS; Lithospheric mantle; sulfide;
zircon
Over the past decade significant advances have been made in geochronology
and geochemistry with the development of a variety of methods for precise
in-situ analysis of trace element compositions and isotope ratios. These
advances are primarily the product of coupling a laser ablation microprobe to
the induced coupled plasma mass spectrometer (ICP-MS) and the rapid
development of the multi-collector (MC-) ICP-MS. In-situ analysis also allows
the isotopic data to be interpreted within a microstructural context and in the
framework of geochemical data from other microanalytical techniques. The
integration of multiple datasets is not only essential to constrain the origin of a
sample, but also to unravel the processes that have subsequently modified it.
In-situ analysis of Re-Os isotopes in sulfides in mantle-derived peridotites
provides a method for constraining the timing of events within the lithospheric
mantle. The sulfides are 'time-capsules': like zircons in crustal rocks they
record many events in the lithospheric mantle. Apart from dating the depletion
events that formed the volume of lithosphere the sulfides provide constraints
on a range of processes that might modify the mantle such as the addition of
metasomatic fluids during lithosphere reworking. The analysis of individual
grains of sulfide indicates that there are multiple generations of sulfides in
most mantle peridotites and whole-rock Re-Os ages reflect a mix of these
different sulfide populations. In many samples the in-situ data yield older ages
for original lithospheric mantle stabilization. The mixtures also reflect the
end-product of multiple melting and metasomatic events in the lithospheric
mantle. Age-relative probability diagrams can be produced using sulfides that
are interpreted to be monosulfide solid solutions that represent residual phases
from partial melting or that crystallized from sulfide melts. These 'age' spectra
for the events in the sub-cratonic lithospheric mantle commonly mirror
temporal signatures for thermal and tectonic events in the overlying crust. The
correspondence of Re-Os model ages and crustal events in young terranes is
heavily influenced by the large populations of sulfides with negative model
ages.
Integration of age information from the lithospheric mantle and overlying crust
can be used to establish linkages between the two and further our
understanding of large-scale geodynamic processes. The importance of zircon
as a 'time-capsule' has been reinforced by the development of in-situ Hf
isotope measurements using the MC-ICP-MS. The combination of U-Pb dating
of zircons with their trace element patterns and Hf isotopes is a powerful
technique for understanding crustal evolution. TerraneChron® applies this
approach to study detrital zircons from modern drainages or sedimentary rocks
to construct records of the addition of juvenile material and reworking from the
terrane to continent scale. Integrated studies of zircons in lower-crustal
xenoliths and of sulfides in mantle-derived xenoliths, in both cratonic and
younger off-craton settings, provide new insights into processes of continental
generation, tectonism and destruction.
W03-40 Poster
Peccerillo, Angelo
S-WAVE VELOCITY MODELS OF THE LITHOSPHERE-ASTHENOSPHERE
BENEATH THE TYRRHENIAN SEA: IMPLICATION FOR MAGMATISM,
GEODYNAMICS AND MANTLE DEGASSING
PECCERILLO Angelo 1, PANZA Giuliano 2, FREZZOTTI Maria Luce 3, AOUDIA
Abdulkarim 2, DOGLIONI Carlo 4
1 - DIPARTIMENTO DI SCIENZE DELLA TERRA, UNIVERSITA' DI PERUGIA
2 - DIPARTIMENTO DI SCIENZE DELLA TERRA, UNIVERSITA' DI TRIESTE
3 - DIPARTIMENTO DI SCIENZE DELLA TERRA, UNIVERSITA' DI SIENA
4 - DIPARTIMENTO DI SCIENZE DELLA TERRA, UNIVERSITA' DI ROMA "LA
SAPIENZA"
Key terms: S-wave tomography; Magmatism; Tyrrhenian Sea; Mantle
degassing; Mantle metasomatism
Shear-wave velocity models, inverted from Rayleigh-wave dispersion
tomography, for the lithosphere-asthenosphere system along four transects
across the Western-Central Mediterranean area, reveal the presence of a thick
layer, at about 70 - 120 km of depth, with low S-waves velocity (VS ~ 4.0-4.2
km/sec), that can identify low-rigidity, fluid-bearing mantle material. This layer
extends from the Balearic Sea to the central and southern Tyrrhenian margins
of the Italian peninsula (Panza et al., 2006), where it thins and raises to a
depth of about 30 km, below the presently active Campanian and Aeolian
volcanoes. Low S-waves velocity layers are absent along the Sicily channel,
where thin shallow lenses with low S-wave velocities (Vs ~ 4.0-4.2 km/sec) are
restricted to volcanic active areas of Ferdinandea-Graham Island and Etna.
17
We suggest that the low S-wave velocity layer across the Balearic Sea and the
central and southern Tyrrhenian Sea is the effect of mantle contamination by
subduction-related C-O-H fluids (e.g. H2O, CH4, CO2) released by the
eastward retreating Adriatic-Ionian subduction plates from Oligo-Miocene to
present. The upraise of this layer to shallow depths beneath the active volcanic
areas of southern Italy is attributed to eastward mantle flow above the
retreating slab and to the release of aqueous fluids from the Ionian slab, that
generates mantle melting and active volcanism. The detected low-velocity layer
lies at pressures corresponding to a minimum in the mantle+H2O+CO2 solidus.
The presence of fluids in the mantle across the Balearic and Tyrrhenian basins
is attributed to the decarbonation-dehydration of the subducting slab during its
retreat from the Provence area to its present position off the Calabria coast.
Decarbonation-dehydration of marly sediments, which have been demonstrated
to have been involved in mantle contamination beneath Italy, is suggested to
represent a main source of mantle fluids. The persistence of this layer along
the track of the migrating slab for long time after the end of active subduction
and volcanism could testify the preservation of small amounts of melts that
were unable to separate from parent rocks. Degassing of this CO2-rich layer
may occur along deep lithospheric faults, like the so-called 41° Parallel
alignment,, and the Tindari-Letojanni-Malta Escarpment fault. The diffused CO2
release in central-southern Italy may be well related to this process.
Recently, Panza et al. (2007) have shown that outside the western
Mediterranean backarc setting, specifically beneath northern Africa, a very
pronounced low-velocity layer occurs at the top of the asthenosphere, between
130-200 km. To the north, in the western Mediterranean backarc basin, this
layer is less evident, possibly diluted and apparently connected to the shallower
aforementioned low-velocity layer. This would suggest that, besides the fluids
contamination, an eastward upraise of the upper part of the fluid-rich, ultra-low
viscosity asthenosphere at shallower layers might be responsible for the
low-velocity layer at shallow depth in the Tyrrhenian Sea.
The ensemble of geophysical and geochemical data rules out the presence of a
mantle plume beneath the Tyrrhenian sea, and excludes that the
Plio-Quaternary intraplate volcanism of Sardinia and along the northern border
of the African foreland is related to deep mantle process.
References
Panza, G.F., Peccerillo A., Aoudia K., Farina B., 2006. Geophysical and
petrological modelling of the structure and composition of the crust and upper
mantle in complex geodynamic settings: the Tyrrhenian sea and surroundings,
Earth Sci. Rev., 80, 1-46.
Panza G.F., Raykova, R.B., Carminati E., Doglioni C., 2007. Upper mantle flow
in the western Mediterranean. Earth Planet. Sci. Lett., 257, 200-214.
W03-41 Orale
Peccerillo, Angelo
MANTLE STRUCTURE AND COMPOSITION BENEATH THE TYRRHENIAN
SEA AREA: EVIDENCE FROM PETROLOGY AND GEOCHEMISTRY OF
PLIO-QUATERNARY MAGMATISM
PECCERILLO Angelo 1
1 - Dipartimento di Scienze della Terra, Università di Perugia
Key terms: Upper Mantle; Italy; Quaternary Magmatism; Geochemistry
Plio-Quaternary magmatism in Italy shows an extreme compositional
variability, from sub-alkaline to ultra-alkaline, from mafic to felsic and from
strongly undersaturated to oversaturated in silica. Trace element and
radiogenic isotope (Sr, Nd, Pb, Hf) signatures are also variable and span almost
entirely the spectrum of magmatic rocks occurring world-wide. Petrological and
geochemical data of mafic rocks allow distinguishing various magmatic
provinces, which differ from each other for major and/or trace elements and/or
isotopic compositions. The Tuscany Province (14-0.2 Ma) consists of silicic
crustal anatectic magmas, of mantle-derived calcalkaline to ultrapotassic mafic
rocks and of mixtures between crustal-derived melts and various types of
mantle-generated magmas. The Latium Province (or Roman Province s.s., 0.8
to 0.03 Ma) is formed of huge multi-center volcanic complexes (Vulsini, Vico,
Sabatini. Albani), which erupted potassic and ultrapotassic magmas showing
extreme enrichments in Large Ion Lithophile Elelements (LILE) and high but
moderately variable isotopic signatures (e.g. 87Sr/86Sr ~ 0.7100-0.7105). The
Umbria-Abruzzi province consist of a few monogentic kamafugitic volcanoes
similar trace element and radiogenic isotope signatures as the Latium
volcanoes. The Campania Province (0.2 Ma to present) is formed by potassic to
ultrapotassic rocks having lower LILE concentrations and Sr isotopic ratios, but
higher High Field Strength Elements (HFSE) than Latium volcanoes. Typical
calc-alkaline rocks, about 2.0 Ma old, have been found by deep borehole
drillings beneath active Campanian volcanoes. Ernici-Roccamonfina rocks
(0.7-0.1 Ma) have very variable trace element and isotopic compositions that
span both Latium and Campania compositions. The Aeolian Arc Province (1 Ma
to present) mainly consists of calcalkaline to shoshonitic rocks. The Sicily
Province contains young to active centres (notably Etna) with a tholeiitic to
OIB-type Na-alkaline affinity. Finally, volcanoes of variable composition occur
in Sardinia and, as seamounts, on the Tyrrhenian Sea floor. Magmas in the
Aeolian arc and along the Italian peninsula have high values of LILE/HFSE
ratios resembling subduction-related rocks, whereas the Sicily and Sardinia
display lower LILE/HFSE, close to intraplate signatures. Intraplate and orogenic
volcanics coexist on the Tyrrhenian Sea floor.
The geochemical and isotopic complexities of Plio-Quaternary magmatism
reveal that the upper mantle beneath Italy is extremely heterogeneous and
consist of a mosaic of compositionally distinct domains, displaying both
"orogenic" and "anorogenic" compositions. Such a compositional heterogeneity
originated from mixing different types of crustal material and various types of
lithospheric and asthenospheric mantle rocks. Geophysical and geochemical
evidence does not support a role of deep mantle plumes. Mantle modifications
probably occurred during the subduction processes which affected the western
Mediterranean area from Oligocene to present .
W03-42 Poster
Perinelli, Cristina
EXPERIMENTAL INVESTIGATION ON PERIDOTITE/ALKALINE-MELT
REACTIONS: IMPLICATIONS FOR METASOMATISM OF NORTHERN
WORKSHOP W03
18
VICTORIA LAND (ANTARCTICA) UPPER MANTLE
PERINELLI Cristina 1, ORLANDO Andrea 2, CONTE Aida Maria 3, ARMIENTI Pietro 1,
BORRINI Daniele 4, FACCINI Barbara 5, MISITI Valeria 6
1 - Dipartimento di Scienze della Terra, Università di Pisa
2 - C.N.R.-I.G.G. U.O. di Firenze
3 - C.N.R.-I.G.G. U.O. di Roma
4 - Dipartimento di Scienze della Terra, Università di Firenze
5 - Dipartimento di Scienze della Terra, Università di Ferrara
6 - I.N.G.V. Sezione di Sismologia e Tettonofisica
Key terms: Mantle metasomatism; peridotites; melt-rock reaction experiments;
Antarctica
Cenozoic alkaline basic lavas of the Mt. Melbourne Volcanic Province (northern
Victoria Land - NVL, Antarctica) host spinel peridotite and pyroxenite xenoliths
that testify the compositional heterogeneity of the NVL upper mantle due to
the combined effects of partial melting and metasomatic processes (Coltorti et
al., 2004; Perinelli et al., 2006). Metasomatism is revealed by the occurrence
of amphibole (modal metasomatism) and by incompatible element enrichments
in bulk rock and clinopyroxenes (cryptic metasomatism). Basing on the mineral
chemistry of the xenoliths, Coltorti et al. (2004) and Perinelli et al. (2006)
inferred that the composition of the metasomatic agent was possibly similar to
that of a mela-nephelinitic sample outcropping at Greene Point (NVL).
To investigate the effects of melt /mantle rocks interaction, high pressure (P) high temperature (T) experiments were performed by placing in close contact a
layer of nephelinite with a layer of lherzolite or wehrlite.
The experiments were carried out in a piston-cylinder apparatus using the
graphite-Pt double capsule technique at P=1.0 GPa, T=1050-1250°C for
wehrlite and 1.5-2.0 GPa and T= 975-1300°C for lherzolite. Experimental
results show that metasomatic reactions took place producing clinopyroxene,
olivine and spinel with different compositions respect to the original phases. In
particular, clinopyroxene exhibits the largest chemical changes ranging from
primary diopside to high Mg-Cr-(Na) augite and omphacite in lherzolite and to
low Mg and high Ti-Al-Fe-Na augites in wehrlite; olivine in wehrlite shows
enrichments in Fe while spinel in lherzolite displays higher Cr/(Cr+Al) ratios.
The lack of amphibole crystallization in our experiments could be explained by
the fixed temperature imposed by the run setting which does not allow to meet
the stability field for this phase that, instead, can crystallize in the natural
system where hot metasomatising melts infiltrate a colder matrix.
The observed systematic variations in mineral compositions are tied to
modifications of invading melt chemistry. This is particularly evident in the
experiments involving wehrlite paragenesis in which a network of melt veins
and/or interstitial glass pools is observed in all runs. In these experiments the
variation of glass composition is related to olivine+clinopyroxene crystallization
coupled with primary clinopyroxene dissolution at the contact between the
metasomatising melt and the solid matrix. The composition of these glasses
approaches that of melt patches associated to both amphibole-free and
amphibole-bearing natural samples.
This mechanism can be identified with a moving reaction front that, though
implying a relative low amount of melts, may induce widespread metasomatic
effects in a wide mantle region.
References
Coltorti, M., Beccaluva, L., Bonadiman, C., Faccini, B., Ntaflos, T. & Siena, F.
2004. Lithos, 75, 115-139.
Perinelli, C., Armienti, P. & Dallai, L. 2006. Contrib. Mineral. Petrol., 151,
245-266.
W03-43 Orale
Perinelli, Cristina
GEOCHEMICAL FEATURES OF SPINEL PERIDOTITES IN THE UPPER
MIOCENE VALLE GUFFARI DIATREME (HYBLEAN PLATEAU, SICILY):
IMPLICATIONS ON EVOLUTION OF SOUTH-EASTERN SICILY
LITHOSPHERE
PERINELLI Cristina 1, SAPIENZA Giovanna Tiziana 2, ARMIENTI Pietro 1, MORTEN
Lauro 3
1 - Dipartimento di Scienze della Terra, Università di Pisa, Italy
2 - Dipartimento di Scienze della Terra e Geologico-Ambientali, Università di
Bologna, Italy
Bologna, Italy; deceased, Nov 18 2006
Key terms: Spinel peridotite xenoliths; pyroxenes; trace elements;
metasomatism; Hyblean Plateau
Upper Miocene Valle Guffari diatreme (Hyblean Plateau, Sicily, southern Italy)
contains large number of upper mantle xenoliths among which spinel-facies
peridotites with coarse-grained texture are the dominant type. Rarely the
xenoliths host fresh glass vein poorly crystallized. The whole rock and mineral
chemistry record distinct events of partial melting and metasomatism. Partial
melting led to variable removing of basaltic components and produced depleted
lherzolites with Fo89-91, En88-91, Cr-Diopside: En48-49 Fs4-6 Wo45-48 and Cr-rich spinel
with cr# = 25-39. The signature of metasomatic event(s) is revealed by bulk
rock incompatible element enrichments and by the REE clinopyroxenes patterns
that show three different profiles: a) LREE-enriched (Lan/Ybn = 7-17); a)
spoon-shaped (Lan/Ybn = 18-20; Lan/Smn = 21-34; Smn/Ybn < 1); c) nearly flat
(Lan/Ybn ~3). These patterns can be associated to more or less complete
equilibration with at least two distinct metasomatic melts: an alkaline silicate
melt resembling the host basalt (patterns a and b) and an hawaiitic melt (in
case of a peridotite containing a fresh hawaiitic glass veinlet, pattern c). Trace
element distribution shows also that the alkaline silicate melt influenced the
HFSE content, and in particular caused the increase of Nb/Ta and Zr/Hf ratios.
fO2 calculation gives a redox state above FMQ (up to +1.7 logunits) related to
melt-driven metasomatism.
P-T estimates on these rocks yield 0.9-1.2 GPa and 870-1050°C, suggesting
that different metasomatising melts percolated the spinel-peridotite matrix
near the Crust-Mantle boundary or just below it. Moreover the P-T data are in
agreement with paleogeotherm reported by Nimis (1998) that is consistent
with a high geothermal gradient. However, the inferred mantle potential
temperatures (two hundred degrees lower than values typical for a mantle
plume), indicates that the assessed thermal regime does not fit with the
occurrence of an active mantle plume beneath the Hyblean area.
References
Nimis, P. 1998. European Journal of Mineralogy, 10, 521-534.
W03-44 Orale
Piccardo, Giovanni Battista
THE LIGURIA MODE, A MANTLE PETROLOGY - BASED CONCEPTUAL
MODEL FOR THE FORMATION OF THE JURASSIC LIGURIAN TETHYS.
PICCARDO Giovanni Battista 1
1 - Dipartimento per lo Studio del Territorio e delle sue Risorse, Universita' di
Genova
Key terms: Jurassic Ligurian Tethys; Mantle petrology; Tectonic-metamorphic
evolution; Asthenosphere partial melting; Lithosphere melt percolation
An ultra-slow spreading ridge class has been recently established on the basis
of the investigations of the South-West Indian and Arctic Ridges. It is
characterized by intermittent volcanism and continuous sea-floor mantle
emplacement over large regions, whereas the spreading rate is approximately
lower than 20 mm yr -1 (Dick et al. 2003, and references therein). Distinctive
petrologic features of ultra-slow spreading ridges are: (1) the relative
abundance of mildly enriched or alkaline basalts, related to melting of
garnet-eclogite or veined mantle sources, (2) the strong compositional
variability of mantle peridotites, related to interaction with percolating melts
(e.g. Hellebrand et al., 2006; von der Handt et al., 2006).
Ophiolites derived from the Jurassic Ligurian Tethys show major structural and
petrologic characteristics (i.e. mantle at the sea-floor and alternance of
volcanic and a-volcanic segments, coupled with abundance of strongly
heterogeneous peridotites and presence of alkaline melts) that allow to
interpret the Ligurian Tethys as a Jurassic analogue of modern ultra-slow
spreading oceans (Piccardo, 2007, and references therein).
A conceptual model for the tectonic evolution of magma-poor rifted margins
have been proposed by Lavier & Manatschal (2006), mostly based on the
behaviour of the crust [i.e. (1) stretching and (2) thinning modes]. Exhumation
of the lithospheric mantle is referred to the last (3) exhumation mode, and
mantle serpentinization is believed to be the key mechanism to allow for
mantle thinning and exhumation, in the absence of magmatic activity to
weaken the lithosphere.
Present knowledge on Alpine-Apennine ophiolitic peridotites document that
mantle lithosphere stretching and break-up were accomodated by
inter-dependent tectonic and magmatic processes. In fact, during the
pre-oceanic rifting stages of the basin: (1) lithosphere extension caused
deformation and tectonic-metamorphic evolution of the subcontinental mantle,
starting from spinel-facies conditions, which were relevant to lithosphere
thinning and subsolidus exhumation of the lithospheric mantle; (2) lithosphere
stretching caused adiabatic upwelling and decompression melting of the
underlying asthenosphere; (3) asthenospheric melts migrated through the
extending mantle lithosphere; (4) heating by asthenosphere upwelling and
reactive melt percolation caused the thermo-chemical erosion of the mantle
lithosphere, which was relevant to weaken the mantle lithosphere and to
enhance the transition from distributed continental deformation to localised
oceanic spreading (Piccardo, 2007; and references therein).
Mantle petrology was significantly different at the different palaeogeographic
settings of the Ligurian Tethys, from the ocean-continent transition (OCT)
zones to the more internal oceanic (MIO) settings. Across-axis variation of
mantle petrology evidences the different evolution stages of the basin: (1) The
rifting (continental) stage, characterized by subsolidus evolution of the
sub-continental lithospheric mantle, which is recorded by the exhumed
subcontinental peridotites cropping out at the ocean-continent transition (OCT)
zones; (2) The drifting state, characterized by appearance of MORB melts in
the extending lithospheric mantle (i.e. asthenosphere decompression melting
and lithosphere melt percolation), which is recorded by the percolated
subcontinental peridotites cropping out at more internal oceanic (MIO)
settings; (3) The spreading (oceanic) stage, characterized by sea-floor
emplacement of refractory peridotites, cogenetic with the Jurassic MORB melts.
Dick, H.J.B., Lin, J. & Schouten, H. 2003.. Nature, 426, 405-412.
Hellebrand, E., Snow, J.E., Dick, H.J.B. & von der Handt, A. 2006a. Ofioliti,
31(1), 235.
Lavier, L.L. & Manatschal, G. 2006. Nature, 440, 324-328.
Piccardo, G.B., 2007. Geol. Soc. London, Special Pubblications (in press)
von der Handt, A., Snow, E.J. & Hellebrand, E., 2006. Ofioliti, 31(1), 248-249.
W03-45 Orale
Powell, William
GEOCHEMICAL FINGERPRINTING: VARIATIONS IN LITHOSPHERIC
MANTLE SIGNATURES WITHIN AND BETWEEN TERRANES
POWELL William 1, O'REILLY Suzanne Y. 1
1 - GEMOC - MACQUARIE UNIVERSITY
Key terms: Mantle metasomatism; Lithospheric mantle composition; Mantle
peridotite; Re-Os isotopes
Geochemical signatures in mantle xenoliths reflect a range of processes
including initial formation, melting history, and the type and extent of
metasomatic processes affecting a specific mantle volume. Geochemical
signatures may vary both within and between domains of different tectonic
style mapped in the overlying crust, and between lithospheric sections affected
by different geodynamic regimes. Detection and recognition of geochemical
signatures in mantle samples, including whole-rock and mineral major,
trace-element and isotopic chemistry is an essential part of unravelling the
history of different mantle processes through time on a variety of scales.
A suite of mantle xenoliths from the easternmost structural element of central
eastern Australia (the New England Orogen) has been studied in order to
characterise the composition, architecture and evolution of sub-continental
lithospheric mantle underlying the region. The New England Orogen represents
a Palaeozoic-Early Mesozoic convergent margin setting, and is typically divided
into two crustal domains separated by a fault system and delineated by a
serpentinite belt, interpreted to represent the suture along which subduction
WORKSHOP W03
took place. The eastern domain is considered to represent a microcontinent
accreted to the Australian margin during subduction, and the western domain
consists of continental shelf material inboard of the subduction zone.
Mantle-derived peridotite xenoliths from six widely spaced localities across the
orogen have been used to help understand the composition, architecture and
evolution of sub-continental lithospheric mantle beneath the region, to assess
regional mantle heterogeneity, and to determine if there are systematic
differences in the lithospheric mantle underlying the two crustal domains.
Geochemical signatures of clinopyroxenes in the xenoliths indicate variations in
the melting history and the type and extent of metasomatism in the
lithospheric mantle both within and between the two crustal domains. Xenoliths
from one locality in the western domain can be divided into two groups
showing distinctly different metasomatic characteristics - one has been
metasomatised by a dominantly silicate agent, the other a carbonatitic agent.
Samples from another locality < 80 km distant, also in the western domain,
have clinopyroxene trace-element signatures indicating progressive
chromatographic metasomatism by an evolving silicate fluid at low fluid-rock
ratios. The presence of amphibole in xenoliths from a third locality (~200 km
away, in the eastern domain) provides evidence for modal metasomatism. In
these samples, amphibole is a significant 'other' host phase for many
trace-elements (other than clinopyroxene), allowing the bulk rock to contain
higher concentrations of (for example) high field-strength elements than the
amphibole-free mantle wall-rock peridotites, and affecting the geochemical
signature of the coexisting clinopyroxene due to its strong partitioning of
certain elements.
In situ and whole-rock Re-Os isotopic data have been used to provide age
constraints on the New England sub continental lithospheric mantle. Rhenium
depletion model ages based on in situ analysis of sulfide grains suggest
different localities have different age signatures, and show that lithospheric
mantle beneath the New England region contains material of at least
Proterozoic age. Comparisons between whole-rock and sulfide in situ Re-Os
data show that multiple populations of sulfides may be present in a given
sample, and consequently, that whole-rock Re-Os data represent a mixture of
these populations and must be regarded as giving only minimum age
constraints.
W03-46 Orale
Puga Rodriguez, Encarnacion
NEW FINDINGS OF LAMPROPHYRIC ACTIVITY WITHIN THE SUBBETIC
ZONE OF THE BETIC CORDILLERA AS EVIDENCED BY DRILLINGS IN
THE CERRO PRIETO LOCALITY
PUGA RODRIGUEZ Encarnacion 1, BECCALUVA Luigi 2, BIANCHINI Gianluca 2,
DÍAZ PUGA Miguel Angel 3, GALINDO-ZALDÍVAR Jesús 4, A. DÍAZ DE FEDERICO
Antonio 1, WIJBRANS Jan 5
1 - Instituto Andaluz de Ciencias de la Tierra (CSIC-UGR)
2 - Università di Ferrara
3 - Universidad de Almeria
4 - Universidad de Granada
5 - Vrije Universiteit Amsterdam
Key terms: Lamprophyres; Mantle metasomatism; Ultramafic xenoliths; Betic
Cordilleras; Subbetic Zone
Two drillings in the Cerro Prieto locality (Málaga province) highlight the
existence of a magmatic body formed by rock-types previously unknown in the
Subbetic zone. This body, according to geophysical data, is formed by basic
rocks and have a lenticular form with about 200 m of lateral extension and 20
m of thickness.
The recovered rocks show a predominant porphyric texture, formed by olivine,
clinopyroxene and phlogopite phenocrysts, up to 1-2 mm in size, in a
microcrystalline to hypocrystalline groundmass composed by alkali-feldspar,
clinopyroxene, phlogopite and abundant magnetite. According to the observed
textures and modal composition, these rocks, emplaced in hypoabyssal
conditions, could be classified as potassic lamprophyres. Major element
composition reveals high-Mg (Mgv 0.67-0.70) trachybasaltic composition, with
Na2O/K2O ranging between 1.0 and 1.4. Primordial mantle normalized trace
element patterns are typical of intra-plate alkali-basalts, and closely approach
some of the Permian lamprophyres recognised in other parts of the Iberian
Peninsula (Villaseca et al., 2004; Perini et al., 2004). Their enrichment in the
most incompatible elements coupled with their low HREE contents (LuN=6-8.6)
suggest that these magmas were generated by low melting degree (< 10%) of
deep (garnet-bearing) highly metasomatized portions of the lithospheric
mantle.
Radiometric dating of these rocks is problematic, as Ar/Ar on phlogopite
separate indicate an age of 217 ± 2.5 Ma (with an MSWD value of 8.4),
whereas Ar/Ar and K/Ar dating of the groundmass gave a series of ages
ranging from 160 to 29 Ma, thus indicating that the Ar system has been
profoundly disturbed.
The Cerro Prieto lamprophyres contain numerous centimetric xenocrysts of
sericitized sodic plagioclase corroded by the magma, and centimetric xenoliths
formed by diopside aggregates. Millimetric inclusions of polycrystalline calcite
are also common. The latter display reactions with the host rock, with
formation of hydro-andradite garnet, diopside and phlogopite crystals.
It has to be noted that the same drillings also exhumed some enigmatic
lithotypes constituted by a prevalent carbonate matrix that surround some
millimetric crystals of mantle provenance such as Cr-spinel and Cr-diopside,
and scarce Opx, Ol, as well as corrensite and hydro-andradite. The
hypothesized pre-existence of garnet in these mantle parageneses is suggested
by the presence of rounded aggregates, up to one centimetre in diameter,
formed by symplectitic textures, consisting of an intimate association of
vermicular crystals of chromian spinel and pyroxenes. Similar symplectitic
intergrowths have been interpreted by different authors as the result of garnet
destabilization in mantle peridotites (Mercier & Nicolas, 1974; Piccardo et al.,
2004).
References
-Mercier J-C. C., Nicolas, A. (1975) Textures and fabrics of Upper-Mantle
peridotites as illustrated by xenoliths from basalts. Journal of Petrology 16, 2,
454-487.
- Perini G., Cebria J.M., Lopez-Ruiz J., Doblas M. (2004).
Carboniferous-Permian mafic volcanism in the variscan belt of Spain and
France: implication for mantle sources. In "Wilson et al. Eds.
19
Permo-Carboniferous Magmatism and Rifting in Europe. Geological Society,
London. Special Publication 223, 415-438.
- Piccardo G.B., Müntener O., Zanetti A., Romairone A., Bruzzone S., Poggi E.,
Spagnolo G. (2004) The Lanzo South peridotite: Melt/peridotite interaction in
the mantle lithosphere of the Jurassic Ligurian Tethys. Ofioliti 29, 1, 37-62.
-Villaseca, C., Orejana, D., Pin, Ch., López García, J.A., Andonaegui, P. (2004).
Le magmatisme basique hercynien et post-hercynien du Système central
espagnol : essai de caractérisation des sources mantelliques. Comptes Rendus
Geoscience 336, 877-888.
W03-47 Orale
Puziewicz, Jacek
MANTLE AND ERUPTIVE METASOMATISM OF PERIDOTITE XENOLITHS
BY HOST NEPHELINITE - AN EXAMPLE FROM KSIEGINKI (SW POLAND)
PUZIEWICZ Jacek 1, KOEPKE Jürgen 2
1 - UNIVERSITY OF WROCLAW, POLAND
2 - UNIVERSITY OF HANNOVER, GERMANY
Key terms: mantle xenoliths; SW Poland; phase relationships; metasomatism
The Lower Silesian part of the Central European Tertiary Volcanic Province in
SW Poland erupted basanites, nephelinites and basalts between 30 and 20 My
(Oligocene-Pliocene), forming ca. 300 isolated occurrences. Mantle xenoliths
are numerous in some places; they are mostly anhydrous (only one
amphibole-bearing xenolith locality has been documented). The Ksieginki
nephelinite contains the greatest abundance of mantle xenoliths in Lower
Silesia. Their sizes reach a few decimetres, and their compositions range from
dunites to websterites and clinopyroxenites.
The Ksieginki peridotites typically consist of protogranular olivine ±
orthopyroxene ± sparse clinopyroxene domains and interstitial clinopyroxene ±
spinel. Some xenoliths are deformed with reduced grain sizes and foliation due
to alternating layers a few mm thick showing different grain sizes. Droplets of
devitrified glass are common and glass pools a few mm in diameter occur in
some xenoliths.
The interstitial clinopyroxene consists usually of low-calcic cores (0.7-0.8
atoms Ca pfu) surrounded by thin, spongy rims of higher Ca (0.8-0.9 a pfu).
The spongy rims correspond compositionally to the cores of nephelinite
phenocrysts, suggesting that they originated due to contact between the
peridotite and nephelinite magma, concomitantly with crystallization of
clinopyroxene phenocrysts in the nephelinite. In some xenoliths the spongy rim
shows an overgrowth of even higher Ca (> 0.9 a pfu) clinopyroxene, identical
to that in the groundmass of the host nephelinite. Its appearance correlates
with a change of the crystallizing spinel phase from Mg-Al-Cr spinel to
magnetite-ulvöspinel. Therefore, the high-Ca overgrowths crystallized during or
after eruption of the nephelinite host. Only the low-Ca cores are remnants of
the mantle from before contact with nephelinite magma. Parts of peridotites
with significant spongy and high-Ca clinopyroxene are usually devoid of
orthopyroxene and contain low-Mg olivine (Fo86.0-88.6). Orthopyroxene, if
present, is slightly less magnesian and more aluminous (#mg = 0.89, Al 0.16 a
pfu, O2- = 6) relative to that in peridotites with more forsteritic olivine
(Fo89.5-92.0), characterized by #mg = 0.91 and 0.10 - 0.14 atoms Al pfu.
The cores of large olivine grains in protogranular domains contain 400 - 600
ppm Ca. Olivine which is recrystallized due to deformation contains 900 - 1100
ppm Ca. Small grains which originated contemporaneously with high-Ca
clinopyroxene contain 1400 - 2000 ppm of Ca, values typical for olivine
phenocrysts in the host nephelinite. The amount of Ca in olivine is not related
to its forsterite content. Cr/(Cr+Al) in spinel is very variable (0.24-0.62) and
positively correlated with forsterite content in associated olivine. Temperatures
of equilibration between ortho- and clinopyroxene (Brey and Köhler algorithm)
cluster around 1100 ºC.
The peridotites sampled by the Ksieginki volcano were affected by interaction
with nephelinite magma both at mantle depths and during eruption. At mantle
depths, this led to metasomatism, manifested by (1) lowering of Fo content in
olivine down to 86 %; (2) crystallization of spongy clinopyroxene rims enriched
in Ca and (3) enrichment of orthopyroxene and spinel in Al. During eruption
the peridotite xenoliths contained drops or small pools of melt, from which
interstitial low-pressure clinopyroxene crystallized. The mineral assemblages
older than the nephelinite interaction are preserved as protogranular domains
of low-Ca (<600 ppm) and high Fo (89.5-92.0) olivine, low-Ca clinopyroxene
and low-Al high-Mg orthopyroxene.
W03-48 Orale
Renac, Christophe
CHARACTERISATION OF THE METASOMATIC AGENT IN MANTLE
XENOLITHS FROM DEVES, MASSIF CENTRAL (FRANCE) USING COUPLED
IN-SITU TRACE- ELEMENT AND O, SR, ND ISOTOPIC COMPOSITIONS
RENAC Christophe 1, TOURON Stephanie 1, COTTIN Jean-Yves 1, O'REILLY
Suzanne Y. 2, GRIFFIN William L. 2
1 - Department of Geology-UMR 6524 "Magmas et Volcans", University of Jean
Monnet, Saint-Etienne Cedex, France
2 - GEMOC ARC National Key Centre, Earth and Planetary Sciences, Macquarie
University, Australia
Key terms: Mantlemetasomatism; Massif Central; In situ trace element; Stable
and radiogenic isotopes
Spinel lherzolites and harzburgites from Mont-Briançon and Marais de Limagne
in the Devès volcanic district display coarse-grained to porphyroclastic
microstructures and the modal content of volatile-bearing phases increases
with the degree of deformation. Clinopyroxene and/or spinel are partly or
totally reacted to amphibole. The coupled interpretations of traces, REE and
O-Sr-Nd data on clinopyroxene and amphibole indicate that the metasomatised
mantle beneath the Devès is a mixture of depleted and enriched mantle
associated with an alkaline, HFSE-poor, LREE-, U- and Th- rich compositions of
carbonate-rich silicate fluid/melt metasomatic agent. Oxygen isotopes and REE
data of clinopyroxene-amphibole pairs indicate an [La/Yb]N enrichment related
to an increasing metasomatic agent/rock ratios.
WORKSHOP W03
20
W03-49 Poster
Renna, Maria Rosaria
PETROGENESIS OF POST-VARISCAN OLIVINE-BEARING CUMULATES
AND ASSOCIATED BASALT DYKES FROM BOCCA DI TENDA (NORTHERN
CORSICA): IMPLICATIONS FOR MANTLE SOURCES
TRIBUZIO Riccardo 1, RENNA Maria Rosaria 1, DALLAI Luigi 2, BRAGA Roberto 3
1 - Dipartimento di Scienze della Terra, Università di Pavia
2 - C.N.R. - Istituto di Geoscienze e Georisorse, Unità di Pisa
3 - Dipartimento Scienze della Terra e Geologico Ambientali, Università di
Bologna
Key terms: Post-Variscan basic magmatism; Sardinia-Corsica batholith; mafic
cumulates; mineral trace element compositions; crustal contamination
The western European Variscides record a widespread intrusion of gabbroic
complexes at 300-275 Ma, associated with post-collisional lithosphere thinning.
In western-central Alps and northern Apennine, these post-Variscan gabbroic
complexes show the emplacement of mantle-derived melts at different
lithosphere levels, from the crust-mantle boundary (Hermann et al. 2001) to
the middle crust (Tribuzio et al. 1999). The intrusion of the basic melts was
commonly associated with a significant process of crustal contamination
(Voshage et al. 1990; Tribuzio et al. 1999), thus hampering to constrain
accurately the nature of their mantle sources. Nevertheless, on the basis of
trace element and isotope studies, some of these complexes provide evidence
for the involvement of MORB-type melts, derived from depleted mantle sources
(e.g. Voshage et al. 1990; Hermann et al. 2001; Montanini & Tribuzio 2001).
In the Sardinia-Corsica batholith, there are several gabbroic sequences, dated
at ~285 Ma, which were emplaced at rather shallow crustal levels (Cocherie et
al. 2005). There is still some uncertainty about the origin of the basic melts
that gave rise to these gabbroic sequences (cf. Tommasini et al. 1995;
Cocherie et al. 2005), as a comprehensive study determining the possible
chemical effects induced by the continental crust is lacking. We have thus
examined the gabbroic complex of Bocca di Tenda, cropping out in northern
Corsica. This complex intrudes a plutonic sequence made of
hornblende-bearing granitoids and is crosscut by basalt dykes with chilled
margins. Whole-rock chemical compositions indicate that the most primitive
Bocca di Tenda intrusives (i.e. the olivine-gabbronorites) are of cumulus origin.
They are mainly composed of olivine (Fo78-72) and plagioclase (An68-60), and
poikilitic clinopyroxene and orthopyroxene. Olivine-gabbronorites show nearly
homogeneous Nd isotope (initial Nd +2.5 to +1.4) and mineral trace element
compositions. In particular, clinopyroxene compositions indicate that the
parental melts of olivine-gabbronorites were LREE- and LILE-enriched relative
to N-MORB. The somewhat elevated 18O values (+6.3 0/00 to +6.7 0/00) of
pyroxene indicate that a substantial crustal contribution was involved in the
petrogenesis of these cumulates. The basalt dykes have initial Nd values and
clinopyroxene trace element compositions overlapping those of
olivine-gabbronorites, thus indicating that these two rock types formed by
mantle-derived magmas with similar compositions.
A comparison with the gabbroic complexes of Porto (western Corsica, Renna et
al. 2007) and Sondalo (central Alps, Tribuzio et al. 1999) was carried out.
Although the most primitive rocks of Bocca di Tenda, Porto and Sondalo
complexes record a process of crustal contamination, their geochemical
features indicate the intrusion of chemically similar basic melts in different
sectors of the original Europa-Adria lithosphere, at shallow to intermediate
crustal levels. We propose that the primary melts of these complexes were
derived from a slightly enriched mantle source, involving a significant
contribution from a plume-type or lithospheric component, thus implying that
the post-Variscan basic magmatism did not involve only typical depleted
mantle sources.
Cocherie A, Rossi P, Fanning CM, Guerrot C (2005) Lithos 82: 185-219
Hermann J, Müntener O, Günther D (2001) J Petrol 42: 189-206
Montanini A, Tribuzio R (2001) J Petrol 42: 2259-2277
Renna MR, Tribuzio R, Tiepolo M (2007) Contrib Mineral Petrol DOI:
10.1007/s00410-007-0205-9
Tommasini S, Poli G, Halliday AN (1995) J Petrol 36: 1305-1332
Tribuzio R, Thirlwall M F, Messiga B (1999). Contrib Mineral Petrol 136: 48-62
Voshage H, Hofmann AW, Mazzucchelli M, Rivalenti G, Sinigoi S, Raczek I,
Demarchi G (1990) Nature 347: 731-736
W03-50 Poster
Rocco, Ivana
PETROLOGY AND GEOCHEMISTRY OF ULTRAMAFIC XENOLITHS FROM
SARDINIA.
ROCCO Ivana 1, LUSTRINO Michele 2, MELLUSO Leone 1, MORRA Vincenzo 1
1 - Dipartimento di Scienze della Terra, Università degli studi di Napoli
"Federico II"
2 - Dipartimento di Scienze della Terra, Università degli studi di Roma "La
Sapienza"
Key terms: Mantle xenoliths; Sardinia; Clinopyroxenes
Mafic alkaline late Miocene-Quaternary volcanic rocks from Sardinia are often
associated with mantle-derived ultramafic xenoliths. They are lherzolites,
harzburgites and websterites with protogranular, porphyroclastic,
equigranular-mosaic and pyrometamorphic textures. Olivine content ranges
from ~50 to ~91%, orthopyroxene from ~6 ~45%, clinopyroxene from 0 to
~17% and spinel from 0 to ~8%. Pyrometamorphic glass enclosing secondary
(subhedral to euhedral) olivine, clinopyroxene, spinel and plagioclase microlites
has been found in a harzburgite and in a websterite-harzburgite composite
xenolith.
Secondary olivine (in glass) shows slightly higher Fo (Fo91-93) compared to
primary olivine (Fo89-90). Enstatite (Wo0.7-4.3En72.5-90.8Fs7-24.4) shows Mg# and Cr#
ranging from 75 to 93 and from 0.86 to 22, respectively, and sometimes is
characterized by clinopyroxene exolution lamellae. Clinopyroxene is diopside
(Wo38.7-51.3En41.4-52Fs4-10) and often occurs as small grains between larger forsterite
and enstatite, or as spongy-textured crystals (indicating incipient partial
melting) while the secondary clinopyroxene occurs as subhedral crystals in
pyrometamorphic glass; spinel occurs both as holly-leaf shaped (sometimes
with a darker rim indicating incipient partial melting) and as symplectitic
crystals; spinel Mg# and Cr# range from 64 to 84 and from 6 to 61,
respectively. Orthopyroxene shows a large compositional range in the
websterite-harzburgite composite xenolith from Gerrei: FeO ranging from 6.50
to 7.38 wt.% in harzburgite, while clustering around 14 wt.% in websterite.
MgO content ranges from ~24 wt.% in websterite to ~32 wt.% in harzburgite.
Clinopyroxene shows two main patterns in primitive mantle-normalized
diagrams: the first (found in large clinopyroxenes in a lherzolite from
Logudoro) is incompatible elements-depleted (IED; LaN <0.25 times PM), the
second type is incompatible elements-enriched (IEE; LaN >3.3 times PM). This
latter group partially overlaps the composition of the mantle clinopyroxenes of
Sardinia described by Beccaluva et al. (2001). All lherzolite clinopyroxenes
shows a positive anomaly at Eu. The (La/Yb)N ratio ranges from 0.008 to 0.08
for lherzolites IED clinopyroxenes, from 0.74 to 5.5 for lherzolites IEE
clinopyroxenes, from 0.15 to 0.3 for secondary clinopyroxenes in glass of
harzburgites, and from 3.1 to 6.5 in websterite clinopyroxenes.
Pyrometamorphic glasses in harzburgites show a basaltic andesite composition,
while glasses of websterites show a basaltic composition. The glass in
harzburgite and in websterite have a similar composition to "LKT" and "HKT"
glasses described by Lustrino et al. (1999) in mantle xenoliths from the same
area (Gerrei), respectively. Primitive mantle-normalized REE patterns of
pyrometamorphic glasses show a LREE enrichment (LaN=5-20 times PM in
harzburgites and 60-130 times PM in websterites) Both glasses in harzburgites
and in websterites show a positive peak at Sr and Ti. Glasses in websterites
show many geochemical similarities with host rock composition: this is
consistent with an origin of the glass as consequence of infiltration of host
magma in the xenolith.
Primitive mantle-normalized diagrams of host basalt and liquids in equilibrium
with primary clinopyroxenes (calculated on the basis of literature KDs) show
that melts in equilibrium with IEE-clinopyroxenes (excluding the samples with a
positive peak at Zr) match the geochemical composition of the host basalt,
while the melts in equilibrium with IED-clinopyroxenes match the composition
of N-MORB melts.
The temperatures of these nodules range from 900 (eastern Sardinia) to 1200
°C (western Sardinia) and the pressure estimates cluster around 10-11 kbar,
corresponding to 35-40 km in depth, just below the Moho discontinuity which is
found 30 km depth in Sardinia.
W03-51 Orale
Scambelluri, Marco
OROGENIC GARNET PERIDOTITES AS TRACERS OF MANTLE WEDGE
TRANSFORMATIONS AND METASOMATISM BY SUBDUCTION FLUIDS
SCAMBELLURI Marco 1, HERMAN Joerg 2, MORTEN Lauro 3, PETTKE Thomas 4,
RAMPONE Elisabetta 1, VAN ROERMUND Hlm 5
1 - Dipartimento per lo Studio del Territorio e delle sue Risorse, Università di
Genova, Italy
2 - Research School of Earth Sciences, Australian National University,
Canberra, Australia
3 - Dipartimento di Scienze della Terra, Università di Bologna, Italy
4 - Institute of Geological Sciences University of Bern, Switzerland
5 - Faculty of Earth Sciences, University of Utrecht, Netherlands
Key terms: Subduction metasomatism; Garnet peridotites; fluids
At subduction zones, the fluid phase released by the dehydrating subducting
plates is the viable agent for slab-to-mantle element transfer, mantle
metasomatism and melting. So far, much work has been focussed on the slabs
and still few are the observations of mantle wedge peridotites, which are the
least known pieces of the subduction factory. For this purpose, information can
be gained by the study of orogenic garnet peridotites which, in several
occurrences, are slices of mantle wedge tectonically sampled by the subducted
continental slabs and which disclose the physical and chemical changes
affecting the mantle in a 100-200 km depth range. Here we show that orogenic
garnet peridotites record influx of incompatible element-rich fluid phases
sourced from the continental crust. A key case-study is represented by the
Ulten Zone (Italian Eastern Alps) peridotite bodies, enclosed in Variscan
high-pressure migmatites and recording transformation of porphyroclastic
spinel peridotites (T=1200 °C; P=1.5 GPa) into fine-grained garnet +
amphibole peridotites (T=850 °C; P=3 GPa). This occurred in response to
corner-flow inside a mantle wedge and to slicing of the wedge peridotites into a
subducted continental slab. In this frame, the garnet + amphibole peridotites
fromed by fluid phase infiltration once the wedge peridotites became close to
the subducting slab. However, the spinel and the garnet + amphibole
peridotites show similar LREE, LILE and light element- enriched signatures,
which imply the recycling of crustal components in various wedge domains. The
garnet + amphibole peridotites display high LILE-HFSE fractionation (cpx Pb/Nb
from 391 to 443), and variable LILE and LREE enrichments, clearly reflecting
addition of a crustal component to formerly depleted mantle rocks. The coupled
increase of water and incompatible elements in the garnet + amphibole
peridotites indicate that metasomatism was caused by crust-derived aqueous
fluids. Since crustal rocks were undergoing high-pressure partial melting, a
mechanism to extract water from hydrous granitic melts must be envisaged.
The ultradeep garnet peridotites and websterites from the Western Gneiss
Region of Norway record an old stage of upwelling and accretion to a cratonic
lithosphere of depleted Archean transition-zone mantle (350 km depth). This
ultradeep mantle was involved in a 430 Ma-old Scandian subduction causing
formation of a new clinopyroxene + orthopyroxene + phlogopite + garnet +
spinel + carbonate assemblage hosting microdiamond inclusions precipitated
by circulating fluids. New observations show that majoritic garnet was
precipitated at grain boundaries and in microveins at 7 Gpa and 900-100 °C by
COH silicate fluids during the Scandian subduction. The trace element patterns
of the UHP subduction minerals are significantly incompatible
element-enriched: the main repository being phlogopite. These features
indicate an influx of crust-derived fluid phases at diamond- to majorite-facies
conditions. The UHP cpx stable with majorite has trace element patterns well
comparable with those of cpx from the lower pressure Ulten Zone garnet +
amphibole peridotites. Although preliminary, this comparison shows that
mantle re-fertilization by subduction of continental crust is an effective
mechanism working on a large depth range. Despite partial melting processes
in the crust, fluids appear as the major mobile agents for mantle wedge
WORKSHOP W03
metasomatism close to subducting slabs over a 100-200 km interval.
W03-52 Poster
Shumlyanskyy, Leonid
AGE OF THE LITHOSPHERIC SOURCE OF THE VENDIAN FLOOD BASALTS
OF THE VOLYN REGION, SOUTH-WESTERN EAST-EUROPEAN CRATON
SHUMLYANSKYY Leonid 1, NOSOVA Anna 2, PER-GUNNAR Andreasson 3
1 - Institute of geochemistry, mineralogy and ore formation of the National
Academy of Sciences of Ukraine, Kyiv, Ukraine
2 - Institute of geology of ore deposits, petrography, mineralogy and
geochemistry of the Russian Academy of Sciences, Moscow, Russia
3 - Lund University, Lund, Sweden
Key terms: Continental flood basalts; Volyn region; Rodinia break-up; zircon;
Nd isotopic composition
A large volume of data regarding the age of flood basalts of the Volyn region
(north-western part of Ukraine, south-western Belarus and eastern Poland)
now exists, including results from SIMS analysis of zircons isolated from
basalts and tuffs, as well as whole-rock Rb-Sr-isochron results. The bulk of the
data suggests an age of formation of the volcanogenic sequence at ca. 550 Ma.
Nd isotopic compositions were recorded from a number of samples that
represent a wide range of rocks from basalts to rhyolite and dacite. Volynian
basalts are rather evolved (#Mg = 0,35 - 0,54) and evidently do not represent
primary mantle-plume related melt. Instead, they carry geochemical evidences
of substantial lithospheric, predominantly lower crustal, contamination. With
respect to Nd and Sr isotopic compositions, the evidence includes
predominantly negative values of Nd550 and high positive values of Sr550. Nd
model ages according to depleted mantle (DM) model vary from 2050 to 1090
Ma. There are two prominent spikes on the histogram of DM model age
distribution at 2000 and 1500-1700 Ma. Zircons separated from Volynian
basalts revealed a wide spectra of 206Pb/ 207Pb ages that can be subdivided into
four groups: (1) ca. 2000 Ma, corresponding to the age of the
Osnitsk-Mikashevichi igneous belt and a very common orogenic event in the
Ukrainian shield; (2) ca. 1820 Ma, coinciding with age of the Belarus-Baltic
granulite belt; (3) ca. 1470 Ma. Rocks of this age are unknown so far in this
region; however, rocks of similar age are rather widely distributed in the
western part of the East-European platform (EEP); (4) "Volynian" 549 ± 29 Ma
old zircons that date the flood basalt event. The first three groups of zircons
are apparently inherited from various crust/lithospheric sources by
contamination with the basaltic melt. There is a good correspondence between
whole-rock Nd DM model ages and 206Pb/207Pb zircon ages. Both embrace
the same time interval while main Nd model age spikes are 100-150 Ma older
than main zircon ages. We believe this is due to the different characters of the
whole rock Nd model ages and zircon ages - while the former correspond to the
time of separation of material from the mantle, the latter date crust-forming
processes. Meanwhile there is a good correspondence between zircon ages and
ages of main crust-forming events in the south-western part of the EEP (i.e.
the formation of the Osnitsk-Mikashevichi Igneous and Belarus-Baltic granulite
belts and widespread magmatism in the western EEP). Such correspondence
suggests significant addition of lower-crustal and probably upper mantle
(lithospheric) material to parental basalt melts. The plume source was
relatively suppressed probably by the large thickness and low permeability of
the lithosphere. However, the role of the plume component increased during
the latest stages of the Volynian flood basalt event when high-Ti basalts
formed. Their trace element patterns and Nd isotopic compositions approach
values typical for OIB that may be related to break-up of the lithospheric plate
that occurred already during the outpouring of high-Ti basalts. The ca.
1200-1400 Ma component of the lithospheric source of the Volynian flood
basalts is so far unknown in the basement underlying the Volynian province.
However, such material is rather abundant to the north-west of the province
and may testify to the location of the plume's centre not immediately below the
Volynian flood basalt province, but further to the north-west. From there, melts
spread south-eastward along the Trans-European Suture Zone that defines the
western boundary of the EEP. The zone itself represented one of the shoulders
of the classical rift system that developed in western (in modern coordinates)
Rodinia and led to its break-up into three continents - Baltica, Laurentia and
Amazonia. The triple point was located nearby present-day Scotland while the
Trans-European Suture Zone experienced gradual opening in a south-easterly
direction.
W03-53 Poster
Tabor, Bryan Ernest
QUANTITATIVE TEXTURE ASSESSMENT OF MANTLE XENOLITHS
TABOR Bryan Ernest 1, TABOR Felicity A. 1, DOWNES Hilary 1
1 - SCHOOL OF EARTH SCIENCES, BIRKBECK, UNIVERSITY OF LONDON,
MALET STREET, LONDON WC1E 7HX, UK
Key terms: Xenolith; Texture; Quantitative
A method for the quantitative characterization of grain size, as observed in
petrological thin-sections, has been established on the basis of a set of spinel
lherzolite xenoliths from the French Massif Central. The method makes use of
whole, or large area, optical scanning of the thin-section, skeletonization of the
mineral identity outlines and computerised measurement of the individual grain
section areas.
The method has now been extended to xenolith materials from other locations
and the results obtained are consistent with the linear plot of arithmetic mean
against additive standard deviation obtained with the original study. This all
suggests that xenoliths of different overall textures tend to form a continuous
series from coarse "protogranular" to fine grained "equigranular", rather than
discrete qualitatively assessed groups that have some times been implied on
the basis of the original Mercier and Nicolas designations (1975).
The statistical significance and character of grain-size distributions observed
has been explored both in relation to their description and possible mechanistic
origin. The variance of the measured samples has been examined in relation to
size and number of grain areas examined. The variation within samples has
been explored using multiple and orthogonal sections cut from several
21
xenoliths, which were of sufficient size to make this possible. These results are
consistent with the observed linear relationship although some xenoliths show
differences in grain size distribution between orthogonal sections.
By direct measurement and comparison of cumulative number and area
distribution curves, it can be seen that the often quoted qualitatively assessed
"typical" grain sizes tend to be influenced by a small number of the larger grain
areas. Our method therefore provides an objective standard for the
classification of xenolith textures.
Although the use of the additive (arithmetic) mean and standard deviation
provide a convenient means for correlation, in practice the distributions are
best described by lognormal functions with multiplicative (geometric)
parameters, for which there are mechanistic theoretical derivations. Linear
log-probability curves again support the idea of continuous series rather than
bi-modal distributions that have sometimes been implied for some
"porphyroclastic" xenoliths.
W03-54 Orale
Tóth, Attila
EVOLUTION OF LITHOSPHERE BENEATH THE EASTERN
TRANSYLVANIAN BASIN (CARPATHIAN-PANNONIAN REGION):
IMPRINT IN GARNET PYROXENITE XENOLITHS
TÓTH Attila 1, DOBOSI Gábor 2, BALI Eniko 3, DOWNES Hilary 4, SZABÓ Csaba 1,
NTAFLOS Theodoros 5
1 - Lithosphere Fluid Research Lab, Eötvös University Budapest, Hungary
2 - Hungarian Academy of Science, Institute for Geochemical Research,
Hungary
3 - Bayerisches Geoinstitut, Universität Bayeruth, Germany
4 - School of Earth Sciences, Birkbeck College, University of London, U.K.
5 - Department of Petrology, Geozentrum, Universität Wien, Austria
Key terms: garnet pyroxenite xenoliths; symplectite; lithospheric upwelling;
Transylvanian Basin; Carpathian-Pannonian Region
Ultramafic xenoliths hosted in the Neogene-Quaternary alkaline basalts of the
Carpathian-Pannonian Region (CPR) have already been studied by several
authors (e.g., Szabó et al., 2004), however most of these xenoliths are
lithologically peridotites. Vaselli et al. (1995) have reported garnet pyroxenite
xenoliths from the Eastern Transylvanian Basin (ETB) but none of them have
carried out a detailed study on these rocks. The Perºani Mts are situated in the
ETB, which is the easternmost Plio-Pleistocene alkaline basaltic volcanic field in
the CPR and is nearby to the East Carpathian subduction zone.
Pyroxenite xenoliths are composed of orthopyroxene (opx), clinopyroxene
(cpx), garnet (grt) ± spinel (spl). The studied xenoliths have been identified as
garnet websterites and one garnet clinopyroxenite. Garnet websterites have
deformation features such as porphyroclastic texture; cracks, sub-grain
formation and exolution lamellae in ortho- and clinopyroxene, whereas the
garnet clinopyroxenite has cumulate texture. In each xenolith garnets are
surrounded by different generations of symplectites composed of
opx+cpx+spl±plagioclase (plg).
Symplectite type-I is situated furthest from the garnet, and could be observed
only in garnet websterites. In these symplectites the pyroxene grains are
rounded and have a size between 200-500 m, the spinels have vermicular,
rounded to euhedral shape. This is the oldest symplectite generation.
Symplectite type-2 is situated between the outer smp1 and the garnet.The
shape of the pyroxene grains in this generation is vermicular and they contain
vermicular spinel inclusions. The size of the grains of smp2 ranges between
20-200 m. These vermicular grains are perpendicular to the garnet surface.
Symplectite type-3 is situated along the cracks in the garnets and at the
margin of the garnets. This type forms ~100 m thick bands with fibrous
textured. Symplectites have not usually consumed more than 10% of the
garnet.
The primitive mantle normalized REE-patterns of bulk xenoliths are similar to
that of N-MORB with slight depletion in LREE and elevated HREE concentration.
Our model calculations suggest that the melt from which the garnet
pyroxenites crystallized were generated by a > 5% partial melting of garnet
peridotite source. In contrast, the host alkaline basalts could have formed by a
1-3% partial melting of a similar source rock. Such high degree (>5%) partial
melting is characteristic for rifting environments, which is consistent with the
MORB-like trace element character of the bulk xenoliths.
Based on the composition of rock forming minerals and the widely accepted
phase equilibria for pyroxenites, we can estimate the formation conditions of
the studied rocks. The estimated equilibrium P-T range is 1.4-1.7 GPa and
1030-1140°C. The obtained P and T reflect that the rocks formed at 45-50 km
depth.
References:
Falus et al. (2000): Terra Nova, 12, 295-302.
Szabó et al. (2004): Tectonophysics. 393, 119-137.
Vaselli et al. (1995): J. Petrol., 36, 23-55.
The presence of the different symplectite generations suggests a multistage
evolution of the studied mantle section. The chemical composition of the three
different symplectite types reveals significant Na- and Ba- and slight
LREE-enrichment compared to the unaltered garnet composition. This indicates
that the symplectite formation happened in an open system. Those
symplectites that contain only opx+cpx+spl were formed at a depth of 40-45
km in equilibrium with cpx, opx, spl in the surrounded area of the whole rock.
Whereas, the opx+cpx+spl+plg-bearing symplectites formed in the plagioclase
stability field, at around 30-40 km depth.
Based on the formation depth of the garnet pyroxenites and the presence of
plagioclase in the symplectites, we estimated that the upwelling of the studied
mantle segment was approx. 15-20 km. It is in agreement with results of Falus
et al. (2000) who proposed ~50-60 km upwelling for the astenopheric mantle
beneath the studied area.
W03-55 Orale
Upton, Brian G. J.
WORKSHOP W03
22
PETROLOGY OF THE SUB-SCOTTISH LITHOSPHERE
UPTON Brian G. J. 1
1 - School of GeoSciences, University of Edinburgh, U.K.
Key terms: Mantle metasomatism; Scotland; Lithospheric mantle;
Carboniferous and Permian volcanism
The Scottish terranes have had complex evolutions as a result of their
proximity to active continental plate margins. Knowledge of their lithospheric
constitution accrues from seismological and xenolith studies. Since the
xenoliths were entrained by silica-poor mafic magmas in the Carboniferous and
Permian, the compositional data generally concern the lithosphere as it was in
the late Palaeozoic. The lithospheric thickness is inferentially 70-80 km thick,
of which the lower half is held to be composed principally of protogranular to
porphyroclastic spinel lherzolite, with subordinate amounts of other rock types
including garnet pyroxenite. Olivines in the lherzolites range Fo91.6 - 87,
typically ~Fo89. Cr# values, (100.Cr/(Al + Cr)), for the spinels are mainly less
than 16 but range up to ~ 60.
'Pyroxenitic' xenoliths (wehrlites, olivine pyroxenites, websterites,
orthopyroxenites, clinopyroxenites, biotite- and pargasite-pyroxenites) are
inferred to have originated as cumulates from underplated basaltic magmas:
their very wide textural and compositional variety suggests that they come
from an ultramafic layer of substantial thickness (several km?) overlying the
peridotitic mantle. This hypothetical layer comprises less magnesian ultramafic
rocks typified by aluminous pyroxenes and hercynitic spinels. Where olivines
occur, they are typically in the range Fo87-72. Whereas ages may vary from
Proterozoic to Palaeozoic, textures in some imply contemporaneity with their
host magmas.
Apart from an inferred discontinuity between the mantle peridotites and
pyroxenitic cumulates, a second, relatively abrupt, discontinuity is deduced,
indicated by the appearance of meta-gabbroic and dioritic rocks containing
abundant plagioclase. Such rocks ('basic granulites') are also believed to be of
cumulate origin, and to be broadly cogenetic with the ultramafic cumulates. All
the lower crustal cumulates are regarded as products of repetitive underplating
events that utilised the density break represented by the incoming of
plagioclase. These two discontinuities may define petrological and seismic
Mohorovicic Discontinuities respectively.
High-temperature alkali feldspar (commonly anorthoclase) occurs with Fe-rich
clinopyroxene, biotite, magnetite, apatite and zircon as megacrysts, composite
megacrysts and (rare) salic xenoliths. Some peraluminous associations, as
indicated by the presence of corundum (sapphire), are also distinguished by
their enrichment in LREE, Y, Nb, Th, and other incompatible elements.
Crystallisation of these highly evolved megacryst suites appears to have been
contemporaneous with the host magmatism. The megacryst protoliths are
inferred to be pegmatitic salic sheets in the shallow mantle and deepest crust.
Whilst their petrogenesis remains enigmatic, such sheets may represent
aggregations of the volatile-rich, salic 'melt pockets', reported globally within
spinel lherzolite xenoliths.
W03-56 Orale
Wilson, Marjorie
TERTIARY-QUATERNARY MAGMATISM IN EUROPE: HOW HAS IT
INFLUENCED OR BEEN INFLUENCED BY THE EVOLUTION OF THE
LITHOSPHEREWILSON Marjorie 1
1 - School of Earth & Environment, Leeds University
Key terms: basalt; lithosphere; Cenozoic; geodynamics
Within-plate (anorogenic) magmatism was widespread in Europe and the
Mediterranean region from early Tertiary to Recent times; contemporaneous
magmatic activity also occurs in north Africa. There is a spatial and temporal
association with Alpine-Pyrenean collisional tectonics, the development of
lithospheric rift systems and, locally, with uplift of Variscan basement massifs
(e.g. Massif Central, Rhenish Massif, Bohemian Massif). Magmatism locally
post-dates an earlier phase of subduction-related magmatism within the
Mediterranean region, the Dinarides, the Pannonian Basin and Bulgaria. There
appears to be a complex relationship between extensional tectonics and the
presence of discontinuities in lithospheric thickness between adjacent terrane
blocks (e.g. Massif Central, Rhenish Massif); extension of heterogeneous
lithosphere, consisting of a collage of accreted Variscan terranes, might have
induced localised convective instabilities in the upper mantle and resultant
decompression melting. Wilson & Downes (2006) and Lustrino & Wilson (2007)
have recently provided comprehensive reviews of the geochemical
characteristics, petrogenesis and geodynamic setting of the magmatism.
In order to understand the processes which have caused both enrichment and
depletion of the European lithospheric mantle during the Phanerozoic we need
to understand the petrogenesis of the Tertiary-Quaternary magmas - in
particular the relative roles of lithospheric and asthenospheric mantle source
components. The major and trace element and Sr-Nd-Pb isotope characteristics
of the most primitive mafic magmatic rocks (MgO > 6 wt %) provide important
constraints on the nature of the mantle source and the conditions of partial
melting. These are predominantly sodic magma types (melilitites, nephelinites,
basanites and alkali olivine basalts); however, locally, potassic magmas (olivine
leucitites, leucite nephelinites) also occur. In several localities (e.g., Sicily;
Vogelsberg and the Rhine Graben, Germany; Calatrava, central Spain) olivineand quartz-tholeiites form a significant component of the magmatism. The
sodic magmas were derived by variable degrees of partial melting (~ 0.5 - 5
%) within a transitional zone between garnet-peridotite and spinel-peridotite
mantle facies, close to the base of the lithosphere. The potassic magma types
are interpreted as partial melts of enriched domains within the lithospheric
mantle; these enriched domains could have originated in supra-subduction
zone tectonic settings during the Hercynian orogeny (~ 300 Ma).
The distribution of the major volcanic provinces within Europe is broadly
anti-correlated with the location of a zone of high-velocity, presumed
subducted slab material, in the base of the upper mantle (500-600 km depth).
Many of the major volcanic fields are located around the periphery of this
velocity anomaly, coincident with the distribution of finger-like slow velocity
anomalies in the upper mantle (imaged by local seismic tomography
experiments). These anomalies could be a dynamic response to subduction and
slab detachment during the Alpine collision ("splash" plumes). Many authors
have proposed that they are thermally anomalous "hotspots" or plumes,
100-150 °C hotter than ambient upper mantle; however the absence of any
evidence for a positive thermal anomaly at Transition Zone depths (400- 600
km) argues against this. An alternative explanation for the "diapirs" is that they
are the products of localised fluid streaming from the top of the Transition
Zone.
References
WILSON, M. & DOWNES, H. (2006) Tertiary-Quaternary intra-plate magmatism
in Europe and its relationship to mantle dynamics. In: Gee, D. & Stephenson,
R. (eds.) Geological Society, London, Memoirs 32, pp 147-166.
LUSTRINO, M. & WILSON, M. (2007) The Circum-Mediterranean anorogenic
Cenozoic igneous province. Earth Science Reviews 81: 1-65.
W03-57 Orale
Witt-Eickschen, Gudrun
THE THERMAL AND GEOCHEMICAL EVOLUTION OF THE LITHOSPHERIC
MANTLE BENEATH THE EIFEL (GERMANY): CONSTRAINTS FROM
MANTLE XENOLITHS, A REVIEW
WITT-EICKSCHEN Gudrun 1
1 - UNIVERSITAT KOLN
Key terms: Eifel mantle lithosphere; Mantle xenoliths; Mantle metasomatism
Different seismological models suggest the presence of a small-scale (50-60
km radius) low-velocity anomaly beneath the West Eifel extending from a
depth of about 50-60 km in the shallow upper mantle down to the 410 km
transition zone. The seismic anomaly is interpreted as an upper mantle plume,
which may serve as the prototype of a moderately weak hotspot in a
continental environment (Ritter & Christensen, 2007).
Spinel peridotite xenoliths entrained in Cenozoic mafic alkaline magmas provide
insights into the thermal, dynamic, and geochemical evolution of the shallow
part of the lithospheric mantle beneath the Eifel. The mantle xenoliths
equilibrated at depths from about 30 km down to 80 km and reflect conditions
of at least three distinct thermal evolutions: (1) Well-equilibrated,
coarse-grained and equigranular recrystallized spinel peridotites plot along a
80-90 mWm-2 conductive model steady-state geotherm. The xenoliths from
the 80 km depth range approach the adiabatic upwelling curve of
asthenosphere and may reflect a young convective heat transport at the base
of the lithosphere. (2) Porphyroclastic xenoliths from shallow depths (~30 km)
record a long-term (50 to 130 Ma) cooling in strong conjunction with a
deformation process. Evidence for a re-heating of these xenoliths is totally
lacking. Hence, a Tertiary to recent conductive heat transport into this shallow
part of the lithospheric mantle near to the crust/mantle boundary can be
excluded. (3) Zoning patterns in pyroxenes recognized in some xenoliths from
mantle depths of about 40-50 km point to rapid (< 0.5 Ma) re-heating probably
as consequence of the Cenozoic volcanism.
Systematic changes in modal compositions with major element chemistry are
consistent with an origin of the spinel peridotite xenoliths as residues of partial
melting. The Re-Os and Sm-Nd isotope systematics of the xenoliths yield a
model age of ~1.6 Ga and ~2.0 Ga, respectively, for an ancient initial melt
extraction. Subsequently, the majority of the Eifel mantle xenoliths were
metasomatized by fluids from distinct mantle sources: (1) Volatile-rich fluids
from an isotopically enriched (EM-like) mantle reservoir caused amphibole
formation during deformation in the shallow upper mantle and generated trace
element patterns similar to those observed in island arc lavas. The fluids
appear to be associated with subduction processes under the Eifel in Paleozoic
time. (2) During a second phase the EM-like lithospheric mantle was affected
by melts from a HIMU-like mantle source. The HIMU-dominated xenoliths have
Pb isotope ratios even more radiogenic than in the uniform asthenospheric
source proposed for the Cenozoic European magmatism. Cretaceous Eifel lavas
show Sr-Nd-Pb isotope ratios nearly identical to these xenoliths. Thus, the
HIMU-like signature may be linked to reactivation of ancient subducted crustal
domains during early Cretaceous plume activity. (3) During a brief final stage
the heterogeneous enriched EM-HIMU subcontinental lithosphere was locally
modified by basaltic melts with isotopic signatures equivalent to the Tertiary
and Quaternary Eifel lavas. The melts migrated along fractures through the
upper mantle and generated magmatic pyroxenite and hornblendite veins as
well as small-scale compositional gradients in the peridotite wall rocks. Trace
element modelling of the zoning profiles shows that this event was rapid. Thus
this last stage of metasomatism is a consequence of the Cenozoic Eifel
volcanism.
Ref.: J.R.R. Ritter & U.R. Christensen (eds.) (2007): Mantle plumes; Springer
Verlag Berlin; ISBN-13 978-3-540-68045-1
W03-58 Orale
Wittig, Nadine
UTILISING "NEW" LITHOPHILE ISOTOPE SYSTEMS TO THEIR FULL
POTENTIAL: U-TH-PB AND LU-HF ISOTOPE TECHNIQUES IN
DECIPHERING MANTLE MELTING, METASOMATISM AND EXOGENEOUS
CONTAMINATION
WITTIG Nadine 1, DOWNES Hilary 2, BAKER Joel 3, PEARSON Graham 1
1 - DURHAM UNIVERSITY, UK
2 - UNIVERSITY OF LONDON, UK
3 - VICTORIA UNIVERSITY/WELLINGTON, NZ
Key terms: U-Th-Pb isotopes; Lu-Hf isotopes; French Massif Central; Hf model
ages
I explore the potential of Lu-Hf and U-Th-Pb isotope techniques in dating
mantle depletion events and subsequent metasomatic enrichment and present
a case study from the French Massif Central (FMC). In addition, we have
examined in some detail the role of late-stage geological and anthropogenic
grain-boundary contamination. For the recovery of pristine U-Th-Pb isotope
systematics in mantle minerals rigorous leaching protocols are required. Pb
isotope data available from the literature for SCLM clinopyroxene highlight that
WORKSHOP W03
the lack of unradiogenic 206Pb/ 204Pb (1st Pb paradox), scarcity of HIMU-like
SCLM and the alleged dominance of EM in continental roots, but these
observations may be reconciled if the present-day Pb isotope database of SCLM
contains samples that were insufficiently leached prior to digestion and thus
are contaminated by anthropogenic Pb.
The intraplate volcanic province of the FMC hosts one of the most extensively
studied peridotites xenoliths suites. Notably, there are distinct compositional
differences between the northern and southern parts of the FMC. The
continental roots beneath the northern FMC have clinopyroxenes with extreme
Lu/Hf ratios and ultra-radiogenic Hf ( Hf = +39.6 to +2586) that reflect
~15-25% partial melting in Variscan times (depleted mantle model ages ~360
Ma). Zr, Hf and Th abundances in these clinopyroxenes are low and unaffected
by hydrous/carbonatitic metasomatism that overprinted LILE and light REE
abundances and caused decoupling of Lu/Hf-Sm/Nd ratios and Nd-Hf isotopes (
Nd = +2.1 to +91.2). Pb isotopes of northern FMC clinopyroxenes are
radiogenic ( 206Pb/ 204Pb > 19), and typically more so than the host intraplate
volcanic rocks. 238U/ 204Pb ratios range from 17 to 68, and most samples have
distinctively low 232Th/ 238U (< 1) and 232Th/ 204Pb (3 to 22).
Clinopyroxenes from southern FMC lherzolites are generally marked by overall
incompatible trace element enrichment including Zr, Hf and Th abundances,
and have Pb isotopes that are similar to or less radiogenic than the host
volcanic rocks. Hf isotope ratios are less radiogenic ( Hf = +5.4 to +41.5)
than northern FMC mantle and have been overprinted by
silicate-melt-dominated metasomatism that affected this part of FMC mantle.
Major element and Lu concentrations of clinopyroxenes from southern FMC
harzburgites are broadly similar to northern FMC clinopyroxenes and suggest
they experienced similar degrees of melt extraction as northern FMC mantle. 238
U/ 204Pb (53 to 111) and 232Th/ 204Pb ratios (157 to 355) of enriched
clinopyroxenes from the southern FMC are extreme and significantly higher
than the intraplate volcanic rocks.
The extreme mantle 238U/ 204Pb (northern and southern FMC), 232Th/ 238U (northern
FMC) and 232Th/ 204Pb ratios (southern FMC), coupled with unremarkable
present-day Pb isotope ratios, constrain the timing of enrichment. Mantle
metasomatism is a young feature related to melting of the upwelling mantle
responsible for Cenozoic FMC volcanism, rather than subduction-related
metasomatism intimately associated with mantle depletion during the Variscan
orogeny. The varying metasomatic styles relate to pre-existing variations in the
thickness of the continental lithospheric lid, which controlled the extent to
which upwelling mantle could ascend and melt. In the northern FMC, a thicker
and more refractory lithospheric lid ( 80 km) only allowed incipient degrees of
melting resulting in fluid/carbonatitic metasomatism of the overlying
sub-continental lithospheric mantle. The thinner lithospheric lid of the southern
FMC ( 70 km) allowed larger degrees of melting and resulted in
silicate-melt-dominated metasomatism, and also focused the location of the
volcanic fields of the FMC above this region.
W03-59 Orale
Yoshikawa, Masako
P-T CONDITIONS, ND-SR ISOTOPIC COMPOSITIONS AND THE TIMING
OF METASOMATIZM RECORDED IN PERIDOTITE XENOLITHS OF FRENCH
MASSIF CENTRAL
YOSHIKAWA Masako 1, KAWAMOTO Kawamoto 1, YAMAMOTO Junji 1
1 - Institute for Geothermal Sciences, Graduate School of Science, Kyoto
University, Japan
Key terms: Peridotite xenoliths; Massif Central; Nd-Sr isotopic compositions;
Mantle metasomatism
Cenozoic volcanoes in French Central Massif brought many peridotite xenoliths
and extensive studies were carried out with those peridotite samples by the
use of petrography, trace element and isotopic compositions. We examined the
P-T conditions of 10 peridotite xenoliths in scoria deposits from Puy Beaunit
and Mont Briançon, and in lava flow from Ray Pic (Bruzet), and describe
textural and chemical features of the partial melt texture of phlogopite vein in a
Puy Beaunit xenolith and discuss the timing of the metasomatism forming the
phlogopite using the Rb-Sr systematics of clinopyroxene and phlogopite.
PT conditions
We determined the equilibrium temperatures based on the two-pyroxene
geothermometer using chemical compositions of Ca-rich and Ca-poor
pyroxenes (Wells, Contrib. Mineral. Petrol., 1977). The density, and therefore
the pressure, of CO2 fluid inclusions in host minerals can be estimated from the
Fermi diad splitting of Raman spectra of CO2. If the pressure of CO2 fluid
inclusions was determined, the depth where the CO2 inclusions were entrained
can be obtained (Yamamoto and Kagi, Chem. Lett., 2006). The estimated
ranges of equilibrium temperatures and pressures are ~900 °C and 0.5-0.7
GPa for Puy Beaunit, ~900 °C and ~1 GPa for Mont Briançon and ~1000 °C
and 0.9-1 GPa for Ray Pic (Bruzet), respectively. Puy Beaunit xenoliths were
derived from obviously shallower depths (~25 km) than the other localities
(~30-40 km). We conclude that the peridotite xenoliths of Puy Beaunit were
brought up from the present Moho depth (~25km, Zanga et al., Contrib.
Mineral. Petrol., 1997). The xenoliths from the Puy Beaunit are characterized
by the followings: (1) recrystallization texture, (2) existence of hydrous
minerals and interstitial glasses, and (3) enriched Sr-Nd isotopic ratios (Mercier
and Nicolas, J. Petrol., 1975; Downes and Dupuy, Earth Planet. Sci. Lett.,
1987). On the basis of isotopic and textural signatures, it has been inferred
that Beaunit xenoliths were from the depth for the Moho discontinuity (e.g.
Mercier and Nicolas, 1975; Downes and Dupuy, 1987). Furthermore, mixing
relationship of major element compositions between interstitial glasses and
Cenozoic magmas has been suggested (Wilson and Downes, J. Petrol., 1991).
Vesiculated glass through partial melting of phlogopite veins
One peridotite xenolith in Puy Beaunit has rounded shape phlogopite
surrounded by vesiculated glass. Chemical compositions of glasses have high K2
O, Al2O3 and CaO contents and enriched isotopic ratios of Sr and Nd than
previously reported (Wilson and Downes, 1991; Downes and Dupuy, 1987;
Downes et al., Chem. Geol., 2003). Sr-Nd isotopic and mineral compositions of
the Cenozoic magmas are plotted between primitive magma and
clinopyroxenes or glasses in this sample. This suggest that metasomatism
forming phlogopite vein plays a role in basaltic genesis in this region as
23
suggested by previous studies. The chemical compositions of the glasses and
the crystalline phases allow us to carry out mass balance calculations among
them. The glass chemistry can be formed by the following reaction in nine
components of SiO2-TiO2-Al2O3-Cr2O3-MgO-FeO-CaO-Na2O-K2O system:
1.1 opx + 0.25 cpx +0.79 phl = 1.0 ol + 1.0 gl + 0.01 sp
opx = enstatite, cpx = diopside, phl = phlogopite, sp = Cr-spinel, ol =
forsterite, gl = glass. From these observations, we suggest that a partial
melting of phlogopite and pyroxenes formed the glass and olivine + spinel
crystallization.
Timing of metasomatism, the formation of phlogopite vein
The Rb-Sr isotopic systematics of phlogopite and clinopyroxene give a
reference age of around 60 Ma.This age is younger compared than previous
obtained melt extraction age of the Massif Central xenoliths (ca. 360Ma;
Witting et al., Geology, 2005) and metasomatized age during Variscan orogeny
inferred from model ages (e.g. Dunai and Baur, Geochim. Cosmochim. Acta.,
1995). We propose that this age represent the modal metasomatism beneath
the French Massive Central.
WORKSHOP W04
Geologia e beni culturali: un esame di co-scienza.
WORKSHOP W05
I luoghi e i modi dell'informazione sulle scienze della terra: dalla
biblioteca al web.
W05-60 Poster
Arte, Assunta
ARCHENVIMAT-PRINTS: THE LIBRARY SERVICE OF NATIONAL
RESEARCH COUNCIL DEVELOPS AN OPEN ARCHIVE FOR THE
SCIENTIFIC COMMUNITY.
ARTE Assunta 1, CAIVANO Rocco 1, MARCHITELLI Andrea 2
1 - CNR, Area di Ricerca di Potenza Servizio Biblioteca
2 - CILEA, Sezione Servizi per le Biblioteche e l'Editoria elettronica
Key terms: Digital collection; Institutional repository; CNR prints
Institutional repositories digital collections that capture and preserve the
intellectual output of research communities respond to two strategic issues
facing scientific institutions: 1) they provide a central component in reforming
scientific communication by stimulating innovation in a disaggregated
publishing structure; and 2) they serve as tangible indicators of an institution's
quality, thus increasing its visibility, prestige, and public value. This paper
examines the institutional repository ArchEnviMat- Prints (Archaeological Environmental - Materials - Prints) from these perspectives, describing its
potential role and exploring its impact on major stakeholders in the scientific
communication process.
The National Research Council ArchEnviMat - Prints Open Archive allows
scientists from Potenza Research Area to post on-line, at no cost, their
scientific work in electronic format. The archive will act as a central source for
research produced at National Research Council Potenza Research Area. The
ArchEnviMat-Prints open Archive's mission is to collect, archive and
disseminate National Research Council Research Institutes information and
research. The mission is also to develop a community that sustains itself
through mutual support and interactions in the fields of archaeology, geology,
physic, chemistry.
ArchEnviMat includes research reports, journal articles, conference and meeting
papers, technical reports, books and chapters of book, thesis, miscellaneus of
documents, and preliminary data in the following subjects: Airborne and
Satellite Remote Sensing, Biochemistry, Biophysical and Biological Monitoring,
Built Enviroment Fisics, Chemical-Physical, Deposition, Diagnostic not
destructive, Environmental Geochemistry and Mineralogy, Environmental
Planning and Modelling, Geoarchaeology, Geomorphological and
hydrogeological risk, Geophysics, GIS, remote sensing and Fotogrammetry,
Historical seismicity, Laser, Lidar, Materials, Medieval Archaeology, Medieval
History, Radiometry and Interferometry, Seismic risk, Spectroscopy.
To provide assistance in the matters, the Library Service has organized this
Open Archive to allow the scientific work of any scientists from Research
Institutes to be posted free of charge. The Library serves scientists and
researches by facilitating their self-archiving ensuring the long-term
preservation of their documents. Authors may upload pre-prints, reprints,
conference papers, pre-pubblication book chapters.
ArchEnviMat is realized with Dspace, an open-source digital archiving system
designed by MIT Libraries and Hewlett Packard to capture, manage and share
research in digital formats. The archive is hosted by AePIC team, at CILEA.
W05-61 Orale
Bollini, Andrea
COMMUNICATING EARTH: OPEN ACCESS IN EARTH SCIENCES
BOLLINI Andrea 1, MARCHITELLI Andrea 1
1 - CILEA
Key terms: open access; scholarly communication; CILEA; open archives
Earth sciences are among the most data-intensive sciences, with a remarkable
cooperative work at international level. Data collecting and experiments are
often expensive and last long years. So, logistics and system costs are very
high.
WORKSHOP W05
24
A main reason for publishing data and results is to maximize access and enable
potential reuse in many more contexts than with traditional communication
means. Fast availability of data and results is a must that cannot attend the
traditional publishers' timeline.
Open access is the simplest choice to facilitate fast access to and reuse of
scholarly communication and data about Earth sciences: publications and
related primary data have to be freely accessible in the broadest and fastest
way. A system of OAI-PMH-compliant data and service providers is the most
effective way to improve the dissemination and impact of research.
CILEA (a non-profit consortium of Italian universities) supports Open Access
and is among the first signatories of the Berlin Declaration. Since 2003 CILEA
operates the AePIC service, providing innovative solutions for electronic
publishing and digital libraries at very competitive costs and timetable,
employing open-source and OAI-PMH-compliant software.
In the field of Earth sciences, CILEA-AePIC holds a significant role. It provides
technical support and hosting to Earth prints http://www.earth-prints.org/,
the open archive created and maintained by Istituto Nazionale di Geofisica
e Vulcanologia (INGV) with the collaboration of Programma Nazionale
Ricerche in Antartide. Earth-prints started in the last quarter of 2004 and
grows rapidly and steadily. The goal of this repository is to collect, capture,
disseminate and preserve the results of research in the fields of Atmosphere,
Cryosphere, Hydrosphere and Solid Earth.
In the last months CILEA-AePIC is working on the new archive of National
Research Council - Research area of Potenza, called ArchEnviMat, that will
allow scientists from Potenza Research Area to post and disseminate on-line, at
no cost, their scientific work in electronic format.
W05-62 Orale
Brancatisano, Ilaria
WHEN MOVIES TALK ABOUT GEOLOGY
BRANCATISANO Ilaria 1, MUSCOLINO Marco 1, STINCO Flaminia 1
1 - Universita' degli studi Roma Tre, Biblioteca di area scientifico-tecnologica
Key terms: movies; geology; science
The Library of the Scientific-Technological Area of Roma Tre, University in
Rome - Italy - owns, and periodically updates, a collection of dvd movies
dealing with topics protagonists reflecting the scientific and technological
world: half of it deals with geology. The end users of the Library may suggest
the films that they wish to see. To increase the value of this specialized and
unusual scientific collection, our Library has created a page on its website with
selected resources concerning the relation between cinema and science,
<http://www.sba.uniroma3.it/docs/biblio/film01.html>.
The Project, originating from an idea of promoting relax and entertainment,
offers to those who deal with geological sciences (from students to
researchers) the possibility to see themselves in movies and through movies,
both at the level of social representation of their own professional role and at
the level of thematic face.
The oral presentation will describe three main areas:
1. The characters. This area individualizes three typologies of geologists that
cinema has represented:
a) the factotum scientist often engaged in impossible searches
b) the unheeded technical alarmist
c) the treasure seeker
2. The places and the symbols of the Earth. The oral presentation illustrates
some places with strong symbolic features: the desert, the volcanoes (in a non
catastrophic perspective but as a metaphoric places) and in Italian circle the
Pianura Padana. The desert is the true narrative protagonist of the classical
western movies and of the Italian spaghetti-westerns. The desert as frontier,
crossed in run towards freedom, meets the road movie genre (once for all...
Thelma and Louise).
The volcano as a place of the soul in Rossellini's Stromboli, terra di Dio; in
many Pasolini's movies the Etna is a place where supernatural or mysterious
events occur. The Pianura Padana is instead protagonist of many classical
movies in the history of Italian cinema (Gente del Po, Il mulino del Po, Tutti a
casa, Ossessione, Paisà, Il grido, Riso amaro, La donna del fiume), but also of
many recent movies.
3. The cinematographic genres: from disaster movies to the "Kolossals". This
area identifies some cinematographic traditions. The Disaster movie is the
cinematographic genre where, with great evidence, geology-related themes are
dealt with. It's a recent genre, developed in the 70's, a genre that represents
the wild side of nature. Movies belonging to this genre perform spectacular
events, with a particular predilection for catastrophic events, such as
earthquakes, submarine earthquakes, hurricanes, volcanic eruptions. Showing
the unbelievable, which is typical of a commercial production, forces the
audience into a "suspension of disbelief".
The disaster movies very often represent the terror and the restlessness of
human infancy, accomplishing a "freeing catharsis" function, thus complying
with the ancestral need of man to defy dangers. A sacrificial and purifying rite
is necessary for human improvement. For this reason these movies always
have a happy endings. The characters are strongly stereotyped (often played
by popular actors) and there is a wide employment of make-up and of special
effects (the sensurround system that in Earthquake concurs with the audience
to recreate the sensation of being himself in an earthquake provoked great
curiosity in 1974). Other movies can be mentioned, which are close to the
catastrophic genre for their spectacularity. The blockbuster movies (the ones
we call as "Kolossals") with a historical background (Lawrence of Arabia, The
last days of Pompeii, Titanic), science/fantasy fiction movies (The Lord of the
Rings, Waterworld) and the faunal tradition's cinema, with animation movies,
whose protagonists are animals, creatures of paleontological origin (dinosaurs)
or monsters (Godzillas, King Kong) that destroy, unstoppable, the megalopolis
of the world and eventually become the solitary heroes of nature against
industry.
W05-63 Poster
Cagnani, Francesca
THE GEOMINERALOGICAL SECTION OF THE UNIVERSITY OF FLORENCE
SCIENCE LIBRARY: HISTORY, COLLECTIONS, CATALOGS AND
SERVICES
CAGNANI Francesca 1, CASINI Simonetta 1
1 - Universita' di Firenze - Biblioteca di scienze - Geomineralogia
Key terms: University of Florence; Science library; collections; catalogs;
services
The Science library was established by an act of the University of Florence in
1999 and includes all libraries pertaining to physical and natural scientific
teachings: Anthropology, Animal Biology, Chemistry and Physics,
Geomineralogy, Mathematics. These are small to medium sized libraries mostly
located inside Departments, in different areas of town with a community of
about 3000 FTE users. The Geological library, established in 1870, was joined
in 1979 with the library of the Mineralogy, Petrography and Geochemistry
Institute. In 2000 this union became physical too, giving birth to the actual
library.
Collections. Its collections widely covers the Earth Sciences area including:
geology, mineralogy, crystallography, geochemistry, petrology, geophysics,
seismology, physical geography, geomorphology, glaciology, oceanography,
meteorology, climatology, natural resources, natural hazards , paleontology.
The collection of more than 95.000 items includes many catalogued books,
serials and other print materials. The library owns several archives (De Stefani,
Cocchi), some historical miscellaneous (Carobbi, Manasse, Aloise), a consistent
number of ancient books, some rare manuscripts and a large collection of
geological maps.
Catalogs. From 1991 the catalogs of the library are part of the University of
Florence OPAC and at present most of the collections acquired before that date
have been integrated into the OPAC. The card catalog, for those documents for
which retrospective conversion has not yet been completed, is still a
meaningful instrument of search. In addition to these catalogs, an online
catalog of theses is also available.
Services. Open stacks reading room, with a wireless access network , offers
three workstations for consulting OPACs and searching the Internet. Loan
service, also tailored for disabled, allows the reservation or renewal of books by
web or phone. From the OPAC the user has also the possibility to check the
availability of full-text journals, by SFX link resolver, or to forward a document
delivery request to his library. An electronic document supply service by Ariel©
is available for internal users. A reference service, with expert librarians, helps
users in retrieving documents from a wide range of print or electronic
resources.
The document delivery service (DD) and the interlibrary loan service (ILL) are
offered to students and professors of the University of Florence or to other
Italian or foreign libraries, and are supplied free or for fee, depending on the
agreements signed by the University of Florence Library System (SBA). The
SBA takes part in SDIAF, Libri in Rete, NILDE and SBN, that are local, regional
or national document exchange systems, aimed at facilitating the exchange of
documents.
The Science library web pages offer a range of services inside or outside the
SBA:
° the access to thousands of e-journals;
° the metasearch of many multidisciplinary databases or other free resources,
through Metalib
° a selection of annotated lists of resources
° some online modules to suggest purchasing, useful links, or to request DD or
ILL services.
W05-64 Orale
Cassi, Marco
NEW OPPORTUNITIES IN ONLINE PROFESSIONAL CONTENT
CASSI Marco 1
1 - EBSCO Italia Srl
Key terms: Open Access; Subscription Services; Online Content; Serials
The status of the STM and professional publishing industry and market is
analyzed, with a special focus on the Open Access initiatives, and on the new
options for libraries and users, available with the migration from print to online.
The presentation includes data and material from the yearly article (titled:
"Serial Wars") featured in the April 15, 2007 issue of Library Journal,
examining current and future state of periodical pricing, and trends in the
Publishing industry.
Initially the environment in the first half of 2007 is outlined, including the
points of view of the different players, and their opposite visions (hence the
title "Serial wars") of the new options available, specially the newest ones. The
dramatic transformation brought worldwide from the fast migration from print
to online has influenced the behavior of all players of the information world
such as librarians, publishers, users, vendors, authors, and information
specialists.
In fact, the serials market is living an increasing contrast and debate
concerning the future of the traditional system of professional scholarly
journals. Serials' prices continue to increase; the trend is towards bundled
content sold to single organizations or consortia; and Open Access and Open
Archives' initiatives are gaining ground.
The presentation also covers a summary of the market trends, and major
players' positioning, as it is seen in 2007. The main initiatives from the
publishers, the users, the subscription agents and the researchers are
presented.
EBSCO, as the leading worldwide Information Services and Subscription agent,
recognized during 2006 a major milestone in the history if the company,
processing more than half of the subscriptions with an electronic component
(online only and online+ print). More in general, serials agents and publishers
keep investing and building infrastructure to manage online content, on
developing and assisting digital archiving, while the support to the alternative
to existing system of publishing way is rising as well. Open Access itself is no
longer considered as subtext, but a real alternative identity to the existing
system. EBSCO themselves include access to all Directory of Open Access
Journals in their administrative, online catalogue, and online registration
WORKSHOP W05
management tools and services.
The presentation ends with a summary of guidelines on how to design a flexible
strategy to extract the best ROI (=Return On Investment) from the new
opportunities that the new publishing and online content practices offer to the
users, the librarians, and the researchers.
W05-65 Poster
Chiado' Fiorio, Pier Giuseppe
LIBRARY OF THE REGIONAL MUSEUM OF NATURAL HISTORY OF TURIN
SPINI Marina 1, CHIADO' FIORIO Pier Giuseppe 1
1 - BIBLIOTECA DEL MUSEO REGIONALE DI SCIENZE NATURALI
Key terms: library; natural sciences; document delivery; Geo-Ref; periodicals
The library of Museo Regionale di Scienze Naturali, a branch of Regione
Piemonte, was opened to the public in 1994. Its users are mainly students from
natural sciences faculties and fine arts academy, researchers, professors and
people who are interested in natural sciences.
At present the library owns about 15.000 modern monographs, 2000 serials
(1000 of which are current) and 6000 ancient monographs of the Spinola
collection (entomology, zoology and travel books published from 1550 to
1850). There are about 3000 monographs and 200 serials which deal with
environment, geology, mineralogy and palaeontology.
Since 2000 the library has become part of the national bibliographic system
(SBN) and all its publications can be found in this data base.
All the books can be consulted and photocopied according to the regulations in
force, while they cannot be loaned. The loan between libraries is possible only
if the requested material is owned only by our library.
Since last year the library has joined the interlibraries document delivery
system NILDE and we are currently putting our periodicals into the ACNP
catalogue.
Our patrons have six computers at their disposal and can query on-line both
the "Zoological Record" and "Geo-Ref".
The majority of our monographs and serials are obtained by exchange
programs which involve more than 500 Italian and foreign institutions such as
the Natural Sciences Museums in London and Paris, the Smithsonian Institution
in Washington, the Field Museum in Chicago : we send our publications
(Bollettino, Monographs, Catalogues, Proceedings, exhibitions Guides) to these
institutions and they send us back material of the same kind and value.
Opening hours: 9:00 - 12:30 14:00 - 17:00 (Friday only 9:00 - 12:30)
e-mail: [email protected]
web site: htpp://
www.regione.piemonte.it/museoscienzenaturali/biblio/index.htm
Librarians : Marina Spini - Pier Giuseppe Chiadò Fiorio
W05-66 Orale
Conti, Paolo
ON-LINE DISTRIBUTION OF PAPER AND MAPS OF THE ITALIAN
GEOLOGICAL SOCIETY.
CONTI Paolo 1, CARMIGNANI Luigi 1
1 - Centro di GeoTecnologie - Università degli Studi di Siena
Key terms: on-line library; web; Italian Geological Society
The Italian Geological Society (SGI) by means of its Library Center ("Centro di
Documentazione della Società Geologica Italiana") now deliver the on-line
version of its publications. Using the web site of the Italian Geological Society
Library Center (WWW.SOCGEOL.INFO) is now possible:
- bibliography search in the entire publication database of the Society;
- download paper in PDF format (since 1970);
- order paper copy or CD-Rom copy of papers;
- on-line view of all the geological maps published by the society since its
foundation;
- download of all the geological maps;
- order paper copy or CD-Rom copy of geological maps;
- on-line search in the database of all the journals owned by the Society on
exchange basis with national and international scientific societies;
- on-line search in the database of all the books and maps owned by the
Society on exchange basis with national and international scientific societies.
It is moreover possible the free viewing and downloading of documents
donated from other private and public institutions. At the moment the more
valuable documents of this type are well logs and seismic sections from various
oil companies operated in Italy in the last 50 years.
All this material was prepared for the on-line distribution and mantained by
personnel and students of the "Centro di Geotecnologie" of the Siena
University.
W05-67 Orale
Dal Monte, Giovanni
THE SCIENTIFIC LIBRARY OF CRA-UCEA
BELTRANO Maria Carmen 1, DAL MONTE Giovanni 1, ESPOSITO Stanislao 1,
IAFRATE Luigi 1
1 - CRA-Ufficio Centrale di Ecologia Agraria
Key terms: climatology; geology; meteorology; seismology; volcanology
The "Ufficio Centrale di Ecologia Agraria" (UCEA), an institute belonging to the
Council for research in agriculture (CRA) possesses an important
meteorological and geophysical library.
The CRA-UCEA library comes from meteorological and geophysical collections
once belonged to the "Collegio Romano Astronomical and Meteorological
Observatory", whose original institution dates back to the1570s by the Jesuits.
But only in 1880 such collections became the core of the CRA-UCEA library:
when the "Regio Ufficio Centrale di Meteorologia" -the first "Central
Meteorological Office" in Italy, and forerunner of CRA-UCEA- was transferred to
25
the Collegio Romano premises already hosting the "Observatory". Since then,
the library has been enriched with a great many books and periodicals (both
national and international) on meteorology, climatology, aerology and
agrometeorology.
In 1887 the "Regio Ufficio Centrale di Meteorologia" took over the responsibility
of the "Italian National Geodynamic Service" too. As a consequence, a lot of
Italian and international books (some of which published in the 17th and 18th
centuries) and periodicals about seismology, volcanology and geology were
acquired by the library.
Since 1940 the activity of the "Ufficio Centrale di Meteorologia" has been the
meteorological and climatological research applied to agriculture.
Consequently, the library has concentrated its interest in the field of
atmosphere sciences and agrometeorology.
The library has also original manuscripts (19th and 20th centuries),
unpublished correspondences (19th and 20th centuries) and interesting
miscellaneous collections, e.g. more than fifty volumes containing memoirs and
papers on meteorology and geophysics, written by the greatest Italian
scientists of the 19th and 20th centuries, such as Domenico Ragona, Pietro
Tacchini, Luigi Palazzo, Giuseppe Mercalli, Mario Baratta, Alfonso Cavasino,
Ludovico Marini, Emilio Oddone, etc.
Although, early in the 1940s, the Ufficio Centrale di Meteorologia transferred
some of its geophysical and geological collections to the National Research
Council, the library still hosts books and periodicals on seismology, volcanology
and geology of high scientific and historical interest. In fact, comprehensive
works, special memoirs, historical papers, noteworthy miscellanea and very
specialized reviews constitute what is left of its geophysical and geological
section.
Finally, the geophysical and geological section of UCEA library hosts very rare
books, i.e. volumes of the 16th century, precious manuscripts, like the "Ufficio
di Meteorologia" historical seismic observations and the scientific
correspondence of Pietro Tacchini and Luigi Palazzo .
A CRA-UCEA project will carry out the computerization of the library and the
on-line catalogue.
W05-68 Orale
Ferrara, Gabriele
INGV LIBRARIES NETWORK AND EATH-PRINTS: A DIGITAL TOOL THE
SHARE INFORMATION, DOCUMENTS, DATA IN GEOSCIENCES
CHIODETTI Anna Grazia 1, FERRARA Gabriele 1
1 - Istituto Nazionale di Geofisica e Vulcanologia, Roma
Key terms: Geosciences; Open archive; tool; information; documents
The Istituto Nazionale di Geofisica e Vulcanologia library network is composed
by 8 libraries located in Milano, Bologna, Pisa, Roma, Napoli, Catania and
Palermo and Porto Venere (SP). The main goal of INGV libraries was to support
research activities through the implementation of quality services and tools
dedicated to researchers and to remote users. The libraries promote and
develop electronic resources in the fields of geophysics and volcanology. One
of the main project is: www.earth-prints.org.
The international open archive aims to satisfy the increasing demand of fast,
up-to-date, easy-accessible, and free-of-charge sources of information in all
branches of Geosciences. It allows earth scientists to deposit electronic
documents into its collections and to index them by subjects and keywords.
Earth-prints provides a time-stamp to all deposited materials to insure
precedence rights to original ideas and scientific results. It deals with copyright
issues through Creative Common standards that offer a wide variety of
licenses. All deposited material is made immediately available to the public.
Subscribers will be sent a daily newsletter according to the topics they have
signed in. It
The archive has a three-level hierarchical structure. The top level includes
Atmosphere, Cryosphere, Hydrosphere, Solid Earth and General. It then
branches into several disciplines within the other two levels. Collections
include different kinds of documents, such as pre-prints, manuscripts,
published papers, conference materials, books, book chapters, posters, theses,
Web products
and databases. Earth-Prints main language is English but it accepts also
documents in other languages, giving visibility to data and studies at local scale
that are indeed of general interests. An abstract in English is always required.
Have a tour in to the many features of Earth-prints.
W05-69 Poster
Ferrara, Gabriele
NAUTILUS - SCIENTIFIC LIBRARY FOR CHILDREN AND YOUNG ADULTS:
NATURAL HAZARDS EDUCATION AND READING SKILLS
CHIODETTI Anna Grazia 1, FERRARA Gabriele 1, CAMASSI Romano 2, NOSTRO
Concetta 1
1 - Istituto Nazionale di Geofisica e Vulcanologia, Roma
2 - Istituto Nazionale di Geofisica e Vulcanologia, Bologna
Key terms: scientific library for children; Natural Hazards; education; reading
skills; interlibrary loan
Scientific outreach in the field of Natural Hazards, Seismology and Volcanology
is one of the main activity of Istituto Nazionale di Geofisica e Vulcanologia. A
working group of INGV scientists organize public events, publish educational
tools and documents for students and readers of different level and promote
projects for schools. INGV Library network offers users services based on the
dissemination of documents, data and information about earthquakes and
volcanic eruptions.
NAUTILUS is a pilot project promoted by INGV:
- to collect, monitorate, analyze European scientific editorial production for
children in the last decade;
- to promote new knowledge itineraries in the field of Earth Sciences and
Natural Hazards to help children, teachers, parents to better understand
natural disaster events and prevention;
- to facilitate children creativeness in these specialized disciplines through
specific initiatives (meetings, reading laboratories, etc.);
WORKSHOP W05
26
- to consolidate the collaboration between libraries, scientists, teachers and
public giving scientific book suggestions and information, new users services
changing the role of a specialized library.
A recent analysis made on 50 Italian books on Earth, Earthquakes, Volcanoes
and Climate demonstrates:
- 80% of the books published in Italy are translated from English and French;
- 50% of the books are dedicated to Earth and Volcanoes (only 10% to
Earthquakes) ;
- 20% books dedicated to Climate and Natural Disasters;
- no narrative books on these subjects (1%);
- scientific information inserted in the volumes are correct;
- books for primary school children in some case are too difficult and should be
used with teacher support
W05-70 Orale
Fiorentino, Andrea
ONLINE LIBRARY: ONGOING EVOLUTION. A BIOSTRATIGRAPHER
APPROACH
FIORENTINO Andrea 1, PAMPALONI Maria Letizia 1, PICHEZZI Rita Maria 1
1 - APAT
Key terms: library; Earth Science; online search
The possibility to browse through Earth Science Journals and look for them by
means of online search engines makes it easier to find references;
furthermore, online catalogues simplifiy the identification of their location and
availability.
Finding and, when possible, consulting publications directly from everyone's PC
reduce significantly the time of searching and, consequently, the waste of time
connected to articles that might turn out to be not relevant for the ongoing
work.
The search for Journals can be performed looking for the title, or part of it,
and/or for author or subject. It is also possible to find relevant articles by
looking for a single word and scanning through titles, titles and abstracts or the
entire article. However, it is not always possible to combine different keys of
research.
Bibliographical search engines often operate only on Journals available online
and do not extend their search as any other search engine would do. Online
catalogues are generally limited to the belongings of each library. Searches
based on the Italian Earth Sciences Thesaurus (ThIST) do not cover entirely all
research fields.
Two main aspects seems to need further development in the next future: 1)
search by keywords or part of them (e.g. nannofossil for nannofossil,
nannofossiles, nannofossilien, nannofossili); 2) the number of articles
catalogued, even when they are not available online.
Finally, hard copies of Journals are still needed, especially as far as images are
concerned, because in most cases digital reproduction does not parallel photo
quality.
W05-71 Orale
Mangiaracina, Silvana
INFORMATION ACCESS, DOCUMENT DELIVERY AND RESOURCE
SHARING IN EARTH-SCIENCE LIBRARIES: THE ITALIAN PROJECT
NILDE
MANGIARACINA Silvana 1, CAGNANI Francesca 2
1 - CNR Biblioteca Area della Ricerca di Bologna
2 - Università di Firenze Biblioteca di Scienze (email:
[email protected])
Key terms: Resource sharing; Inter-Library Cooperation; Electronic document
delivery
The National Research Council (CNR) Bologna Research Area Library is a
multidisciplinary scientific library serving a community of about 1.500 local and
remote users among researchers staff, PhD, undergraduate students and
visiting scientists.
The Library became operative in 1997, progressively integrating the existing
resources of the Institutes belonging to the Research Area thus reducing costs
whilst increasing the quantity and quality of advanced library services, such as:
access to over 6.000 online journals, access to specialised bibliographical
databases, document delivery, etc... Library online collections cover, among
the Earth Sciences, the fields of Geology, Ocenography, Climatology,
Atmospheric and Environmental Sciences.
Among library services, the Document Delivery Service allows rapid supply of
scientific documents, books, theses and other documents not owned by the
Library through Inter-Library loan and exchange or purchase. This service is for
internal users. On the other side, the Library offers rapid and comprehensive
document supply and interlibrary loan to other Italian libraries from its
extensive collection.
Document Delivery (DD) plays an important role in Italian research and
university libraries. The main Internet resources for Document Delivery and
Resource Sharing are the Archivio Collettivo Nazionale dei Periodici (ACNP, the
collective serials Italian catalogue), the Sistema Bibliotecario Nazionale
Catalogue (SBN) and the MetaOpac Azalai Italiano (MAI).
In 1999 the Library started a project aiming at the development of an
Internet-based Document Delivery Service, in order to:
- exploit the new Internet technologies;
- promote cooperation among CNR and Italian university libraries;
- reduce service costs;
- achieve short turnaround times and higher user satisfaction.
The resulting system, NILDE (Network Inter-Library Document Exchange), is a
web based software for libraries and end-users, that allows libraries to manage
the entire work-flow of document delivery activities. The main advantages for
libraries are the provision of synthetic and analytical statistics, provision of
performance indicators such as "fill-rate" and "turn-around time", and support
for secure electronic delivery via Internet by means of a
file-uploading/web-server. The main advantages for end-users are the
possibility to forward a document delivery request to their library from any
OpenURL-compliant bibliographical database (e.g. Web of Science, Scopus,
Scifinder, PubMed, CSA Illumina and SFX platforms) and to check the status of
their requests.
NILDE is presently used by more than 500 Italian libraries and counts about
3.000 registered end-users. It has allowed to build up a large library network,
based on cooperation, resource sharing and a degree of standard quality of
service and fair behaviours. Technical-scientific and bio-medical libraries
represent the core of the NILDE network, performing more than 80% of the
total number of document exchanges.
The most recent progress and implementation of the NILDE project and
software will be presented. We will also focus on the important contribution
made by earth-science libraries to the NILDE network and how it will be
possible to increase it, by actively involving even more libraries and complying
with the user-needs of earth-scientists.
W05-72 Key Lecture
Mari, Gianluigi Maria
THE EARTH SCIENCE LIBRARIES: A NATIONAL OUTLINE
MARI Gianluigi Maria 1, ERCOLANI Giulio 1, LANDRINI Iacopo 1, RUSCITO Valerio 1
1 - APAT Agency for environmental protection and technical Services
Key terms: EARTH SCIENCE; LIBRARY; CENSUS
The note shows the first results of the census of the Earth Science Libraries
active in the national territory. On the occasion of the 6th Forum of the Italian
Earth Science Federation (FIST) we took in consideration the libraries which
operate in research structures, university departments, associations and other
institutes which specifically belong to the Earth Sciences (Geology,
Palaeontology and Geophysics Department-University of Padova; Earth and
Geological-Environmental Sciences Department-University of Bologna) and the
libraries that, even if involved in a wider or smaller area of interest, work in the
field of the Earth Sciences and are usually hosted by well-known scientific
structures (ICRAM Central Institute for the Scientific Research on the Sea, CNR
National Research Council).
The list of the institutions and scientific structures that established a library
exchange program with the APAT Library has been considered as primary
source of information to realize the census. The exchange program has been
inherited from the former library of the Geological Survey of Italy. The list has
been updated with a specific reorganization and finally the exchange program
has been renewed during the 2006 with about 300 scientific organizations and
institutions in Italy and in the foreign countries.
Through an accurate and detailed analysis using the web and its available
search engines other libraries of interest have been detected.
At the present day about one hundred libraries active in the national territory
within universities, scientific structures, observatories and museums have been
found.
We examined their websites to identify general and particular features:
location, opening time, user characteristics, services (loan, interlibrary loan,
document delivery, consulting), library-owned documents (serials,
monographs, grey literature, multimedia material, databases, aerial photos,
maps), employee features (librarians, help-librarians, geologists, computer
experts, technical/administrative staff), users per year, specific projects
realized or still in progress.
The note provides a qualitative evaluation based on the analysis of the
documentation and the information acquired through the libraries websites and
completed in some cases by telephone interview. To assess the specific
structures that operate in the Earth Science and Environmental domains we
referred to the library best known to the authors, the APAT Library, which has
been included in the census and described in his features.
The purpose of the census is to update the consistency and typology of the
owned materials, the services offered and the development perspectives of the
libraries of this specific sector. Moreover to increase contacts and promote
meetings among library operators in order to make a permanent and stable
Earth Science libraries network with the aim of sharing information and
improving services.
W05-73 Poster
Mari, Gianluigi Maria
THE APAT LIBRARY EXCHANGE ACTIVITIES: CHARACTERISTICS AND
PERSPECTIVE OF DEVELOPMENT.
ERCOLANI Giulio 1, MARI Gianluigi Maria 1
Key terms: library exchange program; Library; OPAC
The library-owned documents acquisition generally happens through the direct
purchase of serials and monographs or through the gift and the exchange
activities.
By means of this last procedure the APAT Library collected a lot of number of
scientific serials, monographs, geological and thematic maps (hydrogeological,
geomorphological and so on) realized by universities, research institute,
geological surveys and public administrations in Italy and in the foreign
countries.
The APAT Library has inherited the exchange activity from the Geological
Survey of Italy. Lately the activity lessened owing to many reasons. It is
necessary to take into consideration the intrinsic characteristic of the activity
which generally happens only if a scientific object (publication, paper, map, CD
Rom) has been carried out, the reduction of the publications edited by the
Geological Survey of Italy (Memorie descrittive della Carta Geologica d'Italia
and Bollettino del Servizio Geologico d'Italia), the change of the scientific
institutions address, the change of organization and institutional position of
the Geological Survey of Italy and of the Library too, from the Ministry of the
Industry, to the Ministry for the Environment (1986), to the Presidency of
Cabinet Council (1989) and to the APAT (2002).
Through an accurate analysis using the web and its available search engines
the list of the institutions that established a library exchange program with the
APAT Library has been updated. Finally the exchange program has been started
during the 2006 with about 300 scientific organizations in Italy and in the
WORKSHOP W05
foreign countries within universities, scientific structures, museums. The
exchange program is now in progress.
The note describes the general characteristics of the exchange activity and
deepens some specific aspects. The evolution of the exchange program has
been investigated carefully through the examination of some papers published
in Bollettino del Servizio Geologico d'Italia and in other scientific journals. The
presence or the absence, the consistency and the gaps of the scientific
documents sent from other partners has been carried out in some opportunely
selected cases through the OPAC (On-line Public Access Catalogue).
Moreover the paper supplies some advices in order to increase and to improve
the activity.
W05-74 Orale
Masciocco, Luciano
INFORMATION EXCHANGES FOR ENVIRONMENTAL GEOLOGY STUDIES:
THE EXPERIENCE OF TURIN UNIVERSITY GEOLOGY LIBRARY
MASCIOCCO Luciano 1, CIANCI Emilia 2
1 - Dipartimento di Scienza della Terra-Università di Torino; SIGEA
2 - Dipartimento di Scienza della Terra-Università di Torino
Key terms: scientific information; geology library; collective catalogue
The Directors of Turin University's Earth Sciences Department (in origin
Geology Institute) were always aware of the importance of scientific
information exchange.
The Geology Library, founded in 19th Century, since the beginning was never
conceived as a "locked case". Its aim was to lend itself to cultural interchange,
obviously within the limits of the time's technical possibilities.
After the WWII, a publications' eschange service with libraries in Italy and
abroad was set up. It is still active at today's date, and quite useful to increase
the Library's journals collection.
As soon as the photo-reproduction technology became of common use, the
Library started an informal service of document delivery. Experts who needed
articles from journals, or any other kind of bibliographic material, for their
studies and researches could obrain them by ordinary mail or fax
transmissions.
In 2002 the Library gave its contribute to the project "e-Geo: a Sea of Maps"
authorizing the scansion of ancient and rare maps, now included in an on-line
database of Siena University.
After the relocation of the whole Department from the historical see of Palazzo
Carignano, the Library was able to achieve both wider spaces and an easier
connection to the Net, by "Galileo Ferraris" Institute's new see. This way, it was
possible to provide new and better services to the Library's users.
On the occasion of this relocation, the Turin University Geology Library was
named in honor of Professor Roberto Malaroda.
A gread deal of work was aimed to the users' formation/information, trying to
make them able to use at best the traditional library instruments (monographs,
magazine and map catalogues) and to manage the possibilities given by the
ever increasing information flow by various network sites and databases.
A leaflet, conceived as a students' guide to the web resources for geologic
sciences, was elaborated in collaboration with the Turin University Mineralogy
Library.
Since 2007, the "R.Malaroda" Library's catalogue is accessible through the
University's Portal. The Library joined the Se.Bi.Na system, so its most recent
bibliographical material's description is already consultable on the Collective
Catalogue of the "Sistema Bibliotecario d'Ateneo" (University's Library System".
In time, all the sheets of bibliographic material indexed before 2007 will be
transferred to SeBiNa.
Quite noticeable, in the perspective of improving the information interchange,
was the Mararoda Library's adherence to the Collective Catalogue of Italian
Magazines ACNP and the Network InterLibrary Document Exchange System
(NILDE). This way, its already existing service of publication exchange was
made quicker and more systematic.
In future, initiatives of cooperation with neighbouring libraries will be
increased, in order to improve the local services for users. The Library's aim is
to keep improving the user's possibilities to find the material useful for their
researches.
The Library is planning the reorganization of ancient bibliographic/archival
material recovered during the relocation, to render it available to researchers
from Italy and, hopely, from abroad.
W05-75 Orale
Morroni, Emi
TECHNOLOGICAL INNOVATIONS IN LIBRARIES: THE CASE OF THE
ITALIAN AGENCY FOR THE PROTECTION OF ENVIRONMENT AND FOR
TECHNICAL SERVICES
MORRONI Emi 1
1 - APAT
Key terms: APAT; Library; Technologies; Innovation
The Agency's Library, open to the public, is a scientific library specialized in
Earth Sciences and environmental themes. The task of the Library is to ensure
and safeguard the protection of the bibliographic, cartographic and
photographic resources of the Library itself, thus ensuring its enjoyment by the
public.
Resources
v 61.988 magazine headings volumes
v 33.158 monographs
v 44.801 articles from magazines and monographs
v 51.516 Geological maps
v original lithological and geological cartography currently available in digital
format (3982 pictures)
v 63.000 frames of a national territory photographic library
The prestigious collection of maps includes more than 1000 ancient and
valuable geological and geo-thematic maps, 700 of which are available also on
the online catalogue.
The Library contains also more than 500 valuables works dating back to the
27
Eighteenth and Nineteenth centuries.
The most significant stages
1992-1995: The GEODOC project: a project worth approximately EUR 20
billion, providing for the stocktaking and cataloguing of the entire bibliographic
and cartographic resources of the former Italian Library of the Geological
Service.
1995: With the establishment of the Polo GEA, the Library joins the National
Library Service. The first information catalogue of the Library of the
Department for National Technical Services of the Presidency of the Council of
Ministers starts operating. In particular, bibliographic data are stored in the
National Library Service (SBN) package, in VMS-Digital environment, while
cartographic data - not yet covered by the National Library Service - are stored
in BIBLIO, a kind of database created ad hoc.
1999-2000: Project for a system aiming at querying and spreading data from
the DSTN Library over the Internet: OPAC (www.opac.apat.it). The online
multimedia catalogue of the library allows the access to the entire bibliographic
and cartographic resources.
2001: Acquisition of the SEBINA System: it ensured the permanence on the
network of the National Library Service (SBN) Index as well as a significant
reliability and efficiency, in that
° it gave the possibility of managing magazines, excerpts and loan procedures
that the Digital SBN software did not allow
° it allowed to obtain the necessary update implementation of the procedure
regarding the acquisition, processing and management of cartographic material
with a view to adapting it to the Library requirements
° it contains a module for the management of thesauruses which has
permitted the revision of the Italian Thesaurus of Earth Sciences and the
development of a new multilingual thesaurus of Earth Sciences
2006/2007: Sebina Open Library (OPAC): the objective of the adoption of the
OPAC module proposed by Sebina is to unify management, with respect to the
current two modules, so as to achieve saving and optimisation of costs and
human resources and to improve services regarding the internal and
interlibrary loan system.
Apart from ensuring the access to the entire documental heritage, the new
OPAC may offer users a range of services that include:
1. the chance to know the situation of pending loans, reservations, loan
requests and purchase suggestions
2. the creation of a list of queries made by users, so as to allow a further
activation of them without redigitizating any parameter
3. the development of a personal bibliography
4. recommendations to library administration on the purchase of new material
5. furthermore, browsing the Italian Thesaurus of Earth Sciences, published
by the Agency for the Protection of the Environment and for Technical Services
in 2006 and used for indexing and consulting, provides a semantic approach to
documents
W05-76 Orale
Olivetta, Luca
THIST, THE ITALIAN THESAURUS OF EARTH SCIENCES
OLIVETTA Luca 1
1 - APAT
Key terms: thesaurus; knowledge organization; information retrieval
The Italian Thesaurus of Earth Sciences (ThIST) has recently been published by
the APAT Library. It represents the terminological standard tool for the
knowledge organization within the Earth sciences domain. It presents 10350
descriptors linked to each other through 103854 relationships of hierarchical,
associative and equivalence types in compliance with the norm ISO 2788:
"Guidelines for the establishment and development of monolingual thesauri".
The ThIST is a bilingual thesaurus since each individual descriptor has its
equivalent in English.
The ThIST is applied for:
° the organization on conceptual bases of the bibliographic and cartographic
material owned by the APAT Library (semantic indexing):
° the information retrieval of such a material by users.
From the terminological point of view, the ThIST draws from both the former
CNR Italian Thesaurus and the Multilingual Thesaurus of Geosciences (MTG),
edited by the International Union of Geological Sciences (IUGS). It has been
then completely reassessed and enriched through a selective analysis of
thousands candidate terms coming from the APAT Library database in order to
achieve the present shape.
Its structure has followed the model of the Georef Thesaurus, edited by the
American Geological Institute (AGI).
Now, the ThIST is being reorganized under a new structure based on a faceted
arrangement, according to the current applications of the knowledge
organization systems. In this way, it would be harmonized with the structure of
the new release of the MTG, (presently still in progress) and more accessible
for future interoperability with thesauri covering related subjects.
W05-77 Orale
Plini, Paolo
HANDLING GEOLOGICAL TERMINOLOGY WITHIN AN ENVIRONMENTAL
THESAURUS - THE EARTH THESAURUS
DI FRANCO Sabina 1, PLINI Paolo 1, MAZZOCCHI Fulvio 1
1 - CNR-IIA--EKOLab, Montelibretti (RM)
Key terms: thesaurus; Earth Sciences; terminology; classification
Around 2.500 terms, coming from different sources, related to Earth sciences
but environmentally relevant have been included in the EARTh thesaurus which
is the result of a research project at CNR. Terms have been selected, checked,
validated and then put into the thesaurus.
The organization of environmental knowledge should rely on a referral grid for
the analysis of reality, for the classification of concepts and for the explanation
of their "more essential" meanings.
Each concept has an intrinsic semantic complexity which emphasizes particular
and contingent aspects. Solid conceptual foundations are essential for the
WORKSHOP W05
28
management and the integration of conceptual and terminological
heterogeneity of information systems.
EARTh is based on a faceted structure. Its classification scheme was built
utilizing a deductive-inductive approach and is based on the identification and
adoption of a system of categories. The Thesaurus vertical structure is founded
on categories; it is organized in a framework of different levels and
classification knots, and it comprises hierarchical relationships.
Terms have been arranged in a vertical structure acting as a tool that
highlights the "primary meaning" of terms. The result is a semantic reference
system, stable and partially independent from the context. Due to the rigidity
of the vertical structure the planned model envisages the possibility of
complementing the faceted structure with a system of themes crossing the
vertical structure and forming a matrix system. Themes' function is to
reassemble terms that in the vertical structure have been scattered under the
more general referral concept.
The traditional semantic relationships (associative, equivalence and
hierarchical) has been enriched through an extended set of subrelationships.
The enrichment and the logical clarification of the relationships, reinforce their
potential utilization for navigating on a conceptual basis.
The increase and the specification of the associative relationships will
strengthen the capacity of the system to represent the interconnected feature
of the conceptual area.
Earth sciences terminology has historically posed some critical points,
well-known from the first attempt to apply the Linnaues taxonomy of
organisms to rocks, minerals and soils (E. Mendes da Costa). These criticalities
are due to the effort to organize them in a strictly hierarchical scheme. Morover
the Earth sciences include a great number of different topics: from
paleontology to hydrogeology, from mineralogy to engineering geology; each of
these applied disciplines has its own specific terminology and poses different
problems in terms of conceptual organization. In EARTh the geological terms,
as all the others, belong to three macrocategories: Entities, Attributes and
Dynamic aspects; they have been distributed in different hierarchical branches
under specific facets and node labels. In addition a system of related terms
establishes a direct association between terms that are not hierarchically-based
linked. The result is a network of interrelated concepts, complex in its structure
but easy to browse avoiding unnecessary noise and without loosing the
precision in the navigation.
I.e. the term "coal" has been included both in the following path ENTITIES MATERIAL ENTITIES - NON LIVING ENTITIES - ARTIFICIAL ENTITIES - <
MATERIALS AND PRODUCTS >, to indicate the coal as a material extracted,
manufactured and used while the path for "coal (rocks)" is ENTITIES MATERIAL ENTITIES - NON LIVING ENTITIES - NATURAL ENTITIES - < EARTH
CONSTITUENTS AND MATERIALS > to point out the meaning of the term "coal"
as a sedimentary organic rock. The semantic duplicity of the term "coal" has
been overcome applying two different parenthetic qualifiers to the terms in
order to differentiate the artificial material and the rock, thus avoiding
polyhierarchy.
W05-78 Orale
useful resource for geologists and researchers on environmental subjects and
at the same time represents a technical-scientific tool to increase and improve
the customer services.
W05-79 Poster
Ruscito, Valerio
THE ROLE OF THE LIBRARIAN/SCIENTIST
RUSCITO Valerio 1, OLIVETTA Luca 1
1 - APAT
Key terms: geologist; librarian; library; Thesaurus; Indexing
A large portion of the public opinion continues to picture "librarians" as people
who collect fines and keep both users and materials orderly.
The role of the librarian/scientist as a Geosciences Library Assistant in a
modern scientific library contribute to the creation, application, and evaluation
of new ways to support learning and scientific communication in the earth
sciences, including the support of e-science. In particular, the Geology
Librarian can provide assistance with GIS use, including making maps and
locating and formatting data for use with GIS. Therefore, he/she maintains
close relationships with faculty and research staff to keeps abreast of changes
in areas of research interest and, of course, of new scientific publications.
Earth Science, such as all the other disciplines, has a large and complex
vocabulary that becomes a barrier for a non-science librarian who is trying to
answer a scientific question.
Because of this barrier, the APAT Library has recently published the Italian
Thesaurus of Earth Sciences (ThIST) which is a controlled vocabulary of terms
specifically used for describing the content of all the documents. This process is
called semantic indexing; it is a systematic arrangement of entries assigned to
any documental material in order to enable users, when searching the
database for specific documents, to retrieve just the right document. Building a
thesaurus (a real "work in progress") and indexing documents are some of the
most important activities among those accomplished by the librarian/scientists
in a scientific library.
We believe that the science-technology information specialists give the
non-science librarian enough information to be able to guide the science
students or science professionals to material they need and when to refer a
question to a subject specialist.
Library users more readily accept and acknowledge the librarian/scientist as an
equal - someone who understands and appreciates scientific values,
vocabulary, and methodology. Having a background in the scientific
disciplines, the Geology Librarian gives the information specialist more
confidence in asking questions during the reference interview and a greater
relationship with customers. When the information need has been clearly
defined, the ensuing research in a scientific or technical field by a
librarian/scientist is likely to be more effective and efficient.
Roma, Mauro
THE APAT LIBRARY-OWNED DOCUMENTS RELATED TO THE
GROUNDWATER RESOURCES: AN EXAMPLE OF UTILIZATION BY MEANS
OF A GEOGRAPHICAL INFORMATION SYSTEM.
MARI Gianluigi Maria 1, ROMA Mauro 1, TACCHIA Domenico 1, VENTURA Renato 1
Key terms: Library; Geographical Information System; Groundwater resources
A research project promoted and developed by APAT starting from 2003
collected the studies related to the groundwater resources (identification,
quantitative and qualitative characteristics, utilization, vulnerability) realized by
universities, research institutes and public administrations. The aim is to define
the degree of knowledge on groundwater resources in the national territory and
to carry out a Geographical Information System.
Internet and the APAT Library represented the starting point of the inventory.
The main scientific journals, the proceedings of the conferences and the
publications of some research institutes and universities have been collected in
specific files. Hydrogeological and thematic maps (hydrochemical, intrinsic
vulnerability, permeability, groundwater resources), graphic and cartographic
representations (tables, figures) related to more than 300 studies and
researches have been collected with a scanning procedure and stored in CD
Rom.
The list of the studies related to each scientific journal or congress and the list
of hydrogeological and thematic maps represent the first results of the
research project. It is possible to query them using key words (for example:
geographical localization, maps, groundwater9. This way of utilization however
seemed reductive as regards the quantitative and qualitative characteristics of
the data collected and the Geographical Information System potentialities too.
The purpose of the Geographical Information System is to verify the
documentation upgrades, to improve the information and to obtain a more
effective use by matching the data with their real geographic position.
The paper describes the approach to the GIS realization and the conceptual
scheme, the relational logical model, a preliminary geodatabase and the
functional analysis. The result of the query is a report with data required, the
total number of objects and/or the cartographic representation of the studies.
Several different queries have been considered: for geographic areas, with
indication of type (article or map), author, title, year of publication, and with
possibility to filter the information related to the study or to the presence of
specific elements as hydrogeological complexes, permeability, intrinsic
vulnerability, quantitative or qualitative monitoring network, database and so
on.
A database management software (data entry, modification and validation) and
a consultation software (query, visualization and reporting) have been
specifically designed. An user interface (Windows environment) allows to insert
the data collected (studies and maps). Finally backup and other functions
directly usable by means of the interface have been added.
Now the data entry activities related to the main studies and hydrogeological
maps are in progress.
Moreover the paper describes the utilization of the APAT library-owned
documents related to the groundwater resources by means of a Geographical
Information System. The Geographical Information System proves to be a
W05-80 Poster
Saccenti, Luisanna
LINX: MANAGING EARTH SCIENCES FREE WEB RESOURCES AT MILANO
BICOCCA UNIVERSITY LIBRARY
PAPALIA Chiara 1, SACCENTI Luisanna 1, VERGA Francesca 1
1 - Università degli studi di Milano Bicocca - Biblioteca d'Ateneo
Key terms: free web resources; catalog; information sharing
The library at the Università degli Studi Milano-Bicocca has adopted the Scout
Portal Toolkit (SPT) open-source software. This toolkit is used to catalogue,
display, and share a collection of data about web resources. The result is the
creation of "LINX - Link e strumenti X la ricerca" portal, which integrates a
dedicated 'Earth sciences section'.
LINX is a collection of free resources for both education and research which has
been carefully selected by the library staff; it consists of: web sites, databases,
virtual reference desks and repositories etc. It is an ideal place for both
members of the library and members of the public to suggest and share
resources. Above all, it is available to everybody, not just for browsing, but
also for taking an active part in cataloguing these resources. They are
catalogued with simple and qualified "Dublin Core Metadata Elements", and can
be place in order of classification in one or more categories or subcategories.
LINX can also be searched by resource title, author and keywords, and browsed
by category. With LINX, the library can offer its patrons,
scholars and researchers in general, a chance to share their personal
'bookmarks,' in an informal way, and moreover gain in the advantage of
helping one another find their way among the many resources available
on the net.
A special feature of the LINX portal is that it allows users not only to interact
with library staff by recommending specific resource data, but also to interact
with each other, by way of posting comments on
any existing data. It is easy, even so when recommending a new resource,
there is no need to register: users are simply required to fill in a dedicated
form; the library staff can then evaluate the data, complete the description and
publish it. Users will be notified when their record is published. Registration is
required when users wish to set alerts, rate certain resources or add comments
- ratings and comments can be viewed by other users too.
LINX also has a page called "Risorse suggerite" for logged in users, where the
system suggests other web resources according to the ratings given by the
same user to existing records. The university audience has the advantage of
connecting to LINX from the familiar frame of the institutional library site,
where the home page links directly to the portal. The choice to include only
free resources means that all the data is available to everybody and at any
time, regardless of location and user status.
For the Earth Sciences domain, LINX means finding useful material such as:
cartography websites, directories of open access journals, repositories and
websites of professional associations and institutions already selected and then
grouped into categories and subcategories. The Earth Sciences category is
subdivided into several subcategories corresponding to even more specific
subjects, such as: Mineralogy, Environmental Geology and Oceanography.
This real sense of community is adopted by the freedom to suggest, rate and
WORKSHOP W05
collaborate and comment. In context where today's scholars and researchers
are struggling against information overload, even within a single discipline,
LINX is the perfect tool in which Bicocca has chosen to help its users find the
right material for their needs.
W05-81 Orale
Sardella, Raffaele
PALEOROMA: A TERRITORIAL INFORMATIVE SYSTEM FOR THE
PALAEONTOLOGICAL SITES OF THE PROVINCE OF ROMA.
SARDELLA Raffaele 1, BRUNOTTI Roberto 2, MORTELLARO Rossella 2
1 - Dipartimento di Scienze della Terra, Sapienza Università di Roma /
Serendip, associazione per la diffusione della cultura scientifica
2 - Serendip, associazione per la diffusione della cultura scientifica
Key terms: Pleistocene; Province of Roma; paleontology; web site; territorial
informative system
PaleoRoma is a project carried on by Serendip, a cultural association for the
diffusion of scientific culture, supported by the Province of Rome. The project
includes a territorial informative system about the paleontological site of the
Province of Rome available on the Internet (www.paleoroma.it).
The main goal of PaleoRoma is to increase in a greater audience the knowledge
of palaeontological deposits, school collections, museums, laboratories and
research centers located on the territory. Some of them are (were) of
outstanding scientific importance but unfortunately do not exist anymore. As
an example, Saccopastore quarry can be choosen. This site was canceled by
the urban expansion of Rome after II World despite the discovery from the
fossilferous deposits of two skulls referable to archaic forms of Homo
neandertalensis. Today such fossils are stored at the Museum of Anthropology
at Sapienza University. At present PaleoRoma provides information and data on
the Pleistocene sites of the Province of Rome, with an interactive map of
localities, fossils, and other topic of interest.
W05-82 Orale
Sarti, Silvia
THE ITALIAN ANTARCTIC PROGRAMME LIBRARY: HOLDINGS,
ACTIVITIES, EXPERIENCES IN THE FIELD OF POLAR SCIENCES.
SARTI Silvia 1, CECCONI Michela 1
1 - PNRA S.c.r.l. (on behalf of Biblionova S.c.r.l.)
Key terms: information management; scientific libraries; polar regions;
Antarctica; Programma Nazionale di Ricerche in Antartide
The aim of this presentation is to introduce the Library and documentation
centre of the Consortium for the exploitation of the Italian Antarctic Programme
(PNRA S.c.r.l.).
The Italian Antarctic Programme was born in 1985. Since then 22 scientific
expeditions have been performed, in the framework of 11 research projects. At
the same time was istituted the library and documentation centre of the Italian
Antarctic Programme with the following aims: to collect, preserve and provide
national and international publications on Polar regions; to support Italian
research in Antarctica; to promote the knowledge of Arctic and Antarctic
regions; to cooperate with national and international institutions involved in
Antarctica.
PNRA Library is a scientific library specialized in Polar sciences. It holds
publications on: biology and medicine, geodesy, geophysics, geology,
glaciology, physics and chemistry of the atmosphere, astrophysics,
oceanography, environmental chemistry, law and geographical sciences,
technology.
The PNRA Library owns about 4.000 books, 260 printed journals (40 subscribed
and 220 exchanged or as a gift), 50 thesis, 250 technical reports and grey
literature. Library also collects pictures, movies, VHS, CD-ROM, DVD and
preserve a collection of 680 maps representing the Antarctic continent.
PNRA Library is part of the ENEA Libraries network, which allows to partecipate
to the ENEA collective catalogue and to access the electronic resources
subscribed by this institutions. It has been joining the ACNP collective
catalogue and the NILDE network since 2002.
As a documentation centre PNRA Library manages the PNRA Bibliography, that
is a database actually containing about 4700 records describing publications
produced from 1985 till now with the funds of the Antarctic project.
PNRA Library also cooperates with other Polar libraries in Italy and it is member
of the Polar Libraries Colloquy, an international association of libraries and
institutions dealing with Arctic and Antarctic regions.
As a scientific library it is concerned with some common questions: providing
document delivery and inter library loan service, sharing electronic resources,
managing non conventional publication as grey literature, multimedia, maps.
These common problems and the existing cooperation drive us to build a
network of libraries and researchers involved in earth sciences.
W05-83 Orale
Saso, Anna Laura
APAT LIBRARY AND THE QUALITY PROCESS: CONTINUAL
IMPROVEMENT TO THE SERVICE OF THE USER SATISFACTION
SASO Anna Laura 1, SBREGLIA Nadia 1, INSOLVIBILE Marilena 1
1 - APAT - Agency for Environmental Protection and Technical Services
Key terms: Library Management; Quality Management System; User
Satisfaction; UNI EN ISO 9001:2000 Standard; Continual Improvement
The Agency for Environmental Protection and Technical Services (APAT)
Library, National Geological Service Library heir, specialized in geological
sciences and environmental topics, in cooperation with Quality Management
Service, adopted the International standard UNI EN ISO 9001:2000. In 2006,
APAT Library obtained the certification by CSQ (Italian Federation of
Management System Certification Bodies) for the following process:
29
acquisition, catalographic treatment, internal management, preservation,
protection and use of the bibliographic, cartographic and photographic library
resources. Creation of an "on line public access catalog" (OPAC), providing
information services (reference, local consultation, internal and external loan,
document delivery). The Library, since the beginning of the quality process,
chose as main objective the internal and external user satisfaction. This
objective is consistent with one of the eight principles of the quality
management, which is the user-oriented approach to satisfy the explicit and
implicit needs through the relative monitoring and the continual improvement.
The library is an open system, based on a dynamic balance between needs and
services, request and offer, employed resources and effectiveness of the
provided services. The user satisfaction degree is proportional to the benefits
obtained and to the necessary effort. Libraries are open system articulated in
different functional areas (sub-systems) strictly interdependent. A system is
not only built by the elements forming it, but also by the relation connecting its
elements. Libraries should pay attention to their users' needs. Suggestions and
claims are carefully evaluated to eliminate dysfunctions and inefficiencies and
to obtain the services improvement. Such service improvement can also be
originated from an accurate analysis of the critical issues. The library staff
employed in the attendance to the customers must interact with the users in
the correct way, adopting the so-called welcome attitude, characterized by high
professionality and a smart problem solving. The quality management follows
the four activities of the Deming wheel: Plan, Do, Check, Act applicable to all
the library micro-processes. APAT Library's decision to undertake the way of
quality, although highly demanding and conditioned from the human and
structural resources available, offers significant advantages to users, among
which the back-office activities rationalization, not visible to the users
(identification of responsibilities, simplification and optimization of the job
flows), with the subsequent front-line services improvement, visible to the
users. Among these we underline: enlargement, restructuring and putting in
compliance of the Library rooms; acquisition policies, coherent with the library
mission, but also more responding to the users requests; a more effective,
prompt and efficient communication about the status of the different requests;
a deeper awareness of the staff to the reduction of the times and the
discomforts for the customers (Save the time of the reader, 4th Ranganathan's
law); re-engineering of the website of the library, in order to make easy
recognizable and consultable the traditional information (geological e
geothematical maps, periodical and monographical publications) and the
full-text (thematic, normative and legal data banks) resources through the
on-line catalogue; projects of valorization of the texts of the library
(exhibitions, optical acquisition of cartographic material, etc ).
W05-84 Poster
Saso, Anna Laura
THE LIBRARIES AND THE MODERN SOCIETY OF INFORMATION:
ADVANTAGES AND NEW PERSPECTIVES FOR THE USERS OF THE 21TH
CENTURY
SASO Anna Laura 1, SBREGLIA Nadia 1, CIANCIOTTA Chiara 1
1 - APAT - Agency for Environmental Protection and Technical Services
Key terms: Library Science; user; information divide; intermediation; on-line
public access catalogue
The library is not only the physical place in which volumes are preserved in
order and in a classified way for searching and studying requirements, but it is
also a meeting place for a fecund exchange of ideas and intellectual increase.
Above all it represents the memory of our cultural identity for the being and
future people. The peculiar role of the library, from the antiquity to our days, is
its careful and intelligent mediation between reader and document, its ability to
institute a connection between user and information, without considering the
place where is located or the type of its support, according to the theorem of
the ONLY CONNECT. Its vocation and task still live in the modern society of
information. In the last few decades, the libraries drew large advantage from
the technological innovations (computer science, Internet and websites,
search-engines, magnetic and optical supports, electronic publishing,
instruments of communication like fax for the document delivery, e-mail, the
means of transport more rapid for national and international loan), brightly
managed to pursue their missions in more effective and efficient way. The
users can search directly for a specific document or without a precise strategy
of search (serendipity). The modality of information searching are the
following: punctual search (hunting); navigation (browsing); filtering
(grazing-pasture). Today the user, thanks to the advent of new technologies,
has a multiplicity of services that ties tradition to innovation:
· integrated OPAC (On-line Public Access Catalogue), through which the user
can search, save the output, reserve the volumes of his interest, save the
searches, ask for an updating by mail, create and save bibliographies in his
own virtual desk;
· local consultation, inner or interlibrary loan, article supply upon request
(document delivery DD);
· full-text electronic resources and open access repositories;
· services of alerting upon request, like the selective dissemination of the
information (SDI), filtering based on his profile of interest, ToC (table of
contents), A&I (abstracting and indexing).
In spite of what could be thought at a first sight, the advent of the
information-technology didn't make subordinate the role of the librarian, but,
on the contrary, showed the necessity to have a smart documentary
intermediation acted by specialized professionals used to manage the variety of
sources available, to find correct searching strategies and to evaluate critically
the obtained output. However it doesn't seem that its essential functions have
changed, even if it now has powerful means of information retrieval. The task
of the professionals of the information is to dominate the information overload,
through the identification, ordering, classification and indexing of the
documents. Operating a selection within an exterminated publishing production
is not only essential to reach the kind of desired information, but also
fundamental to keep under control the costs of treatment and conservation of
the material: `the filter' constitutes an added value, it is not an aid for the
incapable ones. The librarian, orienting and assisting the user, helps him to
express his informative explicit and implicit needs. The final objective is to
guarantee to all equal conditions to access to documents in order to render
homogenous the knowledge for the society, pulling down the so-called digital
information divide, that consists in the separation between `information elite'
WORKSHOP W05
30
capable to use the new technologies and `digital illiterates', that are excluded
because of the lack of technical cognitions, technological or lawyers barriers, or
other impediments for the weaker social strata (old, blind or handicapped
people), to which the library intends to give a good and actual support in order
to reduce the cultural and technological discrimination.
W05-85 Orale
Valera, Paolo
WEB DIFFUSION OF INFORMATION: THE VARIOUS ANGLES OF HTML
CODE
VALERA Paolo 1
1 - DIGITA - Department of Geoengineering and Environmental Technologies Faculty of Engineering - Cagliari University, Italy
Key terms: HTML code; Website; Searchmotors; Users
The scientific community has a good opportunity today to acquire visibility, and
in the same time, distinguishing from easy to specialized users, whether can
obtain a comparison, also interdisciplinary, or to develop new collaborations.
The publication of a website, preferably multi languages, is not only a new
change to publicize the own work, but it's also a way to wake up the curiosity
of experts of other disciplines who could find news and data clearly show,
where the subjects deepening published in the site necessarily requires the
webmaster specialized competence.
Without going to much into details about how to diffuse the results of a
research, we could affirm that the required techniques obey to few and simple
rules:
1) choice of keywords and site description;
2) position of the site through the first two pages of biggest searchmotors;
3) clarity and simplicity of exposition;
4) easy reading font;
5) extreme synthesis;
6) at least one image for page.
Concerning the first rule, we strongly suggest to use an average number of 3-5
keywords and to compose one row with not more then 7 words for the
description of each website page.
The second point is the aim of site success considering that around 70% of
users stop their attention at the searchmotors first page results and about 90%
at the second one. Simple rules exist for a website good position in the more
diffuse searchmotors, essentially based on small modifications to the html code
of the individual pages.
Skipping the next three rules and going straight way to the last one, it is
advisable to insert at least one ".gif" image per page in order to better describe
what the user can read in each page.
Some more info and suggestions at the http://www.paolov.net/provaci.html,
where it is also available a short HTML course.
1 - Dip. Geologia e Geodesia - Università di Palermo
2 - Dip. Scienze Geologiche e Geotecnologiche - Università di Milano-Bicocca
Key terms: submarine canyon; continental slope; coastal erosion; calabrian
margin
In the frame of the VECTOR Project the VulCost is a research topic that aimed
at studying both geological setting and geomorphological features of the
Calabria offshore between the villages of Monasterace and Siderno (Ionian
Sea). The goal of the VulCost is to expect possible changes of the coastal
environment induced by relative sea level fluctuations.
The Ionian Calabria coastal zone presently records strong tectonics and
seismicity and is affected by fast uplift rate (1 mm/yr; Cosentino and Gliozzi,
1988). The offshore region shows a narrow (max 3, 5 km) continental shelf and
a steep (4-5°), 1400 m deep upper slope. Along the slope are entrenched two
main canyons, oriented NW-SE, that flow in the Plio-Quaternay Spartivento
Basin.
This paper focuses on the morphological and seismostratigraphic analysis
carried out in the shelf - slope system with special regard to canyon evolution.
The seismo-acoustic surveys have been performed on board of the R/V
Universitatis (CoNISMa) by means of a 50 kHz MBES and a multi-frequency 2-9
kHz SBP, mapping a 350 km2 wide area.
Longitudinal profiles along Caulonia and Marina di Gioiosa canyons are weakly
upward convex; transversal profiles are U shaped with variable amplitude along
the thalweg. The transversal profiles are not symmetric in the Caulonia Canyon
where the northern flank is more sloping than the southern one. Almost three
orders of tributaries merge in the main axial incisions, that are more than 1000
m entrenched inside sedimentary succession of the margin. Submarine canyons
have been eroded mainly by two related processes: turbidity currents along the
thalweg (Daly, 1936) and upward erosion induced by downslope eroding
sediment flows (Pratson et al., 1994) along the flanks.
The preliminary results obtained from our survey reveal mass wasting is
common on this sector of the Ionian Calabrian margin. Infact, also in the area
outside the two canyons, gullies, slump scars and chaotic deposits have been
recognized. Mass wasting ed erosional process appear recent or still actives.
The canyon heads are less than 1km far from the coast and, in the next future,
their erosional ability could menace the coastal zone. As consequence of the
fast uplift of the Calbrian margin, the canyon heads will get near the coastline,
so the canyon drainage could seize the alongshore littoral transport; therefore
the coastal budget will lost a lot of the sediment that will be transported
basinward along the canyons.
Next steps of this Project are: 1) to expect as sea level changes will affect the
canyon evolution and 2) to draw future scenarios for coastal area morphology.
Cosentino D. and Gliozzi E. (1988) - Mem. Soc. Geol. It., 41, 653-665.
Daly R. A. (1936) - Journal of Science, 31 (5th ser), 401-420.
Pratson, L.F., Ryan, W.B.F., Mountain, G.S., Twichell, D.C. (1994) - G. S. A.
Bull., 106 (3), 395-412.
W10-87 Poster
WORKSHOP W06
La stratigrafia in Italia. Problemi attuali in salsa storica.
WORKSHOP W07
Nuove tecniche nucleari per l'ambiente.
WORKSHOP W08
Strutture e processi legati ai cold seeps contributo al progetto europeo
HERMES.
WORKSHOP W09
TurBIOlence. Interazioni tra microscala e biologia in ambienti marini e
lacustri.
A non parametric test ( 2) was performed on raw data to single out
significative variations of each monthly mean. Successively, on the raw data
series, a mobile mean was calculated, by a linear model, to obtain 12
parameters for those years more represented in the measures, so eliminating
every variation due to seasonality. On this group, consisting of 12 parameters
for each year, the ANOVA was carried out followed by the algorithm of Duncan
test to single out years homogeneous groups. The cluster analysis was
performed to detect years homogeneous groups.
WORKSHOP W10
Vulnerabilità delle Coste e degli Ecosistemi Marini Italiani ai
CambiamenTi Climatici e loro RuoLo nei cicli del caRbonio
mediterraneo (Progetto VECTOR).
W10-86 Orale
Alabiso, Giorgio
TEMPERATURE VARIATION IN THE MAR PICCOLO OF TARANTO (ITALY,
MEDITERRANEAN SEA)
ALABISO Giorgio 1, GIACOMINI Mauro 2, RICCI Patrizia 1, MILILLO Matteo 1
1 - IAMC - C.N.R., Taranto, Talassografico "A. Cerruti", via Roma, 3, 74100
Taranto
2 - DIST, Università di Genova, Via Opera Pia, 13 - 16145 Genova, Italia
Key terms: global change; historical series; Mar Piccolo of Taranto;
Mediterranean Sea; temperature
The aim of the present paper is to detect a possible temperature increasing
trend in the Mar Piccolo basin (Taranto) in accordance to what observed in the
western Mediterranean where a significant increase in the average temperature
was registered. In fact, the increasing rate of global climate change observed in
the last century is predicted to accelerate in the present century by the end of
which temperature is expected to rise 1-3.5°C. In particular, enclosed coastal
basins, like the Mar Piccolo, are more subject to temperature increase the
effects of which can be enhanced by the confinement.
Observing climatic fluctuations is of the most importance in that it is well
known that they strongly affect the marine biota and there are evidence that
some observed biodiversity changes in the Mediterranean Sea are related to
increasing seawater temperature. Therefore, the study of temperature
variations is important to better understand the marine communities changes
and, sometimes, to predict such changes.
To verify the existence of an increasing temperature trend in the Mar Piccolo
basin, the historical data series, even though not continuous, in possession of
the Institute of Coastal Marine Environment of Taranto was analysed. The
above temperature data analysed come from a station (lat. 40°28'47" N, long.
17°15'38" E) located in the Primo Seno of the Mar Piccolo in the following
periods: 1919-1923, 1932-1934, 1962-1969 and 1996-2006.
Agate, Mauro
MORPHOLOGICAL AND SEISMOSTRATIGRAPHIC FEATURES AND
EVOLUTION OF CAULONIA AND MARINA DI GIOIOSA CANYONS,
OFFSHORE CALABRIAN MARGIN (IONIAN SEA)
AGATE Mauro 1, DI GRIGOLI Giuseppe 1, TESSAROLO Chiara 2, CORSELLI Cesare 2,
MALINVERNO Elisa 2
2
analysis pointed out that the various years are not significatively different;
only 10 months out 324 are significatively different from the expected mean
value. The calculation of the yearly tendencies did not show specific linear
trends (both slopes and r2 values being close to 0).
Examining the groups of years with similar characteristics, a some uniformity
among contiguous years is detectable with the exception of the years 1920,
1921 and 1922 which are similar to those of the period 1996-2006, and the
year 1996 which is similar to the period 1932-1934. Moreover, it is also clear
that the recent years, except 1996, are comprised in the clusters where the
highest mean values fall. Therefore, it is possible to conclude that, in the Mar
Piccolo of Taranto, the trend to temperature increase is confirmed although the
WORKSHOP W10
available data series does not permit to exactly quantify such increase.
The observed temperature increase is supported by the presence in the Mar
Piccolo of numerous warm-water non-indigenous species, many of which are
lessepsian migrants, which are spreading throughout the basin. On the
contrary, the cold-temperate water species, even though usually reported as
invasive, are undergoing a regression.
In the light of these considerations, to know the temperature trend of a
particular zone could permit to predict marine community changes and, in
particular, the destiny of an introduced species on the basis of both its
biogeographic element and affinity to temperature.
W10-88 Orale
RECORD OF COASTAL TECTONIC DEFORMATION FROM THE NORTHERN
ADRIATIC COAST USING LAST 125 KA, LATE HOLOCENE AND
INSTRUMENTAL DATA
ANTONIOLI Fabrizio 1, AMOROSI Alessandro 2, BONDESAN A. 3, BRAITENBERG G. 4
, BUSETTI M. 5, FONTANA A. 3, FONTOLAN G. 4, FURLANI S. 4
1 - ENEA, Casaccia, Rome Italy
Bologna
3 - Dipartimento di Geografia, Università degli Studi di Padova
4 - DiSGAM, Dipartimento di Scienze Geologiche, Ambientali e Marine,
Università degli Studi di Trieste
5 - OGS, Trieste
Key terms: North Adriatic; relative sea level rise; tectonic movements
Sea-level change along the Italian coast is the sum of eustatic,
glacio-hydro-isostatic, and tectonic factors. The first is global and
time-dependent, while the latter two are also affected by local variations. The
glacio-hydro-isostatic part along the Italian coast has been recently predicted
and compared with field data at sites not affected by significant tectonic
processes. A compilation of published and new radiometric radiocarbon datings
from materials and archaeological remains that are well connected to Holocene
sea-level markers has been carried out in order to estimate short-term tectonic
movements on the NE Adriatic coastline (Amorosi et al, 1999, Fontana et al.,
2007, Massari et al., 2004, l., Mozzi et al., 2003 ). Rates of tectonic downlift
were calculated comparing the observed data with the predicted local sea-level
curves generated from the Lambeck et al. (2004) model. Results show that in
North-eastern Italy, tectonic subsidence (corrected by the anthropogenic
component) increases from east to west, with values between 0.3 and 1 mm/y,
respectively. These data highlight a clear NE-SW tilting between Trieste and
the Po Plain, where the highest subsidence values (around 1 mm/y) are
attained and the base of MIS 5.5 deposits, lying at 120-130 m below sea level
(Amorosi et al., 1999; 2004). New data from Roman age archaeological
remains in Trieste gulf and Istria, lead to a tectonic downlift rate of -0.7 mm/y,
thus implying a possible increase of tectonic subsidence.
At the Gulf of Trieste (Italy), Benac et al., 2005, Antonioli et al., (2004, 2007)
observed at Miramare a submerged tidal notch at an elevation of -0.6 to -0.8 m
(tide corrected). Only ~6 km west, the elevation of the notch decreases to -0.9
m. In a north-west direction between Sistiana and Duino (Italy), the altitude of
the notch continues to decrease from -1.3 m, to -2.5 m. In accordance with the
local tide amplitudes (the highest in the whole Mediterranean sea) the width
and amplitude of the notch are larger than 1 m. Our observations show that
the present day notch is absent along the limestone coasts of the
North-eastern Adriatic, between Duino (Italy) and Kotor (Montenegro), while a
submerged notch occurs at about -0.6 m below the present day sea level.
Several anomalies in the Gulf of Trieste are possible related to areas not
affected by subsidence. New multichannel seismic profiles (Busetti et al.,
submitted) indicate the occurence of a compressional structure, crossing the
Gulf of Trieste with NW-SE orientation from the Istria Peninsula to the Friuli
Plain. Presence of this tectonic structure is confirmed by the compatration
between the 14C analises of lagoonal fossils sampled by Ogrinc et al., 2005,
with the Lambeck model. In order to have a control on our deduced vertical
crustal movements, we compared some instrumental results (tide gauges,
altimetric satellite Topex Poseidon) with the geologically determined values.
Some of the instrumental dataset show agreement with long term data
(Braitenberg et al., 2005).
W10-89 Orale
including glacio- and hydro-isostasy following deglaciation, or local responses
to tectonic movements or deformations including volcanic and sediment loading
. As regards the eustatic contribution of Italian seas, data are scarce, we were
evaluating the tide gaudge data set and the Mediterranean river run-off and
the Gibraltar flux.
What seem to be clear is that tectonic and isostatic coastal movements are well
studied, less is known about eustatic component and the future increase due to
the warming. Three coastal sites will be drilled in order to cross Holocene
marine sediments and reach the Last Interglacial fossils deposits.
W10-90 Orale
Antonioli, Fabrizio
Antonioli, Fabrizio
VECTOR PROJECT - LINE 3
ANTONIOLI Fabrizio 1
1 - ENEA, Casaccia, Rome Italy
Key terms: Sea level rise; tectonic; isostasy
The level of the sea does not remain constant. It changes at varying rates,
geographically and over time. Changes of sea level have affected human
civilisations in the past (asm preserved in legends, such as that of Atlantis),
and anticipated accelerated sea-level rise as a consequence of enhanced global
warming seems certain to have serious ramifications in the future. It is
imperative to identify and quantify the causes contributing to the present
observed sea-level variability and change, in order that better predictive
models can be developed. This will be especially important for planners and
decision makers who will need not only forecasts of global sea-level rise, but
also clearer ideas of how sea-level variability and change will be expressed at
regional and local scales. For this pur pose The line3 of Vector project begun to
study the regional relative sea level rise of the Italian seas. In order to
understand present and future sea-level variability we must understand the
past record, and it is instructive to review how our understanding of the
processes involved has improved over the past two centuries. Ours aim is to
summarise what is known about past sea-level changes, concentrating
particularly on changes in ocean volume (or eustatic sea level) that have
occurred over the past few thousand years since the termination of deglaciation
of the major ice sheets. These changes are driven by global factors, including
climate change and thermal expansion of the oceans, or regional responses,
31
Aucelli, Pietro
GEOLOGICAL AND GEOMORPHOLOGICAL LATE QUATERNARY
EVOLUTION OF THE SELE PLAIN (SOUTHERN ITALY): PRELIMINARY
REPORTS FROM VECTOR PROJECT (VULCOST THEMATIC LINE)
AUCELLI Pietro 1, PAPPONE Gerardo 1, ALBERICO Ines 2, AMATO Vincenzo 1,
CESARANO Massimo 1
1 - Dipartimento STAT - Università degli Studi del Molise
2 - CIRAM
Key terms: coastal plain evolution; Sele plain; VECTOR; Campania; Italy
The Sele plain (Salerno, south Italy) is one of the areas selected for the study
of the future impacts connected to the various effects of the climatic change
along the Italian coasts. The Sele Plain orinates from the aggradation of a
Plio-Quaternary depression located along the rifted inner margin of the souther
Apennine Chain. It is about 400 kmq wide with a triangular plan outline, which
is defined seawards by a straight sand coast, stretching between the towns of
Salerno and Agropoli. The plain is closed landwards from Lattari and Picentini
Mts. to the N and NW; and Alburni, Soprano-Sottano and Cilento Mts. to the
SE. The boundaries of the plain are defined by NW-SE and NE-SW trending
scarps, active during Early and Middle Pleistocene. The most internal portion of
the orige marine embayment racked continental condition thanks to the huge
phases of clastic sedimentary aggradation (up to 2000 metres of clastic
deposits part of which are related to "Eboli Conglomerates"), during the
Quaternary subsidence. Further seawards, there is the strip of plain that
formed during the Last Interglacial (Tyrrhenian stage, OIS 5). It forms terraces
between about 25 and 15 m a.s.l. and shows three orders of beach-dune ridges
that interfinger at their back with lagoonal and fluvio-palustrine deposits. The
present elevation of the Tyrrhenian complex proves that the plain has
moderately been uplifted since the last interglacial. Only the youngest and
most external of the Tyrrhenian coastal ridges still has a good morphological
evidence (Gromola-Arenosola ridges). Between the Tyrrhenian ridge and the
present shoreline, a last strip of plain occurs, which is not more than 5 m a.s.l.
elevated. This strip was accreted during the Holocene. It includes a composite
sandy ridges which is partly exposed along the present coast and disappears
inland under a muddy, flat depression. Stratigraphic, paleoenvironmental and
chronological known data allow to interpret the present setting of Sele plain's
outer strip as the result of a barrier-lagoon system that migrated alternatively
landward and seaward during the Holocene. After being exposed to subaerial
condition during the last glacial regression, the study area gradually entered
brackish water condition at the beginning of the Holocene. The inversion of
tendency, from retrogradational to progradational, most probably can be
ascribed to a decline of the rate of sea level rise below the threshold of balance
with the progradation due to fluvial sedimentation. The progradation was
interrupted by at least three minor trasgressive phases occurred between 8.4 e
2.0 ky BP, with formation of sandy coastal ridges, knows as Laura and Sterpina
(I and II). In this time the lagoon was largely gained by palustrine condition
which persisted partially until very recent times. The preliminary study of this
last part of the plain have allowed to identify some areas mainly located in the
back part of the most recent and external coastal ridges where the vulnerability
seems to be important. Actually these areas are elevated only few metres a.s.l
(from 0 to 4-5 m a.s.l.). Furthermore, this area has been interested by ponds
and marshes until to the drainages operated in Borboun times and during the
first half of the 1900. A dense series of drain-channels, connected through
collectors to water scooping machine, allows the actual agrarian use of this
depressed territory. The beach, that margins it seaward, stablised by a
pinewood planted in the years 1930, is not wide and relatively steep, because
of the withdrawal of the last decades; producing berms in attacking the coastal
ridge deposits. This tendency of the present is more marked, due to the action
along the principal rivers of the plain (Sele, Tusciano, Picentino) of anthropic
riverside modifications and as well as by a river dam before the Sele river
enters in its plain.
W10-91 Poster
Basso, Daniela
INVESTIGATING THE GROWTH RATE OF MEDITERRANEAN RED
CALCAREOUS ALGAE (NONGENICULATE CORALLINALES)
BASSO Daniela 1, CARAGNANO Annalisa 1
1 - Univ. Milano-Bicocca, Dip.to Sc. Geologiche e Geotecnologie
Key terms: Corallinales; growth rate; coralligenous; Mediterranean
Calcareous red algae are widely distributed along the Mediterranean shelf.
Literature data show that they are a major component of the coralligenous
framework (=Coralligène; Pérès, 1982) and other hard-substrate associations
(review in Laborel, 1987; Bressan et al., 2001). As data on their abundance
and distribution on soft substrates increase, their importance as common
component of large areas of the Mediterranean shelf sediments becomes clear
(Toscano et al. 2006; Canals & Ballesteros, 1997; Basso, 1998). At this stage
of our knowledge, two issues require further investigation through a
coordinated, multidisciplinary approach. The first involves the acquisition of
data on the growth rate of the most common corallines. Growth rate data are
the background infomation for subsequent studies of primary production,
carbonate production and role of Corallinales in the present-day global carbon
cycle, and for modelling a scenario of increased atmospheric CO2 concentration.
Presently, the few available data on coralline growth rate result from
experiments at sea with a variety of techniques (capture-staining-recapture;
WORKSHOP W10
32
weight increment; photographic survey) or were obtained in lab after tank
culture. Data comparison is mostly prevented by inhomogeneous data units
(the photographic survey provides a measure of surface increment, whilst the
staining technique provide data on the thickening of the thallus) and selection
of different target species (Foster, 2001).
The second issue is related to the estimate of shelf surface covered by living
corallines, in order to obtain a regional quantification of their role on a global
scale. For this purpose, geophysical survey associated with groundtruthing
seems a promising tool (Sañé Schepisi et al., 2004).
Some pilot investigations on tank growth estimates of Lithophyllum
stictaeforme (Areschoug) Hauck and Mesophyllum lichenoides (Ellis) Lemoine,
collected from the coralligenous of the Ligurian Sea, yelded preliminary data of
10-60 µm/yr thickening for Mesophyllum lichenoides and 21-80 µm/yr for
Lithophyllum stictaeforme, and marginal elongation of 1290-3260 µm/yr for
Mesophyllum lichenoides (Basso & Rodondi, 2007). Further investigation with
tank cultures is in progress.
Experiments at sea started on April 2007. Several thalli of common
coralligenous species have been collected along the western rocky coast of
Bonassola (SP) at 6 m depth. Samples have been Alizarin-S stained (0,25 g/l
for 24h) and cemented at the same place of collection. Water temperature and
PAR (Photosynthetically Active Radiation) measurements are recorded regularly
during the experiment.
Basso D. and Rodondi G. - First results of growth rate in colture of the
calcareous algae Lithophyllum stictaeforme and Mesophyllum lichenoides. 38
SIBM Congress, 28/5-2/6/2007, Santa Margherita Ligure (GE).
Canals M. and E. Ballesteros, 1997 - Production of carbonate particles by
phytobenthic communities on the Mallorca-Menorca shelf, Northwestern
Mediterranean Sea. Deep Sea Research II - 44:611-629.
Foster M.S., 2001 - Rhodoliths: between rocks and soft places. J. Phycol., 37,
659-667.
Sañé Schepisi E., Abdelahad N., Basso D., Chiocci F. - Rhodolith facies
distribution on the Pontine Islands shelf. - 4th Annual conference IGCP Project
464 Continental shelves during the last glacial cycle: knowledge and
applications. Roma, Aug. 28-31/2004.
W10-92 Poster
Bellafiore, Debora
VECTOR PROJECT - LINE 5 - ACTIVITY 2 - HYDRODYNAMICS AND
CLIMATOLOGY
BELLAFIORE Debora 1, UMGIESSER Georg 1
1 - ISMAR-CNR, Institute of Marine Science, Venice, Italy
Key terms: Climatology; state of the art; timeseries
In this work results during the first year of activity of VECTOR PROJECT, Line 5
CLIVEN, Activity 2 - Hydrodynamics and Climatology - are presented. This
activity is concerned with a climatological characterization of the Venetian
Lagoon and the nearby coastal areas. The hydrodynamics is the focus of the
project that tries to connect and compare former studies. The state of the art
of knowledge and monitoring in the Venetian area is presented and new results
from statistical analysis and numerical modeling are discussed.
The first step consisted in cataloging the spatial and temporal coverage of
hydrodynamical variables (water levels, meteorological data, waves, currents,
temperature and salinity, solid and suspended transport, river discharges and
bathymetries) in the study area considering former data analysis and adding
new elaborations. The meteorological data, in particular wind speed and
direction, have been taken as the topic of study. Three locations have been
chosen, the CNR oceanographic platform, 15 km offshore in front of the lagoon,
Lido, a barrier island, and Tessera Airport, in the Venetian inland. This choice
allows us to characterize longitudinally the venetian area. The examined period
spans from 1972 to 1987 with a good temporal data coverage. The main
directions and the averaged wind speed values have been computed in the
three stations, identifying two main patterns, one coming from NE, Bora wind,
and the other from SE, Scirocco wind. The wind speed signal shows an
averaged attenuation going inland.
A speed correlation analysis between the three datasets has been applied to
define quantitatively whether a common wind pattern is present in the lagoon.
The correlation increases for low wind periods, which can be linked with low
direction variability phenomena. Lido and CNR platform, spacially close, are
well correlated. Finally a comparison with a former study, done on Lido wind
dataset in the period 1923-1930 (Crestani, 1930), has been performed. The
average of monthly averaged speed values have been computed, for each
month, and these values have been compared with Crestani's ones. The results
show the same trend in both datasets, eccept for the winter months where an
attenuation (negative derivative) in the more recent measurements is
registered. The values computed in the present work are systematically
underestimated and this could be due to a real signal attenuation during the
last century or to different calibrations of the instruments.
The last topic in this activity is connected with numerical modeling, which will
be applied, in the next year, to reproduce extreme events in the past and
future scenarios from a climatological point of view.
A 3D finite element model, SHYFEM, created and developed at ISMAR-CNR, in
Venice, will be applied using historical forcings, boundary and initial conditions
that are already available.
W10-93 Poster
Boldrin, Alfredo
PARTICULATE MATTER AND ORGANIC CARBON DOWNWARD FLUXES IN
THE SOUTHERN ADRIATIC SEA
BOLDRIN Alfredo 1, LANGONE Leonardo 2, MISEROCCHI Stefano 2, TURCHETTO
Margherita 1, TESI Tommaso 2
1 - ISMAR - CNR - Venezia
2 - ISMAR - CNR - Bologna
Key terms: Particulate Organic Carbon; Downward particle flux; Carbon export;
Southern Adriatic
Particulate matter in deep sea areas, is mainly related to autotrophic
production processes occurring in the upper layer of water column, supported
by the seasonal mixing, upwelling phenomena and deep convection events. In
these environments, productivity may be estimated by the amount of organic
matter that falls out from the photic zone and the downward fluxes measured
by sediment traps represent a good tool to have continuous information on
biological production processes occurring in the photic layer. In addition,
organic matter changes qualitatively and quantitatively while sinking through
the water column with several implications on biogeochemical cycles.
Here the results obtained during the first year of the VECTOR Project, are
discussed. The main objective is to characterize the particulate organic matter
in the water column and study the sinking processes in the southern Adriatic
Sea.
Data on total suspended matter (TSM), particulate organic carbon (POC) and
the carbon stable isotope delta13C of particulate organic carbon in the water
column have been collected during 3 oceanographic surveys, carried out in
November 2006, February and April 2007, along the Bari-Dubrovnik transect.
From November 2006 to April 2007, the export of particulate matter below the
photic zone (150 m depth) and near the bottom has been estimated through
the downward particle fluxes measured with automated sediment traps, in a
station located in the centre of the South Adriatic Pit (1200 m depth). The
particulate material was collected at sampling intervals of 7 - 15 days.
The preliminary results of the first year of activity, concerning the particulate
matter distribution and origin along the water column and the vertical particle
fluxes measured in the first 6 months of deployment, are here presented.
To evidence possible changing in biogeochemical cycles in the last 10 years,
data obtained have been compared with similar information available in the
same area and collected since 1994.
W10-94 Orale
Brunet, Christophe
COMPARATIVE FUNCTIONAL DIVERSITY OF THE PHYTOPLANKTON
COMMUNITY FROM THE SOUTH ADRIATIC AND SOUTH TYRRHENIAN
SEAS: A PIGMENT STUDY
BRUNET Christophe 1, CASOTTI Raffaella 1, LAVEZZA Rosario 1, TRAMONTANO
Ferdinando 1, CONVERSANO Fabio 1
1 - SZN "A. Dorhn" - Villa comunale - Napoli - Italy
Key terms: Picoplankton; Pigments; functional diversity
Results on photosynthetic and photoprotective pigments of phytoplankton
analyzed by HPLC from the South Adriatic and South Tyrrhenian seas are
presented. The aim of this study is to compare between the two sites the
functional diversity of the algal community using pigments analyzed by HPLC.
Phytoplankton pigments are biomarker molecules for many biological or
ecological processes, as the community structure in term of algal groups, size
and succession, the physiological and photoacclimative state of cells, the
degradation processes related to senescence of algae or grazing by
zooplankton. The two sampled sites correspond to the stations sampled in the
framework of the Italian project VECTOR, from the South Adriatic (AM) and
Tyrrhenian (TM) seas. Four campaigns have been carried out from November
2006-May 2007. Samples for pigment analysis by HPLC had been taken at 5 to
7 depths, mainly - but not only - covering the euphotic zone of these two
stations. Size Two algal size classes were investigated: the picoplankton (<
3µm diameter) and the nano- + micro-plankton (> 3µm) thanks to fractionated
filtration on-board of the water samples. Results highlight the presence of
different algal composition and functional traits of the community between the
two sites, in agreement with the different trophism of the water masses.
W10-95 Orale
Buia, Maria Cristina
CAULERPA RACEMOSA VAR. CYLINDRACEA IN THE GULF OF SALERNO:
FROM THE MOLECULE TO THE ECOSYSTEM.
BUIA Maria Cristina 1, LORENTI M. 1, PROCACCINI G. 1, GAMBI M.C. 1, FLAGELLA
M.M. 1, GUGLIELMO R. 1, JONGMA D. 1, IACONO B. 1, PATTI F.P. 1, RANDO V. 1, et al.
1 - Stazione Zoologica 'A. Dohrn' - Laboratorio di Ecologia del Benthos - Punta
San Pietro - Ischia (Napoli)
Key terms: gulf of Salerno; Caulerpa racemosa; ecosystem
The occurrence of the green macrophyte Caulerpa racemosa represented by its
invasive variety cylindracea has been recorded in the gulf of Salerno since the
mid-1990s. At that time the bottom surface covered by the alga was estimated
to be one of the largest in the Western Mediterranean Sea. The structure and
functioning of the algal populations and their role in affecting soft-bottom
communities in the gulf of Salerno are now being investigated at three levels:
population genetics, plant ecophysiology and effect on macrofaunal abundance
and diversity.
In order to assess the genetic potential of the species in surviving and adapting
in the newly colonized areas and to clarify the modalities of colonizing new
biotopes, ninety samples have been collected by scuba diving. A standardized
sampling design which will allow comparing results with other areas within the
Mediterranean distribution of the species was followed. Genomic DNA has been
extracted from each single thallus and polymorphic microsatellite markers will
be utilized as molecular markers. Results will allow inferring about the genetic
polymorphism underlying the morphological plasticity of this species. Gene flow
within the Gulf of Salerno and among distinct localities will be related to
dispersal vectors and marine currents regime.
As highlighted by our previous research, C. racemosa var. cylindracea exhibits
a remarkable plasticity also of its photosynthetic traits with respect to major
environmental variables. In the present study, the response to temperature,
irradiance level and photoperiod is being investigated, and results so far
obtained provide new insights into the acclimation capabilities of the alga. This
may have important implications about how the local climate may affect its
spread potential.
Although characterized by a marked seasonal variability, the broad distribution
of the alga on soft bottoms of the gulf has been confirmed by surveys
conducted along selected transects in the Northern and middle gulf, seemingly
enhancing the habitat complexity of the bottoms which Caulerpa stands
WORKSHOP W10
occupy. How this affects the diversity and structure of local macrofaunal
assemblages is the object of a further research line. Preliminary data on major
taxa such as polychaetes indicate that C. racemosa may act as an engineering
species impacting the structure of soft-bottom communities.
Authors indicated as et al.:
Scipione M.B. 1, Zupo V. 1
W10-96 Orale
Burca, Mihai
ESTIMATION OF THE PHYSICAL PUMP FUNCTIONING IN THE
NORTHERN ADRIATIC SEA
BURCA Mihai 1, KOVACEVIC Vedrana 1, MANCA Beniamino Bruno 1
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS
Key terms: Northern Adriatic Sea,; monthly climatology; mixed layer depth
In the framework of the VECTOR project ("VulnErabilità delle Coste e degli
ecosistemi marini italiani ai cambiamenti climaTici e loro ruolO nei cicli del
caRbonio mediterraneo") the vertical mixing efficiency is studied in the shelf
area of the Northern Adriatic Sea. In this relatively shallow area (depths are <
50 m) two major competing buoyancy forces are at work: fresh water
discharge and winter cooling. The latter induce formation of the dense water,
which consequently spreads toward the south.
The study zone has been spatially divided into cells of 12' x 12' degrees
longitude-latitude. On the basis of available temperature (T) and salinity (S)
data, collected by various projects, a corresponding density ( ) profiles have
been calculated. Monthly climatological profiles were then determined in each
cell for each of the three parameters. They were subsampled at regular depths
every 2 m from surface down to 20 m, and every 5 m from 20 m down to the
bottom. The climatological profile of the three parameters consists of the mean
value, the number of data used, and variance at each subsampled depth. The
horizontal distribution of the mean monthly T, S, and
are presented at four
selected depths, 2, 5, 10 m and bottom.
Mean annual salinity and temperature distributions in the surface layer are
characterised by a front between fresher and colder waters in the east and
saltier and warmer waters in the west, according to the thermohaline cyclonic
circulation in the basin. At the monthly scale, both parameters show high
variability. In particular, during December, January and February, east-west
gradient of T and S is strongly evident, indicating colder and fresher waters
confined along the western coast. During the warm season (May-July) the
surface layer is more uniform in temperature, while the path of fresh water
spreads eastward.
In the bottom layer the temperature distribution for the whole year ranges
between 6.95 and 23.25 °C. The salinity distribution throughout the year is
relatively uniform, ranging between 35.1 and 38.6, except downstream the Po
River where it can drop down to 25.12. The temperature field during the winter
period is characterized by colder water in the shallow coastal regions with
respect to a warmer offshore area. On the contrary, during the summer season
shallow near-shore waters are warmer than the rest of the basin, where the
thermocline does not reach the bottom.
From individual density profiles in each cell, mixed layer depth (MLD) is
computed using the difference criteria, with the density variation
= 0.06
kg/m3. Subsequently, the mean MLDs are calculated, and compared to the
total bottom depth. The MLD evolution at monthly scale is mapped over the
study region. Moreover, the MLD is analysed individually during several
particular buoyancy forcing conditions, more and less favourable for vertical
homogenization of the water column over the shelf.
W10-97 Poster
Busetti, Martina
THE MORPHOLOGICAL AND SEISMIC STRATIGRAPHIC
CHARACTERIZATION OF THE GRADO AND MARANO LAGOON
(NORTHERN ADRIATIC)
BUSETTI Martina 1, GORDINI Emiliano 1, BARADELLO Luca 1, COVA Andrea 1,
CABURLOTTO Andrea 1, DEPONTE Michele 1, NIETO Daniel 1, TOMINI Isabella 1
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - Trieste
Key terms: Grado and Marano Lagoon; seismic stratigraphy;
morpho-bathymetry
The Grado and Marano Lagoon, located along the Northern Adriatic coast,
extends from the Tagliamento to the Isonzo Rivers for about 50 km, covering
an area of about 160 km2. The lagoon is protected from the sea by the sand
banks and 1 km northward, by islands distributed in an arch shape separated
by mouths.
The lagoon probably formed about 5500 ys BP in the western part (Marano
Lagoon), and further, about 1000 ys BP to East (Grado Lagoon). The
development of the Grado Lagoon is probably related to the diversion of the
Isonzo River from the area of Grado to its present position eastward.
The present evolutionary trend at century scale, due to the actual transgressive
regime, is constituted by progressive translation of the whole system of islands
and sand banks toward the land.
The Grado and Marano Lagoon is a moderately antrophized system, still having
the possibility of natural evolution. For this reason it has been choose as one of
the study sites where investigate the vulnerability of coastal environment
induced by climatic and sea level changes.
To study the relationship between sea level rise and the response of the lagoon
system, multi and single channel seismic profiles have been acquired from very
high to intermediate resolution in order to investigate the Holocene and
Pleistocene evolution of the area. Three profiles of multichannel intermediate
resolution have been acquired from land to lagoon. Moreover
morpho-bathymetric data have been collected in key areas.
W10-98 Orale
Cardin, Vanessa
33
DECADAL TREND OF THERMOHALINE PROPERTIES IN THE SOUTHERN
ADRIATIC AND REMOTE FORCING
CARDIN Vanessa 1, GACIC Miroslav 1
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, Trieste, Italy
Key terms: Adriatic Sea; deep convection; current field
Hydrographic observations conducted during the first year of the VECTOR
project depict a change of a trend, if compare to what was observed during the
past decade. The observations highlight the importance of the intermediate
waters and confirmed the dominating prevalence of the highly saline Levantine
Intermediate Water, which seems to have replace the Cretan Intermediate
Water after 2003 in the layer below 600m.
The open-ocean vertical convection has been considered as the most important
mechanism in forming the Adriatic Dense Water (AdDW) which then becomes
the prevailing component of the Eastern Mediterranean Deep Water (EMDW).
This process takes place in the South Adriatic Pit in the centre of the cyclonic
gyre (1). The extension of the vertical mixing, which rarely in the last 15 years
has reached the bottom layer, varies on the interannual and decadal
time-scales in function of the air-sea heat fluxes and the pre-conditioning
vertical density structure (2).
In the last decade (1997-2007) in the South Adriatic Pit, the average
temperature of the water column in the layer between 200 and 800m has
increased in average by about 0.5 C. This increase, although weaker, started
already in 1991. During the last decade, the maximum average temperature
was reached in 2003 a value of 13.7°C, much higher than 12.9°C as observed
in 1997. After 2003 a decrease in the deeper layers temperature is observed.
In parallel, an increase in average salinity by about 0.12 has also been
documented (being more intense after 2003) but maintaining this tendency
also until 2006 and then showing slight decrease. The increase in temperature
and salinity resulted in a decrease in density between 1997 and 2003 indicating
that the influence of temperature prevailed in determining the density and that
the lighter water filled up the deep layers of the South Adriatic Pit. After 2003
the densest water of the last decade occupied the layer between 200 and 800
m probably due to extremely high salinity.
The deep layer considered the one below 800 m depth (Otranto Sill depth)
shows that before 2006, was filled by the ADW (Adriatic Deep Water) from
local origin characterised by higher temperature and salinity, while afterwards
the deep layers seem to be prevalently ventilated by dense waters coming from
the northern Adriatic. This fact is confirmed by the decrease in both
temperature and salinity.
After 2003, the intermediate layer in the Pit shows strong changes in its
well-known characteristics, previously filled by the Levantine Intermediate
Water (LIW), evidenced by the intermediate salinity maximum (S > 38.76).
Presently in this layer of the area a new warmer water mass with even higher
salt content is present and could be traced back in the Ionian/Cretan Sea. This
water mass can be responsible for the recent increase in ventilation of the
Adriatic since it provides a source of salt needed to intensify the convection
process.
1. Gacic M., Lascaratos A., Manca B.B. and Mantziafou A., 2001. Adriatic deep
water formation and interaction with the Eastern Mediterranean Sea
Pp.111-142. In: Physical Oceanography of the Adriatic Sea, B. Cushman-Roisin
et al. (eds.), Kluwer Academic Publishers.
2. Cardin, V. and Gacic M., 2003. Long-term heat flux variability and winter
convection in the Adriatic Sea. Journal of Geophysical Research, J.Geophys.
Res., 108, C9,8103.
W10-99 Poster
Caroppo, Carmela
CYANOBACTERIAL DIVERSITY AND POTENTIALLY TOXIC SPECIES IN
THE MAR PICCOLO OF TARANTO (NORTHERN IONIAN SEA)
CAROPPO Carmela 1
1 - IAMC - Unità Operativa di Taranto - CNR, Via Roma, 3 - 74100 Taranto
(Italy)
Key terms: cyanobacteria; toxic species; Mar Piccolo
arine cyanobacteria are found in all the oceans of the worlds, in a variety of
forms which may differ among seasons and geographical locations (Schopf,
1996; Golubic et al., 1999). Illuminated coastal sediments normally host
cyanobacterial communities (Golubic et al., 1999), so that benthic
cyanobacteria are also sporadically found in the water column, because of
physical processes such as wave action. Only a few cyanobacterial forms
occupy pelagic environments, since they are represented almost exclusively by
the two picoplanktonic genera Synechococcus (Waterbury et al., 1979) and
Prochlorococcus (Chisholm et al., 1988; Urbach et al., 1992).
On the basis of these considerations, we focussed our study in Mar Piccolo of
Taranto (Northern Ionian Sea) to assess, over an annual cycle the culturable
filamentous cyanobacterial abundances and taxonomy. Furthermore the
presence of the potentially toxic cyanobacterial species was also monitored.
The seawater samples were concentrated 200 times by filtration on a 0.45 m
pore size membrane filter and were plated on solid seawater-enriched medium
(De Philippis et al., 1993). The cultures were incubated at 26 ± 2 °C under
white fluorescent light at a photosynthetic photon flux abundance of 20 mol
photon m -2 s -1 (Kana & Glibert, 1987). The isolated cyanobacteria were
identified according to Komárek & Anagnostidis (1999; 2005) and Castenholz
(2001).
Results evidenced that, in addition to the typical picoplanktonic Synechococcus,
the culture techniques allowed us to isolate and identify cyanobacteria
belonging to the oscillatoriacean genera Geitlerinema, Leptolyngbya,
Oscillatoria and Spirulina. Even if these filamentous morphotypes represent a
minor fraction of the total cyanobacterial community, their importance could be
related to their contribution to the phytoplankton diversity.
Among the cyanobacterial species, the presence of a potentially toxic species
Oscillatoria nigro-viridis must be underlined, taking into account the intense
musselculture activities which take place in the Mar Piccolo of Taranto.
WORKSHOP W10
34
W10-100 Poster
Caroppo, Carmela
W10-102 Poster
PICOPLANKTON DYNAMICS IN THE MAR PICCOLO OF TARANTO
(NORTHERN IONIAN SEA)
STABILI L. 1, CAROPPO Carmela 1
1 - IAMC - Unità Operativa di Taranto - CNR, Via Roma, 3 - 74100 Taranto
(Italy)
Key terms: heterotrophic picoplankton; picophytoplankton; Mar Piccolo
Picoplankton has been reported to include not only pico-sized, heterotrophic
bacteria but also, often to a considerable extent, < 2 m pigmented organisms,
i.e. cyanobacteria, prochlorophytes, and small pigmented eukaryotes (Li et al.,
1992, Sherr and Sherr, 1994). Small autotrophs constitute significant fraction
of the total primary production in many systems where they are superimposed
on the classical pathway based on the larger phytoplankton. Algae liberate a
variety of monomeric and polymeric organic compounds (Fogg, 1983; Jütner,
1981) which constitutes a major source for the heterotrophic bacteria.
Heterotrophic bacteria play a vital role in nutrient cycling and food-web
structure being responsible for the organic matter hydrolysis. In this study we
determined autotrophic and heterotrophic picoplankton abundances over an
annual cycle in the Mar Piccolo of Taranto. A monthly sampling was conducted
in two stations and water samples were collected at 0.5 m below the surface by
using a 5 - l Niskin sterile bottle. In order to estimate the picoplankton
abundances, water samples were preserved with formaldehyde (2%) and kept
at 4 °C until they could be counted. The cell counts were made using a Zeiss
Standard Axioplan microscope equipped with a halogen (Hg 100) light. Results
evidenced that picoplankton abundances were comparable to those of other
coastal environments subjected to antrophogenic pollution (e.g. Coffin e Sharp
1987; Maugeri et al., 1992; Acosta Pomar e Giuffrè, 1996; Caroppo, 2002).
W10-101 Orale
Catalano, Giulio
FEASIBILITY OF A CARBON BUDGET ALONG THE TRANSECT NEW
ZEALAND - ROSS SEA FROM DATA COLLECTED DURING THE
ITALIANTARTIDE EXPEDITIONS (VECTOR - TASK 9.2)
CATALANO Giulio 1
1 - CNR - Istituto di Scienze Marine - Sede di Trieste, Italia
Key terms: Carbon cycling; key parameters; box model; biological pump; Ross
Sea
The objectives of this budget are both the thermodynamic disequilibrium of the
CO2 between atmosphere and ocean and the fluxes of carbon between its
different reservoirs in the water column down to the sediment.
A such exercise, limited to the carbon fluxes in the water column, has been
successfully performed for the Ross Sea applying a box model technique and
utilizing the data collected by the researchers of several Italian institutes and
universities who have participated to ItaliAntartide cruises from 1987 to 2001
(Catalano et al., accepted). This attempt has been carried out in the frame of
the book on Carbon and nutrient fluxes in continental margins: A global
synthesis ( Liu, Atkinson, Quinones, Talaue-Mc Manus, eds.) which aims to
evaluate the role of the continental shelf pump, that is the weight of the
processes of coastal areas and shelves, toward the export of carbon into the
deep ocean.
The budget of carbon for the Ross Sea has been calculated taking as
independent variables: temperature and salinity for the hydrological properties
of the water column and water masses, the pattern of the currents for the
water exchange with the open ocean through the continental shelf edge, the
primary production for the carbon sequestration in the upper layer, both the
nitrate drawdown and the sediment traps for the downward settling of
particulated matter, the microbial community respiration for the carbon
regeneration in the deep layer and, finally, the burial rates for the carbon
sedimentation at the sea floor. All the other quantities, necessary to balance
the budget, have been derived from these.
Really, the Italian data set had the same some gaps which it has been
necessary to fill with data made available by American colleagues in the frame
of past and present collaborations (US-JGOFS and ROAVERRS).
Although the budget that we have obtained must be considered still coarse, the
editorial board has recognized it as the first attempt of synthesis carried out for
the Ross Sea and accepted its conclusions.
What I think important of this work it is to put in evidence that all the partners
involved have shared both their data and their own expertise in a well defined
work plan, making in this way possible this attempt. The task 9.2 of VECTOR
was born just thinking to this experience.
Now taking into account all that, we must realize that after several months
from the start, and in spite of the efforts done, we are still lacking of the
inventory of the Italian data available for the region of interest. I wish to
underline that this step is absolutely not evadible and we cannot even think to
prosecute without fulfilling it, beyond the possible data gaps that we shall meet
which are still to be identified.
In this first phase I do not want to resort to foreign data, but just for
comparison, I wish to underline the difference with the US cruise routines: in
the Palmer cruise in the Ross Sea of November-December 2006, which I
participated to, many data of general interest such as navigation,
meteorological, underway (surface temperature and salinity, fluorescence,
primary productivity, pCO2) and the CTD casts were already made available in
real time through ship intranet and usable by partecipants.
Reference:
Catalano, G., Budillon, G., La Ferla, R., Povero, P., Ravaioli, M., Saggiomo, V.,
Accornero, A., Azzaro, M., Carrada G.C., Giglio, F., Langone, L., Mangoni, O.,
Cristina Misic ,C. & Modigh ,M. (accepted). The Ross Sea. In: K.K Liu, L.
Atkinson, R. Quinones, & L. Talaue-Mc Manus (eds.), Carbon and nutrient
fluxes in continental margins: A global synthesis, Global Change, The IGBP
Series, Springer, Berlin.
Cavallo, Rosa Anna
POTENTIALLY PATHOGENIC VIBRIOS AND MICROBIAL POLLUTION
INDICATORS IN MAR PICCOLO OF TARANTO (LINEA 4 ATTIVITÀ 5.2)
CAVALLO Rosa Anna 1, ACQUAVIVA M.I. 1, NARRACCI M. 1, STABILI L. 1
1 - IAMC-CNR- Taranto, Via Roma,3 74100 Taranto
Key terms: Vibrio; Microbial pollution indicators; Mar Piccolo of Taranto
Vibrios are gram-negative, curved, halophilic, nonspore-forming bacteria,
autochthonous inhabitants of the marine and estuarine environments. Some
Vibrio species are pathogenic for fish and shellfish as well as for humans. By
contrast to several enteric pathogenic bacteria flowing into the water thorough
sewage, vibrios are normal residents in coastal waters and their number
depends on environmental parameters. Several studies have demonstrated the
that the occurrence of vibrios is not related to the presence of the microbial
pollution indicators. In this framework we studied the dynamic of vibrionaceae
potentially pathogenic as well as the density of the microbial pollution
indicators over annual cycle in water, sediment and mussel samples collected
in the Mar Piccolo of Taranto. Results evidenced the prevalence of V.
alginolyticus, V. mediterranei and V. splendidus II in the samples examined.
Among these vibrios V. alginolyticus is considered a potentially pathogenic
specie responsible of episodes of diarrhea or cutaneous infections, in particular
for frail people. Microbial pollution indicators densities were high in the
mussels, low in water samples and zero in the sediments.
W10-103 Poster
Cavallo, Rosa Anna
INTERACTIONS (RELATIONSHIPS) BETWEEN BACTERIA AND
PHYTOPLANKTON IN THE MAR PICCOLO OF TARANTO (IONIAN SEA).
(LINEA4 ATTIVITA' 5.7)
CAVALLO Rosa Anna 1, ACQUAVIVA M.I. 1, NARRACCI M. 1, STABILI L. 1, CAROPPO
C. 1
1 - IAMC-CNR- Taranto, Via Roma,3 74100 Tarant
Key terms: heterotrophic bacteria; phytoplankton; Mar Piccolo of Taranto
Several studies have already been carried out to characterize heterotrophic
bacteria and phytoplankton communities in ocean sites and in different coastal
areas of temperate, tropical and polar zones. Mar Piccolo of Taranto (Ionian
Sea) is a semi-enclosed basin subject to pollution and receives a considerable
amount of sewage and industrial waste.
The aims of this work was to analyse the qualitative and quantitative
composition of heterotrophic bacteria and phytoplankton communities and the
interactions between these two planktonic components. Samples of sea-water
were collected monthly from September 2006 to August 2007 in two stations of
the Mar Piccolo at the surface and bottom layers.
Among the Gram-negative bacteria, the predominant genus were Aeromonas,
Photobacterium and Pseudomonas. Gram-positive bacilli were abundant at all
sampling points. Among pigmented bacteria, Flavobacterium was predominant.
As regards phytoplankton communities, quantitative data evidenced high
abundance values in the spring time and they were characterized by the
dominance of diatom and phytoflagellate groups. Dinoflagellates and
coccolithophorids accounted only for low percentage values. During the
sampling period, diatoms were dominant with high cell densities in the spring
and were mainly represented by Pseudo-nitzschia spp., Chaetoceros spp.,
Cylindrotheca closterium, and Thalassiosira sp.. Indeed, phytoflagellates,
mainly represented by the undetermined forms < 10 m and by
cryptophyceans, had a wider distribution over time.
As regards the interactions between bacteria and phytoplankton, our data must
be considered preliminary, but they seemed to evidence that phytoplanktonic
spring bloom could be probably responsible for the availability of organic
matter for bacterial populations. But, further studies will evaluate whether the
balance in time between the positive dissolved factors (nutrients from
phytoplankton bloom) and the negative particulate factors (grazing) could be
considered to be a major determinant of the temporal fluctuations of bacterial
density in Mar Piccolo.
W10-104 Poster
Cecere, Ester
WHY IS THE POPULATION OF THE INTRODUCED KELP UNDARIA
PINNATIFIDA (OCHROPHYTA, LAMINARIALES) UNDERGOING A
REGRESSION IN THE MAR PICCOLO OF TARANTO (SOUTHERN ITALY)CECERE Ester 1, PETROCELLI Antonella 1, ALABISO Giorgio 1, RICCI Patrizia 1
1 - IAMC - C.N.R., Taranto, Talassografico "A. Cerruti", via Roma, 3, 74100
Taranto
Key terms: global warming; introduced species; Mediterranean Sea; Undaria
pinnatifida
Undaria pinnatifida (Harvey) Suringar is a kelp native of Japan, China and
Korea. Like all the Laminariales, it has a strongly heteromorphic, diplohaplontic
life cycle, with an alternation between highly differentiated diploid sporophytes
(the macrothalli) and microscopic haploid gametophytes (microthalli). In April
1998, U. pinnatifida sporophytes were observed for the first time in the Mar
Piccolo of Taranto settled on a quay in the old city. In the years 2000-2001 and
2001-2002, the population dynamic and the phenology of U. pinnatifida
sporophytes were studied to know the seasonal variation of recruitment,
settling density and thallus length. It resulted that: 1) the population extended
for about 100 m along the quay where thalli were settled from the upper
sublittoral to the bottom (-1.5 m at most); 2) sporophytes were present from
December throughout June; 3) the highest recruitment value was observed in
February; 4) the maximum mean settling density was of 23 thalli/0.25 m2; 5)
the highest length values was about 1 m.
Successively, two surveys performed in 2003 and 2004 to check the possible
WORKSHOP W10
spread of U. pinnatifida in the basin, highlighted that it remained in the zone of
the first collection even though numerous thalli were observed on floating
wharves which had been positioned near the quay a short time before.
After five years, in 2006-2007, a new study on the population of U. pinnatifida
sporophytes was undertaken in the same zone, which outlined that: 1)
currently, the population extends for 20 m along the quay where thalli were
settled only in the upper sublittoral (-50 cm); 2) sporophytes were present
from February throughout June; 3) the highest recruitment value was observed
in March; 4) the maximum mean settling density was of 1 thallus /0,25 m2; 5)
the highest length values did not exceed 40 cm.
Therefore, the above recent study pointed out that, in the Mar Piccolo of
Taranto, U. pinnatifida population is undergoing a regression. This is in contrast
with that occurred in other localities outside the Mediterranean basin (e.g. The
Netherlands, Argentina, Australia, New Zealand), where U. pinnatifida spread
quickly and showed an invasive behaviour to induce local researchers to try
eradication experiments. Also in Venice, U. pinnatifida spread throughout the
lagoon after its first finding at Chioggia in April 1992 and proved to outcompete
local species.
The regression of U. pinnatifida population observed in the Mar Piccolo is
probably due to the high temperature values of the basin seawater. In fact, a
careful study carried out on the population of U. pinnatifida introduced in
California, highlighted that temperature has a significant effect on survivorship
of microscopic gametophytes and young sporophytes; in particular,
temperatures below about 15°C seem to stimulate gametophyte development
so affecting recruitment. In the Mar Piccolo, temperature drops below 15°C
only from December throughout March. Especially in late summer-autumn,
when the oversummering microscopic gametophytes undergo sexual
reproduction, seawater temperature is indeed higher than 15°C (from 1996 to
2006 the mean temperature values recorded in September, October and
November were 24.1 ± 0.4, 21.1 ± 0.5;18 ± 0.5, respectively). In particular,
in October an increasing trend is clearly detectable over the eleven year period
1996-2006 (R=0.66) which might have progressively affected U. pinnatifida
recruitment, causing the observed population decline.
Therefore, it can be concluded that: 1) the concept of "invasive species" is not
absolute, in that local environmental variables may heavily affect the success
of an introduction; 2) the warming of the Mediterranean basin can limit the
spreading of cold-temperate introduced species.
W10-105 Orale
Chiocci, Francesco Latino
THE VECTOR PROJECT: OMBRONE RIVER DELTA'S AREA
CHIOCCI Francesco Latino 1, TARRAGONI Claudia 2, BELLOTTI Piero 2, CARBONI
Maria Gabriella 2, CONFORTO LUISA Davoli Lina 2, DEL MONTE MAURIZIO Tortora
Paolo 2, LA MONICA Givanni Battista 2, LANDINI BRUNA Manfra Luigia 2, PRANZINI
Enzo 3, TOMMASI Paolo 4
1 - Università di Roma "La Sapienza" - IGAG-CNR
2 - Università di Roma "La Sapienza"
3 - Università di Firenze
4 - IGAG-CNR
Key terms: Vector Project; climate change; delta
The Ombrone River delta and the facing marine area between Monti
dell'Uccellina and the Bruna River mouth, is one of the 5 study areas within
research lines 2 (Vulcost) and 3 (Varcost) of the VECTOR Project.
The area has long been investigated through multidisciplinary studies
(micropaleontology, sismostratigraphy, geomorphology etc), aimed to
reconstruct the evolution of depositional systems during the last
climatic/eustatic cycle.
One of the main objective of the VECTOR Project is to analyse the most recent
stratigraphic interval in order to define the possible sedimentary response to
short-lived (at the scale of the last few millennia or centuries) changes in
sedimentary supply and sea level. Supply fluctuations depend on the impact of
climate on the drainage area and its effects on sediment yield. These data,
once available, represent important constraints for evaluating the
environmental response to possible rapid changes for the near future.
Analyses performed in the study area include:
- geomorphologycal analysis of the entire area;
- detailed geomorphology of coastal ponds ("chiari" in the local terminology)
- lithologic analysis of the uppermost (few metres) interval of the coastal area
and characterization of the dune-beach system evolution during sea level
change and shoreline migration;
- appraisal of the rainfall, the liquid capacities and the torbid outflow and the
eventual recent variations;
- identification and estimate of the frequency of storm and flood events
based on sedimentologic and multy-proxy analyses (stable isotopes, heavy
metals, foraminifers assemblages);
- detailed seismo-stratigraphy of the highstand deposit in order to identify
discrete subunits and/or key stratigraphic surfaces characterised by
high-correlability and relatable to depositional events detectable through other
proxies.
- Identification of hyperpichnal flows based on morpho-bathymetry and
sedimentologic analysis.
The above analyses will be targeted to define the possible scenarios for the
evolution of the coastal and deltaic environment within the next 25, 50 and 100
years.
W10-106 Orale
Conversano, Fabio
TEMPORAL SERIES IN THE SOUTHERN TYRRHENIAN SEA: THE
ACTIVITIES OF THE GROUP INVOLVED IN LINE 8 CARPEL (THE CARBON
CYCLE IN PELAGIC AREAS OF THE MEDITERRANEAN) - ACTIVITY 2
CONVERSANO Fabio 1, DELFANTI Roberta 2
1 - Stazione Zoologica 'A. Dohrn', Villa Comunale, 80121 Napoli, Italy
2 - ENEA-CRAM, Forte Santa Teresa, 19036 Pozzuolo di Lerici, Italy
Key terms: Tyrrhenian Sea; Carbon cycle; Double diffusion processes
35
The oceanographic campaigns are part of the experimental activity envisaged
within the VECTOR project (Vulnerability of the coasts and Italian marine
ecosystems to climatic changes and their role in the carbon cycles of the
Mediterranean) - Line 8 CARPEL (The carbon cycle in pelagic areas of the
Mediterranean) - Activity 2: Temporal series in the Southern Tyrrhenian at a
fixed station (39°30' N 13°30' E).
The general aim of the project is the study of the main processes controlling
the seasonal and interannual variability of the carbon exchange between the
atmosphere and the open sea environment and its possible segregation in the
deep sea.
The specific objective of the campaigns is to conduct process studies for the
definition of the carbon cycle in the pelagic area of the Southern Tyrrhenian
Sea. Particular focus will be given to the response of the pelagic populations to
the abiotic forcing both in the surface layers as well as in the meso- and
bathy-pelagic zones.
The activity plan of oceanographic campaigns, foresees hydrological sampling
in 6 stations located along a section extending from the Gulf of Naples to the
time-series station VECTOR (coordinates 39°30' N, 13°30' E) situated offshore
on the bathymetry of 3500 m, a site affected by intense processes of deep
vertical mixing and double diffusion.
The experimental activity of the group involved in line 8.2, conducted during
the first year, will be presented.
W10-107 Poster
Conversano, Fabio
MULTIDISCIPLINARY STUDY OF THE PELAGIC ENVIRONMENT OF THE
SOUTHERN TYRRHENIAN SEA: THE CONTRIBUTION OF SZN TO
VECTOR-LINE 8.2
CONVERSANO Fabio 1, et al.
1 - Stazione Zoologica 'A. Dohrn', Villa Comunale, 80121 Napoli, Italy
Key terms: Tyrrhenian Sea; Biochemical properties; Deep vertical mixing
The ecological laboratories of the Stazione Zoologica Anton Dohrn (SZN) are
presently involved in the national program VECTOR aimed at studying the main
processes controlling the seasonal and interannual variability of the carbon
exchanges between the atmosphere and the open Mediterranean Sea, and its
possible segregation in the water column.
In the frame of Line 8 CARPEL (The carbon cycle in pelagic areas of the
Mediterranean), which started in February 2006 and will last for three years, an
intense field activity is being carried out in the Southern Adriatic Sea and in the
Southern Tyrrhenian Sea to investigate, on seasonal scale, the responses of
the pelagic communities to abiotic forcing all along the water column from the
surface to the the meso- and bathy-pelagic areas. Our interests focus in
particular on the southern Tyrrhenian Sea, which is still poorly studied in
comparison with other Mediterranean regions, although it plays a key role in
the complex dynamics of exchange between the eastern and western
Mediterranean basins.
The activities in the Tyrrhenian Sea are performed at 6 stations along a
transect from the Gulf of Naples to a fixed station (39°30' N, 13°30' E, about
3500 m depth), which seems to be affected by intense processes of deep
vertical mixing and will become a long-term observatory.
The SZN contribution focuses on the analysis of the vertical and seasonal
patterns of dissolved oxygen, nutrients, spectral light penetration and
absorption properties of the water mass, phytoplankton pigment diversity,
primary productivity and phytoplankton community composition and microand meso-zooplankton biomass and composition.
Preliminary integrated results of the surveys conducted in winter 2006-2007
and spring-summer 2007 will be presented and discussed. The integration of
the different information allows to derive some hypothesis on the functioning of
the trophic web, taking into account also the microbial food web, and its
relationship with the physical and chemical environment.
W10-108 Orale
Conversi, Alessandra
ANALYSIS OF PLANKTON AND CLIMATE VARIATIONS OVER 30 YEARS
IN THE GULF OF TRIESTE: PRELIMINARY RESULTS
CONVERSI Alessandra 1, FONDA-UMANI Serena 2, CORTI Susanna 3, PELUSO
Tiziana 1, COLUCCI Renato 4
1 - CNR - ISMAR - La Spezia
2 - Universita' di Trieste
3 - CNR - ISAC - Bologna
4 - CNR - ISMAR - Trieste
Key terms: climate; zooplankton; Gulf of Trieste; ECMWF; time series
Understanding the impact of climate change on plankton populations is of
major importance, as plankton constitutes the basis for higher trophic levels in
the marine chain. In this study, in the framework of the national program
VECTOR, we use the multi-decadal mesozooplankton abundance time series in
the Gulf of Trieste to investigate its seasonal and interannual variability in
relation to atmospheric and physical parameters. For the selection of
atmospheric and physical parameters we have used the European Centre for
Medium range Weather Forecast (ECMWF) ERA-40 and analysis data on a 0.5°
X 0.5° grid over the Adriatic Sea; the Comprehensive Ocean Atmosphere Data
Set (COADS) on 1° X 1° grid; and local data (Trieste, CNR-ISMAR Station,
45°38'34''N, 13°45'14''E), over the period 1970-2005. We have selected a few
variables (SST, sea level pressure and wind stress) which are good candidates
for proxies of marine circulation changes and are possibly related to changes in
plankton productivity. Our preliminary analyses of the climate data show
ECMWF underestimating wind speed in the Gulf of Trieste. With regard to
biological variability, the comparisons of the interannual trends of the dominant
copepod species indicate an overall change over the 30 year period.
W10-109 Orale
Cossarini, Gianpiero
WORKSHOP W10
36
MODELLING THE CARBON CYCLE IN THE NORTHERN ADRIATIC SEA
COSSARINI Gianpiero 1, DEL NEGRO Paola 1, FONDA UMANI Serena 2, SOLIDORO
Cosimo 1
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (Ogs)
2 - Universita' di Trieste
Key terms: Biological model; Northern Adriatic Sea; Carbon cycle; Bacterial
Respiration; Primary production
The interaction between physical and biological processes is a key factor for
analysing and understanding the functioning of the Northern Adriatic
continental shelf pump. In fact, the downward flux of carbon from the photic
zone to the deeper layer of the water column is manly due to water circulation
over the Adriatic Shelf and mixing processes, as well as to carbon uptake by
autotrophic plankton, nutrient recycling and respiration of organic carbon by
heterotrophic component.
In the frame of this workpackage, the functioning of the continental shelf pump
is studied using short-term simulations performed by a coupled
transport-carbon cycle model. The transport model is MitGCM, and the
biological model has been developed ad hoc for this application.
The biological model represents a synthesis of the current paradigms of the
marine ecological modelling and it is in agreement with specific ecological
literature on the area of interest.
Some of the processes represented in the model are studied in deep, since
their critical role on the process. Different formulations of primary production
and exudation, and different parameterisations of light limitation are
implemented and compared. Further, bacterial respiration and nutrient
recycling are the other processes subjected to a critical review.
The comparison between model results and the results of statistical analysis of
data on Northern Adriatic Sea represents a fundamental step for testing and
validating the different formulations and parameterisations of the biological
model.
W10-110 Orale
Crise, Alessandro
DECADAL SIMULATIONS OF THE MEDITERRANEAN SEA ECOSYSTEM
WITH A 3D BIOGEOCHEMICAL MODEL
CRISE Alessandro 1, LAZZARI Paolo 1, SALON Stefano 1, TREVISANI Sebastiano 1,
BERANGER Karine 2, SCHRÖDER Katrin 3, CERRATI Gabriella 4
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS),
Trieste, Italy
2 - Ecole Nationale Supérieure de Techniques Avancées (ENSTA), Paris, France
3 - CNR ISMAR sezione di La Spezia, Italy
4 - ENEA CRAM sezione di La Spezia, Italy
Key terms: Med Sea; eco-hydrodynamical; Decadal Simulation
CO2 sequestration by means of the oceanic areas represents one of the most
important subjects among the ongoing studies regarding the climate change.
The processes that rule the CO2 absorption into the sea are today not very well
understood. In particular, the Mediterranean Sea appears to be a site of wide
interest, where the entity of the sequestration potential is characterized by a
large uncertainty.
In the framework of the VECTOR project, a series of decadal simulations of the
Mediterranean Sea ecosystem have been planned to be implemented in order
to assess and estimate the amount of the CO2 cycle, with a particular interest
in the vertical transfer processes that involve the CO2 within the trophic web.
The system used to perform the simulations is a three-dimensional coupled
eco-hydrodynamical model (BFM and OPA-tracer model) for the whole
Mediterranean Sea. The biogeochemical module is characterized by a
multi-nutrient carbon-based biogeochemical flux model (BFM). Key aspects of
the model are the potential for limitation by macronutrients (nitrogen,
phosphate and silicate), adjustable (i.e. non-redfilian) C:N:P:Si ratio into
zooplankton and phytoplankton compartments, chlorophyll to carbon variable
dependency. The forcing fields for the Tracer model consisting of temperature,
salinity, zonal and meridional currents, vertical eddy diffusivity are obtained
subsampling a high resolution OGCM (OPA-MED16 -about 5km horizontal
resolution, ENSTA/LOCEAN). The atmospheric forcing fields are obtained from
ECMWF analyses (about 50 km for horizontal resolution) and the period
considered is 1998-2005.
MED16 simulation was focussed on the investigation of the interannual
variability of the convection whose role in the biogeochemical processes is
particularly relevant.
The results of simulations are studied, in order to evaluate temporal and
vertical evolution of the concentration of the key variables, such as
macronutrients, chlorophyll, phytoplankton biomass and productivity.
W10-111 Poster
morphodynamic response to the hydrodynamic processes occurring near Sele
river mouth. Numerical modelling is based on four year wave data monitoring
and two coastline measurement. Model calculations of shoreline change from
2001 to 2004 were in agreement with the measurements. This study is part of
VECTOR Project (VulnErabilità delle Coste e degli ecosistemi marini italiani ai
cambiamenti climaTici e loro ruolO nei cicli del caRbonio mediterraneo)
research line 2 VULCOST (coastal area vulnerability due to global climatic
changes).
W10-112 Orale
W10-113 Poster
SHORELINE EVOLUTION AT SELE RIVER MOUTH: COMPARISON OF
FIELD DATA WITH NUMERICAL MODEL RESULTS
VICINANZA Diego 1, FERRANTE Vincenzo 2, D'ARGENIO Bruno 3, MARSELLA Ennio 3
1 - Seconda Università di Napoli, Istituto per l'Ambiente Marino Costiero - CNR
2 - Seconda Università di Napoli
3 - Istituto per l'Ambiente Marino Costiero - CNR
Key terms: shoreline evolution; numerical model; Sele River mouth
Near a river mouth several important coastal morphology phenomena can take
place. These processes are due to the sediment transport caused by the wave
currents.
A numerical approach is presented to evaluate the coastal morphology
processes and shoreline evolution near the Sele river mouth.
The hydrodynamic and morphodynamic phenomena are described by using a
2DH numerical model. The model consists of three parts: the first simulates
wave propagation, the second simulates hydrodynamic behaviour and the last
performs morphodynamic and shoreline evolution. In this study the numerical
simulation and field data comparison are carried out to evaluate shoreline and
Falco, Pierpaolo
PRELIMINARY RESULTS OF VECTOR OCEANOGRAPHIC CRUISES HYDROLOGY OF THE SOUTHERN TYRRHENIAN
FALCO Pierpaolo 1, ZAMBIANCHI E. 1
1 - CoNISMa, ULR Parthenope, Dipartimento di Scienze per l'Ambiente Università Parthenope, Via de Gasperi 5 - 80133, Napoli
Key terms: Southern Tyrrhenian; Vector Program; processes developing
In the framework of research line 8, task 2, of the VECTOR program, whose
focus is on time series in the Southern Tyrrhenian collected by moored
instruments, since november 2006 we have carried out three ocenographic
cruises in that area. The ultimate goal of this data collection activity consists in
understanding processes developing in the water column affecting and /or
ruling the carbon cycle in that pelagic area.
To this aim, we identified the position of one station where a mooring was
deployed, with sediment traps, conventional and acoustic current meters,
temperature and conductivity sensors, and where hydrological and
biogeochemical investigations are being carried out on a regular (seasonal)
basis.
In addition to this focal point (39°30' N, 13°30' E, bottom depth 3450 m, 90
nm off the Italian continental coastline), we have collected hydrological data
over a transect connecting it to the Gulf of Naples, in SW-NE direction.
In this poster we show the first results of the analysis of the hydrological data
collected during the first three cruises. In particular, we present vertical
sections of the main physical parameters (temperature, salinity, density)
focussing the attention on the geostrophic velocity field associated with the
vertical structure of the water column, and to the double diffusion processes,
easily identified in the salinity profiles.
W10-114 Poster
D'Argenio, Bruno
Delfanti, Roberta
VARIABILITY OF POC EXPORT FLUX FROM THE EUPHOTIC ZONE AT THE
VECTOR TIME SERIES STATIONS.
SCHIRONE Antonio 1, CONTE Fabio 1, MALAGUTI Antonella 2, SALVI Stefano 3,
ABBATE Marinella 1, GIROSI Laura 1, DELFANTI Roberta 1
1 - ENEA Centro Ricerche Ambiente Marino, La Spezia, Italy
2 - ENEA Centro Ricerche "E. Clementel", Bologna, Italy
3 - ENEA Centro Ricerche Brasimone, Camugnano (BO), Italy
Key terms: carbon cycle; Thorium; Mediterranean Sea; Particulate organic
carbon
As part of the VECTOR Project, two areas, in the Southern Adriatic and the
Southern Tyrrhenian Sea, have been selected for the study of the main
processes controlling the seasonal and interannual variability of the carbon
exchange between the atmosphere and the open sea environment. The two
areas are chracterised by different trophic regimes: the Southern Adriatic Sea
shows large spring blooms while the S. Tyrrhenian Sea is one of the most
oligothrophic areas of the Mediterranean. Time series of the main physical and
biogeochemical parameters are being collected at the two stations. POC export
fluxes are estimated by two complementary methods: the 234Th/238U
disequilibrium method and sediment traps. The 234Th/238U disequilibrium
method has been increasingly used over the past decade, because it has the
advantage of providing a temporally integrated record (weeks to months) of
particle export operating from ships and without the apparent biases that
characterise sediment traps.
In this work we first briefly discuss the Thorium method and its accuracy for
POC flux estimates at the VECTOR time series stations. We then present the
data obtained during the first year of activity at both stations and discuss POC
export fluxes in relation to total, new and regenerated primary production and
to microphytoplankton population.
Ferraro, Luciana
MARINE COASTAL ENVIRONMENT OFF SELE RIVER PLAIN,
PRELIMINARY RESULTS OF VULCOST ACTIVITY (VECTOR PROJECT).
ALBERICO Ines 1, BUDILLON Francesca 2, FERRARO Luciana 2, LIRER Fabrizio 2,
PELOSI Nicola 2, D'ARGENIO Bruno 2
1 - CIRAM, Centro Interdipartimentale Ricerche Ambiente, Università Federico
II, Napoli
2 - IAMC, Istituto per l'Ambiente marino Costiero (CNR), Napoli
Key terms: Marine coastal environment; coastline evolution; Sele river plain
offshore
Vulcost is the research line of the Vector Project that aims at evaluating the
vulnerability of the Sele and Bussento (Campania, Italy) coastal systems,
respect to possible future sea level changes.
The first step has been to asses the recent evolution of the coastline and the
present day littoral morphology as well as that of depositional systems and
ecosystems down to 50 m below the sea level. To this aim several proxies have
been integrated:
- comparative analysis of georeferenced technical maps, evidencing the
changes in the coastline in the time interval spanning from 1984 to 1998;
WORKSHOP W10
- swath bathymetry and acoustic mosaics of the seabed, calibrated by sediment
sampling and analysis to delineate the present day distribution of the main
lithofacies associations and the algal and marine plants coverage;
- statistical analysis of the main benthic foraminiferal species distribution, to
provide information on ecological niches, since it has been observed that
specific faunas, do colonize well distinct environments.
All the information concurred to define four peculiar shallow marine
environments:
- a submerged beach and a fluvial delta sector, wave dominated, down to
15/18 m of depth;
- a sandy pelitic seabed from 15/18 m down to about 30 at places with patches
of Cymodocea nodosa and Caulerpa racemosa, mainly controlled by extreme
storm events and bottom currents;
- an homogeneous pelitic seabed down to 50 m of depth, swept by bottom
currents;
- a littoral sector characterized by rocky outcrops and relict of Posidonia
oceanica matte, between 10 and 20 m off the coast enclosed by the Salso and
the Solofrone river.
W10-115 Poster
Fonda Umani, Serena
CARBON CYCLE VARIABILITY IN THE NORTHERN ADRIATIC
ECOSYSTEM: A RE-ANALYSIS OF HISTORICAL DATA
FONDA UMANI Serena 1, RAVAIOLI Mariangela 2, KOVACEVIC V. 3, CARDIN
Vanessa 3, COZZI S. 4, GIANI Michele 5, CATALETTO Bruno 3, SOCAL Giorgio 6,
SAGGIOMO V. 7, RUSSO Aniello 8, et al.
1 - Dipartimento di Biologia, Università degli Studi di Trieste
2 - ISMAR CNR Sezione di Bologna
3 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS;
Trieste
4 - ISMAR - CNR Sezione di Trieste
5 - ICRAM, Brondolo Chioggia (Ve)
6 - ISMAR - CNR Sezione di Venezia
7 - Stazione Zoologica "A. Dohrn", Napoli
8 - Dipartimento di Scienze del Mare - Università Politecnica delle Marche,
Ancona
Key terms: Carbon cycle; northern Adriatic; variability
The northern Adriatic has been recognized for many years as a region of high
marine production at several trophic levels from phytoplankton to fish. The
rivers draining into the northern Adriatic are the major sources of external
nutrient input, especially during stratified periods. The water mass exchange
between the northern region and the remainder of the essentially oligotrophic
Adriatic has a great influence on the productivity and standing crops of
different sub-areas. A terrigenous supply of nutrients all along the western
coast via run-off influences the productivity of a relatively narrow coastal belt,
and consequently the biomasses and production rates are spatially very
variable. In shallow turbulent environments, like the northern Adriatic, where
increased nutrient availability is episodic, the microbial or the grazing food web
can alternately dominate in the carbon flow over short time periods. In spring,
as a result of episodic nutrient enrichment of the euphotic zone and insufficient
grazing, as a controlling factor of their population size, large-sized
phytoplankton blooms occur that consequently determine a major export to the
bottom via sedimentation. On the opposite, microbial food web is typical of low
energy environment, mostly based on regeneration processes. As a
consequence, the final fate of photosynthesised carbon can strongly change
over time in the same environment as a function of the planktonic food web
structures. In the framework of VECTOR project ("VulnErabilità delle Coste e
degli ecosistemi marini italiani ai cambiamenti climaTici e loro ruolO nei cicli del
caRbonio mediterraneo") a re-analisys of the entire available data set of
parameters relevant in driving C fluxes and export rates has been planned to
provide conceptual models and appropriate parametrizations to modelers, with
the aim to hindcast and forecast ecosystem scenarios at the basin scale.
M. Crisciani 4, F. Spagnoli 9, A. Boldrin 6, A. Schirone 10, E. Paschini 9, R. Danovaro 8,
B. Manca 3, R. Del Fanti 10, A. Pugnetti 6
9: ISMAR - CNR Sezione di Ancona
10: ENEA Centro Ricerche Ambiente Marino, La Spezia
W10-116 Orale
Fontolan, Giorgio
COASTAL VULNERABILITY ASSESSMENT: THE GRADO AND MARANO
BARRIER ISLANDS
FONTOLAN Giorgio 1, PILLON Simone 1, BEZZI Annelore 1, DELLI QUADRI
Francesca 1, BURLA Ivonne 2
1 - Università di Trieste, DISGAM - Coastal Group
2 - Università di Trieste, DISGAM
Key terms: coastal vulnerability; risk assessment; sea-level rise; storm surge;
Grado and Marano lagoons
Maximum vulnerability is normally considered for the lowest parts of the
coastal system, as the barrier islands and subsiding deltaic areas. Inundation
risk of the Grado and Marano lagoons depends on the elevation of the inner
plain and on land use values. Most of the area surrounding the inner lagoon is
below the mean sea-level, and is presently defended only by dikes constructed
along the inner lagoon margin after the November, 1966 storm. Two main
tourism localities (Lignano and Grado), as well as an important industrial area
(Porto Nogaro) and significant agricultural and commercial activities are
presently the main targets due to sea-level rise.
A twofold adaptation measure has to be considered: 1) a measure linked to the
possible expansion of the lagoon limit landwards, in order to compensate for
the unavoidable drowning of the present lagoon, 2) a measure linked to the
defense of the barrier islands, in order to abate the erosional phenomena that
could lead to the opening and loss of the entire lagoons, and reduce the direct
impact of storms.
The lagoon has a double barrier island chain, given by dynamic and elongate
37
outer sand banks, detached from the ancient and fixed inner barrier, to form a
para-lagoonal intermediate area.
Onshore movement and connection to the inner barrier is the secular trend of
the main sand banks, thus testifying an overall rollover tendency possibly due
to relative sea-level rise.
In a sediment-starved system the rollover process not necessarily occurs with
mass conservation.
Barrier thinning and shoreline erosional trend can be seen as the main
responses due to flooding of the coastal area without sufficient sediment
compensation.
A GIS-based coastal vulnerability index has been constructed using a multiple
regression procedure that considers a set of coastal morphodynamic and
physical factors. The present beach configuration as well as the recent
shoreline and shoreface evolutionary trends are the main variables to consider
in order to achieve information on the possible behavior of beaches and barrier
island systems to sea-level rise and climate-changes.
The procedure permitted to obtain a simple coastal zoning that emphasize the
most critical areas, that could become the main erosional hot spots in case of
submergence and concomitant recurrence of storms.
W10-117 Poster
Galati, Maria Barbara
MEDITERRANEAN WAVE CLIMATE: VARIABILITY AND TREND
GALATI Maria Barbara 1, LIONELLO P. 1
1 - Univ. of Salento, Lecce, Italy
Key terms: wind waves; extremes; trend; seasonal cycles; climate
This contribution analyses the wave fields in the Mediterranean Sea, during the
second half of the 20th century (1958-2001), in order to study the climate
variability of SWH (Significant Wave Height) and its recent trend. The results
are important for planning and managing coastal defences and off-shore
activities. In this study, the SWH fields are produced by a the third-generation
wave model, WAM (WAve Model), at 0.25 degs lat-lon resolution. The two sets
of forcing wind fields used are provided by the ERA-40 reanalysis and the
HIPOCAS project. ERA-40 have a 0.5 deg grid step and a temporal resolution
of 6 hours. The HIPOCAS have the same grid step and a hourly temporal
resolution. Output wave parameters fields (SWH and direction) are saved every
hour. The comparison between the two simulations and with satellite is used
for assessing the accuracy of the results. The project aims at describing the
mean wave fields, their seasonal cycles, extreme values and climate trend.
W10-118 Orale
Gambaro, Andrea
STUDY OF ORGANIC SULPHUR COMPOUNDS (DMS, DMSP AND DMSO)
IN LAGOON ECOSYSTEMS: THE CASE OF THE VENICE LAGOON
GAMBARO Andrea 1, BENITEZ MACIAS1 A. 2, CORAMI F. 3, CESCON P. 1
1 - Dipartimento di Scienze Ambientali, Università Ca' Foscari, Dorsoduro 2137,
I-30123 Venezia (Italy) and Istituto per la Dinamica dei Processi Ambientali,
IDPA-CNR, Dorsoduro, 2137. 30123, Venezia
2 - Dipartimento di Scienze Ambientali, Università Ca' Foscari, Dorsoduro 2137,
I-30123 Venezia
3 - Istituto per la Dinamica dei Processi Ambientali, IDPA-CNR, Dorsoduro,
2137. 30123, Venezia, and Istituto per la Dinamica dei Processi Ambientali,
IDPA-CNR, Dorsoduro, 2137. 30123, Venezia
Key terms: Dimethyl sulphide; Dimethylsulphoniopropionate; water; climate
change; Venice Lagoon
During the past decade much of the research on volatile sulphur compounds
(VSCs) has focused on their production and fate in the oceans and coastal
marine environments. This intense interest arises from an awareness that
biogenic sulphur gases play an important role in the cycling of sulphur and in
global climate regulation. Dimethyl sulphide (DMS) is the most important
marine source of sulphur released into the atmosphere.
The Venice lagoon is the largest wetland of the Mediterranean and it is
characterised by different subsystems which determine its elevated complexity
and diversity. It can be considered an ecosystem of transition between land
and sea, which continuously exchange matter and energy with the drainage
basin and the Adriatic Sea.
This study of the origin and fate of dimethyl sulphide (DMS) and the
relationship with climate in a particular and complex lagoon ecosystem such as
that of the Venice lagoon focuses on the temporal evolutions of DMS
concentrations in surface water together with those of
dimethylsulphoniopropionate (DMSP), dimethyl sulphoxide (DMSO), nutrients
(nitrate, nitrite, ammonium, phosphate, silicate), chlorophyll a, chlorinity,
water temperature and phytoplankton (composition and density).
Measurements were made during 1997 at six stations in the Venice lagoon.
The temporal trends of DMS concentration were different at the six stations
and they showed no relation to DMSP or to the chlorophyll a concentration at
four stations whereas at two stations DMSP concentrations in the surface water
is related to DMS and chlorophyll a concentrations suggesting that the
production and the fate of DMS could be different for the two periods.
W10-119 Orale
Gasparini, Gian Pietro
HYDROGRAPHIC AND TRANSPORT VARIABILITY IN THE SICILY STRAIT
GASPARINI Gian Pietro 1, SPARNOCCHIA S. 2, SCHRÖDER K. 1, VETRANO A. 1
1 - CNR - ISMAR, sezione territoriale della Spezia, Forte Santa Teresa, 19036
Pozzuolo di Lerici
2 - CNR - ISMAR, sezione territoriale di Trieste, Viale R. Gessi 2, 34123 Trieste
Key terms: Hydrography; Transport; Sicily Strait
The Sicily strait is a key point to observe the exchanges between the eastern
WORKSHOP W10
38
and western Mediterranean basin, both in term of water masses and their
associated properties. Variations of volume and of hydrographic characteristics
can induce important modification in the adjacent basins. This is particularly
evident during the last 15 years, when the Eastern Mediterranean Transient
(EMT), reached the Strait and propagated in the Western Basin.
The effects of the EMT in the eastern basin are far to be concluded and its
perturbation still propagate through the Sicily strait. In previous works,
different characteristics and phases of propagation have been described.
Changes in the hydrographic conditions went to modify firstly the deep layer
and successively the intermediate. Recently, starting from 2006, a new deep
phase seems to be active in the Strait. A denser water was observed to cross
the western sill, sinking at greater depth when reached the Tyrrhenian sea.
Two currentmeter moorings, positioned in correspondence of the western sill of
the Strait, are maintained for a long term monitoring of water mass exchanges
through the Strait. The principal time scales have been investigated together
with the response to the wind forcing. Transport has been estimated along the
examined period and related to the hydrographic conditions.
W10-120 Poster
Ghezzo, Michol
MODELLING HYDRODYNAMICS AND WATER QUALITY OF THE TARANTO
SEA: EARLY RESULTS
GHEZZO Michol 1, PERILLI A. 2, ALABISO Giorgio 3, MARCELLI M. 1, SCOCCARO I. 4,
UMGIESSER G. 4, CUCCO A. 2
1 - Università della Tuscia, DECOS, via di S. Decollato 1, 01100 Viterbo, Italia
2 - Istituto Ambiente Marino Costiero, IAMC-CNR, U.O. Oristano, c/o IMC International Marine Centre, Località Sa Mardini, 09072 Torregrande-Oristano,
Italia
3 - Istituto Ambiente Marino Costiero, IAMC-CNR, U.O. Taranto, Italia
4 - Istituto di Scienze Marine, ISMAR-CNR, U.O. Venezia, S. Polo 1364, 30125
Venezia, Italia
Key terms: numerical model; Taranto sea; hydrodynamic; water quality
The Taranto sea (Mar Grande and Mar Piccolo) is a remarkable site for trading,
strategical and ecological aspects. It is divided into two sub-basins: the Mar
Grande and the Mar Piccolo connected to the sea and one each other by the
First Inlet and the Second Inlet. The Northern-most area of the Mar Piccolo and
the south-eastern area of the Second Inlet are subjected to environmental
safeguarding restrictions.
Informations about the physical and biochemical processes that drive the
ecosystem have been provided by bibliographic data. We have applied the
hydrodynamic and water quality modules of the numerical model
SHYFEM-EUTRO to study some features of this site. The SHYFEM-EUTRO is a
well tested numerical model already adopted to study coastal areas
characterized by complex bathymetry.
We analysed the available meteorological data of this site in order to evaluate
the most frequent wind intensities and directions in the Taranto sea. The model
have been applied in bi-dimensional version with realistic forcings in order to
study the spatial and temporal variability of the velocity fields in the monthly
time scale. Other similar simulations lasting one full year have been carried out
to examine the seasonal evolution of the temperature, salinity, chlorophyll a
and zooplankton fields.
We compared the numerical results of hydrodynamical and ecological variables
with available bibliographical data. In particular results about temperature,
salinity and chlorophyll have been compared with spatially averaged data for
the three different basins. From an hydrodynamic standpoint the current
velocity is generally low and mainly influenced by the wind action. In particular,
in the Second Inlet of the Mar Piccolo, where the hydrodynamic activities is
generally low, the southern wind can often strengthen the water circulation.
The model can suitably simulate the evolution of the temperature field but
overestimates the salinity, particularly in the Second Inlets, probably due to
unknown fresh water input. What concerns the water quality, the model can
reproduce the spatial and temporal variability of the phytoplankton and
zooplankton dynamics but it is not able to fit appropriately the measurements.
This preliminary results shows some critical points: the quality and the quantity
of input data need to be improved, some assumptions of the setup of the
hydrodynamical model of the basin should be re-evaluated (barotropic system)
and some aspects of the water quality code could not be adequate for the
Taranto Sea.
The future developments of this work will be to estimate the different inputs for
the system and to compare the hydrodynamical results with velocity or level
measurements in order to validate the circulation field. The availability of long
and complete ecological data timeseries will allow the calibration of some
ecological variables and eventually to develop some parts of the code to adapt
it to the Taranto sea features.
W10-121 Orale
Giani, Michele
FLUXES OF SETTLING PARTICULATE MATTER AND ORGANIC CARBON
IN THE ADRIATIC SHELF: A REVIEW OF EXISTING DATA
GIANI Michele 1, BOLDRIN Alfredo 2, PUGNETTI Alessandra 2, SPAGNOLI Federico 3,
FRASCARI Franca 4
1 - Istituto Centrale per la Ricerca scientifica e tecnologica Applicata al Mare
2 - Istituto di Scienze del Mare ISMAR-CNR Venezia
3 - Istituto di Scienze del Mare ISMAR-CNR Ancona
4 - Istituto di Scienze del Mare ISMAR-CNR Bologna
Key terms: Organic carbon; settling particulate matter; Adriatic sea
The waters overlying the Adriatic shelf receive the contribution of the riverine
discharges and are among the most productive areas of the Mediterranean
Sea. The fluxes of settling particulate matter are elevated and contribute to the
sustenance of benthic fauna (e.g.: filter and suspension feeders) and to the
bacterial activity whereas only a fraction is definitively buried.
In the framework of the VECTOR project a review of the published data on
particulate matter fluxes toward the Adriatic shelf sediments measured by
sediment traps and a census of the most significant metadata available has
been carried out.
The analysed data regard coastal areas (in front of Po, Adige and Sile rivers), a
offshore station (20 nautical miles E from Chioggia) and a station in the gulf of
Trieste.
The considered parameters concern the fluxes of particulate matter and of
organic carbon, nitrogen and phosphorus.
The settling fluxes of organic carbon were compared with the primary
production, where available, to estimate the carbon exported and the
importance of advective transport and resuspension processes were also
evaluated.
W10-122 Poster
Giani, Michele
TOWARD A SEDIMENTARY ORGANIC CARBON BUDGET FOR THE
WESTERN ADRIATIC SEA
GIANI Michele 1, FRIGNANI Mauro 2, LANGONE Leonardo 2, MISEROCCHI S. 2,
RAVAIOLI Mariangela 2
1 - ICRAM, loc. Brondolo, Chioggia, Italy
2 - ISMAR-CNR, sede di Bologna, via Gobetti 101, Bologna, Italy
Key terms: Adriatic continental shelf; sediment; organic carbon; mass balance;
data review
The extent of the settling particulate organic carbon (OC) that escapes
resuspension and bacterial degradation is ultimately buried and will be partially
preserved in the sediments. Therefore, they act as a sink for the fraction of
CO2 fixed by primary production. The estimate of the OC burial in the western
Adriatic continental shelf can be considered as a first step toward the
calculation of a global carbon budget for the Adriatic. In this regard, a review of
all available OC data has been undertaken in the framework of VECTOR project.
The coupling between OC contents in surficial sediment and mass accumulation
rates allows to estimate the sedimentary OC mass balance.
In the last 20 years, mass accumulation rates were obtained from 210Pb and
137Cs activity-depth profiles in a suite of papers with different purposes.
Among these, Frignani et al. (2005) and Palinkas et al. (2006, 2007) show the
most extended areal coverage (>210 sites). On the other hand, OC contents in
sediments were measured over the years to assess sediment composition and
biogeochemical characteristics, estimate the effects of eutrophycation and
understand the relationships with pollutant concentrations. In particular, within
the PRISMA1 project, OC contents were determined in surface and subsurface
sediments covering an extensive area of the Adriatic platform. High
concentrations were found especially in the western part of the Adriatic shelf
both due to the elevated allochthonous inputs, mainly trough riverine
discharges and primary and secondary production. Furthermore, OC content
and isotopic composition of were used as tracers of the riverine contribution to
the Adriatic shelf sedimentation in the framework of US- and EU-funded
projects EUROSTRATAFORM (2000-2005). Several oceanographic cruises,
carried out to study the subaqueous delta of the Po River and the north and
middle Adriatic shelf, allowed the collection and analysis of 430 surface
sediment and 823 suspended particulate matter samples. Major results have
been discussed in Tesi et al. (2006, 2007) and Miserocchi et al. (2007).
W10-123 Poster
Giorgetti, Alessandra
THE PAN-EUROPEAN INFRASTRUCTURE FOR OCEAN DATA
MANAGEMENT INCLUDES VECTOR META-DATA
GIORGETTI Alessandra 1, SEADATANET Consortium 2
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS
2 - SeaDataNet Consortium
Key terms: Interoperability; distributed; marine data management; meta-data
SeaDataNet EU-funded project (2006 - 2010) is developing basic tools for
implementing the data management activities in conformity with internationally
agreed protocols. It aims to improve the level of quality, the long term
assistance and the accessibility of marine data. A distributed pan-European
infrastructure for marine data management networks the existing National
Oceanographic Data Centres, Satellite Data Centres and Modeling Centres from
nearby all coastal states bordering the European seas. It provides through a
unique portal integrated on-line access to comprehensive, standardized and
validated in-situ and remote sensing marine data, meta-data and products. The
development and adoption of common communication standards (common
formats and vocabularies for data and meta-data), of discovery,
transformation, downloading and viewing services will ensure the Centres
interoperability.
OGS/NODC information system is one of the interoperable nodes linked to the
infrastructure, adopting standardized methodologies and technology for quality
control, data and meta-data distribution. OGS/NODC maintains a catalogue
service, aiming at facilitating marine data searching, location and retrieval,
containing different levels of data and information (meta-data). This includes
the ROSCOP/Cruise Summary Report inventory, the pan-European Directory of
Marine Environmental Data, the more recent European Directory of the Ocean
Observing Systems. All the meta-data are public and accessible through
OGS/NODC on-line server, while the access to the measured data follows a
Data Policy, defined by the data providers.
The Vector field activities are constantly included in the high level
pan-European inventories available through OGS/NODC and SeaDataNet Web
Portals.
W10-124 Orale
Giuseppe, Civitarese
SEASONAL AND INTERANNUAL VARIABILITY OF THE OCEANOGRAPHIC
PROPERTIES IN THE SOUTHERN ADRIATIC (VECTOR ACTIVITY 8.1).
GIUSEPPE Civitarese 1, IBELLO Valeria 1, CANTONI Carolina 1, CATALANO Giulio 1,
COZZI Stefano 1, LUCHETTA Anna 1
WORKSHOP W10
1 - CNR-ISTITUTO DI SCIENZE MARINE, TRIESTE (ITALY)
Key terms: Southern Adriatic; Carbon dynamics; nitrogen dynamics; climatic
change; trophic web
Long-term ocean multidisciplinary time-series are widely considered valuable
tools in documenting and understanding complex phenomena that are the
result of the combined interplay of physical, chemical and biological factors.
The Southern Adriatic, the southernmost and the deepest sub-basin of the
Adriatic Sea, is a site of deep water formation and the origin of the semi-closed
thermohaline cell in the Eastern Mediterranean. Changes in the thermohaline
and biogeochemical properties have revealed the prompt response of this basin
to the multiscale variability of the external forcings. In addition to the seasonal
and interannual variability, variations have also been noticed on decadal time
scale related to the change in deep and intermediate thermohaline circulation
in the Eastern Mediterranean.
Non-linear dependence of vertical particles flux on surface nutrient availability
(with strong interannual variability) suggests the presence of a threshold in the
efficiency of the biological pump. Year-to-year fluctuations of primary and
secondary production and change in phytoplankton and zooplankton species
composition related to change in the horizontal and vertical dynamics in the
basin have been observed.
Here, we present the activity and the first preliminary results obtained in the
frame of the national research program called VECTOR (Vulnerabilità delle
coste e degli ecosistemi marini italiani ai cambiamenti climatici e loro ruolo nei
cicli del carbonio mediterraneo). The main objective of the Activity 8.1
(Collection and analysis of multidisciplinary time series in Southern Adriatic) is
to collect a two-year multidisciplinary dataset in order to assess the
biogeochemical dynamics of carbon and related elements in relation with the
meteorological and hydrographical conditions of the subbasin. Planned
investigations include, among the others: basic hydrological, biogeochemical
and biological measurements along the section Bari-Dubrovnik; currents
measurement; carbon system in the water column; nitrogen dynamics;
observations of key components of the trophic web; vertical carbon flux and
fluxes through the sediment-water interface.
.
W10-125 Orale
Grilli, Federica
PRELIMINARY RESULTS OF OCEANOGRAPHIC DATA ALONG THE
SECTION VIESTE-SPLIT DURING SIX CRUISES MADE FROM NOVEMBER
2005 TO SEPTEMBER 2006
GRILLI Federica 1, MARINI Mauro 1, PASCHINI Elio 1, RUSSO Aniello 2, IERMANO
Ilaria 2, BOOK Jeff 3
1 - Istituto of Marine Sciences, CNR-ISMAR
2 - Department of Marine Sciences, Polytechnic University of Marche
3 - Naval Research Laboratory, Stennis Space Center, USA
Key terms: CTD data; nutrients; currents; fluxes; Adriatic Sea
A national research program ("VulnErabilità delle Coste e degli ecosistemi
marini italiani ai cambiamenti climaTici e loro ruolO nei cicli del caRbonio
mediterraneo", VECTOR) is devoted to investigate the impacts of the climate
changes on the Mediterranean Sea and the role of this basin on the CO2 cycle.
The continental platform of the Adriatic Sea is one of the widest shelf area of
the Mediterranean Sea, with high biological production, and it is influenced by
the various effects of the climatic change. The aim of the study is to quantify
the transport of organic and inorganic carbon and the other biogenic elements
from the zone of platform towards the deep sea due to the effect of
thermoaline circulation and atmospheric forcing.
From November 2005 to September 2006 six oceanographic cruises were
carried out along the section Vieste-Split and current profilers (ADCP) were
positioned on the bottom of the section. Hydrographic stations were sampled
with the CTD/Rosette to measure physical (temperature, salinity and density)
and chemical (oxygen, orthosilicate, orthophosphate and dissolved inorganic
nitrogen- DIN) parameters. The geostrophic method was used to compute the
currents across the transect from the CTD data and current data were used to
validate the results. Geostrophic currents allowed estimation of water fluxes
and the net nutrient transports were estimated from these and nutrient
concentrations. A hydrodynamic model with a biogeochemical fluxes module
(Regional Ocean Modular System, ROMS) is implemented in the Adriatic Sea
and results will be validated by observation. Measurements of CO2 will be
subsequently made (in 2008 oceanographic cruise) to calculate and quantify
the carbon fluxes through the section, using modeling results, too.
Some preliminary results concerning oceanographic properties, water current
time series, water and nutrient fluxes in the water column were successfully
achieved.
W10-126 Orale
Guglielmo, Letterio
VECTOR PROJECT: ROLE OF ZOOPLANKTON IN THE PELAGIC CARBON
CYCLE
GUGLIELMO Letterio 1, MINUTOLI Roberta 1
1 - Department of Animal Biology and Marine Ecology, University of Messina,
Italy
Key terms: Zooplankton biomass; zooplankton migration; pelagic carbon cycle;
carbon remineralization; Mediterranean Sea
Zooplankton plays a key role in the carbon flux of the water column among
different layers, taking part also in the POC remineralisation phenomenon. With
the death of the organisms and with their metabolism products, like fecal
pellets, the zooplankton passively increases the concentration of organic
particulate matter that flows from the surface, decreasing, to the bottom.
Furthermore the zooplankton takes part actively in the carbon transfer. Many
species in fact, show day-night vertical migrations, feeding themselves on
phytoplankton in surface during night and coming back to lower depths at
sunrise. This phenomenon is very important in the pelagic carbon cycle, being
39
responsible of the C transfer. The zooplanktonic species actively moreover
takes part into the carbon remineralisation, using for their structures C from
the POC sinking flux, changing this element from a particulate form to biomass.
The study of the role of zooplankton in these processes is the main topic of our
researches carried out inside the lines 8.1, 8.2 and 8.5 of the VECTOR project.
In lab we evaluate the oxygen and carbon demands from any zooplankton
sampled layer, trough the ETS (electron transport system) analysis. The
sampling instrument is the electronic multinet BIONESS, that collects at
different layers, investigating so all the water column. During any trawl,
chemical, physical and biological parameters are measured in real time, like the
temperature, fluorescence, salinity, pH, size spectrum, etc. The samples are
splitted immediately into two subaliquotes, one preserved in 4% buffered
formaldehyde and sea water for the quali-quantitative analyses, the other one
frozen in liquid nitrogen for the ETS analyses. This kind of evaluation is carried
out in lab trough a spectrophotometric assay of the sample absorbance at 490
nm, after their processing in accordance with the methodological protocol of
Martin et al. 1971 and Koppelmann et al. 2000. The elaborated results give us
values of umolO2/g*h, umolC/g*h, ugC/g*h and ugC/g*d, suggesting the
quantity of carbon consumed for gram of zooplanktonic biomass for a day and
for any sampled layer. Moreover to the ecological study of the zooplanktonic
compartment (trophic chain, migrations, vertical and horizontal distribution,
biodiversity, biomass), we study in this way the role of zooplankton in the
carbon vertical flux, analyzing the percentage with which this group takes part
in to the remineralization of particulate organic C at different depths inside the
water column. The VECTOR project involves the use of sediment traps
positioned in the fix stations named AM1 for the south Adriatic and VTM for the
south Tyrrhenian in order to register the sinking flux at different depths.
Sampling and processing zooplankton in stations where there is a sediment
trap, we can have the following informations:
°evaluation of oxygen consumption by zooplankton in any sampled layer
°conversion into carbon requirement (King et al., 1978) for any layer
(ugC/gwwt/d)
°mesozooplankton carbon demands in the water column were calculated by
multiplyng the biomass of each zooplankton sampling interval and the carbon
consumption rates
°the study of zooplankton taxonomic composition of any layer and its C
consumption, let us to justify an higher or lower demand from the key species
of the sampled layers
°evaluation of relations between day-night vertical migrations and vertical
organic carbon flux in the water column.
°estimation of particulate carbon sinking flux at different depths
°evaluation of carbon losses from the surface to the bottom in this flow
°evaluation of % contribution with which the zooplankton of any layer takes
part into the remineralization phenomenon.
Until now we have participated at the oceanographic cruises AM1, AM3 and
TM3, and we have collected in total 184 samples fixed in formaldehyde and sea
water and 164 frozen for ETS calculation. In the sampling stations (AM1 and
VTM) the sampling were repeated four times (every six hours) in 24 hours in
order to study the vertical migrations. The sampled layers were for the Adriatic
0-1000, 1000-800, 800-600, 600-400, 400-300, 300-200, 200-100, 100-80,
80-60, 60-40, 40-20, 20-0 m and for the Tyrrhenian one 0-2000, 2000-1600,
1600-1400, 1400-1200, 1200-1000, 1000-800, 800-600, 600-400, 400-300,
300-200, 200-100, 100-80, 80-60, 60-40, 40-20, 20-0 m. The samples are
now processing and the preliminary results will be presented at the Workshop.
W10-127 Orale
Ibello, Valeria
NITROGEN DYNAMICS IN THE PELAGIC SYSTEM OF THE
MEDITERRANEAN SEA, WITH SPECIAL EMPHASIS TO DINITROGEN
FIXATION
IBELLO Valeria 1, CANTONI Carolina 1, COZZI Stefano 1, CIVITARESE Giuseppe 1
1 - CNR - Istituto di Scienze Marine, Sede di Trieste. Viale Romolo Gessi 2,
34123 Trieste. ITALIA
Key terms: Inorganic nutrients; nutrient budgets; organic nitrogen; nitrogen
fixation; Mediterranean Sea
Dynamics of the production processes in the Mediterranean Sea is strongly
influenced by the availability and ratios of inorganic nutrients that, in turn, are
driven by a combination of continental inputs, atmospheric deposition,
circulation, water mass exchange through the Strait of Gibraltar and interior
biogeochemical modifications in the water column.
Inorganic N/P ratios significantly higher compared to the classical oceanic
Redfield's model characterize the bulk of Mediterranean Sea, whose occurrence
has not been ultimately explained, to date. Moreover, several uncertainties
remain about basic processes that determine the budget of nutrients in this
basin. Two hypotheses were mainly considered to explain this excess of
inorganic nitrogen compared to inorganic phosphorus. The contribution to the
nutrient budget of the dissolved organic nitrogen, entering from Gibraltar
because of the lateral advection, and the presence of a not negligible N2
fixation in the pelagic system, which contributes to sustain the microbial
community over the uptakes of inorganic N-nutrients making available new
nitrogen from the atmospheric N2. Elevated N2 fixation rates were recently
reported for the East Mediterranean, but the information available in the
literature is still far to be sufficient for the evaluation of the significance of this
process on basin scales.
Preliminary data presented in this work show the dynamics of inorganic
N-nutrients, dissolved and particulate organic nitrogen and N2 fixation rates in
different sub-areas of the Mediterranean Sea. Data were collected during
TRANSMED oceanographic cruise carried out in the framework of VECTOR
Research Project (June 2007). Experimental results are discussed in
relationship to the hypothesis previously mentioned.
W10-128 Orale
Kovacevic, Vedrana
THERMOHALINE STRUCTURE ALONG THE OTRANTO SECTION AS
OBSERVED DURING THE VECTOR OCEANOGRAPHIC CAMPAIGNS IN
2006 AND 2007
WORKSHOP W10
40
KOVACEVIC Vedrana 1, URSELLA Laura 1, DEPONTE Davide 1, MANCA Bruno 1,
BARBANTI Riccardo 1, BURCA Mihai 1
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS,
Sgonico (Ts), Italia
Key terms: Water masses; thermohaline properties; water exchanges; Otranto
Strait
Characterisation of the water masses and their spatial distribution along the
Otranto section has been used in determining the water exchange between the
Adriatic and Ionian Sea. In particular, shelf cool and less saline waters are
tracked in the outgoing branch along the western flank, warmer and saline
Ionian surface, and Levantine intermediate waters inflow along the eastern
flank. Of particular interest there is a water mass at the western continental
slope at depths between 700 and 1000 m, which characterizes the Adriatic
Deep Water outflow. During the recent Eastern Mediterranean transient it had
been competing with the dense Cretan Sea waters in filling in the Eastern
Mediterranean abyss. The most recent oceanographic cruises, conducted in the
framework of the VECTOR project, put in evidence the patterns of the
hydrographical properties in the Strait of Otranto in November 2006 and in
April 2007. The use of the available vessel-mounted ADCP (Acoustic Doppler
Current Profiler) data, associated to the vertical thermohaline patterns,
completes the dynamical picture encountered during the two campaigns. These
recent observations are compared to the historical ones.
W10-129 Poster
La Ferla, Rosabruna
MICROBIAL BIOMASS AND ACTIVITY ESTIMATES AT A SOUTHERN
TYRRHENIAN SEA PELAGIC STATION
AZZARO Maurizio 1, CARUSO Gabriella 1, LA CONO Violetta 1, MAIMONE Giovanna 1
, MONTICELLI Luis Salvador 1, YACHIMOV Michail 1, LA FERLA Rosabruna 1
1 - CNR-IAMC- Messina
Key terms: Tyrrhenian Sea; Microbial Biomass; Microbial Respiration; Bacterial
Production; Enzymatic activities
The Southern Tyrrhenian Sea is a basin of the Mediterranean Sea, crossed by
the biological fluxes that take place between the western and the eastern
basins. In spite of its important geographical location, only a few marine
pelagic studies have been performed on this sea, which has become the study
site of national and international scientific projects carried out in the most
recent years only.
The present study is a part of multidisciplinary project (VECTOR), aimed at
studying the carbon cycle in different pelagic areas of the Mediterranean Sea.
Particularly, the specific aim of our Operational Unit is to evaluate the carbon
fluxes through the microbial community along the water column at a selected
pelagic station (VTM, Latitude 39° 30' N; Longitude 13° 30' E) during different
seasonal conditions. Besides the estimate of the total (DAPI staining) and
autotrophic bacterioplankton standing stock, three main processes in which
microorganisms are involved are investigated: the decomposition through
enzymatic hydrolysis (Extracellular Enzyme Activity) of proteins and
polysaccharides (due to leucine aminopeptidase and ß-glucosidase,
respectively), the incorporation of the released monomers with new biomass
production (bacterial carbon production, estimated with the 3H-leucine
incorporation method) and the re-mineralization of organic matter through the
microbial respiration (Electron Transport System assay). Prokariotic diversity,
and in particular the composition of the microbial community involved in
carbon dioxide fixation and ammonia oxidation is also investigated.
To date, three oceanographic cruises have been performed at VTM station
(November 2006; February and April 2007), during which the above-cited
microbial parameters have been measured along the water column at the epi-,
meso- and bathypelagic layers. Interpretation of the obtained data will be
undertaken also in the light of knowledge gained during previous cruises
carried out in July and December 2005 at the same station under study.
W10-130 Poster
La Ferla, Rosabruna
VARIABILITY OF MICROBIAL BIOMASS AND ACTIVITIES IN THE
SOUTHERN ADRIATIC SEA (NOVEMBER 2006-APRIL 2007)
LA FERLA Rosabruna 1, AZZARO Maurizio 1, MAIMONE Giovanna 1, MONTICELLI
Luis Salvador 1, ZACCONE Renata 1
1 - CNR-IAMC-Messina
Key terms: Adriatic Sea; Microbial biomass; Microbial respiration; Bacterial
production; Enzymatic activities
Microbial community plays a key role in the remineralization of macro- and
oligo-elements in the whole water column, determining discontinuities in the
transfer of biogenic matter towards the sediments. Moreover, bacterial
metabolism interferes with the complex mechanism of CO2 sequestration
within oceanic depths, assuming a primary role in modulating the "biological C
pump".
Aiming at defining the efficiency of the physical and biological pumps in the
Mediterranean Sea, in the frame of VECTOR project, line 8 (CARPEL), three
multidisciplinary oceanographic surveys in the Northern Adriatic Sea from
November 2006 to April 2007 were carried out.
Our operative protocol foresaw seawater samplings at a fixed pelagic station
(41°38'N, 17°47'E), located in the central zone of a cyclonic gyre, till about
1200 m depth.
The following parameters were studied:
-Total and phototrophic picoplankton biomass (abundances and biovolumes by
imaging analysis);
- Hydrolytic enzymatic potential rates of organic polimers (Extracellular
Enzymatic Activity: EEA) by estimating leucine-aminopeptidase, b-glucosidase
and alcaline-fosfatase, degrading proteins, polysaccharides and organic
phosphates, respectively.
-Potential rates of bacterial production (Heterotrophic Bacterial Production:
HBP) by 3H-leucine uptake;
- Respiratory rates (R) by ETS assay (Electron Transport System activity).
The joined analysis of the examined parameters in different situations (preand post-convective) will provide a synoptic picture of the seasonal variability
of C flux through the heterotrophic microbial compartment.
W10-131 Poster
La Ferla, Rosabruna
FIRST MICROBIOLOGICAL DATA FROM THE LAGOON AREA OF CAPE
PELORO (MESSINA)
ZACCONE Renata 1, AZZARO Maurizio 1, AZZARO Filippo 1, CARUSO Gabriella 1,
GIACOBBE Maria Grazia 1, MANCUSO Monique 1, MARINI Antonella 1, MONTICELLI
Luis Salvador 1, MAIMONE Giovanna 1, LA FERLA Rosabruna 1, et al.
1 - CNR-IAMC-Messina
Key terms: Cape Peloro; lagoon area; Vibrio; cyanobacteria; HABs
The Cape Peloro (Messina) lagoon area frequently suffers dystrophic crises. In
September 2006 a massive fish death took place in Ganzirri lake; samples
collected during that episode pointed out the occurrence of an algal bloom,
ascribable to Dinoflagellates, mostly belonging to the species Prorocentrum
mexicanum, recognised as a toxic algae, which has been found both in
tropical/subtropical and temperate ecosystems, colonised by macroalgae. The
bloom spreaded over the lake, causing a marked reduction of the dissolved
oxygen at some sampling stations; the recorded temperature was 27,8°C.
In the framework of VECTOR -DIVCOST Project the research team was
interested in studying the dynamics of selected species of potentially
pathogenic Vibrio, toxic cyanobacteria and toxic phytoplankton (HABs), in
relation to environmental changes in the Cape Peloro (Messina) lagoon area.
In particular, the experimental study concerned six stations, whose one was
located in Faro lake and the other five in Ganzirri lake, which were sampled
seasonally during September and December 2006, March and July 2007.
The quantitative study showed a decreasing abundance of total vibrios from
September 2006 to March 2007 in both lakes. The most frequent species were
V. vulnificus and V. fluvialis. Bacterial indicators of faecal pollution (Faecal
coliforms and Enterococci) followed a trend similar to Vibrios. The abundance of
aerobic heterotrophic bacteria was more variable, ranging from 102 to 103
CFU/ml. Temperature values were comprised within a range of 23,4 and
24,9°C in September, reaching minima in December (range: 15,92 - 16,37 °C).
Cyanobacterial community analysis did not reveal the occurrence of potentially
toxin-producing species. Similarly, the highest suspended matter content was
found in September in Ganzirri lake (90,20 mg/l), with a progressive decrease
in the following samplings (December'06: 32,13mg/l; March '07: 22,98mg/l).
The above-cited parameters were also studied in mussels collected from Faro
lake; the most isolated Vibrio species was V. alginolyticus.
At the end of the first research year a possible correlation between the studied
microbiological parameters and the environmental data will be obtained.
W10-132 Orale
Marani, Marco
CLIMATE CHANGE AND MULTIPLE EQUILIBRIA IN TIDAL
ECO-GEOMORPHOLOGY
MARANI Marco 1, ANDREA D'Alpaos 1, STEFANO Lanzoni 1, LUCA Carniello 1,
ANDREA Rinaldo 1
1 - Dip. IMAGE e Centro Int. di Idrologia D. Tonini - Università di Padova
Key terms: geomorphology; tidal environments; climate change
The dynamics of estuaries and lagoons are the result of complex feedbacks
between coupled biotic
(e.g. linked to halophytic vegetation and microphytobenthos) and abiotic
processes (chiefly sediment erosion and deposition, hydrodynamics, eustatism
and sea-level change).
In contrast, our understanding of their dynamics has so far evolved within
separate disciplines, e.g. concerned with the morphological evolution of tidal
flats, marshes and channels or with specific compartments of tidal ecosystems,
such as marsh vegetation or microphytobenthos. Here we introduce an
eco-geomorphological model for the time evolution of the elevation of a tidal
platform regularly inundated by the tide. The model, based on the sediment
continuity equation, includes the effects of vegetation and microphytobenthos
on sediment erosion and deposition. A variable set of stable and unstable
equilibria emerges, depending upon suspended sediment availability, type of
vegetation, disturbance of the benthic biofilm, and rate of sea level change. We
show that switches between stable states may occur providing explanations for
the observed response of real tidal systems to disturbances and changes in
external forcings.
W10-133 Orale
Mauri, Elena
CHLOROPHYLL CONCENTRATION IN RESPONSE TO THE OPEN SEA
WINTER CONVECTION IN THE SOUTHERN ADRIATIC
MAURI Elena 1
1 - Istituto Nazionale di Oceanografia e Geofisica Sperimentale, Borgo Grotta
Gigante 42/c, Sgonico, Trieste, Italy
Key terms: South Adriatic Gyre; concentration chlorophyll; SeaWiFs; MODIS
The Southern Adriatic sub-basin shows oligotrophic characteristics year round,
only during winters the open sea convection provides nutrients to the
phytoplankton in the euphotic zone. The surface signature of the response to
this nutrient injection can be monitored by ocean color satellite sensors
(SeaWiFs and MODIS) in cloud-free conditions. The open sea convection varies
from one year to the other and is localized in the deepest part of the sub-basin
characterized by a quasi permanent cyclonic circulation, called the South
Adriatic Gyre (SAG).
March and April weekly composites of SeaWiFs and MODIS data are analyzed
WORKSHOP W10
to study the inter-annual variability of the surface chlorophyll concentration in
the Southern Adriatic for the period 1998 to 2007. The weekly time scale is
chosen because it is able to capture the intense bloom episodes which occur in
the center of the SAG in calm weather conditions following violent vertical
mixing events. Basic statistics are estimated to study the variability and
anomalies of the chlorophyll concentration signal.
W10-134 Poster
Merola, Gerardo
LAND USE VARIATIONS IN THE SELE AND BUSSENTO RIVER BASINS
(1990-2000)
MEROLA Gerardo 1, FAGNANO Massimo 1, CEFARIELLO Roberto 1, ALBERICO Ines 1
1 - Università degli studi di Napoli Federico II
Key terms: Land use; Corinne land cover; Sele; Bussento
In the frame of the Vector project, the variations of Land use between 1990
and 2000 have been analyzed in the Sele and Bussento river basins (data of
years 1990 and 2000 from the APAT project CLC/200).
The total area is 396000 ha, 85% of which belongs to the Sele basin. In 1990
this basin was mainly represented by latifoliae forests (37%) and by rainfed
crops such as winter cereals (17%). The Bussento basin has the highest part
covered by latifoliae forests (55%), while the 10% is represented by grassland.
Urbanized areas covered in 1990 the 2% (7215 ha) of total area, half of which
represented by not-continuous urban texture. In the year 2000 the most
spread categories were latifoliae forests and rainfed croplands while the
urbanized areas increased of 418 ha.
The variations between 1990 and 2000 cover 1231 ha on the whole are. The
most changed category has been the latifoliae forest of the Sele river basin
that increased of 72 ha. Urbanized area increased of 425 ha over the previous
rainfed crops (192 ha), while permanent crops cover an area of 124 ha.
W10-135 Poster
Ortolani, Franco
CLIMATE CHANGE AND BEACH EVOLUTION IN THE MEDITERRANEAN
AREA
ORTOLANI Franco 1, PAGLIUCA S 2
1 - Naples University Federico II, Italy
2 - CNR-ISAFOM, Ercolano, Naples, Italy
Key terms: climate change; environmental change,; Historical period; littoral
evolution; Mediterranean Area
Correlation of the geoarchaeological stratigraphy with the reconstruction of
multicentennial solar activity shows that significant and cyclical environmental
changes occurred in the Mediterranean Area in concomitance with significant
multicentennial changes in solar activity. During the periods in which the
temperature increased by 1-2° C the coastal zones were affected by
desertification up to a latitude of about 42° N (Roman "Greenhouse Effect",
100-300 A.D.; Crusades "Greenhouse Effect", 1100-1270 A.D.). The littorals
with silicoclastic sands where affected by severe erosion while the beaches with
organogen sands where characterised by evident progradation. During the
decreases in temperature the areas of the alluvial plains subject to human
impact and settlements were affected by an accumulation of huge volumes of
sediments with consequent aggradation and progradation of the coastlines in
the northern part of the Mediterranean while severe erosion occurred along the
beaches with bioclastic sands of the southern part (Archaic Little Ice Age,
500-300 B.C.; Dark Age Little Ice Age, 500-750 A.D.; Little Ice Age,
1500-1830 A.D.).
On the basis of scientific data it is possible to predict that the beach erosion
affecting the littorals with silicoclastic sand, prevalently caused by the climate
variation, will continue for 150 years at least.
Many thousands of kilometres of the Mediterranean coastline are affected by
serious erosion which undermines not only the aggressive anthropisation that
has taken place up to a few metres from the sea, but also the social and
economic structure of entire regions whose economy is largely based on
seaside tourism.
It is undeniable, in fact, that coastline economy based on quality tourism,
fostered by beautiful beaches, has made a considerable contribution to the
improvement of the social and economic position of the coastal regions.
The beach erosion, consequently, represent a direct economic danger for the
national and regional socio-economic condition.
Without effective and coordinated planning of the safeguarding, improvement
and protection of the coastal areas, deterioration accentuated by predictable
defence work made necessary by local emergency situations, will become more
and more seriuos.
On the base of the climatic-environmental cyclicity it is possible to predict that,
in the near future, the littorals of Southern Italy and of the Southern part of
the Mediterranean, with organogen sand, will be affected by very active
sedimentation and progradation, as it happened during the Medieval Warm
Period.
W10-136 Poster
Pacciaroni, Massimo
CARBON GEOCHEMICAL VARIABILITY IN THE MEDITERRANEAN
ECOSYSTEM
PACCIARONI Massimo 1, CRISPI Guido 1
1 - OGS
Key terms: geochemical carbon cycle; field of mass; alkalinity
The geochemical system in the water mass is represented by employing
dissociated chemical species at equilibrium according to their own apparent
dissociation constant. The scheme requires the total concentrations of
carbonates, phosphates, borate, silicate, hydrogen and hydroxide ions, and the
41
total alkalinity. Its subdivision in the carbonic, phosphoric, boric, silicic acids
and water dissociation contributions allows the determination of pH (in
seawater scale - SWS) and CO2 partial pressure.
Keeping constant the temperature in the water and varying the salinity, from
fresh water low values to open sea higher ones, the corresponding variations in
terms of pH and pCO2 are determined. The apparent dissociation constant
values change and consequently both the carbonic acid concentration in
seawater and pH. Increasing salinity at specific temperature, the pH value
decreases and the seawater mass is acidified.
Following these variabilities and in order to deal with the ecosystem dynamic as
a whole, it is appropriate to include CO2, CH4, N2, O2 exchanges at air-sea
interface. These fluxes depend both on the partial pressure in the two media
and on the meteomarine conditions.
W10-137 Orale
Patara, Lavinia
LONG-TERM ADJUSTMENTS IN THE PHYSICAL-BIOLOGICAL FEEDBACKS
OF THE EQUATORIAL PACIFIC
PATARA Lavinia 1, VICHI Marcello 1, PIER GIUSEPPE Fogli 1, SIMONA Masina 1,
ELISA Manzini 1
1 - Istituto Nazionale di Geofisica e Vulcanologia (INGV) - Centro
Euro-Mediterraneo per i Cambiamenti Climatici (CMCC), Bologna
Key terms: Biogeochemical Cycles; Earth System Model; Climate Feedbacks
Marine ecosystems are major components of the Earth System and contribute
to the regulation of atmospheric CO2. The main productive regions of the
oceans are responsible for most of the air-sea exchange of inorganic carbon
and for the likely organic carbon export to the deep ocean. The high
concentration of phytoplankton biomass is also responsible for the attenuation
of the penetrating irradiance in the water column, which modifies the thermal
budget of the surface ocean. The equatorial Pacific is particularly sensitive to
heat budget variations as recent numerical experiments have shown
(Nakamoto et al., 2001; Murtugudde et al., 2002; Sweeney et al., 2004). The
CMCC-INGV Earth System Model is a fully coupled ocean-atmosphere general
circulation model including sea-ice and marine biogeochemistry
parameterizations. About 400 years of simulation were produced and analyzed,
of which 200 years contain marine biogeochemistry (GREEN experiment) and
200 years contain only the physical components (BLUE experiment). We
focused on the equatorial Pacific region, where we compared the BLUE and
GREEN experiments in order to assess the effects of biology on the physics.
The differences show a long term adjustment involving the whole equatorial
Pacific area. During the first 50 years the GREEN simulation experiences in the
western equatorial Pacific an increase of sea surface temperatures exceeding
0.6 °C, while during the last 50 years this difference falls below 0.2 °C. During
the first period, the dominant zonal winds and the equatorial divergence grow
weaker and precipitation intensifies in the west. However these effects
attenuate during the last 50 years, consistently with the reduction of the
surface warm anomaly in the west. In the GREEN experiment the radiative
effect of phytoplankton contributes to the formation of an initial positive
temperature anomaly with respect to the BLUE experiment. This anomaly is
transported and maintained in the west because of zonal advection, where it
produces a precipitation increase and thus an intensification of the Walker
circulation. This effect is however transitory, since the coupled
atmosphere-ocean dynamics has the tendency to reduce the initial anomaly
induced by phytoplankton. This work suggests that phytoplankton is to be
considered an important dynamical component of the climatic variability of this
region.
W10-138 Poster
Percopo, Isabella
PHYTOPLANKTON DIVERSITY AT OFFSHORE TYRRHENIAN SEA
STATIONS
PERCOPO Isabella 1, ZINGONE Adriana 1
1 - Stazione Zoologica "A. Dohrn", Villa Comunale 1 80121 Naples, Italy
Key terms: Phytoplankton diversity; microalgal community; Offshore
Tyrrhenian Sea
Small microalgae (< 10 m) are characterized by a high taxonomic diversity
and a great difficulty in the identification using traditional methods (LM). The
combination of several techniques is needed to better understand the dynamics
and the ecology of this important fraction of the phytoplankton which is
responsible for the largest part of primary production in oligotrophic waters. LM
cell counts on fixed samples, serial dilution cultures (SDC) and electron
microscopy (EM) were used to study the microalgal community of an open-sea
area of the Southern Tyrrhenian Sea during three oceanographic cruises
carried out along a transect in November 2006, February and April 2007. LM
counts showed the lowest phytoplankton abundances at surface in November
(average: 2.3 x 102 cell ml-1) and the highest abundances in April (average:
4.3 x 102 cell ml-1). Rather homogeneous phytoplankton assemblages were
observed in fixed samples, which were largely dominated by small-sized cells,
mainly phytoflagellates (up to 90%) and coccolithophorids (up to 29%). In
April, small diatoms (Bacteriastrum parallelum, Skeletonema pseudocostatum,
Chaetoceros sp.) were abundant (ca 40% of the microalgal assemblage) only in
surface waters at the most inshore station of the transect. In contrast with the
apparent homogeneity of fixed samples, a considerable specific diversity was
detected in SDCs, where more than 20 species belonging to 6 different classes
were identified. Scanning EM observations allowed the identification of about
50 coccolithophore species, with different populations among the sampling
periods.
W10-139 Orale
Querin, Stefano
NUMERICAL SIMULATION OF DENSE WATER FORMATION PROCESSES
WORKSHOP W10
42
IN THE NORTHERN ADRIATIC SEA
QUERIN Stefano 1, LAURENT Célia 2, CRISE Alessandro 1, SOLIDORO Cosimo 1
1 - ISTITUTO NAZIONALE DI OCEANOGRAFIA E DI GEOFISICA SPERIMENTALE
(OGS)
2 - UNIVERSITÉ DE VERSAILLES SAINT-QUENTIN-EN-YVELINES
Key terms: Numerical model; Northern Adriatic Sea; Circulation; Dense water
This numerical study presents recent results obtained by running a
hydrodynamic model for the Northern Adriatic Sea. The aim of this activity, in
the framework of the VECTOR project, is to study the formation and transport
of dense water masses, which originate in the Northern Adriatic Sea in winter
and spread along the basin. Wintertime seawater temperature usually reaches
minimum values in February, because of the strong atmospheric cooling.
Concurrently, low riverine discharges due to snow heap on the watershed
increase water salinity. These factors cause the formation of the dense water
masses (7°C, 38 psu, 1030 kg/m3), especially in the Gulf of Trieste and in the
surrounding areas. In order to reproduce and analyze the process, simulations
are carried out customizing the MITgcm, a three-dimensional, finite volume,
non-hydrostatic, general circulation model. The model domain (0.0225° (~ 2.5
km) horizontal resolution) is limited by the transect along the 100 m isobath
(from 80 km south of Ancona -along the Italian coast- to 50 km south of Zadar
-along the Croatian coast-). The bathymetry and the initial thermohaline
conditions are obtained from interpolation of experimental data, while passive
radiation conditions are applied to the southern boundary. Riverine flow rates
are derived from in situ measurements and are modeled in such a way as to
consider both the thermohaline and momentum contribution. The surface
atmospheric forcing is interpolated from a high resolution Limited Area Model
(LAM: ETA006). Since winter 2006/2007 has been particularly mild, simulations
are run both with realistic conditions (measured ICs, BCs and ETA006 forcing)
and idealized conditions (strong and dry winds and intense negative heat
fluxes). A comparison of the results obtained in the two forcing conditions is
carried out, together with a discussion about the phenomena that trigger the
dense water flux.
W10-140 Orale
Ravaioli, Mariangela
THE ROLE OF THE SEDIMENTS OF THE ROSS SEA AND PACIFIC SECTOR
OF THE SOUTHERN OCEAN (ANTARCTICA) IN THE GLOBAL BUDGET OF
THE CARBON CYCLES. BIOSESO AND ABIOCLEAR PROJECTS
HISTORICAL DATA SERIES
RAVAIOLI Mariangela 1, CAPOTONDI Lucilla 1, FRIGNANI Mauro 1, GIGLIO F. 1,
LANGONE Leonardo 1
1 - Istituto di Scienze Marine, sede di Bologna, Via Gobetti 101, 40129
Bologna, Italia
Key terms: Marin sediment; organic carbon; particles fluxes; Southern Ocean;
historical data series
The polar areas, and the southern one in particular, play a key role in the
cycles of greenhouse gases, and hence the global climate. However, it has long
been debated if the Southern Ocean is a CO2 sink due to summer productivity
or an annual source due to the upwelling of deep water. From 1999 onwards,
several research projects (BIOSESO I/II - Biogenic sedimentation in the
Southern Ocean, 1999-2005 and Abioclear - Antarctic BIOgeochemical
cycles-CLimatic and palEoclimAtic Recostructions, 2006-2008) have been
carried out to better understand the role that the Ross Sea and the Pacific
Sector of the Southern Ocean play in the global carbon cycling. Within the
framework of these projects, the researcher team of the Marine Science
Institute of Bologna (CNR) collect data on sinking particle compositions and
fluxes and sediment records in these areas to estimate organic carbon primary
production, export from the photic layer, remineralisation in the water column
and in surficial sediments, and burial. The data set obtained from the projects
include particle samples collected during ca. 8 years by moored automatic
sediment traps at 2 different levels (one just below the photic levels and the
other about 50 m above the sea bottom). More than 100 sediment cores and
box-cores were also collected. We believe that this extensive data set could be
used to quantify the actual role of the area in the global carbon cycle.
W10-141 Poster
boundaries.
The network of marine scientists envolved in VECTOR CARADRI has recently
(August 2006) been included in the international (I-LTER) and European
(E-LTER) long-term ecological networks.
Different institutions are cooperating in the management of the different
stations and in the gathering and sharing of data in this site. At all the stations
of the NAS automatic acquiring devices ensure a continuous gathering the main
meteo- and hydrological parameters.
Process oriented measures such as: vertical fluxes, primary production rates
regarding both bacterial and plankton systems, isotopic tracers (U/Th),
Dissolved, Particulate of inorganic and organic carbon concentration, allow a
better comprehension of the origin and faith of the main fractions of carbon
flowing through the ecosystem. During the meeting will be presented some
results.
Michele Giani 4, Aniello Russo 5, Fabio Raichich 1
4: Istituto centrale per la ricerca scientifica e tecnologica applicata al mare,
ICRAM, Chioggia
5: Dipartimento di Scienze del Mare, Università Politecnica delle Marche,
Ancona
W10-142 Orale
W10-143 Poster
AUTOMATIC DATA GATHERING AND PERIODIC SAMPLINGS IN THE
NORTHERN ADRIATIC SEA
RAVAIOLI Mariangela 1, CARDIN Vanessa 2, CRISCIANI Fulvio 1, CATALETTO
Bruno 2, SPAGNOLI Federico 1, BASTIANINI Mauro 1, FONDA UMANI Serena 3,
MARINI Mauro 1, SOCAL Giorgio 1, BOLDRIN Alfredo 1, et al.
1 - Istituto di Scienze Marine, CNR-ISMAR
2 - Istituto Nazionale di Oceanografia e Geofisica Sperimentale, OGS Trieste
3 - Dipartimento di Biologia, Università di Trieste
Key terms: Adriatic; carbon cycle; automatic data; metereological data;
oceanographic buoy
In the framework of the national research program VECTOR (VulnErabilità delle
Coste e degli ecosistemi marini italiani ai cambiamenti climaTici e loro ruolO nei
cicli del caRbonio mediterraneo), a wide array of data-sets have been merged
in the effort to a better understanding of ecosystems functions and of their
feedback to environmental changes. VECTOR focuses at different sites, in
particular the research line CARADRI will study the carbon cycle in the Adriatic
given the reactivity of this ecosystem, considered the Mediterranean area with
the highest mean primary production. Both research and ecological monitoring
of a wide range of variables cover key areas of the basin (Gulf of Trieste, Gulf
of Venice, Po Delta, Ancona). One of the key feature of CARADRI is its
long-term approach and the presence of automatic data gathering systems
which ensures continuity to the collection of data. The ability of buoyed
observatories to make long-term measurements of ongoing processes also
gives the study the potential to play an important role in oceanographic and
climatic studies. They could track the flow of major currents along the adriatic
Rinaldi, Alice
ATMOSPHERIC FORCING ESTIMATION FOR THE ASSESMENT OF HEAT
FLUXES CALCULATION AT THE AIR-SEA INTERFACE IN THE GULF OF
TRIESTE
RINALDI Alice 1, CARDIN Vanessa 1, GACIC Miroslav 1
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale-OGS
Key terms: Gulf of Trieste; Adriatic Sea; Air-Sea Interaction; atmospheric
forcing
Heat flux estimation is very important due to the role that they play in the
distribution of water masses and circulation.They are directly connected with
buoyancy and therefore to the mixing of the water column, dense water
formation process and to the transport of nutrients. In order to assess fluxes
estimation using meteorological data from the model ECMWF, fluxes were
calculated and compared using data coming from fixed station in the Gulf of
Trieste. Meteorological data measured continuosly in each of the buoys
(Mambo, Paloma and Pirano) were analysed and compared with those coming
from the ECMWF model for the period between April 2005 and March 2006.
The comparison of meteorological data between fixed stations reveals that the
Mambo buoy shows higher variations in temperature and relative humidity,
reaching the highest discrepancy during the winter period and the lowest one
during the summer. This fact may be due to the relative vicinity of the buoy to
the coast of Trieste. The analysis of the ECMWF time series shows generally a
very good correlation with the time series of the two buoys (Pirano and
Paloma) following the same trend. On the contrary, a poor correlation with the
Mambo buoy was observed.
The wind speed coming from the model seems to be underestimated by a
percentage varying from 10 to 60% with respect to the wind measured at the
fixed stations. This may be due to the coarse grid of the model (0.5°
latitude/longitude grid) that does not resolve in an adequate way the
orography of the Northern Adriatic Sea. This underestimation is already been
pointed out in literature by several authors.
Heat fluxes have been calculated only in two of the three stations (Paloma and
Pirano) due to the data gaps in the Mambo station time series during the
studied period. Generally, total heat fluxes show similar behaviour in time
between the fixed stations and the model, only differing in the minimum values
because of the turbulent components. Monthly heat fluxes are positive in the
three case studies between april and july 2005, and not until
september/october as it has been reported in literature. This feature may be
due to the meteorological conditions experienced during august/september
2005, cold, rainy and cloudy. For the rest of the year heat fluxes are negative
indicating a loss of heat. Finally, a comparison with previous years
(2003-2004) indicates a good agreement either as far as meteorological time
series are concerned as well as those relative to heat fluxes.
Rivaro, Paola
DISTRIBUTION OF CARBON DIOXIDE SYSTEM PARAMETERS IN THE
SOUTHERN TYRRHENIAN SEA
RIVARO Paola 1, MESSA Roberta 1, FRACHE Roberto 1
1 - Department of Chemistry and Industrial Chemistry, University of Genoa,
Genoa, Italy
Key terms: Southern Tyrrhenian Sea; inorganic carbonate system; parameters
variation
Since the Mediterranean Sea is considered as a vulnerable sea due to the high
population density surrounding it, it is essential to have a better knowledge of
the present state of the carbonate system, to predict his behaviour in the
carbon cycling and climate change.
In this context, the Southern Tyrrhenian Sea is an area of particular interest
due to the physical and chemical properties and the circulation of the water
masses. In the framework of the VECTOR Project activities - research line
CARPEL 8.2 "Serie temporali nel Tirreno Meridionale"-, sea water samples were
collected for chemical analyses.
The sampling was carried out in the Southern Tyrrhenian Sea along a section
from the Gulf of Naples to the Vector station (39°30'N, 13°30'E) in November
2006, February and April 2007 cruises. In order to characterize the carbonate
system in the studied area, Total Alkalinity (TA) and pH in total scale (pHT)
were determined. TA and pH measurements were performed using a
modification of the potentiometric methods described in the DOE Handbook of
methods for CO2 analysis. The accuracy of TA measurement was evaluated
using Certified Reference Material (CRM, Batch 76 and Batch 79, provided by
Dr. A.G. Dickson, Scripps Institution of Oceanography, USA).The precision of
TA measurement was evaluated by duplicate analyses of the CRM.
WORKSHOP W10
In this work, preliminary results are presented and discussed.
The results made possible to assess the vertical distributions (2m - 3400 m)
and the seasonal variations of the considered parameters and to describe the
inorganic carbonate system.
W10-144 Poster
Rubino, Fernando
43
dinoflagellate Scrippsiella trochoidea, that reached 15.3% of the entire resting
stage bank abundance in the study area.
This study is the first regarding the entire cyst bank produced by plankton at
the considered spatial scale, in a complex marine system with a different
typology of basins characterized by a high confinement gradient.
W10-146 Orale
Russo, Aniello
STRATIGRAPHIC DISTRIBUTION OF PLANKTON RESTING STAGES IN
THE MAR PICCOLO OF TARANTO (IONIAN SEA, MEDITERRANEAN)
BELMONTE M. 1, RUBINO Fernando 1
1 - CNR-Istituto per l'Ambiente Marino Costiero, Talassografico "A. Cerruti", Via
Roma 3, 74100 Taranto
Key terms: Plankton; cyst bank; stratigraphic record; environmental
variations; Taranto, Ionian Sea
Sea bottoms in coastal areas, specially in confined basins, host high densities
of resting stages (cysts) produced by pankton. These letargic forms accumulate
in sediments over time producing cyst banks analogous to the seed banks of
terrestrial plants, with millions of cysts/m 2 of bottom.
The presence of resting stages in the life cycles of planktonic species ensure
their persistence in a marine area, even when environmental conditions
become hard, concerning both abiotic and biotic factors, such as predation
pressure and resources availability.
The recruitment of the excysted individuals in the water column occurs when
favourable conditions are reestablished, according to the seasons' cycle.
Not all the potential, in terms of viable propagules, is recruited each time, so
that cysts accumulate in muddy sediments and are buried as new material
settles to the bottom. As a result, sediments of confined marine areas, act as a
continuous recorder of the planktonic community structure, for resting stage
producers at least.
The analysis of deep layers in a sediment core produces a series of instant
pictures that match definite temporal periods. The power of resolution of this
method relies entirely on the basin features, in terms of reworking possibilities
of surface sediment layers, due to bioturbation and/or water column turbulence
near the bottom.
The Mar Piccolo of Taranto is a confined sea characterized by low
hydrodynamism, mainly due to minimal tidal currents. Mean depth is 10 m,
with a maximum of 13 m in the centre of the 1 st Inlet. The muddy bottom has
an oxygenated layer 2-3 cm deep, the rest being strongly anoxic.
Nine sediment cores were collected in November 2006 in 3 stations located in
the 1 st Inlet of the Mar Piccolo, in order to study the plankton cyst bank at
sediment depths of 5, 10 and 20 cm.
Resting stages were found at all the investigated layers, with number of taxa
and densities decreasing from 5 th to 20 th cm. At the 5 th cm, 18 different cyst
morphotypes were identified. This value decreased to 8 at the 20 th cm. A great
variability was observed among replicates. Practically all the cyst found were
produced by dinoflagellates. Only few morphotypes and very low abundance of
resting stages produced by ciliates, rotifers and copepods were registered.
COLLECTION OF OCEANOGRAPHIC DATA SETS IN THE NORTHERN
ADRIATIC SEA AND EFFECTS OF CLIMATE CHANGE: PRELIMINARY
RESULTS
RUSSO Aniello 1, MONETA A. 1, GRILLI F. 2, PASCHINI E. 2, BASTIANINI M. 3, SOCAL
Giorgio 3
1 - Dipartimento di Scienze del Mare, Università Politecnica delle Marche,
Ancona
2 - Istituto di Scienze Marine, CNR-ISMAR Sede di Ancona
3 - Istituto di Scienze Marine, CNR-ISMAR Sede di Venezia
Key terms: Adriatic Sea; climate change; climatology
In the framework of the Italian research program VECTOR (VulnErabilità delle
Coste e degli ecosistemi marini italiani ai cambiamenti climaTici e loro ruolO nei
cicli del caRbonio mediterraneo), a widespread collection of historical and
recent data is being carried out, aiming to define recent climatic anomalies, to
individuate changes in the marine systems and to obtain a robust data set for
model simulations. The northern Adriatic Sea is a relevant area of the
Mediterranean Sea under several aspects, in particular it receives the highest
river runoff and related nutrient loading, and dense waters eventually forming
here in winter are important contributors to the Eastern Mediterranean Deep
Water. So the northern Adriatic Sea plays an important role in the carbon
cycle, and climate change could have major effects on this area (this is the
northernmost area of the Mediterranean Sea, and climate studies evidence that
most changes happen in poleward areas). Being also the most sampled area of
the Mediterranean Sea, the northern Adriatic Sea would represent an optimal
area where to assess effects of climate change on water masses properties;
such aspect is made challenging by the relevant higher frequency variability of
this sub-basin (due to its peculiar characteristics: shallow continental basin
with huge river runoff).
Oceanographic stations collected in the Adriatic Sea have been extracted from
the MEDATLAS 2002 data base, and again quality checked, so removing
hundreds of stations (in particular many duplicate stations still present in the
data base). Data collected from 1951 to 1990 (over 4000 casts in the northern
Adriatic Sea) have been used to define spatial climatologic normal for the four
seasons. Recent data (collected mostly by ISMAR-CNR) have been used to
define the seasonal climatologies for the period 1991-2006 (over 7000 casts).
Preliminary analysis on the already available data has been performed,
computing departure of the recent period thermohaline properties from the
climatologic normal for the northern Adriatic area. First results will be showed,
while the work of data assemblage is still in progress.
W10-145 Poster
W10-147 Orale
Rubino, Fernando
THE CYST BANK OF PLANKTON IN TARANTO SEAS (IONIAN SEA,
MEDITERRANEAN): A STUDY AT DIFFERENT SPATIAL AND TEMPORAL
SCALES
RUBINO Fernando 1, SANTESE N. 1, BELMONTE M. 1
1 - CNR-Istituto per l'Ambiente Marino Costiero, Talassografico "A. Cerruti",Via
Roma 3, 74100 Taranto
Key terms: plankton; cyst bank; surface sediments; environmental variations;
Taranto, Ionian Sea
Resting stage production by planktonic organisms represents an adaptation to
seasonal fluctuations of the environment on an annual scale and to its
variations on a pluriannual scale. In the muddy bottoms of confined marine
areas, high densities of plankton resting stages (usually named cysts) exist,
analogous to the seed banks of terrestrial plants. These large amounts of cysts
constitute an insurance against unforeseen events. In fact, their accumulation
in sediments brings to a storage of biodiversity that planktonic communities
can exploit at the onset of favourable conditions.
The study of cyst bank structure of an area can provide more complete
information, compared to classical plankton surveys and, if the study is
replicated on a temporal scale (e.g. annually), it is possible to gain data on the
variation of the planktonic communities structure as well.
A sampling plan of surface sediments was carried out in November 2006 in the
four basins that constitute the Taranto sea system, namely the Gulf, the Mar
Grande and the two Inlets of the Mar Piccolo, in order to characterize the cyst
bank produced by the plankton of the area. The four basins show a high
confinement gradient, moving from the Gulf to the inner part of the 2nd Inlet
of the Mar Piccolo, indicated also by a change of the plankton structure.
In the framework of the VECTOR Project (Line 4 DIVCOST, Activity 5.3), our
goal was to evaluate this trend of confinement also for the cysts' population in
the sediments and to integrate the study of the plankton dynamics in the water
column, carried out with classical methods from November 2004 to date. The
sediment sampling will be replicated in November 2007 to evaluate mid term
variations of the plankton communities in the sediments, eventually correlated
with the fluctuations and variations of abiotic variables.
A total of 106 different cyst morphotypes were identified: 71 were produced by
dinoflagellates, 11 by ciliates, 4 by rotifers and 11 by copepods. Most of the
morphotypes (72.4%) were identified at least at the genus level, while 9 of
them remained unidentified. Total densities showed higher values moving from
the Gulf to Mar Piccolo, according to the confinement gradient. The highest
values (1289±551 cysts/ml) were recorded in the 1st Inlet of Mar Piccolo and
the lowest (145±42 cysts/ml) in the Gulf. Number of taxa together with the
ecological indexes (H', J') reached higher values in the more confined basins
with a slight decrease in the 2nd Inlet of Mar Piccolo, confirming the
confinement gradient already observed in a previous study in the water column
for zooplankton. The most abundant cyst morphotype was produced by the
Santinelli, Chiara
DISSOLVED ORGANIC CARBON DISTRIBUTION AND DOM
STOICHIOMETRY IN THE ADRIATIC SEA
SANTINELLI Chiara 1, IBELLO Valeria 2, CIVITARESE Giuseppe 2, NANNICINI
Luciano 1, SERITTI Alfredo 1
1 - IBF-CNR, Via Moruzzi 1, 56124 Pisa, Italy
2 - ISMAR-CNR, Viale R. Gessi 2, 34123 Trieste, Italy
Key terms: Dissolved organic carbon; Dissolved organic nitrogen; Dissolved
organic phosphorous; Adriatic Sea
Dissolved organic matter (DOM) is the largest reservoir of reduced carbon in
the Sea and represents the source of food for heterotrophic bacteria.
Notwithstanding its importance in the global carbon cycle, at today DOM
remains the most complex and the less understood pool of carbon in the
Ocean. Due to the very low concentrations of DOC, dissolved organic nitrogen
(DON) and dissolved organic phosphorous (DOP), occurring in the sea, and to
the difficulty to concentrate seawater samples, without loss of significant
fractions of DOM, information on its molecular characteristics, its lability, and
its dynamics are very scarce. DOC export is directly linked with DON and DOP
export, but the C:N:P stoichiometry of DOM dynamics is poorly understood.
Here DOC, DON and DOP distribution in seawater samples collected, during
VECTOR cruises, in the Adriatic Sea, are reported, to get some information on
the mechanisms regulating production, export and mineralization of DOM. DOC
showed different concentrations in November 2006 and in February 2007. The
main difference was observed in the surface layer with DOC values of 75±9 µM
in November and 53 ±6 µM in February. A significant difference can be
observed also in the deep layer (below 1000 m) where an increase until 69 µM
was observed in November, against concentration of about 50 µM in February.
An input of DOC in November and a consumption or transport in other areas in
February can be hypothesized. Moreover, a different DOM stoichiometry, both
in surface and deep layer, can occur in the two periods. A comparison with data
referring to the same station, collected in the framework of SINAPSI project
(1999-2002) will also be performed
W10-148 Orale
Santinelli, Chiara
DISSOLVED ORGANIC CARBON, DISSOLVED OXYGEN AND NUTRIENT
TRENDS IN THE SOUTHERN TYRRHENIAN SEA
SANTINELLI Chiara 1, CONVERSANO Fabio 2, LAVEZZA Rosario 2, NANNICINI
Luciano 1, RIBERA D'ALCALÀ Maurizio 2, SERITTI Alfredo 1
1 - IBF-CNR, Via Moruzzi 1, 56124 Pisa, Italy
2 - Stazione Zoologica 'A.Dohrn', 80121 napoli, Italy
WORKSHOP W10
44
Key terms: Tyrrhenian Sea; Dissolved Organic Carbon; Dissolved Oxyen;
Nutrient
Dissolved organic carbon, dissolve oxygen and nutrients were measured,
during three cruises, in the Southern Tyrrhenian Sea in the framework of
VECTOR project. The cruises were carried out in November 2006, February and
April 2007. The very high stability of the water column in the Tyrrhenian Sea is
clear visible from vertical profiles of salinity, potential temperature and
dissolved oxygen. In November a marked thermocline of about 5°C (from 19°C
to 14°C) was observed at a depth of 50 m, while in February it became very
weak (only 1,5°C). Dissolved oxygen exhibited a typical vertical distribution
with a sub-surface maxima of about 240 µM and a minimum (180 µM) at 500
m. This oxygen minimum was observed in the core of the Levantine
Intermediate Water (LIW), in correspondence to the salinity maximum.
Inorganic nitrogen and silicate showed very low values in the surface layer, and
a sharp increase with depth below 100 m, to reach their maximum from 2000
m to the bottom. In the first two cruises dissolved oxygen and nutrients
showed concentrations and vertical profiles very similar, with the exception of
the surface layer (0-100 m), in which a higher extent of variability was
observed. The stability of water column and the occurrence of the thermocline
have a clear influence on DOC vertical profiles. DOC showed a vertical trend
similar to those observed in oceanic waters, with higher values at surface and a
decreasing till a minimum (40 µM) at 400 m. Below 400 m no significant
variations were visible. These trends were observed in all the stations of the
section. The most significant difference in DOC trends, observed between the
first two cruises, was at surface. Between 0 and 50 m, DOC showed values of
58±2 µM in November and of 49±1 µM in February. The occurrence of a more
marked thermocline in November than in February, may allow the
accumulation of semi-labile DOC in the mixed layer, this may be consumed or
transported at higher depths whit the breakeven of the thermocline. In general,
in the deep layer, DOC showed concentrations significantly lower than those
reported in other Mediterranean regions. The minor extent of winter convection
in this area, with a consequent absence of DOC transport at depth can explain
this behavior.
Correlation between DOC, DO and nutrients will be also investigated to better
understand DOM dynamics and carbon fluxes in the deep waters of this region.
Finally the assessment of stoichiometric ratio between DOC, DO and nutrients
will be studied in order to give information about mineralization processes.
W10-149 Poster
Sclavo, Mauro
THE EVALUATION OF THE LONG TERM WAVE CONDITIONS - A
COMBINED USE OF BUOY, MODEL AND SATELLITE DATA
CAVALERI Luigi 1, SCLAVO Mauro 1, CARNIEL Sandro 1, BERTOTTI Luciana 1,
MARTUCCI Gianni 1, CHIGGIATO Jacopo 1
1 - Institute of Marine Sciences (ISMAR) , S.Polo 1364 , 30125 Venice, Italy
Key terms: long term wave conditions; satellite data; calibration of the model
data
Long time series of meteorological and oceanographic parameters, in particular
wind and waves, are required for many obvious purposes. These range from
the assessment of climatology to the more immediate needs of oceanographic
and coastal engineering. These time series are particularly required for the
determination of long term trends associated to the much discussed climate
change. Objective measurements, extended over long periods of time, are
probably the best way to check the local effects of what is happening at the
global level.
Historically three objective sources of data are available in the sea: buoys and
platforms, satellites, and numerical models. No one succeeds in providing the
accurate and distributed data requested for a sufficiently long period. Our aim
is to describe how such a result can be obtained for an inner sea, like the
Mediterranean Sea, making use of the information from the different available
sources. In particular, we focus on the calibration of the model data making
use of satellite data.
The parameters we consider in this work are wind and waves. The complicated
geometry and orography of the Mediterranean, and in particular the Adriatic,
Sea make rather difficult for a meteorological model to reproduce with the
required accuracy the distribution of the wind fields into the basin. In particular
we have verified a substantial underestimate of the wind speeds. The
underestimate depends on the resolution of the model, so it is larger for the
global, operational models. Expectably this leads to a substantial
underestimate of the derived modelled wave heights.
On the other hand modelled wave heights are the most continuous and detailed
source of data, because buoys, as accurate as they are, are few and not
capable to properly describe the spacially highly variable wave fields that
characterise the Italian peninsula. The solution is to perform an extensive
comparison between the available buoy, model (ECMWF) and altimeter data.
The buoys are used to check the performance of the altimeter as wave
measurements, in particular in coastal areas. This has indicated that the wave
altimeter data are good enough in the Mediterranean Sea for our present
purposes.
The following step is to intercompare corresponding model and satellite data.
This requires various interpolations. In fact the model data are available at six
hour intervals at the grid points, while the satellite data vary in space and time.
Therefore the model data need to be interpolated, in space and time, to
evaluate the co-located corresponding model data. The overall purpose is to
derive, after a suitable intercomparison and correction place by place, the
calibrated long term time series at the grid points. These can then be used to
derive extended statistics, both as general distributions, and as one- and
two-dimensional local distributions.
Once these statistics are available, they can be used as boundary conditions for
local high resolution modelling. This can be done at various stages of
sophistication. First we can use a third generation wave model, e.g. Swan to
derive the wave conditions in the whole considered area. Nesting can then be
used to focus with higher resolution on a specific spot. Finally an advanced
sophisticated coastal circulation model can be fully coupled to the wave model
to obtain a realistic estimate of the coastal conditions, both as waves and
current.
W10-150 Orale
Sclavo, Mauro
WAVE CLIMATE AND EXTREME EVENTS IN THE ITALIAN SEAS
MARTUCCI Giovanni 1, CHIGGIATO Jacopo 2, SCLAVO Mauro 2, CARNIEL Sandro 2,
CAVALERI Luigi 2, BERTOTTI Luciana 2
1 - Consorzio Venezia Ricerche c/o PST VEGA di Venezia, Via della Libertà, 12 30175 Marghera - Venezia - Italia
2 - CNR-ISMAR, San Polo 1364, I-30125 Venezia
Key terms: climate; weather parameters; italian seas
Climate is defined by the type, frequency and intensity of weather events.
Average values of specific weather parameters over fixed time intervals provide
an information about the mean status of the atmosphere, the soil and the sea
during those intervals The occurrence and severity of extremes might become
relevant as their mean frequency increases monotonically over a period like it
happens during the few last decades. Anthropogenic climate change has the
potential to alter the prevalence and the impact of extremes such as heat
waves, storms, floods and droughts. This study focuses on the relevance that
the extreme weather events have in modifying past evolutions and future
scenarios of the Italian coasts and seas. Precisely, this work makes use of
widely recommended methods for the statistical analysis of extreme waves.
The current level of understanding in this field, allows to: select wave datasets
of independent and identically-distributed (idd) data; identify the best fit to the
data distribution; evaluate, from the distribution, the extreme waves values
and return periods (Tn).
Waves are treated as parameters being characterized by the value of two
properties: their incoming direction and their significant height. Important
information about the relevance of potentially occurring extreme events at the
return period Tn is provided by the mean and cumulative persistence of the
extreme waves over a fixed threshold. Two methods are principally used for
this study, one uses the idd data as the result of a selection of largest r-annual
events (normally r
5), the other obtain the idd data by keeping only the
peaks-over-threshold. The two methods are based on different choices and
both apply to a 42-years length time-series (part of the ERA40 reanalysis from
1957 to 2002) of wave data. The first method optimizes the level of data
independence within the selected dataset, but dramatically reduces the number
of elements (larger statistical errors), the second increases the dataset size
(smaller statistical errors), but also increases the autocorrelation coefficient of
the data.
The statistical analysis of the entire and the independent wave-dataset as well
as a comparison of the return period and values by utilizing the two different
method are presented here.
W10-151 Poster
Socal, Giorgio
PHYTOPLANKTON SEASONAL PATTERNS FROM PLURIANNUAL TIME
SERIES IN A HIGHLY VARIABLE COASTAL ECOSYSTEM (NORTHERN
ADRIATIC SEA)
BASTIANINI Mauro 1, ACRI Francesco 1, BIANCHI Franco 1, BAZZONI Anna Maria 1,
BERNARDI AUBRY Fabrizio 1, PUGNETTI Alessandra 1, SOCAL Giorgio 1
1 - ISMAR CNR Venezia
Key terms: Phytoplankton; Long Term Ecological Research; Nothern Adriatic
The broad variability of marine environment conditions, occurring as a
consequence of meteo-climatic forcing and anthropogenic pressure, might
induce changes of the plankton community structure at a wide range of time
scales. Phytoplankton appears very sensitive to climatic changes and could be
used as a proxy of the variations occurring in the environment. The overall
complexity of coastal ecosystems and the remarkable interannual variability of
environmental factors, make multiannual series of data a powerful tool for a
reliable reconstruction of the plankton seasonal cycles and of their driving
factors. The phytoplankton studies in the Northern Adriatic Sea (a shallow,
eutrophic, coastal basin) started more than 20 years ago but, in the last 10
years, the investigations have become more intensive, both in space and time.
The ecological monitoring activities carried out in this ecosystem permit, from
one side, to define the short-term (monthly, seasonal) and interannual
phytoplankton variability, and, from the other, to understand the time scales of
the processes that control and modulate the variability of the hydrochemical
features (temperature, salinity, nutrients) of the area. A clear trend of
increasing water temperature, related to the eastern Mediterranean climatic
transient, has been evidenced in the whole Northern Adriatic basin, starting
form the late eighties. The long-term studies on the phytoplankton allowed the
elucidation of the seasonal pattern of biomass and the description of the
seasonal variations of the prevalent phytoplankton species, so that a sort of
"calendar of plankton" could be defined. The availability of a wide array of
ecological parameters and the joint efforts of different researchers and
institutions working in this coastal ecosystem, entitled the Northern Adriatic
Sea to enter the International Long Term Ecological Research network (ILTER)
as a fundamental site for marine studies on long-term series.
W10-152 Orale
Tedesco, Letizia
A 1-D SEA ICE THERMODYNAMIC MODEL FOR STUDIES OF SEA ICE
BIOGEOCHEMISTRY
TEDESCO Letizia 1, VICHI Marcello 1, HAAPALA Jari 2, STIPA Tapani 2
1 - INGV - CMCC Euro-Mediterranean Center for Climate Change, Bologna
2 - Finnish Institute of Marine Research, Helsinki, Finland
Key terms: Sea ice model; Sea ice ecosystem; Biogeochemistry model
A 1-dimensional thermodynamic model capable of simulating seasonal changes
of ice, snow ice, superimposed ice and ice thicknesses has been developed.
Particular attention has been paid to reproduce the snow ice formation when
WORKSHOP W10
heavy snow loads cause sea water flooding at the ice-snow interface, and the
superimposed ice formation when melted snow re-freezes at the snow-ice
interface under positive temperature gradient within snow and ice. Following
Semtner 0-layer model, the sea ice system consists of one layer of ice and one
layer of snow on top. If the ice draft exceeds the ice thickness, snow ice
formation is initiated. Snow density and compaction are changed accordingly
and a new isostatic equilibrium is formulated. No seawater mass is added and
snow is compressed to an amount of new snow ice equal to the initial
depression below the water line. If melted snow re-freezes under freezing
conditions, superimposed ice formation is also initiated by transforming a
fraction of snow, depending on snow properties, in superimposed ice. Snow ice
and superimposed ice play important roles, not only because they change the
snow properties and the consequent rate of the ice growth, but also because
they create suitable habitats for sea ice algae, bringing nutrients where the
light is a minor limiting factor. Micro algae find a larger access to nutrients and
more stable environmental conditions in the last centimeters of the ice sheet,
but are often limited by thick snow covers that prevent sufficient light to
penetrate. As a first testbed application in data-rich areas, the model has been
implemented in the Baltic Sea and validated in four different stations (Ajos,
Kummelgrund, Jussaro, Kotka) against observations provided by the Ice
Service at the Finnish Institute of Marine Research. Atmospheric forcing data
are from the ECMWF-ERA 40 Reanalysis. Other geophysical properties, such as
salinity, density and brines characteristics have been recently included, since
they are closely related to the physiological and ecological response of sea ice
algae. A coupled version with BFM (Biogeochemical Flux Model) is currently
under development. The BFM represents the biogeochemical processes of
pelagic ecosystem emphasizing the flows of the major biogeochemical elements
from the (in)organic pelagic pools through the food web as a function of
organisms' demand and trophic relationships. Sea ice ecosystem is still poorly
understood, due to sparse observations and complexity of the interactions
between environmental factors and ice biota. Ecosystem models can be thus a
valuable tool to better understand the processes that control the dynamics of
the sea ice algal community, its contribution to the total primary production in
relation to its phytoplankton counterpart, its fate after being released in the
water column, and its contribution to the global carbon cycle. The coupled
model can be further coupled with a 1-dimensional turbulence model to better
resolve the oceanic fluxes and mixing/stratification processes. In the future it
will further be extended with a dynamic model of ice growth for 3-dimensional
simulations.
W10-153 Orale
Tessarolo, Chiara
A CASE STUDY OF THE CORRELATION BETWEEN STEEP AND NARROW
MARGIN WITH THE DEVELOPMENT OF FLUVIAL STRUCTURES: THE
IONIAN CALABRIAN AREA
TESSAROLO Chiara 1, CORSELLI Cesare 1, AGATE Mauro 2, DI GRIGOLI Giuseppe 2
1 - CONISMA
2 - UNIPA
Key terms: Ionian Calabrian Margin; basins and shelf morphology; seafloor
topography
The Calabrian Ionian margin represents a particular geo-structural setting for
the development of an original fluvial system, peculiar for this own area.
Structural movements, correlated to the opening of the Tirrenian sea, have
encuraged a rapid and important uplift of the area localized in the frontal part
of the arc in translation, determinating quite high relief inland, and a narrow
and less well developed shelf offshore.
In association to this structural setting, the particular climate regime of this
area, characterized by seasonal, very intense an sporadic meteorological
events, point up to the development of short but steep rivers, with a medium
extension in basins area and responsible for an intense and active mass
transport to the shelf and the upper slope: the called Fiumara.
This kind of rivers have also been responsible for the development of erosional
structure, even wide and deep, localized offshore.
On the base of this assumption, in the framework of Vector Project (line
Vulcost), five (four in the original project) rivers (Fiumara Torbido, Allaro,
Amusa, Precariti, Novito) have been selected to point out the correlation
between these peculiar fluvial frameworks and the interrelate generation of two
very wide systems of canyon, on the shelf and beyond it: the Caulonia and the
Marina di Gioiosa Canyons.
A Multibeam (Seabat 8160) and Sub-bottom Profiler (GeoChirp II) survey
collected in 2006, and a subsequent study of the Morphological and
stratigraphic characteristics of the area, in association to an elaboration and
evaluation of data of the basins onshore, have enabled to point out a
preliminary characterization of the geo-morphological peculiarities of the
selected area.
This study has been developed considering in that way the relation between
the typology of margin, the kind of hydrographic basins developed, the
sedimentary and erosive processes in act, and the correlated progress of
marine structures offshore, in the aim of an evaluation of the coastal zone
modification and evolution.
W10-154 Poster
Tosi, Luigi
COULD SALT WATER INTRUSION AND LAND SUBSIDENCE TRIGGER
SOIL DESERTIFICATION IN THE CATCHMENT SOUTH OF THE VENICE
LAGOON (ITALY)TOSI Luigi 1, TEATINI Pietro 2, STROZZI Tazio 3, RIZZETTO Federica 1, CARBOGNIN
Laura 1, PUTTI Mario 2
1 - Istituto di Scienze Marine - Consiglio Nazionale delle Ricerche, Venezia,
Italy
2 - Dipartimento di Metodi e Modelli Matematici per le Scienze Applicate,
Università di Padova
3 - Gamma Remote Sensing, Gümligen BE, Switzerland
Key terms: saltwater intrusion; land subsidence; soil desertification; Venice
45
Lagoon; Bacchiglione-Brenta river mouth
The catchment south of the Venice Lagoon is threatened by shallow aquifer
salinization and land subsidence. Although the area is not experiencing
everywhere saline contamination and high sinking rates, a very serious
situation has been brought to light in a large portion of the coastal farmland.
The salt water contamination, recently investigated within a series of research
projects, i.e. ISES, BRENTA, Co.Ri.La. 3.10-3.16, extends up to 20 km inland
from the coast (Carbognin and Tosi, 2003; Rizzetto et al., 2003; Carbognin et
al., 2005, 2005b). The depth of the fresh/salt-water interface varies from 1 to
30 m below the ground level and exhibits a significant, mainly seasonal, time
variation. The dynamics of the soil salinization process is especially sensitive to
changes in river (Brenta, Bacchiglione, Adige, Gorzone) discharges, in
groundwater and channel levels regulated by a number of pumping stations of
the reclamation network, and in weather conditions.
At the same time an ongoing land subsidence with rates varying from few
mm/yr to cm/yr affects the southern lagoon margin and the nearby watershed
(Tosi et al., 2000; Teatini et al., 2007). The settlement of these territories is
mainly due to natural consolidation (Teatini et al., 2005) and geochemical
subsidence, i.e. peat oxidation promoted by farming activities (Gambolati et
al., 2005).
Salt water intrusion and land subsidence combined with significant dry seasons
expose this area to the potential soil desertification. The combined effect of
both processes is producing an alarming social and environmental impact on
the south Venice coastland, also in relation to the expected global climate
change.
Aknoledgements
This research is part of the National Project "VECTOR, Line 5, Activity 3
"Morphdynamics". We acknowledge ISES, BRENTA and Co.Ri.La.
3.1b-3.10-3.16 Projects to make available data.
References
Carbognin, L., Tosi, L., Il Progetto ISES per l'analisi dei processi di intrusione
salina e subsidenza nei territori meridionali delle Province di Padova e Venezia.
Progetto ISES, Grafiche Erredici, Padova, 2003.
Carbognin, L., Teatini, P. & Tosi, L., Land Subsidence in the Venetian area:
known and recent aspects. Giornale di Geologia Applicata, 1, pp. 5 -11, 2005a.
Carbognin, L., Rizzetto, F., Tosi, L., Teatini, P. & Gasparetto-Stori, G.,
L'intrusione salina nel comprensorio lagunare veneziano. Il bacino meridionale.
Giornale di Geologia Applicata, 2, pp. 119-124, 2005b.
Gambolati, G., Puttti, M., Teatini, P., Camporese, M., Ferraris, S.,
Gasparetto-Stori, G., Nicoletti, V., Rizzetto, F., Silvestri, S., Tosi, L., Peatland
oxidation enhances subsidence in the Venice watershed. EOS-Trans. Amer.
Geoghys. Union, 86(23), pp. 217-224, 2005.
Rizzetto, F., Tosi, L., Carbognin, L., Bonardi, M. & Teatini, P., Geomorphological
setting and related hydrogeological implications of the coastal plain south of
the Venice Lagoon (Italy). Hydrology of the Mediterranean and Semiarid
Regions, eds. E. Servat et al., IAHS Publ. n. 278: Wallingford, UK., pp.
463-470, 2003.
Teatini, P., Tosi, L., Strozzi, T., Carbognin, L., Wegmüller, U., Rizzetto, F.,
Mapping regional land displacements in the Venice coastland by an integrated
monitoring system. Remote Sensing of Environment, 98: 403-413, 2005.
Teatini, P., Strozzi, T., Tosi, L., Wegmüller, U., Werner, C., Carbognin, L.,
Assessing Short- and Long-time displacements in the Venice Coastland by SAR
Interferometric Point Target Analysis. J. Geophysical Research, 112, F01012,
2007.
Tosi, L., Carbognin, L., Teatini, P., Rosselli, R., Gasparetto-Stori, G., The ISES
Project subsidence monitoring of the catchment basin south of the Venice
Lagoon (Italy). In: Carbognin L, Gambolati G, Johnson AI (eds) Land
subsidence, La Garangola, Padova (Italy), II, pp 113-126, 2000.
W10-155 Poster
Tramontana, Mario
GEOMORPHIC EVOLUTION OF WAVE-CUT CLIFFS AT THE NORTHERN
MARCHE RIVER MOUTHS
BISICCIA Cesare 1, COLANTONI Paolo 1, NESCI Olivia 2, SAVELLI Daniele 2,
TRAMONTANA Mario 1, TROIANI Francesco 2
1 - Istituto di Scienze della Terra, Università degli Studi di Urbino "Carlo Bo"
2 - Istituto di Geologia, Università degli Studi di Urbino "Carlo Bo"
Key terms: Wave-cut cliffs; Coastal evolution; River mouth; Northern Marche
The north Marche coast reach between Gabicce and Senigallia is characterised
by a relatively continuous coastal plain at places narrowed or interrupted by
rocky cliffs (i.e. San Bartolo and Ardizio, north and south of Pesaro
respectively). The seafloor is constituted by soft sediment of various grain size
(from sand to mud) except for the seafloor off San Bartolo cliff, where a wide,
still active rocky wave-cut bench occurs. The coastal plain merges into the
terminal sectors of the major fluvial plains and also encloses the downstream
reaches of minor streams debouching directly into the sea. Two important
morphologic features characterise the coastal plain: (i) the coastal plain ends
landwards against either the base of hill-slopes straightened by marine erosion
or rocky paleo-cliffs; (ii) the coastal plain is locally stepped by a minor
discontinuous wave-cut cliff cutting late Quaternary gravels and sands. Such
wave-cut cliff is a distinctive landform occurring close to the major river
mouths; elsewhere, this landform appears only in some areas, in particular at
the mouth of minor streams draining directly into the sea (e.g. Ponte Sasso,
Fosso Sejore). Indeed, the wave-cut cliff is clearly connected with river
mouths. It is well-formed, with sharp profiles and heights reaching 5-8 m at
the Metauro and Cesano river mouths; it is recognisable at the Foglia and Misa
river mouths as well, nonetheless here it is less defined displaying smoothed
profiles and heights not exceeding 2-3 m. This landform is associated with late
Pleistocene-early Holocene coastal fans, built up in conditions of relatively low
sea-level and likely related with cold climate stages (Dryas). Such chronological
attribution is supported by some radiocarbon datings spanning from 10,700+95
to 10,880+95 yr B.P.
The fans grew seaward for some kilometres off the modern shoreline, while the
fan apexes are found as far as 5-10 km upstream the modern river mouths.
The higher the fan relief, the greater the gravel supply from the drainage basin
and, in turn, the gravel availability was a function of the amount in the
drainage basin of resistant rock outcrops. The eustatic sea level rise accounts
for the erosional removing of a large part of the downstream portions of the
coastal fans; only the apex areas, extended within the river valleys, have been
WORKSHOP W10
46
preserved. The erosion of the intermediate and lower sectors of fans
characterised by different relief and convexities explains the differences in
heights and recognisability of the wave-cut scarps at different river mouths.
Moreover, since the fans occur at the river mouths, the wave-cut scarps
resulting from their erosional remoulding locate just around the river mouths
themselves.
W10-156 Poster
Tramontana, Mario
ACTIVITY OF THE URBINO WORKING GROUP WITHIN THE VECTOR
PROJECT: STATE OF THE ART.
BISICCIA Cesare 1, COLANTONI Paolo 1, NESCI Olivia 2, SAVELLI Daniele 2,
TRAMONTANA Mario 1, TROIANI Francesco 2
1 - Istituto di Scienze della Terra, Università degli Studi di Urbino "Carlo Bo"
2 - Istituto di Geologia, Università degli Studi di Urbino "Carlo Bo"
Key terms: VECTOR Project; Northern Marche Region; Coastal area
The activity of the Urbino University Research Group has been focused on the
detailed analysis of the northern-Marche coastal area embracing the Foglia and
Metauro river mouths. A large-scale analysis of the entire hydrographic basins
of these rivers has been performed as well. At the scale of the hydrographic
basins digital terrain models based on the 3D digital topographic map of the
Marche Region have been reconstructed; the geostatistic kriging method with
resolution of 40 m has been used to interpolate the whole dataset. An 1.50.000
geolithologic map and a land-use map at the same scale have been elaborated
based on previous data, while an 1.50.000 geomorphologic map has been
realised based on both pre-existing data and new surveys in key-areas. Such
operations have been performed at a more detailed scale (i.e. 1:10,000) in the
coastal sectors between the Foglia and Metauro river mouths. Here a high
resolution DTM has been also elaborated. In the offshore area the realisation of
a bathymetric contour map and a related DEM based on existing data is still in
progress. In the coastal submerged area the near-bottom sediment
characterisation and some analyses of the benthic faunal assemblages have
been already started. In key-areas close to the Foglia and Metauro river
mouths, studies addressed to the reconstruction of late Pleistocene and
Holocene coastline variations and geomorphic evolution have been started
allowing to recognise coastal fans-related convexities causing the development
of discontinuous wave-cut scarps during the last sea level eustatic rising.
W10-157 Poster
Ursella, Laura
WATER FLOW IN THE BOTTOM LAYER OF THE OTRANTO SECTION AS
OBTAINED FROM HISTORICAL CURRENT-METER DATA (1997-1999)
AND VECTOR PROJECT DATA (2006-2007)
URSELLA Laura 1, DEPONTE Davide 1, KOVACEVIC Vedrana 1, GACIC Miroslav 1
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS, Borgo
Grotta Gigante 42/c, 34010 Sgonico (Ts), Italia
Key terms: Otranto Strait; Current profiles; frequency analysis
Currents measured in the bottom layer of the Otranto section have been used
to determine the deep water outflow from the Adriatic and Ionian Sea and its
dependence on seasons and particular climatic conditions. The signal at
different frequencies has been studied in order to separate low-pass currents
from tidal and inertial contributions. During MATER project (1997-1999) a
certain number of ADCP (Acoustic Doppler Current Profiler) and current-meters
have been deployed in order to analyze horizontal and vertical current
structure in the bottom layer. In particular, in the Otranto section the tidal
structure of the main components (K1 and M2) shows a seasonally dependent
behaviour, and an intensification of amplitudes near the coast along the shelf.
Low-pass currents, prevalently directed southward at the western flank of the
strait, strengthen during winters when Adriatic Deep Water is formed and the
outflow intensifies, and are particularly strong in early spring 1999 after a very
cold winter. The most recent measurements (from November 2006 to April
2007) conducted in the framework of the VECTOR project, permit to compare
recent vertical and horizontal structures with the previous ones, and to study
the evolution of the dynamics in the bottom layer of the strait. In addition,
vessel-mounted ADCP data collected during VECTOR campaigns and covering
the entire Otranto Strait section have been analyzed.
W10-158 Poster
Vichi, Marcello
MODELLING APPROACH TO THE ASSESSMENT OF BIOGENIC FLUXES IN
THE ROSS SEA
VICHI Marcello 1, COLUCCELLI A. 2, RAVAIOLI Mariangela 3, GIGLIO F. 3, LANGONE
Leonardo 3, AZZARO M. 4, AZZARO F. 4, LA FERLA R. 4, CATALANO G. 5, COZZI S. 5
1 - Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC) e Istituto
Nazionale di Geofisica e Vulcanologia (INGV)
2 - Università politecnica delle Marche
3 - ISMAR - CNR Sezione di Bologna
4 - ISMAR - CNR Sezione di Messina
5 - ISMAR - CNR Sezione di Trieste
Key terms: Biogeochemistry model; Ross Sea; Carbon cycle; Sedimentation
Several biogeochemical data have been collected in the last 10 years of Italian
activity in Antarctica (ABIOCLEAR, ROSSMIZE, BIOSESO-I/II). A
comprehensive 1-D biogeochemical model was implemented as a tool to link
observations with processes and to investigate the mechanisms that regulate
the flux of biogenic material through the water column. The model is ideally
located at station B (175E - 74S) and was set up to reproduce the seasonal
cycle of phytoplankton and organic matter fluxes as forced by the dominant
water column physics over the period 1990-2001. Austral spring-summer
bloom conditions are assessed by comparing simulated nutrient drawdown,
primary production rates, bacterial respiration and biomass with the available
observations. The simulated biogenic fluxes of carbon, nitrogen and silica have
been compared with the fluxes derived from sediment traps data. The model
reproduces quite well the magnitude of the biogenic fluxes, especially those
observed in the bottom sediment trap, but the peaks are delayed in time.
Sensitivity experiments have shown that the characterization of detritus, the
choice of the sinking velocity and the degradation rates are crucial for the
timing and magnitude of the vertical fluxes. An increase of velocity leads to a
shift towards observation but also to an overestimation of the deposition flux
which can be counteracted by higher bacterial remineralization rates. Model
results suggest that observed fluxes could be explained by the size-distribution
and quality of the locally-produced biogenic material. It is hypothesized that
the bottom sediment trap collects material originated from rapid sinking of
particles and also from previous years production periods, likely modulated by
advective and aggregation mechanisms which are still not resolved by the
model.
W10-159 Poster
Yari, Sadegh
WATER MASS TRANSPORT ACROSS THE STRAIT OF OTRANTO
YARI Sadegh 1, GACIC Miroslav 2, KOVACEVIC Vedrana 2
1 - Istituto Nazionale di Oceanografia e di Geofisica Esperimentale, Sgonico (
TS ) - Italy and Abdus Salam International Centre for Theoretical Physics,
Trieste, and University of Trieste
2 - Istituto Nazionale di Oceanografia e di Geofisica Esperimentale, Sgonico (
TS ) - Italy
Key terms: Adriatic Sea; Strait of Otranto; water masses transport
Characteristics of currents across the Strait of Otranto are studied in detail
using the direct current measurements for almost one year (November
94-November 95). The Otranto Strait is a channel with 75km width and 800m
depth and connects the Adriatic Sea with the Ionian Sea and Eastern
Mediterranean. The current data are measured on 6 stations at near surface,
intermediate and near bottom layers. Spectral analysis is used to study the
partition of the variance of current data as a function of frequency. A complex
Fast Fourier Transform (FFT) is used to calculate the power spectrum. The
harmonic analysis is done to calculate the most significant tidal constituents
and also to remove the effect of tides from the current data in order to obtain
residual (nontidal) currents. After removing the tidal effect form current data, a
low pass filtering with 33 hour weights is applied to remove some other high
frequency fluctuations like inertial oscillations.
The current data time series include gaps, because of instruments or batteries
malfunctioning. For a better evaluation of mass transport, these gaps were
filled using linear regression analysis. Multivariate linear regression models are
applied using data of the nearest stations to estimate currents during the
gappy periods.
The annual and seasonal mean inflow (northward) and outflow (southward) are
calculated. By means of mean currents the water mass transport across the
Strait of Otranto is evaluated.
The result shows that across the Strait of Otranto there is a mean cyclonic
(anticlockwise) shear. The mean water flow across the strait consists of an
inflow on the eastern side and an outflow on the western side, while there is a
two layer structure in the central part. The latter has an inflow in the surface
layer and an outflow in the bottom layer.
W10-160 Orale
Zaffagnini, Fabio
DEVELOPMENT AND VALIDATION OF A BENTHIC FLUX MODEL FOR THE
ADRIATIC SEA
ZAFFAGNINI Fabio 1, VICHI Marcello 2, FRASCARI Franca 3, SPAGNOLI Federico 4,
MARCACCIO Marco 5, BERGAMINI Cristina 3, RAVAIOLI Mariangela 3
1 - Centro Euro-Mediterraneo per i Cambiamenti Climatici (CMCC)
2 - Istituto Nazionale di Geofisica e Vulcanologia (INGV)
3 - ISMAR - CNR Sezione di Bologna
4 - ISMAR - CNR Sezione di Ancona
5 - ARPA Bologna
Key terms: Benthic Flux Model; Adriatic Sea; Biogeochemistry; Diagenetic
processes
The simulation of benthic processes, both due to organism interactions and to
early-diagenesis, is less developed with respect to pelagic biogeochemistry
model. This is mostly due the requirement of large amount of data for
validation and to the generalized sparsity of available observations.
Comprehensive models of benthic sediment dynamics are available, although
the testing in the Adriatic Sea has generally been mostly experimental. It is
however clear the role played by sediments in the northern part of the basin,
which might exert a pivotal control on the fate of the organic part produced in
these mesotrophic regions. The Biogeochemical Flux Model (BFM,
http://www.bo.ingv.it/bfm) is now being applied in the Adriatic Sea in
3-dimensional pelagic simulations with simplified benthic processes. The BFM
describes both pelagic and benthic dynamics and the coupling between them,
concentrating on the biogeochemical processes affecting the flow of carbon,
nitrogen, phosphorus, silicon and oxygen, in terms of benthic fluxes and
concentrations over time.
The final aim of this project is to adapt and further develop the BFM for
applications in different Adriatic Sea regions, distinguished on the basis of
various biogeochemical indicators. The study will focus on long-term
equilibrium simulations and on the seasonal variability of the major processes
in selected representative locations.
The part of the work presented here consists in identifying the initialization
parameters, starting from the data collected by ISMAR-CNR in the past 30
years, undergoing a basic descriptive statistical analysis. Once these
benchmarks have been detected, the algorithms of the model have been
partially modified and enriched to obtain an adequate description of the
processes occurring in the various facies of the Adriatic Sea.
WORKSHOP W10
W10-161 Orale
Zambianchi, Enrico
PRELIMINARY RESULTS OF VECTOR ACTIVITIES ON THE SURFACE
CIRCULATION IN THE GULF OF NAPLES
BUONOCORE
B. 1, MENNA M. 1, MERCATINI A. 1, UTTIERI M. 1, ZAMBIANCHI Enrico
1
1 - CoNISMa, ULR Parthenope, Dipartimento di Scienze per l'Ambiente Università Parthenope, Via de Gasperi 5 - 80133, Napoli
Key terms: Gulf of Naples; meteorological data; surface transport phenomena
Wind represents the main forcing of the short term surface circulation in the
Gulf of Naples. In this presentation we thus first of all characterize the area of
the Gulf on the basis of three years worth of meteorological data collected in
three sites: one weather station managed by the Department of Environmental
Sciences of the Parthenope LRU of CoNISMa, located along the urban littoral in
Naples, one weather station managed by APAT, the Italian agency for the
protection of the environment and for the associated technical services, located
in the harbour of the same city, and one grid point of the ECMWF atmospheric
model.
After identifying the main meteorological regimes in the area, we selected
surface current data collected by a coastal radar system managed in the area
by the Parthenope LRU, corresponding to the typical wind patterns measured in
the Gulf.
After a first, qualitative analysis, we present results of the investigation on the
connections between wind and currents, carried out on the basis of the
cross-correlation function between the two data sets. In particular, the surface
currents have been examined in two sites, one in the Bay of Naples and the
other in the interior of the Gulf, so as to detect possible differences in the
response of the two sea sectors to wind action. The results show that the
interior surface currents are well correlated with northeasterly winds within a
20 hr time lag; no significant correlation shows up in the Bay. Southwesterly
winds do not show any strong correlation with the surface currents measured
in the two locations.
We finally present the results of a preliminary implementation of a lagrangian
code for the study of surface transport phenomena in the Gulf of Naples,
estimating residence times and water renewal and focussing the attention on
exchanges between coastal subareas and the interior of the Gulf.
W10-162 Orale
Zavatarelli, Marco
ADRIATIC SEA DENSE WATER FORMATION AND BIOGEOCHEMICAL
CYCLES
ZAVATARELLI Marco 1, BUTENSCHOEN Momme 2, POLIMENE Luca 1, VICHI
Marcello 3
1 - Univ. Bologna-CIRSA
2 - Univ. Bologna Dip. Fisica
3 - INGV
Key terms: Ecological modelling; Biogeochemical cycles; Adriatic Sea; dense
water formation
The influence of the (highly variable) dense water formation occurring over the
shallow northern Adriatic sea and over the deep southern Adriatic is
investigated by mean of a coupled physical/ecological three-dimensional
numerical model.
The modeling system used is constituted by the Princeton Ocean Model (POM)
for the physical/hydrodynamical part and by the Biogeochemicl Flux Model
(BFM) for the biogeochemical/ecological part.
The modeling system is implemented in the Adriatic Sea with an horizontal
resolution of about 5 km and with 21 sigma layers. Surface forcing is
climatological.
Simulations are analysed in order to highlight the role exerted by the dense
water formation processes (and the associated spreading) in transporting
nutrient and organic matter to the deeper Adriatic (northern Adriatic shelf
dense water formation) and in controlling the surface phytoplankton dynamics
(southern Adriatic dense water formation).
The work is preliminary to the activities of national and international research
projects aiming to highlight the role of climatic variability in constraining the
ecosystem dynamics.
W10-163 Orale
Zingone, Adriana
INTERANNUAL VARIATIONS IN PHYTOPLANKTON ASSEMBLAGES FROM
THE GULF OF NAPLES AND THEIR RELATIONSHIPS WITH CLIMATE
CHANGE
ZINGONE Adriana 1, SARNO Diana 1, DUBROCA Laurent 1, CORATO Federico 1,
SAGGIOMO Vincenzo 1, RIBERA D'ALCALÀ Maurizio 1
1 - Stazione Zoologica Anton Dohrn, Napoli
Key terms: phytoplankton; long term variations; climate; hydrography;
Mediterranean Sea
Climatic variations may directly affect phytoplankton communities due to the
impact of changing temperature on geographic ranges and seasonal patterns of
single species. In addition, hydrographic variations resulting from changing
atmospheric forcing may significantly affect different phases of the seasonal
cycle. We use our time series to trace seasonal and interannual variability in
the atmospheric forcing (local and basin scale) and hydrographic conditions
and the concurrent variability in phytoplankton communities in the Gulf of
Naples. The analysis will consider different aspects of phytoplankton
populations, including the seasonal patterns of occurrence of single species and
of the species assemblages, as well as the size spectrum of microalgal
populations. Preliminary results suggest that the abundance and dominance of
phytoplankton assemblages varies over the years in relation with the external
forcing. In contrast, a large number of phytoplankton species exhibit a
47
remarkable regularity in their annual patterns of occurrence that does not
match the wide interannual variability of the majority of environmental
parameters. A possible explanation for the regular species-specific patterns of
occurrence is that endogenous mechanisms similar to those regulating
phenological traits of higher plants may also operate in unicellular algae.
W10-164 Poster
Zingone, Adriana
POTENTIALLY TOXIC AND HARMFUL MICROALGAE OF THE CAMPANIA
COASTAL WATERS
SARNO Diana 1, KOOISTRA Wiebe H.C.f 1, MONTRESOR Marina 1, SIANO Raffaele 1,
ZINGONE Adriana 1
1 - Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli
Key terms: potentially harmful microalgae; Campania coastal waters; VECTOR
A total number of 45 potentially harmful microalgae have been identified along
the coasts of the Campania region (South Tyrrhenian Sea, Mediterranean Sea).
This number is based on a revision of the results of over 20 years of research
at a coastal station in the Gulf of Naples, 4 years of monitoring activity along
the Campania coasts and of a series of scattered and sporadic observations.
The list includes both species so far confirmed to produce toxins and species
that have caused seawater discolorations in the study area. In the frame of
VECTOR activities, a study on the group of the naked dinoflagellates was
carried out. The group is particularly interesting for two main reasons: 1) it
comprises several potentially ichthyotoxic species, 2) it underwent a
taxonomical revolution few years ago. Two species (Karlodinium sp.1,
Lepidodinium viride) were identified for the first time in the Mediterranean Sea
whereas Karlodinium veneficum was recognised for the first time in the Gulf of
Naples. The taxonomic position of three strains (Takayama sp., Woloszynskia
sp. #1 and Woloszynskia sp. #2) needs further investigations probably leading
to the description of new microalgal species. Information on the most probable
period of occurrence of the species indicate the late spring and summer as the
time of maximum risk of harmful events. Despite the variety of potentially toxic
species, no human health problems nor fish kills have ever been recorded in
Campania. The reasons for this apparent paradox are probably to be found in
the ecological factors that regulate the abundance, toxicity and spatial
distribution of the potentially harmful species and reflect as well the relatively
low number of aquaculture farms in the area.
WORKSHOP W11
Partecipazione italiana al progetto di perforazione oceanica. IODP
(Integrated Ocean Drilling Program).
W11-165 Orale
Camerlenghi, Angelo
SUBMARINE GEOHAZARDS. A NEW VENUE FOR SCIENTIFIC DRILLING
CAMERLENGHI Angelo 1
1 - Institució Catalana de Recerca i Estudis Avançats (ICREA) and Dept. of
Stratigraphy, Paleontology and Marine Geosciences, University of Barcelona,
Barcelona, Spain
Key terms: Scientific drilling; Submarine geohazards; Submarine landslides;
Tsunami; Earthquakes
The international scientific community, supported by IODP, the European
Consortium for Ocean Drilling (ECORD), and the European Science Foundation
(ESF), is active promoting initiatives that will generate new drilling proposals
focusing on submarine geohazards.
From October 25 to 27 2006, the workshop 'Scientific Ocean drilling behind the
assessment of geo-hazards from submarine slides' was held in Barcelona
(Spain). The workshop, sponsored primarily by the ESF, grouped 50 scientists
and representatives of private companies, mainly from the European area,
representing a wide spectrum of disciplines such as geophysics, stratigraphy,
sedimentology, paleoceanography, marine geotechnology, geotechnical
engineering and tsunami modeling. (Camerlenghi et al., 2007; Urgeles et al.,
2007).
There are several reasons why submarine slope instability is to be considered
as an important objective of scientific investigations in general:
° It affects offshore infra-structures (platforms, pipelines, cables, sub-sea
installations);
° It may affect directly the stability of coastal areas;
° It may trigger tsunamis and affect coastal structures and population;
° It can be used as proxy of paleo-seismicity;
° It affects (destructively and constructively) the marine environment;
° It may trigger or it may be triggered by gas hydrate dissociation;
° It has a relevance to the understanding of natural climate changes;
° There is a relationship between volcanic eruptions and stability of volcanic
island flanks;
° It helps understanding sedimentary basin evolution;
° It helps in reservoir characterization.
It is to be recognized that until now geohazards have been only tackled by
scientific drilling as a complementary goal. In the view of the ESF workshop
participants, there is a need of an explicit reference to geohazards in the next
revised version of the IODP Initial Science Plan. The participants agreed that
both mega slides and smaller size slides should be addressed by drilling where
slope instability is recognized as a recurrent phenomenon in the stratigraphic
succession. Not only sediments that have failed should be studied, but also
sediments that are presently undergoing deformation and un-failed slopes
should be addressed. The drilling strategies should include classical
stratigraphic drilling, dedicated geotechnical drilling, and installation of
borehole observatories as well as sea?oor observatories.
Another workshop, sponsored by IODP-MI, entitled Addressing Geologic
WORKSHOP W11
48
Hazards Through Ocean Drilling planned from August 26 to 30 2007 in
Portland, Oregon - USA will bring together a wide range of scientists and
engineers with the goals to review the current state of community knowledge
and activity in submarine geologic hazards in a wide variety of geologic
settings, define outstanding research questions that can be addressed through
scientific ocean drilling, establish scientific priorities, identify potential drilling
targets, evaluate existing technologies and scientific approaches, and
recommend the development of new instruments and/or new deployment
strategies.
As a first outcome of these initiatives, an IODP pre-proposal (#715-Pre) has
been submitted in April 2007 to address a suite of medium size submarine
slides in different geological environments of the Western and Eastern
Mediterranean basin (namely Ebro Continental slope, Eivissa Channel, Gela
Basin, Nile deep sea fan, Israel continental slope).
References
Camerlenghi, A., Urgeles, R., Ercilla, and Bruckmann, W., 2007. Workshop
Report: Scientific Ocean drilling behind the assessment of geo-hazards from
submarine slides. Scientific Drilling, 4:45-47.
Urgeles, R., Camerlenghi, A., Ercilla, G., Anselmetti, F., Brückmann, W.,
Canals, M., Gràcia, E., Locat, J., Krastel, S., and Solheim, A., 2007. Scientific
ocean drilling behind the assessment of geo-hazards from submarine slides
(Meetings Section). EOS, Trans., AGU, 88(17), p. 192.
W11-166 Poster
Fontana, Emanuele
3D-STRUCTURE OF UPPER OCEANIC CRUST FORMED AT A SUPERFAST
SPREADING RIDGE (ODP-IODP SITE 1256, EQUATORIAL PACIFIC): A
CORE-LOG INTEGRATION APPROACH
FONTANA Emanuele 1, TARTAROTTI Paola 1
1 - Dipartimento di Scienze della Terra "A.Desio", Università degli Studi di
Milano, via Mangiagalli, 34 - 20133
Key terms: East Pacific Rise; ponded lava; core-log integration
3D-structure of the upper oceanic crust basement formed at a superfast
spreading rate (ca. 220 mm/yr) is inferred by integrating core data with
electrical-acoustic images. The core-log integration approach enables to
reorienting core structures, which were measured with respect to core
reference frame, to magnetic north. The study area is ODP-IODP Site 1256 (6°
44N, 91° 56W; Guatemala Basin, Cocos Plate, East Pacific Ocean) drilled during
ODP leg 206, IODP Expedition 309 and Expedition 312. The drilling was carried
out on the eastern flank of the East Pacific Rise in a 15 Ma old oceanic
lithosphere. Hole 1256D drilled for the first time a complete section of the
upper oceanic crust from the extrusive lavas, through the sheeted dikes
complex, and into uppermost plutonic rocks.
Method employed to reorienting brittle structures (veins, shear veins, joints
and microfaults) in the whole core was tested on the upper basement unit of
Hole 1256D consisting in a ca. 75m-thick massive lava flow interpreted to be a
lava pond. The high recovery percentage of the lava pond unit and its massive
structure (with rare breccias) make it suitable to test reorienting methods.
Brittle structures were reoriented to the geographic coordinates by correlating
structures observed and measured on cores with structures interpreted in
oriented, high resolution borehole log images. The borehole images were
obtained by the Formation MicroScanner (FMS) tool, that provides electrical
resistivity-based images of the formations crossed by the hole, and by the
Ultrasonic Borehole Imager (UBI), that supplies acoustic images of borehole
walls. The FMS tool includes the General Purpose Inclinometry Tool (GPIT) that
enables to orient the images with respect to magnetic north.
The core pieces cannot be recorded at their drilled depth and, according to
ODP-IODP convention, all recovered core pieces are moved to the top of each
core barrel. In addition, many cores from the lava pond have recoveries
>100% because the core barrel contained material cored but not retrieved
during previous coring runs. In order to minimize the bias due to a recovery
100%, it was developed a specific procedure to reallocate every core pieces at
a truthful drilled depth. All core pieces (and the associated structures) that can
be depth-matched were rotated and oriented with respect to true geographic
north.
The application of this methodology to the whole core provides an accurate and
true distribution of all measured structures with their own relative dip and dip
direction.
Variation of structures attitude in relation with depth and lithological changes,
in addition to the downhole structures density allow to make some
considerations about the lava flow morphology and emplacement conditions
(like seafloor topography), hydrothermal circulation pattern, local and regional
stress perturbations (including thermal stress resulting from contraction of the
cooling lithosphere). A comparison between reoriented structural data and focal
mechanisms acquired from the East Pacific Rise area, Cocos-Nazca Ridge and
the Middle America Trench, enables to test the relationships between ridge
push and slab pull forces which are the two main driving mechanisms for the
motions of plates.
W11-167 Poster
Tamagnini, Paola
NANNOFOSSIL BIOSTRATIGRAPHY AND PALEOECOLOGICAL
RECONSTRUCTIONS OF THE CENOMANIAN-TURONIAN INTERVAL AT
ODP SITE 1261 (LEG 207) AND IN THE TETHYS OCEAN.
TAMAGNINI Paola 1, ERBA Elisabetta 1
1 - Università degli studi di Milano, Dip. Scienze della Terra "A. Desio"
Key terms: Oceanic Anoxic Event 2; Demerara Rise; Cenomanian-Turonian
interval; nannofossil biostratigraphy; paleoecological reconstructions
The Cenomanian-Turonian interval was characterized using calcareous
nannofossils with the aim of reconstructing paleoclimatic/paleoceanographic
conditions before, during and after the Oceanic Anoxic Event (OAE) 2.
During ODP Leg 207 five sites were drilled on the northern margin of Demerara
Rise in a depth transect from 3200 to 1900 meters below sea level (modern
water depth). Site 1261, located in a water depth of 1899 mbsl on the dipping
northwest-facing slope of Demerara Rise, is the shallowest site of the transect.
The Cenomanian-Santonian interval consists of 82 m of black shales
(claystones with abundant organic matter) as dominant lithology, and few
levels of clayey limestone and chalk.
A total of 208 samples were prepared following two different methodologies
aimed at semiquantitative analyses for biostratigraphy (simple smear slides)
and quantitative analyses for estimates of absolute abundances and
paleofluxes (settling boxes). All slides were studied under a light microscope
with a magnification of 1250X. In the first phase, dissolution and overgrowth
were carefully checked to, eventually, eliminate samples with poor preservation
quantitative investigation.
Nannofossil abundance is higher in the lower part of the studied interval and
decreases upwards; minimum values are detected in the upper Lower Turonian
and in the Upper Turonian. The occurrence of marker species allowed the
identification of the NC11* through NC17 biozones of Late Cenomanian to Early
Santonian age.
A Temperature Index (TI) was calculated using the ratio between cool
temperature-related taxa and warm temperature-related ones. At Demerara
Rise, the Cenomanian interval is characterized by cool surface waters; at the
onset of the OAE2 the temperature starts to increase (Hardas & Mutterlose,
submitted), reaching a maximum at the Cenomanian/Turonian boundary. The
cooling episode begins in the lowermost Turonian and TI pointed out even
cooler events recorded by E. floralis peaks.
A fertility Index (FI) was calculated as the ratio between high fertility related
taxa and low fertility related ones. The Cenomanian interval at Demerara Rise
is characterized by low fertility of surface water. The fertility starts to increase
at the onset of OAE2 (Hardas & Mutterlose, submitted), remains high until the
middle Turonian and then progressively decreases.
Nannofossil TI, FI and abundances obtained at Demerara Rise are compared to
the ones from the Umbria-Marche Basin, where the Cenomanian-Turonian
Bottaccione and Furlo sections were studied in detail. Here
Temperature-related taxa and the TI indicate very warm surface waters during
the late Cenomanian with a thermal maximum coinciding with OAE2. A
significant cooling starts in the earliest Turonian, just above OAE2, although
fluctuations characterize the general trend towards cooler surface waters. The
FI shows a decrease upwards reaching minimum values at the base of OAE2
and it remains low in the lower Turonian. A discrete interval of higher fertility
was detected approximately 400-300 kyrs before the onset of OAE2.
The nannofossil fertility story in the Umbria-Marche Basin apparently
contradicts the patterns documented at Demerara Rise and the general
reconstructions based on independent proxies. In fact, a general consensus has
been reached on the paleoceanographic reconstructions for OAE2 pointing to
anoxia derived from enhanced primary productivity. A possible explanation
derives from the notion that nannofossils cannot trace eutrophy, because under
such conditions they are replaced by other phytoplankton. If so, at Demerara
Rise fertility increased to mesotrophy but in the Tethys excess nutrients trigged
productivity of non-calcareous phytoplankton.
Hardas & Mutterlose, submitted. "Changes in calcareous nannofossil
assemblages during Oceanic Anoxic Event 2 at the equatorial Atlantic:
implication of an eutrophication event".
WORKSHOP W12
Progetto MaGIC (Marine Geohazards along the Italian Coasts).
Morfo-batimetria ad alta risoluzione e cartografia degli elementi di
pericolosita dei fondali marini italiani.
WORKSHOP W13
Geoscienze e Istruzione: una nuova interazione tra Universita e Scuola
Superiore
SESSIONI TEMATICHE
49
50
SESSIONE T01
Biogeochimica e inquinamento delle aree costiere
T01-1 Invitato
Rinaldi, Attilio
EUTROPHICATION AND OTHER PROCESSES IN EMILIA ROMAGNA
COASTAL WATERS: LONG-TIME DATA SERIES OF DAPHNE
OCEANOGRAPHIC VESSEL
RINALDI Attilio 1
1 - Struttura Oceanografica Daphne-ARPA Emilia - Romagna
Key terms: MUCILLAGE; EUTROPHICATION; ADRIATIC SEA; MONITORING;
CLIMATE CHANGE
Eutrophication and mucilage are events that determine periodical
environmental emergencies in the high and low Adriatic Sea since many years.
Eutrophication is a relatively recent event. The first documented sharp
occurrence was in 1975; since then periodical recurrences were visible often
with seasonal cadence and with episodes of bottom water anoxia, organolectic
alteration of waters and progressive reduction of the biodiversity. The random
factors were mainly characterized by the nitrogen and phosphorous load
carried from the rivers to the sea and from coastal settlements. The area under
influence is only a limited zone of the Adriatic: only the North Western area is
characterized by medium-high trophic levels, whereas the remaining part of
the Adriatic (about 80% of its extent) shows an oligotrophic condition.
The eutrophic alerts within the cited area have reduced since the end of 1980's
both as extension and duration. The actions taken to limit the sources of
phosphorous have progressively reduced its load to the sea. On the other hand
nitrogen shows a certain stability both in the load and in the measured
concentration.
The mucilage phenomenon is not a recent event. It has been documented
about thirty times in the last three centuries, the oldest evidence dated back to
1729. It occurs in all the seas and oceans in the world, but only in few
situations, and the Adriatic is one of these, it has an invasive form and quite
extended surfacings. Its origin is biologic; under a chemical point of view the
mucilaginous aggregate is made out of complex polysaccharides. The sharpest
stage of the cycle of formation and aggregation usually takes place in the
summer season. In recent years, to be precise during the period 1988-2007,
the phenomenon took place 9 times: in 1988, '89, '91, '97, 2000, '01, '02, and
'04.
The effects on the marine ecosystems are usually not relevant. More effective
damages involve fishery and tourism.
The effects of the climatic change on the Adriatic Sea have been causing
significant structural and biological changes. The surface water temperature
shows a clear increasing trend in the summer and autumn season since the
mid 1980's, while a sort of stability appears in the winter and spring season.
This situation positively influences the "meridionalization" processes, migration
and shift of the termophil ichthyic species from the mediterranean zones of the
Mediterranean Sea to the north. The rainfall drop brought about, at least since
the last four years, a strong flow reduction both in the Po river and in the other
rivers of the Po-Adriatic plain. A marine current reduction matches this
condition with a following slow down in the turn over process of the Adriatic
basin water. This stagnation is also influenced by the long time stable
meteorological condition during the winter and spring season, which
determines a reduction of the wind strength blowing from northern quadrants.
Undesired events such as the massive appearance of mucilage, the massive
arrival of jellyfishes and algal blooms caused by the microalga Fibrocapsa
japonica are also to be linked to these persisting conditions.
T01-2 Invitato
Giani, Michele
CARBON, NITROGEN, AND PHOSPHORUS DISTRIBUTION AND C:N:P
VARIATIONS IN THE SEDIMENTS, SETTLING AND SUSPENDED MATTER
OF THE ADRIATIC SEA
GIANI Michele 1, BERTO Daniela 1, SAVELLI Fabio 1
1 - ICRAM , Istituto Centrale per la Ricerca scientifica Applicata al Mare,
Chioggia, Italy
Key terms: carbon; nitrogen; phosphorus; Adriatic Sea
A comparative study of the pools of carbon, nitrogen and phosphorus in
suspended matter, settling matter and sediments of the Adriatic is presented.
This is based on previous works carried out by our group on particulate matter
collected by Niskin water samplers (Gismondi et al., 2002, Giani et al, 2003),
gelatinous aggregates collected by scuba diver (Giani et al,2005), settling
matter collected by sediment traps (Giani et al., 2001) and sediments sampled
by box cores and gravity corers (unpublished data). Strong variations of the
pools and of the C.N:P ratios take place in the Adriatic due to the strong
salinity and trophic gradients from western zone highly influenced by riverine
waters and resuspension to the central and eastern part of the basin.
In the low salinity waters the concentrations of particulate organic carbon
(POC), nitrogen (PN) and phosphorus (PP) are higher and more variable than in
the dense waters, mainly due to dilution effects which induce an abundant
phytoplankton growth.
The POC, PN and PP concentrations in the coastal waters underneath the
pycnocline are greatly reduced due to stratification and to degradation
processes taking place during the settling of particles. In open waters, the
highest variability corresponds to the subsurface chlorophyll maximum when
the seasonal thermocline is established. High standing stocks of organic
particulate matter are found in the western Adriatic coastal waters, due to the
high primary production induced by the nutrient load carried by riverine
waters.
The decrease of POC and PN concentrations across the saline gradient from the
coastal to the offshore waters can account for an up to 3-4 fold reduction. The
decrease of particulate phosphorus is more relevant revealing an efficient
51
removal of P through settling in the bottom sediments of the coastal belt.
The particulate matter in the oligotrophic waters of the North Adriatic is
extremely depleted of phosphorus and the deviations of C:P and N:P ratios
from the Redfield ratio are more enhanced than those found in other part of
the Mediterranean sea. Also the mucilaginous aggregates formed in summer
time in the Adriatic present high C/P values as well as the colloidal organic
matter. This support both a faster degradation of organic phosphorus and /or
the presence of a relevant organic fraction depleted in phosphorus as
exopolysaccharides,
During sedimentation of the particles in the upper layer, the organic matter
changes the biogeochemical composition in relation to degradation and
recycling processes occurring in the upper layers of the water column. The C:N
atomic ratios in the settled matter collected in bottom
traps were on average higher than in the suspended matter but lower than in
the sediments, indicating a probable faster degradation of the nitrogen
component as protein, amino acid, etc. with respect to organic carbon during
sedimentation. The C:P atomic ratios in the coastal waters were lower than the
Redfield ratio, indicating the increase of phosphorus contribution from riverine
particulate matter or from resuspension of bottom sediments. In the offshore
waters, the C:P ratios reach values much more elevated than the Redfield ratio
due to phosphorus depletion in the particulate matter. The C:P ratios of settling
matter are intermediate between the lower values of the sediments and the
much higher ratios found in the particulate matter. This highlights the relative
accumulation of inorganic phosphorus in the sediments, with respect to organic
carbon and nitrogen, which has profound effects on the characteristic of the
C:P ratio in settled matter through resuspension.
T01-3 Orale
Spagnoli, Federico
BENTHIC REMINERALIZATION AND NUTRIENT RECYCLING IN CENTRAL
AND SOUTHERN ADRIATIC AND IONIAN SEAS
SPAGNOLI Federico 1, BARTHOLINI Gabriella 2, FIESOLETTI Federica 1, MARINI
Mauro 1, LOIACONO Francesco 2
1 - CNR-ISMAR, Sede di Ancona
2 - Università degli Studi di Bari
Key terms: Benthic fluxes; Early diagenesis; Adriatic sea; Ionian sea; Nutrient
recycling
Assessing processes affecting the carbon cycle and solute exchanges between
sediments and overlying water at sediment-water interface in Adriatic and
Ionian seas were the aims of The CaDi Cruise (PITAGEM Project). In particular,
the objectives were to study the mechanisms responsible of the recycle of
carbon and nutrients at the sediment-water interface and to understand the
role of sediments to the nutrient mass balance in Central and Southern Adriatic
and Ionian seas.
The study has been carried out in 7 stations located in environments
characterized by different bathymetry, hydrological setting and trophic
conditions. Northern stations, located in central and southern Adriatic
depressions, are characterized by shallower depths, higher sedimentation rates
and higher organic matter inputs. Southern stations, located in the Northern
and Central Ionian Sea, are characterized by increasing depths, different
provenances of terrigenous sediments, lower productivity, lower sedimentation
rates and organic matter inputs.
In each stations sediment cores were collected to analyze pore waters (pH, Eh,
O2, NO3, NO2, NH4, PO4, alkalinity, DIC, Si(OH)4, Ca, Mg, Fe and Mn) and
solid phase (grain size, organic C) and to calculate diffusive benthic fluxes.
Pore water profiles highlighted regional differences between the Adriatic and
Ionian basins. The first one is characterized by oxyc and suboxic-non sulphidic
organic matter degradation. In this area the most intensive degradation
processes occur in the Otranto Channel station where oxyc and sub-oxyc
reactions are stronger and confined at lesser depths respect to the Mid-Adriatic
and Southern Adriatic depressions. This suggests higher inputs of reactive
organic matter along the western side of the Otranto Channel respect to the
mid and Southern Adriatic depressions, where already degraded organic matter
arrive at the sediment. In the Ionian basin the remineralization processes takes
place mainly by means of oxyc reactions (the depth of oxygen penetration is
higher, the denitrification processes reach greater depths and produce lower
organic matter degradation products (DIC and NH4)). This means that the
inputs of reactive organic matter in these area are lower for the lower
productivity of this basin, for the greater water column depth and for the
higher distance from fluvial inputs. In both basins nitrification processes,
stronger in the Ionian basin, take place in the uppermost layers.
Benthic diffusive fluxes reflect the early diagenesis processes recorded in the
Adriatic and Ionian pore water profiles showing a northern-southern and
shallow-deep trend characterized by lowering of remineralization processes,
this generate weaker oxygen fluxes into the sediments and DIC fluxes outside
the sediments. Ammonium and nitrate fluxes are complicated by the
nitrification/denitrification processes occurring in the oxyc zone.
T01-4 Orale
Catalano, Giulio
DETERMINATION OF THE SEDIMENT OXYGEN DEMAND IN DIFFERENT
CONDITIONS OF BOTTOM CURRENT STRESS
CATALANO Giulio 1, MATTEUCCI Gabriele 2, FOCACCIA Paola 3
1 - CNR - Istituto di Scienze Marine - Sede di Trieste, Trieste, Italia
2 - Gruppo CSA SpA - Rimini, Italia
3 - CNR - Istituto di Scienze Marine - Sede di Bologna, Bologna, Italia
Key terms: bottom layer; sediment oxygenation; clay sediments; oxygen
exchange; Northern Adriatic
The oxygen exchange with the sediments can be decisive for the oxygenation
of the water bottom layer in the Northern Adriatic Sea as well as in other
shallow seas. Bottom currents caused in the coastal marine environment by
natural events, such as general circulation, strong winds, tides or biological
activities and anthropogenic perturbations, trawling and dredging, can favorite
the sediment resuspension, that on turn may strongly influence the
SESSIONE T01
52
mineralisation rate of the organic matter deposited at the bottom. In the
shallow depths, a significat deposition of primary production is normally
mineralised at the surface sediments that can become both a source for
nutrients and a sink for oxygen.
To deepen this theme and to quantify the oxygen exchange with different
sediments and bottom currents, three experiments were carried out in
microcosm during the ANEMRE cruise (north Adriatic, May-June 2006) using
sediments coming from Fossa di Pomo, from a station offshore Cesenatico and
from the station S1, located at SE of the Po River delta.
The sediments sampled in the three sites were characterized respectively: in
the Fossa di Pomo area from extremely thin clays clearly oxidized and
hydrated; in the Cesenatico area mainly from mild oxidized clays with low
fraction of silt and sand; in the S1 site from a clear predominance of thin clay
sediment on average well oxidized.
Experiments were made by putting the polycarbonate core liners with inside
the sediment and about 20 cm of the own bottom water, into an on deck
circulating sea water incubator. The sediment cores were incubated for 16 -24
hours in the dark and tightly closed to prevent the oxygen exchange with the
atmosphere. In addition, just above the sediment but without touching it, a
rotating propeller simulated a bottom current. In each experiment it was
tentatively incubated 4 cores, two of them with water and sediment plus a third
with only bottom water were maintained at a low stirring velocity, about 10
rpm of the propeller, in the fourth, with sediment and water, the propeller was
put at about 100 rpm to mimic a stronger current. The liner filled with only
bottom water was then used as a blank to estimate the oxygen demand due
the organisms and substances present in the water above the sediment.
In order to calculate the oxygen consumed by the biogeochemical processes in
the sediment, a double sampling of the water above the sediment was carried
out in each core at the beginning and at the end of the experiment. The oxygen
consumed by the sediment, expressed in mol h -1 dm -2 , has been then calculate
after the blank subtraction.
The results are presently discussed for different types of sediment collected
and stirring velocities applied. These, on turn, have been converted in bottom
current speeds.
The final goal of this experiment is to parameterize the oxygen exchange to be
assimilated in the biogeochemical models describing the sediment-bottom
water interactions.
T01-5 Orale
Bertolotto, Rosa Maria
DETERMINATION OF BACKGROUND LEVELS OF CONTAMINATION IN
ESTUARY SEDIMENTS
GASPARINO Ugo 1, BERTOLOTTO Rosa Maria 1, QUAGLIATI Mauro 1, GAINO
Federico 1
1 - ARPAL, Genova, Italia
Key terms: Liguria; contaminated sediments; background levels; chromium
Introduction: As a result of more than a century of chemical industrial activity,
contamination by heavy metals, and specifically by hexavalent chromium, has
become a focus of ecological and human health concerns in Cogoleto, Genoa Italy. The potential risks related to the contaminated land-site and the nearby
estuary and coastal area, have urged the Italian Ministry of the Environment to
include the ex-industrial site among the so-called "environmental national
priorities". This study focuses on the coastal sediments and in particular on
how to discriminate between industry related anthropogenic contributions and
"natural background". A multivariate statistical approach shows how a
positioning of sampling points based on an "a-priori knowledge" of sediment
dispersion pathways in marine estuary results to be essential to characterize
the contaminated sediments.
Methods: Sediment cores provide a record of past conditions as recently
deposited sediments at the top overlie older sediments below. Therefore, 57
drilling core samples (up to 3 m depth) were collected in the area under
investigation. The sampling strategy was mainly based on a regular grid,
complemented by a more detailed investigation of the volumes where sediment
deposition was expected theoretically, the prevalent coastal current being
westward. Four sub-sections were extracted from each drilling core at different
depth intervals, and analyzed (about 40 physical and chemical parameters).
Results: The lowest Cr concentrations tend to be detected in the deepest
(pre-industrial) levels (radiometric analysis suggests sedimentation rates of
0.3-1 cm/y). Furthermore, it seems that concentrations tend to decrease in the
last decades. In the bottom layer, greatest enrichment of Cr tend to be
prevalently found in the depositional region, whereas in upper layers
contamination is more widespread. A deeper analysis shows that Cr
concentrations in the bottom layer have a "bi-modal distribution", whose first
component is interpreted to reflect natural background, whereas the second
can be referred to anthropogenic contribution. This "conceptual model" is
strongly supported by a multivariate factor analysis of the concentrations of the
14 measured heavy metals. The analysis tend to suggest the existence of 3
"latent factors" (explaining about 70% of total variance). A 3-D spatial analysis
in this factor space (instead of the original "physical" one) facilitate the
"isolation" of the "natural background" and allows a determination of its main
characteristics.
T01-6 Orale
Mugnai, Cristian
IDENTIFICATION OF CHEMICAL REFERENCE VALUES FOR THE
MANAGEMENT OF SANDS DREDGED FROM CECINA RIVER MOUTH
(TUSCANY)
MUGNAI Cristian 1, OLIVIERO Lisa 2, PILATO Fabiano 2, MACCHIA Simona 2, LERA
Samantha 2, DENTONE Letizia 2, ONORATI Fulvio 2, PELLEGRINI David 2
1 - ICRAM - ISMAR Bologna
2 - ICRAM
Key terms: reference values; dredging; sands; Chromium; Nickel
The relocation of marine and river sediments, together with surveys to find
suitable sands for beach nourishment, are topics of great importance for
national and local stakeholders. In the Cecina river mouth (Tuscany), that often
undergo silting events, the necessity of maintenance dredging combines with
the need of restitution of sands to the surrounding eroded beach.
Notwithstanding this, the management of Cecina river sediments, mainly
sandy, poses some difficulties for the quite high concentrations of Chromium
and Nickel (up to 1100 mg kg -1 and 600 mg kg -1, respectively). These values,
determined after a total mineralization (that dissolves the mineral matrix), are
highly above the chemical limits proposed for the sediments that should
undergo a remediation process (Leg. Decree 152/06).
The aim of this research is to try to determine the background concentration of
Cr and Ni in the study area. In particular, an attempt to identify Cr and Ni local
reference values for the management of sands dredged from Cecina river
mouth, using an integrated approach.
Sediment samples were collected from the beach and the river mouth and
sieved with 4 mm, 2 mm and 63 m mesh, thus obtaining the coarse fraction
(sand and gravel) and the fine fraction (silt and clay). This procedure was
necessary for the determination of reference values, since the grain size affects
the content of trace element in the sediment. On each sample, chemical
analyses for Cr and Ni content were carried out using both the total digestion
(with nitric, hydrochloric and hydrofluoric acids) both the mineralization with
nitric acid only. Moreover, petrographic analyses (transmitted light microscopy)
and bioassays to assess the toxicity and the bioaccumulation of Cr and Ni were
performed.
All the analyses carried out on sands collected from the surrounding beach
provided results similar to those of the river mouth. The petrographic study
showed mineral paragenesis attributable to ultramafic and igneous rocks of
possible ophiolitic origin. Most Cr (III), and probably Ni, is stored in the crystal
lattice of chromian spinel and associated mafic minerals(olivine and pyroxene).
Consequently, in this environment, most Cr and Ni has a natural origin and its
leaching occurs with very low dynamic. This was confirmed also by the lack of
any significant correlation between Cr and Ni content and the toxic responses
detected with bioassays.
In order to identify reference values (local Baseline Chemical Level, BCL-loc)
we elaborated the results of chemical analyses (with the two different leaching
procedures), including also data obtained in previous surveys.
Cr and Ni content was not significantly correlated with the grain size; this may
be explained by the not homogeneous content of these elements, mainly in the
sandy fractions of sediments.
The statistical elaboration (t-test) evidenced significant difference (p < 0.05)
between the total and nitric acid leaching procedures for Cr, regardless of the
grain size; as far as Ni is concerned, the two leaching procedures lead to
statistically different results only for coarse sediments (sand and gravel). From
the estimate of the coefficient of variation (CV), the mineralization with nitric
acid provided more homogeneous results (lower CVs) than the total leaching.
From these considerations, the Cr and Ni reference values for Cecina river
mouth were referred to the nitric acid leaching procedure and calculated as the
mean value among samples with grain size < 63 m, raised by twice the
standard deviation (370 and 335 mg kg -1 for Cr e Ni, respectively).
T01-7 Orale
Di Leonardo, Rossella
SOURCES AND TIMING OF ANTHROPOGENIC POLLUTION IN TWO
AREAS OF THE SICILIAN COAST, CENTRAL MEDITERRANEAN
DI LEONARDO Rossella 1, BELLANCA Adriana 1, CUNDY Andrew 2, NERI Rodolfo 1
1 - Dipartimento di Chimica e Fisica della Terra ed Applicazioni alle Georisorse e
ai Rischi Naturali (CFTA), Università di Palermo, Via Archirafi 36, 90123
Palermo, Italy
2 - School of the Environment, University of Brighton, Moulsecoomb, Brighton,
BN2 4GJ, United Kingdom
Key terms: box-core sediments; trace metals; Sicily
Marine sediments are a fundamental component of biogeodynamic cycles of
many inorganic and organic compounds and tend to act as sinks. The
distribution and accumulation of pollutants in the sediments are controlled by
physical and chemical mechanisms depending on sediment texture,
mineralogical composition, and reduction/oxidation state. Trace metals and
organic compounds, both of natural and anthropogenic origin, can influence the
marine biosphere through bio-accumulation and bio-magnification processes,
with potentially toxic effects both on the environment and on human life.
Sediments accumulated near industrial and urban areas are reasonably
considered as potential point sources from which contaminants can be released
towards surrounding aquatic ecosystems through biological and
physico-chemical processes and anthropogenic activities.
For this work, a valuable sets of geochemical data - including concentrations of
major elements, and trace metals, - are obtained from box-core sediments
collected offshore of the Palermo and Augusta urban/industrial areas (Sicily).
Elemental profiles of sediment cores, dated by radiometric analyses of 210Pb and
137
Cs, are described and related to the local processes occurring in sediments.
Geochemical information is used to assess perturbation of the coastal
ecosystem in the presence of complex industrial, commercial and urban
activities and improve the knowledge on the relationship between
nearshore-offshore marine zones in order to make inferences about the
possible influence of coastal/local processes on the open sea environment.
Obtained results support the idea that pollutant inputs in these areas are
mainly derived from industrial/harbour and urban activities. Pollution levels
ranged from low to high for certain metals, notably Hg, showing concentrations
consistent with those typically found in urbanised and industrialised coastal
environments. Metal enrichment is considerable principally for the nearshore
sediments and is significantly in excess for Hg, Pb, and Sn of background
concentrations estimated for Sicilian sediments. In the nearshore cores, heavy
metal contamination has increased approximately from ca. 1940-1950 and
1920-1930 in the Augusta and the Palermo areas, respectively. These
contaminants, entering into the sea from the urban/industrial coastal areas via
relatively unregulated effluents, cause the continual pollution of the coastline.
The impacts of contaminants appear not confined to the coastal zone, but they
also influenced the offshore areas. Natural conditions (such as topography and
water circulation) together with the dredging activities, occurred at different
time in the Augusta bay during the 1980s, are the main drivers of the
SESSIONE T01
contaminant flux towards the Augusta offshore area. On the basis of
comparison with sediment quality criteria heavy metal data for the studied
sediments could be hazardous for the biosphere.
T01-8 Orale
Russo, Aniello
BIOGEOCHEMICAL FLUXES SIMULATIONS IN THE ADRIATIC SEA AND
REAL TIME SHORT-TERM FORECASTING OF ANOXIA IN THE RIMINI
AREA
RUSSO Aniello 1, IERMANO Ilaria 1, COLUCCELLI Alessandro 1, DESERTI Marco 2,
CHIGGIATO Jacopo 3, FERRARI Carla Rita 4, BORTOLUZZI Giovanni 5
1 - Università Politecnica delle Marche
2 - ARPA-EMR, Bologna
3 - CNR-ISMAR Ve & ARPA-EMR Bo
4 - ARPA-EMR, Cesenatico
5 - CNR-ISMAR, Bologna
Key terms: model; Adriatic Sea; hydrodynamics; fluxes; biogeochemical
Adriatic Sea hydrodynamics and biogeochemical fluxes have been simulated
from 2003 to 2006 by means of the Regional Ocean Modular System (ROMS), a
finite difference, primitive equations, hydrostatic, free-surface, 3-D model,
which includes a biogeochemical fluxes module. Such simple marine ecosystem
model simulates inorganic carbon and nitrogen dynamics and includes variables
as nitrate, ammonium, phytoplankton, zooplankton, chlorophyll and detritus,
all expressed in terms of nitrogen and carbon. Besides that, the module is able
to simulate the dissolved oxygen dynamics, considering processes like
photosynthesis, respiration, mineralization. The integration with the
hydrodynamic model allows to consider physical processes which influence
dissolved oxygen concentration (air-sea exchange, advection, diffusion). The
water and nutrient inputs from rivers is considered by including several sources
along the Adriatic basin.
The relatively simplified biogeochemical fluxes module allows to reach high
spatial resolutions while maintaining computation time compatible with
operational applications. Hypoxic and anoxic events are quite often detected in
the northern Adriatic Sea, and a real time short-term forecasting system of
such events in being implemented in the Rimini area (thanks to the European
project LIFE EMMA LIFE04 ENV/IT/000479). A new higher resolution (500 m)
ROMS implementation, nested in the basin scale one, provides every day the
dissolved oxygen forecast during the three following days. Momentum, heat
and water fluxes through the air-sea interface play an important role for the
dissolved oxygen forecasting in shallow water; such fluxes are computed from
the high resolution (about 2.8 km) LAMI (Limited Area Model Italy)
atmospheric model operational forecasts. The EMMA observing system provides
data used to analyze the forecasting system accuracy and to initialize dissolved
oxygen, in particular with the near real-time periodic monitoring of the
ARPA-Daphne oceanographic department and the continuous monitoring of the
EMMA meteo-oceanographic buoy, integrated by other available data. Both
data and forecasts are collected by a Local Information Center (LIC) and
distributed to local end-users.
T01-9 Invitato
Zavatarelli, Marco
MODELLING TRANSPORT AND FATE OF THE EUTROPHIC LOAD IN THE
ADRIAATIC SEA
ZAVATARELLI Marco 1, POLIMENE Luca 1
1 - Bologna University -. CIRSA
Key terms: Adriatic Sea; Ecological models; Marine ecosystem dynamics
The Adriatic Sea coastal zone transport and the utilisation of the riverborne
(organic and inorganic) eutrophicating substances is analysed by means of
numerical simulations carried out with a coupled (hydrodynamics and
biogeochemistry) model constituted by the Princeton Ocean Model (general
circulation) and the Biogeochemical Flux Model (biogeochemical cycling).
Numerical simulations have been carried out under quantitatively (chages in
the eutrophicating load) and qualitatively (changes in the N:P ratio) different
scenarios of river mediated input of inorganic nutrients and dissolved organic
matter, in order to evaluate the impact on the dynamics and the trophic
structure of the Adriatic Sea marine ecosystem.
T01-10 Invitato
Giuliani, Silvia
A MULTI-SEGMENT FUGACITY/ACQUIVALENCE MASS BALANCE
CONTAMINANT FATE AND TRANSPORT MODEL OF THE VENICE
LAGOON, ITALY AND RELATED UNCERTAINTY ANALYSIS
SOMMERFREUND Julie 1, DIAMOND Miriam Leah 1, FRIGNANI Mauro 2, GIULIANI
Silvia 2, BELLUCCI Luca Giorgio 2, CAPODAGLIO Gabriele 3
1 - Dept. of Geography, University of Toronto, 45 St. George Street,
Toronto-Ontario (Canada)
2 - CNR-ISMAR, Via Gobetti 101, 40129 Bologna (Italy)
3 - CNR-IDPA, Dorsoduro 2137, 30123 Venice (Italy)
Key terms: Contaminant fate modelling; Venice lagoon; Source apportionment;
Uncertainty analysis
Contaminant loadings to the Venice Lagoon peaked between the 1950s and
1980s during a time of rapid industrialization. Although loadings have declined
since the 1980s, contamination levels in the lagoon are still of concern.
Furthermore, the contaminated sediments in the central basin, due to previous
and current loadings, pose a potential new source of contaminants to the
Lagoon due to the increase of erosive processes. The relative importance of
in-place pollution of sediment as a contaminant source, and contaminant fate
in light of current particle dynamics of the Venice Lagoon, were evaluated
through the modification and application of a fugacity/aquivalence based
53
model. The contaminants studied were OCDD/F, PCB 180, Pb and Cu. The
Lagoon was segmented according to modelled hydrodynamic circulation
patterns and the model explicitly considered sediment erosion. In addition, for
metal contaminants, the loosely coupled TRANsport and SPECiation model
(TRANSPEC) that accounts for metal chemistry and phase was incorporated. A
probabilistic approach for contaminant fate and transport modelling was used
to quantify model uncertainty. In-place pollution, current industrial discharges
and tributary loadings were identified as the main sources of contaminants to
the Venice Lagoon, with negligible contributions from the atmosphere (except
for PCB 180). The fate of the selected contaminants in the lagoon was
governed by extensive sediment-water exchange with simultaneous advective
transport by the dominant water circulation pattern. Contaminant loadings
originating in the central and northern basin were circulated amongst all the
segments in the northern and central basins with only a small fraction reaching
the far southern basin and the Chioggia inlet. Since the Chioggia inlet is the
main channel for water export, the transfer to the Adriatic Sea is limited,
trapping the majority of contaminants within the lagoon sediment. The range of
model output distributions, defined by the uncertainty analysis, can vary up to
an order of magnitude, exhibiting both contaminant- and site-specific
variability.
T01-11 Poster
HYPOXIA AND ANOXIA IN THE NORTHERN ADRIATIC SEA WITHIN
ANOCSIA(MUR-FIRB) AND EMMA (UE-LIFE) PROJECTS: PLANNING AND
SOME (FIRST) RESULTS
RAVAIOLI Mariangela 1, CATALANO Giulio 2, ARNERI Enrico 3, RUSSO Aniello 4,
SERRATORE Patrizia 5, FERRARI Carla Rita 6, PREVEDELLI Daniela 7, MATTEUCCI
Gabriele 8, STANLEY Chiara 9, BAJT Oliver 10, et al.
1 - CNR - Istituto di Scienze Marine - Sede di Bologna, Bologna, Italia
2 - CNR - Istituto di Scienze Marine - Sede di Trieste, Trieste, Italia
3 - CNR - Isituto di Scienze Marine - Sede di Ancona, Ancona, Italia
4 - Dipartimento di Scienze del Mare, Università Politecnica delle Marche,
Ancona, Italia
5 - Dip. di Sanità Pubblica Veterinaria e Patologia Animale, Università di
Bologna, Centro Ricerche Marine, Cesenatico, Italia
6 - Struttura Oceanografica Daphne, ARPA Emilia Romagna, Cesenatico, Italia
7 - Dipartimento di Biologia Animale, Università degli Studi di Modena e Reggio
Emilia, Modena, Italia
8 - Gruppo CSA SpA - Rimini, Italia
9 - Comune di Rimini, Assessorato alle Politiche Ambientali, Settore Ambiente e
Sicurezza, Rimini, Italia
10 - National Institute of Biology, Marine Biology Station, Piran , Slovenia
Key terms: Northern Adriatic; anoxia; multiparametric buoy; predicting model;
managing strategies
The morphologic, oceanographic and climatic characteristics together with the
anthropic forcings make the north Adriatic basin an environment particularly
suitable to the grow of ipo-anoxic phenomena of its water. During the last
decade the increasing frequency of these episodes has caused a relevant
economic damage to the North Adriatic coastal regions, particularly to the
Emilia Romagna region which is mainly affected for the environmental quality
of the coast, for the quality and quantity of the fishery and mariculture
products, and for the health defence in bathing zones.
For this reason the ANOCSIA Project (2004-2007) financed by MIUR-FIRB
focused on the study of these phenomena in order to identify the natural and
anthropical set off processes. Also thanks to the knowledge gained with this
project it was at the same time possible to set the basis for a new innovative
research project called EMMA. Approved within the LIFE-Environment sector of
the E.U. the project has an application-managing value directed to the
improvement of the awareness of the necessity to use integrated
observational-modellistic-predicting systems for the management of the
environment by the authorities who have to administrate the territory, to
transfer the scientific-technologic knowledges, by the public administration and
by the socio-economic subjects in order to start concerted steps and
interventions able to counteract the causes of the marine ecosystem
deterioration and to mitigate its impact.
Therefore EMMA aims to create: i) an experimental site for the study anoxic
events as integration of the pre-existent monitoring network of the North
Adriatic; ii) a space-temporal predicting model (72 h) of O2 concentration iii)
short term intervention strategies consisting in temporary rules to manage
anoxic events in progress; iv) long term intervention strategies which integrate
the present day public instruments of territorial pianification and management
through concrete measures for the prevention and reduction of the harmful
effects of the anoxic events in the study area; v) identification of possible
indicators of anoxic conditions through the study of the behaviour of some
ichthyic and mariculture species.
The actions so far realized have been: i) planning and realization of
multidisciplinary databases and informatization of the historical maps of the
ipo-anoxic events; ii) historical reconstruction of the ipo-anoxic episodes
occurred in the North Adriatic.
a) 3 oceanographic cruises for the acquisition of sediment and water column
data useful to the characterization of the area under survey also thanks to the
integration with the allowable historical data;
b) real time monitoring through the two multiparametric sites E1 and S1 for
the acquisition of meteo-oceanographic data useful to implement the 3D
predicting model;
c) implementation of a 3-dimensional model for the space-temporal prediction
of the O2 concentration in the water;
d) setup of a LIC (Local Information Center), a network for collecting and
exchanging data and results of the predicting model;
We will present and discuss here some of the most representative results
obtained during the oceanographic campaigns and thanks to the continuous
monitoring of the oceanographic buoy and the connections with the predicting
models and the managing applications.
Authors indicated as et al.: Focaccia P. 1, Alvisi F. 1, Luchetta A. 2, Cantoni C. 2,
Cozzi S. 2, Morello E. 3, Iermano A. 4, Negri A. 4, Morigi C. 4, Falco P. 4, Trentini M. 5,
Tarlazzi S. 6, Simonini R. 7, Favi E 9.
SESSIONE T01
54
T01-12 Poster
Socal, Giorgio
PHYTOPLANKTON PRODUCTION IN A HIGHLY VARIABLE COASTAL
ECOSYSTEM (THE NORTHERN ADRIATIC SEA)
PUGNETTI Alessandra 1, BAZZONI Anna Maria 1, BERNARDI AUBRY Fabrizio 1,
BOLDRIN Alfredo 1, CAMATTI Elisa 1, SOCAL Giorgio 1
1 - ISMAR CNR Venezia
Key terms: Primary production; Phytoplankton; Northern Adriatic Sea
Studies on the phytoplankton production (PP) in the Northern Adriatic Sea
(NAS) have been performed since the seventies by different working groups
and in the framework of several research projects. In the present work we will
focus on the data gathered by the CNR ISMAR since the early nineties, with the
main aim of presenting a review of the most relevant results obtained in the
last 15 years and to evidence the possible open questions.
In the NAS the major PP variations occur along the trophic gradient and,
typically, a negative correlation between phytoplankton production and salinity
has been reported. The range of phytoplankton production in this area is
considerable, with annual values ranging between 60 and 90 and 120 and 210
g C m-2 y-1 for offshore and coastal waters, respectively. Moreover, marked
differences in the vertical distribution of primary production characterize the
trophic gradient: the productive layer is generally restricted to the upper
meters at the coastal sites, while offshore the productive layers include
frequently the entire water column. Specific production (Pb: PP/chlorophyll a)
frequently exceeding 5 mg C mg chl a-1 h-1, with peaks up to 20 mg C mg chl
a-1 h-1, are commonly observed in the NAS, as well as dramatic changes of
this parameter, in relation with nutrient dynamics. The largest part of the NAS
is, indeed, characterized by rapid variation of nutrient availability, with
alternating N and P limitation, in relation with abrupt changes in the Po River
flow, to nutrient distribution in the basin and to phytoplankton uptake. The
complex relation between PP and phytoplankton biomass in this ecosystem,
makes difficult the parameterization of the production process and hampers the
possibility to predict PP from simple covariables (such as light and chlorophyll
a). Moreover, the elevated variability of nutrient inputs may lead in the NAS to
an uncoupling between photosynthesis and growth and to a shift from biomass
growth to pure polysaccharide production that does not require N and P.
Indeed, the average rate of exudate release in the NAS is close to the highest
values reported in the literature.
The relations between daily PP and biomass variations have been recently
analyzed too, in order to evaluate the matching between production and
biomass loss factors. The strength of this coupling might give significant
indication about the fate of the carbon organicated by phytoplankton and about
the prevalent trophic webs.
T01-13 Poster
Giani, Michele
RIVERINE ORGANIC MATTER AND HUMIC SUBSTANCES IN THE
SEDIMENTS SOUTH OF THE PO PRODELTA
BERTO Daniela 1, GIANI Michele 1, RAMPAZZO Federico 2, SAVELLI Fabio 1, ALVISI
Francesca 3, RAVAIOLI Mariangela 3, FRASCARI Franca 3
1 - Istituto Centrale per la Ricerca scientifica e tecnologica Applicata al Mare
(ICRAM), Chioggia, Italy
2 - Università di Venezia, Dipartimento Chimica Fisica, Venezia, Italy
3 - Istituto di Scienze Marine ISMAR-CNR, Bologna, Italy
Key terms: Po river; Adriatis Sea; organic carbon; humic acids; sediments
The shallow northern part of the Adriatic Sea receives large river runoff,
predominantly from the Po River, which is the main allocthonous source of
nutrients and organic matter. In the coastal bottom waters south of Po river
prodelta frequently hypoxic or anoxic conditions set up during the summer and
autumn. The origin and quality of organic matter deposited in the sediment can
influence the degradation processes. Sampling of sediments was carried out on
May 2004 in 28 sites of the coastal area between Po and Reno rivers. In order
to evaluate the origin and the transformation of organic matter, elemental
analysis, carbon stable isotope and spectroscopic features of humic acids (HA)
extracted from the sediments were performed. Different sources of organic
matter as riverine sediments and suspended particulate matter, marine
phytoplankton and zooplankton were also analysed. The distribution of pelites
strongly influences that of organic carbon. A positive relationship between the
two parameters both in surface and subsurface sediments (p<0.001) have
been found. The accumulation of organic carbon in surface layer of sediment
near Reno river mouth and Po delta showed a relevant contribution of organic
matter in this area. Western Adriatic Coastal Current highly contribute to the
export southward of these organic materials.
The exponentially increase of organic carbon at the decrease of the redox
potential (Eh) both in surface and subsurface sediments suggests that an high
deposition of organic matter (from the rivers and autochthonous production)
could induce an anoxic environment.
The relevant allochthonous (fluvial and terrestrial) input in the study area was
confirmed by carbon stable isotopes in sedimented organic matter and the
UV-visible ratios (A(272)/A(407), A(465)/A(665) of HA extracted from the
surface and subsurface sediments. The concentration of HA extracted from
surface sediments follows the distribution of organic carbon and was more
concentrated in surface sediments than in subsurfaces ones. The contribute of
HA carbon to the sediments is relevant. The anaerobic environment seems to
favour the HA formation as shown by their negative correlation (p<0.05) with
the redox potential in subsurface sediments suggesting an important role of HA
in anoxic environments and an influence of the chemical interaction between
functional groups of the HA and mineral surfaces in diagenesis processes of
organic matter within sediments.
PARTICULATE MATERIALS AND SURFICIAL SEDIMENTS FROM THE
WESTERN ADRIATIC SEA (ITALY)
TESI Tommaso 1, MISEROCCHI Stefano 1, GOÑI Miguel A. 2, LANGONE Leonardo 1,
BOLDRIN Alfredo 3, TURCHETTO Margherita 3
1 - CNR, ISMAR-BO, Italy
2 - College of Oceanic and Atmospheric Science, Oregon State University, USA
3 - CNR, ISMAR-VE, Italy
Key terms: organic matter; stable isotopes; sediment; particulate matter;
western Adriatic Sea
In this study, organic carbon (OC), total nitrogen (TN), stable carbon isotopic
and CuO reaction product compositions were used to identify the sources of
organic matter (OM) and to quantify the relative importance of allochthonous
and autochthonous contributions to the western Adriatic Sea, Italy. Suspended
particulate material (195 samples) and surficial sediments (0-1 cm, 70
samples) from shallow cross-shelf transects were collected in February and May
2003, respectively. Vertical water column profiles were acquired along the
same transects. Data include depth, potential temperature, salinity, density
and chlorophyll fluorimetry. PCAs were used to understand the spatial
variability in the surficial sediments. End-member mixing models were applied
to quantitatively assess the OM contributors in suspended material and surficial
sediments.
Along the western Adriatic shelf in the near-shore region, the phytoplankton
growth was influenced by dynamics of the buoyant plumes from the Po and
Appennine rivers. A small amount of very fine terrigenous material remained
suspended within the coastal current and was exported southward along the
shelf to the slope. High variability in the bulk composition was detected in the
Po prodelta surficial sediments, whereas the western Adriatic shelf, although a
larger area, exhibited a narrower range of values. A significant decoupling was
observed between suspended particles in the water column and surficial
deposits. The organic material collected in the water column was
compositionally heterogeneous, with contributions from marine phytoplankton,
riverine-estuarine phytoplankton and soil-derived OM. Frequent physical
reworking of surficial sediments likely leads to the efficient oxidation of marine
OC, resulting in the observed accumulation and preservation of refractory
soil-derived OC delivered by the Po and Apennine rivers.
T01-15 Poster
T01-16 Poster
T01-14 Poster
Langone, Leonardo
ORGANIC MATTER ORIGIN AND DISTRIBUTION IN SUSPENDED
Del Negro, Paola
ORGANIC CARBON CYCLING IN SHALLOW COASTAL SEDIMENTS
DEL NEGRO Paola 1, DE VITTOR Cinzia 1, CIBIC Tamara 1, FONDA UMANI Serena 2
1 - OGS - Dipartimento di Oceanografia Biologica, Via A. Piccard 54, I-34014
Trieste
2 - Università di Trieste - Dipartimento di Biologia, Via Giorgeri 10, I-34127
Trieste
Key terms: organic carbon; coastal sediment; Adriatic Sea
In the Gulf of Trieste (northern Adriatic Sea), where the euphotic zone usually
reaches sea floor sediments, the microphytobenthic community, mainly
composed of epipelic diatoms, represents an important primary producer,
controlling the oxygen balance at the water-sediment interface. As a producer
of new organic carbon that can enter the benthic and pelagic trophic web,
microphytobenthos is a key component in the carbon cycle in coastal
environments.
Seasonal and interannual variations in biochemical composition of sedimentary
organic matter, in primary and secondary production of benthic community
were followed monthly during 2 years to provide information on the potential
organic matter turnover in subtidal muddy sediments.
Surface patterns of microphytobenthic biomass and daily gross production were
significantly related with P.A.R. levels, underlining that the irradiance
availability is the limiting factor for the efficiency of benthic photosynthesis.
Using the net oxygen production and respiration data set, the Benthic Trophic
State Index (BTSI) was calculated. The sediment habitat was characterised by
different trophic conditions shifting over time from photoautotrophy to
heterotrophy.
In spite of the differences revealed during two years of study, the BTSI annual
mean value did not change, indicating that this subtidal sediment system is
generally characterised by a trophic condition ranging between net
heterotrophy and net photoautotrophy.
Even if BTSI was very similar between years, the other measured parameters
showed great variations from year to year. This suggested that the benthic
trophic state was more conditioned by the balance between oxygen
consumption and production, and between production and mineralisation of
organic carbon than by the absolute biomass of different organisms (producers
and consumers - from bacteria to macrofauna).
Sedimentary organic carbon utilization by benthic consumers is strictly
influenced by its biochemical composition mainly consisting of proteins followed
by lipids and water-soluble carbohydrates. Potential organic carbon (OC)
turnover is generally rapid (7-14 d-1) suggesting freshly produced material to
the sea floor. The faster turnover times corresponded to greater dissolved OC
benthic efflux, confirming an efficient bacterial decomposition. On the other
hand, vertical fluxes provide very low OC inputs that cannot explain the
observed values of benthic production. The microphytobenthic production is a
potentially important alternative OC source for benthic consumers.
Our results reveal that, in general, the benthic ecosystem of the Gulf of Trieste
does not seem to be able to sustain itself, neither when heterotrophic nor
photoautotrophic conditions were realised. Therefore, in addition to the
substantial autochthonous production of phytoplankton and
microphytobenthos, this coastal ecosystem needs to receive large inputs of
allochthonous organic carbon.
Tramati, Cecilia
COMPARATIVE ANALYSES OF CHEMICAL, TROPHIC AND
MICROBIOLOGICAL VARIABLES IN SEDIMENTS FROM AN EASTERN
SICILIAN PORT: DIFFERENCES IN SPATIAL ACCUMULATION
SESSIONE T01
TRAMATI Cecilia 1, VIZZINI Salvatrice 1, SAVONA Andrea 1, CANGIALOSI Maria
Vittoria 1, MAZZOLA Antonio 1
1 - Università degli Studi di Palermo
Key terms: heavy metals; microbiology; sediment; pollution; port
Coastal areas represent complex environments affected by many
interdependent environmental constraints which are influenced by the
hydrological, geomorphological and economic conditions of the system
considered. Sediments, as a reservoir of polluting agents, are used as sensitive
descriptors for monitoring the contamination levels in aquatic environments.
Among coastal areas, ports, which delimit water bodies of restricted extension
with limited water circulation, represent sites where pollutants tend to
accumulate. The present study deals with the determination of pollution levels
in sediments from a port along a horizontal transect from the inner to the outer
part to examine whether ports, as well as being sinks, can act as sources of
pollutants for adjacent marine areas.
The area investigated was the port of Siracusa (Eastern Sicily), which is a
natural port located to the south of the city of Siracusa. The waters inside the
port are characterized by elevated turbidity due to the continental water
contribution through two small rivers and also from anthropic effluents.
Sampling of sediments was carried out using cores (length: 1.5 m) in
September 2006. In each area 10 cores were collected and from each core two
layers were obtained: the most superficial 20 cm and the deepest 20 cm. The
variables analysed were: organic matter content, total nitrogen, total
phosphorus and heavy metal (Cd, As, Hg, Cr, Cu, Pb, Ni, Zn and Al)
concentrations, faecal coliforms, total coliforms, faecal streptococci,
sulphide-reducing clostridia, and Salmonelleae density and grain size. All the
analyses were carried out in triplicate. Data were elaborated by means of
multivariate analyses.
This study showed a distinction between the three sampling areas (inner,
central and external) and the two depths of the port of Siracusa sediments.
Organic matter, total nitrogen and total phosphorus showed very small
variations between the sampling areas, while the levels of heavy metals were
higher overall in the inner area of the port, and in the superficial layer of the
sediments.
The microbiological analyses did not show the presence of faecal coliforms
(<10 MPN/g d.w.) or Salmonelleae, while total coliforms showed higher values
in the superficial layer (2593.81 MPN/g d.w. in the inner area) than in the
deeper one (29.39 MPN/g d.w in the external area). Faecal streptococci were
found mainly in the superficial layer, with a maximum value of 71.38 MPN/g
d.w. in the inner area of the port. The same result was found for
sulphide-reducing clostridia. As regards grain size, all samples presented a low
percentage of gravel (less than 10%) and a very high content of the fraction <
63 .
Analysis of similarity (ANOSIM) showed significant differences between the
three sampling areas and depths; moreover, the significant differences are
attributable to many variables (Similarity percentages: SIMPER).
Along the horizontal transect a higher accumulation of heavy metals was
observed in the inner area of the port of Siracusa, probably as a consequence
of the lower dispersal of pollutants and the large contribution of city effluents.
Differences along the vertical transect showed more concentration of heavy
metals in the superficial portion of the sediment, indicating the recent
accumulation of trace elements within the area studied.
T01-17 Poster
Bertelli, Linda
GEOCHEMICAL AND MICROBIOLOGICAL MONITORING OF THE
SEDIMENTS OF "SACCA DI GORO" COASTAL LAGOON (PO RIVER
DELTA)
BERTELLI Linda 1, MALAGUTI Antonella 2, TESINI Enrico 2, STANTE Loredana 2,
VACCARO Carmela 1, CELLAMARE Carmela 2
2 - ENEA - Dipartimento Ambiente, Cambiamenti Globali e Sviluppo Sostenibile.
Bologna, Italia
Key terms: sediment; heavy metal; microbiology; monitoring
"Sacca di Goro" is a coastal lagoon, south of the Po River Delta, and it is one of
the most important aquacultural systems in Italy. That area has a strong
environmental value for its large biodiversity and it is inserted in SCI (Site of
Community Importance) and SPAs (Special Protection Areas) areas. This paper
reports the data of geochemical and microbiological characterization and
monitoring of sediments carried out in the 2003, 2004, 2005 and 2006 years.
All samples were collected from the surface sediment (20 cm) on the entire
extension of the lagoon. Sediments were analysed after oven drying at 50°C
for 48 hrs, except microbiological parameters. The major elements (expressed
in percentage of oxide) and the trace elements (expressed in ppm) were
carried out by X ray Fluorescence. The granulometric classification was carried
out according to Shepard diagram in order to estimate the granulometric
variations in the time. Carbon and nitrogen elemental measurements were
performed by aqueous acidification procedure to remove carbonate [1].
Samples were then analysed by a Carlo Erba CHNS-O 1108 elemental analyser
configured for C and N analysis. Polycyclic aromatic hydrocarbons (PAHs), were
determinated by an Agilent GC (6890N)/MS (5973) after extraction, clean up
and chromatographic separation according to EPA methods (3500B 3540C
3600C 8000B). The microbial analyses were performed within 18-24 hrs and
include: total coliforms, faecal coliforms, faecal streptococci by MPN methods
[2, 3], Salmonellae by the enrichment and selective media [2]; spores of
solfate reducing bacteria.
The heavy metal concentration in the sediments of "Sacca di Goro" is similar to
the Po river alluvional plain sediments near the city of Ferrara ("background
level"). The range of the quality of "Sacca di Goro" sediments is from poor to
medium - good as a grain size function of that kind of sediments.
Total Organic Carbon ranged from 0.14 to 1.40 % (dry weight). PAHs
concentration ranged from 89 to 326 mg/Kg (dry weight). The values of total
and faecalis coliform ranged from 1 to 49 and from 1 to 33 MPN (g),
respectively. The content of faecalis streptococci was generally low ranging
from 1 to 33 MPN (g) except two samples (1400 and 8800 MPN (g)). Spores of
solfate reducing bacteria were not present. Salmonellae was present only from
55
the samples collected in the year 2005. Moreover near the coastal arrows and
the lagoon mouth an increase in the coarse grain fraction is observed and the
sediments quality improve.
The research individualities Sacca areas with low quality sediments located in
internal areas near the shore. These areas are not fit to aquaculture system.
The work shows moreover the good quality of the sediments present in coastal
arrows and in the zones near the lagoon mouth. Litologically sediments
features are not variable during the experimental time and the work shows the
correlations between the tessiturally-structural characteristics of the sediments
and the kind of pollution. The sediments in the lagoon area extending from the
shore nearly 1 Km on shore, show an high percentage of fine grain fraction
with an increased heavy metal content, exceeding the values of the Italian
laws.
References: [1] Hedges, J.I. & Stern, J.H. (1984). Carbon and nitrogen
determinations of carbonate containing solids. Limnology and Oceanography
29, 657-663; [2] APAT-IRSA-CNR (2003) Metodi analitici per le acque. 3
Sezione 6000 Metodi microbiologici; [3] EPA (1999) 821R98-003 Method 1680:
Fecal Coliformi in Biosolids by Multiple-Tube Fermentation and Membrane Filter
Procedures.
T01-18 Poster
Bertolotto, Rosa Maria
CHARACTERIZATION OF LIGURIAN COASTAL SEDIMENTS: THE
RESULTS OF A FIVE-YEAR MONITORING PROGRAM
BERTOLOTTO Rosa Maria 1, D'ARENA Davide 1, ALBANESE Sonia 1, CUNEO Cecilia 1
, GAINO Federico 1
1 - ARPAL, Genova, Italia
Key terms: Liguria; surficial sediments; chemical pollution; environmental
quality
Between 2001 and 2006 the Italian Ministry of Environment conceived and
financed a National Monitoring Program of the Marine Coastal Environment. All
the coastal regions carried out the same sampling and the same analysis with
comparable methods. In Liguria the program was carried out by the Ligurian
Regional Agency for the Environment (ARPAL) in five areas, selected by the
Ministry because of their different environmental conditions. For five years, in
each sampling station CTD parameters were measured and samples of water
taken and analyzed twice a month, while sediments were sampled every six
months and marine biota once a year. Four study areas were meant to account
for different pressures and impacts: Imperia (flower greenhouses and olive oil
mills), Vado Ligure (power plant and oil refineries), Cogoleto (chemical plant)
and Marinella (Magra River estuary), whereas the environment at Punta Mesco
(within the protected marine area of Cinque Terre) was taken as reference.
Concentrations of metals and organic pollutants in surficial sediments are
reported and commented. The problem related to threshold values in Italian
law and other national guidelines is also discussed, together with the absence,
in the new national environmental law (D.Lgs. 152/2006) of sediments as key
element for the quality assessment of marine coastal environments.
T01-19 Poster
Acquavita, Alessandro
HEAVY METALS AND ORGANIC POLLUTANTS IN COASTAL REGION OF
FRIULI-VENEZIA GIULIA (ITALY)
ACQUAVITA Alessandro 1, PREDONZANI Sergio 1, MATTASSI Giorgio 1,
TAMBERLICH Francesco 1, ROSSIN Pietro 1, SCHIOZZI Laura 1, GIORGINI Luigi 1,
VALIC Iztok 1, COVELLI Stefano 2
1 - ARPA Friuli-Venezia Giulia
2 - DiSGAM- Università di Trieste
Key terms: Sediment contamination; heavy metals; POP
Coastal areas of Friuli-Venezia Giulia, located in the North-eastern part of the
Adriatic Sea, extend for about 100 km from Tagliamento river mouth to Punta
Sottile (border between Italy and Slovenia. The shoreline is densely populated
with several economic and industrial activities (harbours, plants, tourism
facilities), consequently it was subjected to inputs of inorganic and organic
contaminants. Owing to provide information about the sources, mechanisms of
transport, sites of accumulation and potential threats to marine ecosystem and
human beings, it was of great concern to perform a preliminary study of
contaminants in bottom sediments.
In October 2005, 21 sediment core samples were collected by means of a
gravity box-corer along 7 transects perpendicular to the shoreline. Surface
sediments (0-5 cm, as reported in Italian law, e.g. D.M. 367/2003) were
homogenized, subsampled and analyzed for heavy metal, PolyAromatic
Hydrocarbons (PAHs), Polychlorinated Biphenyls (PCBs), TriButylTin (TBT) and
dioxins (PCDDs/PCDFs) contents. In addition, ancillary parameters (grain-size,
Organic Carbon and Total Nitrogen) were determined.
Grain-size distribution revealed the prevalence of silt fraction (mean value
78.1±7.5%), respect to both sand and clay (mean values 8.2 and 13.7%,
respectively), with the exception of 2 sites located in the Western areas where
prevailed sand fraction (max value 41.05%). Colloidal fractions (<0.5 m)
showed always values <5%, thus they were assumed to be not statistically
significant.
Organic carbon contents ranged from 0.51% to 1.48% (mean value
0.93±0.24%). Nearby the Trieste harbours area, values were significantly
higher thus suggesting an intense settling rate and/or the presence of particles
enriched in organic compounds. The C/N atomic ratio ranged between 4.3 and
7.52 indicating the autochthonous origin of organic matter.
Two geochemical areas were distinguished on the basis of Al contents. Data
obtained were in agreement with previous geological studies, which pointed out
the presence of distinct calcitic and quartz-feldspar areas. Particularly, Al
contents in the Gulf of Trieste were >4.5%, while in other sites values <4.5%
were detected. In addition, significant correlation of Al with trace elements
(except for Hg and Zn) proved their relationship with mineralogical composition
rather than grain-size of sediments. Conversely, no relationship was found in
areas subjected to a high degree of industrialization (Trieste harbour) due to a
SESSIONE T01
56
superimposed contents of heavy metals. Therefore, further investigations will
be necessary in order to determine the background levels and to estimate the
relative enrichment factors.
Results obtained from organic contaminants analysis showed that both
harbours and shipping channels may be considered as high vulnerability areas.
In fact, PAHs, PCBs, PCDDs/PCDFs and TBT reached their maximum values
with 8.56 µg g -1, 102.4, 0.024 and 32.8 ng g -1, respectively. In addition, a good
correlation between PAHs and PCDDs/PCDFs was found, thus suggesting a
common origin from pyrogenic atmospheric pollution. Nevertheless, a
petrogenic source of PAHs due to maritime traffic, oil refinery and petroleum
terminal can not be rule out.
On the contrary, in Western areas, which were less subjected to industrial
activities, organic contaminants values obtained were always lower. Moreover,
the absence of some trends and/or correlations can not allow to identify a
possible source and pathway for these compounds.
In conclusion, these preliminary data suggested that new studies will be
necessary in order to understand sources, mechanism of transport and sites of
accumulation of both inorganic and organic pollutants in these sediments.
Biogeochemical markers and thin section core analysis should be good tools to
define the background values, while ecotoxicological studies could be
appropriate to understand the environmental impact of these pollutants.
T01-20 Poster
Giglio, Federico
HEAVY METALS DISTRIBUTION IN THE ADRIATIC SEA SECTOR
INFLUENCED BY SEDIMENT INPUT FROM NERETVA RIVER
GIGLIO Federico 1, ROMANO Stefania 1, RAVAIOLI Mariangela 1, FRANCHI Fulvio 1
1 - Istituto di scienze marine sede di Bologna - CNR
Key terms: Neretva River; Heavy Metals; Marine Sediments
Neretva is the largest river of the eastern part of the Adriatic basin. Its total
length is 225 km of which 203 km in Bosnia Herzegovina and 22 km in the
Republic of Croatia including a large delta of 12.000 hectare. Riverine waters
are polluted with fertilizers and chemicals from agriculture. Large parts of the
area have been degraded by drainage and agricultural development. Moreover
over 90% of the soil surface is exposed to water and wind erosion of varying
intensity. The situation is particularly severe in the karts area, where erosion
has already reached the geological base. These strong sediment inputs flow
into the Adriatic Sea. Because of this critical situations it is fundamental to
study the distribution of these materials in the Adriatic Continental Shelf, to
prevent the damages that are likely to happen when considering the degree of
contamination in the riverine sediments. The river delta waters flow into a
narrow marine channel limited by the Croatian cost at north-east and from
Peljesac Island at SW part. This latter is separated from land by a narrow
passage.
In order to contribute in evaluating the distribution and the preservation
potential of polluted sedimentary deposits, the objective of the present study is
to trace the distribution of particles input of Neretva River in the Adriatic Shelf
area following the temporal and spatial distribution of organic and inorganic
components.The surficial sediments of 17 stations were analysed for grain size,
organic carbon and nitrogen contents and Organic Carbon stable isotopes
compositions. Moreover the distribution of several heavy metals (Pb, Cr, Ni and
Zi) will be discussed. Finally, radiochemical analyses of 210Pb and 137Cs were
performed to obtain the chronology of the sediment deposits.
T01-21 Poster
Tranchina, Luigi
HEAVY METALS IN THE FINE FRACTION OF COASTAL SEDIMENTS FROM
GULF OF PALERMO.
TRANCHINA Luigi 1, BRAI Maria 1, CARUSO Antonio 1, COSENTINO Claudia 1
1 - Università di Palermo - Dipartimento di Fisica e Tecnologie Relative, Viale
delle Scienze Edificio 18
Key terms: Heavy metals; Sediments; Fine fraction; Palermo Gulf
Industrial and human activities are more and more localized near the coastal
areas; thus in recent years, pollutant concentrations in coastal marine
environment have increased. A constant monitoring of contaminant
concentrations (among which metals) in sediments is needed to evaluate the
marine coastal environment condition. Many authors have focused their
attention on marine sediments from industrialized coastal areas, finding that
metal concentrations in sediments are strictly influenced by human activities
and that metal distributions in sediments are a good tool to evaluate the
degree of environmental marine pollution.
Metals in natural environments have both natural and anthropogenic origins.
Since metals are not subject to bacterial degradation, after their inflow they
can remain permanently in the sea and, in consequence, they can be
accumulated in sediments. Assessing the input of metals in the environment as
a result of human activity is complicated by the very large natural input (i.e.
erosion of ore-bearing rocks, wind-blown dust, volcanic activity, and forest
fires).
In this work are presented data of Cr, Cu, Hg, Pb and Zn concentrations,
measured with a Varian AA220 FS Atomic Absorption Spectrophotometer, in
the mud fraction of 59 sediment samples collected in the Gulf of Palermo. We
selected this sediment fraction of sediment for measurement for several
reasons: i) metals tend to concentrate in the silt-clay size; ii) this fraction is
transported almost entirely by suspension; iii) it is possible to compare results
among samples with different texture characteristics; iiii) sieving does not
affect the metal concentration. Samples were collected on the soft-bottom
marine sediment using a Van Veen grab; only the upper part of the sediment,
far from grab sides, was collected by using a plastic blade to avoid metal
contamination. After wet sieving, fines were dried in oven at 80 °C until
constant weight was reached.
The Gulf of Palermo is an area where a harbour area, with a dockyard inside,
sewage pipes, and river mouths are present. Two principal rivers flow into the
Gulf of Palermo: the Oreto and the Eleuterio.
Oreto River flows into the middle part of the Gulf and its waters transport clays
and quartz coming from relieves that border Palermo Plain. Besides, its waters
are mixed, in the last 2 km, with industrial and domestic sewage. The Eleuterio
River flows into the eastern part of the Gulf, and several domestic sewage
discharges in these waters.
The waters with domestic sewage are discharged, both in the gulf and in the
rivers, in many cases, without any depuration treatment.
Relationship among metals concentrations in marine sediments collected along
the coastline and distribution of pollution sources inside the studied area has
been statistically analyzed. We used the Ratio-matching methods to obtain
information about the influence of local input on the measured metal
concentrations in sediment. The Geoaccumulation Index (Igeo) and the
Enrichment Factor (EF) were calculated by using as reference values of metal
concentrations in fines the mean values obtained by measurements on
sediment fine fractions sampled in clean areas of the Gulf.
Analysis of data permitted us to clearly indicate that more polluted zone
(significantly higher concentration values than clean zones) is located in the
part of the Gulf enclosed between the harbor area and Oreto River. Principal
component analysis shows that a gradient in metal concentration is present in
the sediments of the Gulf. Particularly, the area located in the North-Western
part of the Gulf is a clean area (not polluted by metals), the area enclosed
between the harbor area and Oreto River is heavily polluted, the central part of
the gulf is an intermediate polluted area and the North-Eastern part of the gulf
is again an area not polluted by metals.
This work was partially granted by Agenzia Regionale per la Protezione
dell'Ambiente (ARPA-Sicilia).
T01-22 Poster
Bellucci, Luca Giorgio
HEAVY METALS IN TRANSITION AND MARINE COASTAL
ENVIRONMENTS OF NORTHERN MOROCCO
EL MOUMNI Bouchta 1, BELLUCCI Luca Giorgio 2, ROMANO Stefania 2, TURETTA
Clara 3, ALBERTAZZI Sonia 2, GIULIANI Silvia 2, FRIGNANI Mauro 2, CAPODAGLIO
Gabriele 3
1 - Tangier University, Morocco
2 - CNR-ISMAR-BO
3 - CNR-IDPA-VE
Key terms: heavy metals; sediments; coastal lagoons; northern Morocco
Planning a sustainable development policy requires a basic knowledge of
contaminant sources, distribution mechanisms (that allow to identify pathways
and sites where chemicals tend to accumulate), potential risk and actual
danger to the human and environmental health. Therefore, it is important to
assess the degree of contamination of key areas and this can be done through
the analysis of sediment samples. Furthermore, cores of undisturbed sediment
very often provide a means to reconstruct the pollution history of an area. On
the other hand, coastal lagoons are being considered very valuable
environments, from both naturalistic and economic points of view.
Furthermore, ports are known to be areas where highly polluted sediment can
accumulate, and usually pose problems of recovery and disposal of dredged
materials, whereas the marine coastal zone is the final repository of most
materials mobilized on land. Because of this we studied sediment cores from
two lagoons (Nador and Merja Zerga), two ports (Tangier and Larache) and
several marine sites, three of them in the Mediterranean Sea (in front of the
Martil River mouth) and one in the Atlantic Ocean. The purpose of the work
was to obtain a first insight into the contamination by heavy metals of these
environment and follow the input trends over time. Analyses of Mn, Cd, Cr, Cu,
Hg, Pb, and Zn where performed, whereas apparent sediment accumulation
rates and chronologies were established, for the least disturbed sediments,
though 210Pb and 137Cs activity-depth distributions. Concentrations of
anthropogenic metals, especially Cd, Cu, Pb and Zn, are highest within the port
of Tangier, whereas Cr is high at Larache. The lagoons show much lower metal
concentrations, except Cr at Merja Zerga, and marine sediments are even less
contaminated. These data are discussed with respect to those already available
for the Martil River, the soils around the industrial town of Tetouan and a salt
marsh from the Nador Lagoon, which may represent polluted and pristine
environments, respectively.
T01-23 Poster
Bellucci, Luca Giorgio
RECORDS OF ANTHROPOGENIC METAL DELIVERY IN SEDIMENTS OF
THE INDUSTRIAL AREA OF PORTO MARGHERA (VENICE LAGOON,
ITALY)
BELLUCCI Luca Giorgio 1, FRIGNANI Mauro 1, RUIZ FERNANDEZ Ana Carolina 2,
PAOLUCCI Daniele 3, GIULIANI Silvia 1, ALBERTAZZI Sonia 1
1 - CNR-ISMAR-BO
2 - UNAM-Mazatlan-Mexico
3 - Polimeri Europa SpA
Key terms: Venice Lagoon; sediments; toxic metals; industrial pollution;
chronology
Starting from the early 1920s, with the construction of the 1st Industrial Area,
the Venice Lagoon has been subjected to the input of anthropogenic chemicals
derived from many kinds of industrial production processes. The inputs
increased when, after World War II, the 2nd Industrial Area was built nearby to
host mainly petrochemical plants. The degree of sediment contamination,
history of inputs, trends, and responsibilities have been debated extensively,
but only the analysis of sediment cores allowed the direct determination of
recent and historical inputs of metal contaminants to this aquatic environment.
Five sediment cores collected from the canals of the industrial area were
studied in order to assess the temporal trends of As, Ba, Cd, Hg, Pb and Zn
inputs. Maximum values were found in the Brentella Canal (2315, 41, 5367,
34259 mg g-1 for As, Cd, Pb and Zn, respectively). High values also
characterize the Nord Industrial Canal (120, 70, 49, 929, 8295 mg g-1 for As,
Cd, Hg, Pb and Zn) and the Salso Canal. Hg and Ba, the first used as cathode
in chloro-alkaly plants and the second as a catalyst in the production of trielin,
show very high downcore maxima in the Lusore-Brentelle Canal (4901 and
SESSIONE T01
57
9399 mg g-1, respectively). Chronologies, based on 210Pb and 137Cs
activity-depth profiles, show that the highest fluxes occurred in the 1970s and
early 1980s, and that the input of these materials is now decreasing. The
correlation of some metals with dioxins and furans within the 1st Industrial
Area suggests that some of these pollutants originated from the same series of
processes starting from pyrite roasting for the production of sulfuric acid.
Lagoon sediments show much lower concentrations and this means that most
of the pollutant load discharged in the past has been retained within the
industrial canals. This paper exemplifies the search for historical information on
sources, levels and trends of anthropogenic metals in a zone subjected to the
influence of multiple industrial sources.
PAHs originated mainly from petroleum, with the exception of Lang Co, where
combustion prevailed, and TG-CH that is influenced from both petrogenic and
pyrogenic sources.
T01-24 Poster
T02-1 Key Lecture
Frignani, Mauro
POLYCHLORINATED BIPHENYLS IN SEDIMENTS OF NORTHERN
MOROCCO'S COASTAL ENVIRONMENTS
PIAZZA Rossano 1, EL MOUMNI Bouchta 2, BELLUCCI Luca Giorgio 3, VECCHIATO
Marco 1, FRIGNANI Mauro 3, CESCON Paolo 1
1 - CNR-IDPA, Venice, Italy
2 - Tangier University, Morocco
3 - CNR-ISMAR-BO
Key terms: PCBs; sediments; pollution; coastal environments; northern
Morocco
Polychlorinated biphenyls (PCBs) are ubiquitous and persistent compounds that
can be found in various environmental media and biota. They are characterized
by very low solubility in water, good affinity for many organic solvents, low
volatility, except for the very low molecular weight congeners, and tendency to
adsorb onto sediment particles. PCBs were produced in great amount for a
variety of uses starting from the 1930s. Despite regulations and bans
empowered starting from the mid 1970s, they are still dangerous to both
environment and human beings. In spite of this, little is known about PCB
pollution in many coastal environment. This is also the case of Morocco, and
PCB concentrations in key areas are needed to assess present levels of
contamination and related risks, identify the sources and understand the
pathways. Sediments, which can keep a record of the conditions of the
environment at the time of their deposition and accumulation, can be used to
reconstruct levels, history and trends of contamination processes. On the other
hand, coastal environments are of particular importance as final repository of
all the materials mobilized from the continent. Since previous work had pointed
out that ports could be the areas where most pollutants tend to accumulate,
we studied sediment cores from the ports of Tangier, Larache, the second in
Morocco for fish catch, and Kenitra. However, since lagoons are considered
very valuable environments from both environmental and economical points of
view, sediments were also taken from the lagoons of Nador and Merja Zerga.
Finally, surficial samples collected in the Mediterranean Sea, in front of the
Martil River, and in the Atlantic Ocean were analyzed. Results show that only
SESSIONE T02
I gas idrati: dall'impatto sull'ambiente a possibile risorsa energetica
Di Profio, Pietro
found in marine samples reach values of 5 and 10 g kg-1. The new data are
compared with those already obtained for salt marshes in the lagoons of Nador
and Merja Zerga, the terminal tract of the Martil River, the port of Tangier and
a soil taken close to the industrial town of Tetouan. These series of data
permits to discuss the presence of different PCB mixtures, the potential sources
and the role of atmospheric transport and deposition.
CLATHRATE HYDRATES OF METHANE AND HYDROGEN: A NANOTECH
APPROACH
DI PROFIO Pietro 1, ARCA Simone 1, GERMANI Raimondo 1, SAVELLI Gianfranco 1
1 - Center of Excellence on Innovative Nanostructured Materials (CEMIN),
University of Perugia
Key terms: Promotion; Inhibition; Methane hydrate; Hydrogen hydrate;
Nanotechnology
The study of clathrate hydrates of methane (natural gas) has been historically
carried out and developed by geologists and geochemists on the side of natural
deposits, and by chemical engineers as pertains to the problems of flow
assurance into pipelines. Moreover, gas hydrates are being increasingly
considered as convenient media for gas storage and transportation as the
knowledge of their properties progresses, in particular as relates to methane
and hydrogen. Finally, clathrate hydrates may represent an ideal sequestration
technology for carbon dioxide, due to a well defined P/T range of stability, and
several research programs are addressing the feasibility thereof. Though the
understanding of the molecular structure and supramolecular interactions
which are responsible of most properties of hydrates have been elucitated in
recent years, the underlying theoretical physico-chemical framework is still
poor, especially as relates to the role of "conditioners" (inhibitors and
promoters) from the molecular/supramolecular point of view. In the present
communication we show some results from our research approach which is
mainly focused on the supramolecular properties of clathrate hydrate systems and their conditioners - as a way to get access to a controlled modulation of
the formation, dissociation and stabilization of gas hydrates. In particular, this
communication will deal with (a) a novel, compact apparatus for studying the
main parameters of formation and dissociation of gas hydrates in a single,
reproducible experiment, which can be easily and rapidly carried out on board
of a drilling ship;[1] (b) an overview on the effects of amphiphile molecules
(surfactants) as inhibitors or promoters of gas hydrate formation;[2] and (c)
preliminary results on a novel nanotechnology for a reliable and quick
production of hydrogen hydrates, and its application to fuel cells.[3,4]
[1] Arca, S., Di Profio, P., Germani, R., Savelli, G., International Patent
Application PCT/IT2006/000274
[2] Di Profio P., Arca S., Germani R., Savelli G., 2005, "Surfactant promoting
effects on clathrate hydrate formation: are micelles really involved?", Chem.
Eng. Sci., 60, pp. 4141-4145
[3] Di Profio P., Arca S., Germani R., Savelli G., 2006, "Novel Nanostructured
Media for Gas Storage and Transport: Clathrate Hydrates of Methane and
Hydrogen", J. Fuel Cell Sci. & Tech., February 2007, vol. 4.
[4] Arca, S., Di Profio, P., Germani, R., Savelli, G., International Patent
Application PCT/IT2007/000218.
T01-25 Poster
T02-2 Invitato
sediments from the ports are significantly contaminated (up to 450 g kg-1).
PCB concentrations in lagoon sediments are relatively low, whereas those
Giuliani, Silvia
PRESENCE AND ORIGIN OF POLYCYCLIC AROMATIC HYDROCARBONS
IN NINE CENTRAL VIETNAM COASTAL LAGOONS
SPROVIERI Mario 1, FEO Maria Luisa 1, GIULIANI Silvia 2, NGUYEN Huu Cu 3,
MARSELLA Ennio 1, BELLUCCI Luca Giorgio 2, FRIGNANI Mauro 2
1 - CNR-IAMC, Calata di porta di Massa, Naples (Italy)
2 - CNR-ISMAR, Via Gobetti 101, 40129 Bologna (Italy)
3 - IMER, 246 Da Nang Street, Haiphong City (Vietnam)
Key terms: Central Vietnam; Coastal lagoons; Sediments; PAHs; Chronology
Several natural and anthropogenic processes cause the formation of polycyclic
aromatic hydrocarbons (PAHs), a well known class of compounds with
carcinogenic properties that are regarded as priority pollutants by the US
Environmental Protection Agency. Anthropogenic sources include combustion of
fossil fuels, coal gasification and liquification processes, waste incineration,
production of coke, carbon black, coal tar pitch and asphalt and petroleum
cracking. Another common anthropogenic source of PAHs is spillage of fossil
fuels, as both unrefined and refined products. PAHs also stem from natural
combustion sources such as forest fires, and certain congeners (perylene and
retene) are thought to be diagenetically produced. Because of their
hydrophobic nature, PAHs in the aquatic environment are accumulated by
sediments. It is known that the information in Vietnam about pollutant sources
and distribution is very poor, despite the Indochinese Wars (1945-1975)
related events and the recent economic development are both likely to have
determined a strong impact on the environment. Therefore, the major
objective of this study was to assess history of PAH contamination, relative
importance of the sources, present trends, and potential toxicological
significance in central Vietnam lagoons, as these areas represent key
environments from both naturalistic and economic points of view, being
valuable and diverse ecosystems, important tourist attractions and sites for
fishing and aquaculture activities. Samples from nine coastal lagoons of central
Vietnam were analysed in order to assess PAH contamination levels and
historical trends. Twenty two congeners were quantified for the Tam Giang-Cau
Hai (TG-CH) Lagoon, whereas eighteen were analysed for the others.
Concentrations range between 103 and 1574 ng g-1. PAH depth profiles
account for increasing trends in most cases but values are still low when
compared to international guidelines for sediments. In these environments
Panieri, Giuliana
RELATIONSHIP BETWEEN HYPOGEAN HYDROLOGY AND FLUID ESCAPE
IN THE EASTERN PO PLAIN (NORTHERN ITALY)
CASTELLARIN Alberto 1, PANIERI Giuliana 1
1 - Dipartimento di Scienze della Terra e Geologico Ambientali, Università di
Bologna
Key terms: hypogean hydrology; surficial soil collapse; fluid escape; Po Plain;
northern Italy
Gas hydrates are naturally occurring ice-like crystalline compounds in which
gases are trapped within a lattice of water molecules. The presence of gas
hydrates is controlled by temperature, pressure and the availability of
appropriate gases and water. In the last decade the number of publications and
scientific sessions dedicated to gas hydrate has increased consistently
reflecting a broad national and international interest for this research field. The
awareness on these deposits is related to the role that they also presently play
in global and regional processes including public and economic significance.
From a geological point of view the presence of gas hydrate can affect the
physical, geophysical and geochemical properties of sediments. Recent findings
from ongoing research programs illustrate that the eastern Po Plain sector is
interested by surficial soil collapse and phenomena of aquifer contaminations
by highly brackish waters. The monitoring of these aquifers performed over the
last ten years evidences hydrochemical and thermal anomalies in the hypogean
waters. Besides, mesoscopical ground collapses observed in several areas are
associated to fluid (mainly methane, carbon dioxide and accessories) escapes.
These phenomena appear to be related to residual tectonic activities affecting
the frontal zone of the Apennines as documented by the seismic events of the
last decades.
T02-3 Orale
Clari, Pierangelo
CH4-DERIVED CARBONATES OF ALFIANO NATTA (MONFERRATO, NW
ITALY): THE ROOT ZONE OF A CENOZOIC MUD VOLCANO.
CLARI Pierangelo 1, MARTIRE Luca 1, CAVAGNA Simona 1
SESSIONE T02
58
1 - Dipartimento di Scienze della Terra, Università di Torino
Key terms: CH4-derived carbonates; mud volcano; Monferrato
Two major groups of CH4-derived carbonates may be distinguished in
Monferrato:
° Lucina-bearing rocks, resulting from the colonization by chemosymbiotic
communities and early lithification of localized portions of the sea floor
corresponding to sites of CH4-rich fluid seepage.
° Strongly cemented clastic sediments devoid of chemosymbiotic organism
remains (macro-concretions).
Macro-concretions are interpreted as the product of sub-surface bacterial
degradation of CH4 flowing through the sediment column: they may have been
lithified at any time after sedimentation and at any depth during burial.
In Monferrato, macro-concretions are much more common than
Lucina-chemoherms and range from few decimeters up to a hundred of meters
in size and show tabular or massive, nearly equidimensional geometries.
Alfiano Natta represents the largest of such macro-concretions so far
recognized. The cemented sediments pertain to the Upper Oligocene Cardona
Formation which consists of fan delta conglomerates, arenites and silty
mudstones. Because of the pervasive cementation and of the large size of the
macroconcretion, these rocks have been quarried in the past. The abandoned
quarry front, about 30 m high, thus provides an unusually wide window on this
kind of rocks. The most remarkable feature of this site is the abundance of
clastic dykes and authigenic carbonate-filled veins. Most of them can be traced
all along the whole vertical extent of the quarry front. The veins, up to 10 cm
thick, clearly stand out on the outcrop because of their white colour. Dykes
range in thickness from a few millimeters to more than 1 metre and are mainly
filled with dark grey to light brown, tightly cemented mudstones. At a closer
view, both dykes and veins appear as polyphasic and show complex
cross-cutting relationships highlighted by filling sequences that reveal
continuous switching from sediment injection to carbonate precipitation. Where
dyking and veining is denser, the rock appears as a coarse breccia with angular
clasts. Equally complex are the fillings of veins where different mineralogies
and growth morphologies of cements are recognizable. In fact, calcite,
aragonite and primary dolomite occur together in most veins. Aragonite is the
most abundant phase and forms cm-thick fringes with splay morphologies.
Calcite occurs both as inclusion-rich fibrous rims and as limpid blocky spar.
Cathodoluminescence observation evidences that commonly aragonite has
experienced different stages of dissolution and the resulting voids have been
filled with calcite and dolomite. Finally, microcrystalline and peloidal cements
document the role of microbial communities in triggering carbonate
precipitation. Isotope analyses of intergranular and vein-filling cements show a
bimodal distribution of data. Strongly negative (down to -50 0/00 PDB) 13C
values are associated with nearly marine 18O values (around 0 0/00 PDB);
another set of data, on the contrary, combines less depleted 13C values
(around -20 0/00 PDB) with markedly positive 18O values (up to +8 0/00 PDB).
These values point to the contribution of methane degradation in carbonate
precipitation and suggest that part of the methane could have been trapped as
clathrate before the final seeping.
On the basis of the described features, the Alfiano Natta macroconcretion may
be interpreted as the root zone of a mud volcano whose surficial edifice has
been wiped away by erosion. This allows to link the better known sea-floor
expression of massive fluid seepage, such as pockmarks and mud volcanoes,
with large cemented sediment volumes devoid of any chemosymbiotic fossil
assemblage that represent their root zones, whose present-day counterparts lie
hidden at variable burial depths below the sea floor.
T02-4 Orale
Artoni, Andrea
TECTONIC AND CLIMATIC CONTROLS ON DEPOSITION OF
SEEP-CARBONATES IN THE MIDDLE-LATE MIOCENE SALSOMAGGIORE
RIDGE (NORTHERN APENNINES, ITALY)
ARTONI Andrea 1, CONTI Stefano 2, PIOLA Gianluca 3, TURCO Elena 1, SILVIA
Iaccarino 1
1 - Dipartimento di Scienze della Terra, Università degli Studi di Parma
Reggio Emilia
3 - v. Berlinguer 14, 43044 Collecchio Parma Italia
Key terms: seep carbonate; Miocene; Northern Apennines
In the Northern Apennine compressional wedge, seep-carbonates of the
Salsomaggiore area provide a unique opportunity for analyzing depositional
characters and factors controlling the evolution of a seepage system in a
thrust-related anticline at the leading edge of an orogenic wedge.
Seep-carbonates usually occur in pelitic successions from different settings of
the middle late Miocene foreland basin system. In the middle-late Miocene
Salsomaggiore intra-basinal Ridge, seep-carbonates cemented and/or
encrusted coarse-grained sandstones and conglomerates of Serravallian
foredeep deposits.
The carbonates, typically depleted in
C(values ranging from -8 to -41PDB),
13
show a variable 18O depending on the morphotype in which they occur. The
isotopic data confirm their genesis as hydrocarbon-seep authigenic carbonates
related to destabilization of gas hydrates; contamination with normal marine
water and microbial activity is likely.
Depending on the position of the fluid-pathway feeders within the
Salsomaggiore Ridge, seep-carbonate facies and sediment instabilities strictly
relate to variable intensities in tectonic stresses. A two phase model is
suggested for the evolution of venting in this thrust-related anticline (Conti et
al., in press). A slow-seepage phase was typified by precipitation of encrusting
or cementing seep-carbonates; a fast-seepage phase was characterized by
mass-wasting and diapirically emplaced deposits. The acme of fluid emissions
and sediment destabilization was strictly related to an important tectonic event,
which rearranged the leading edge of the collisional orogen.
The seep-related deposits can be attributed to late Serravallian, when a global
transition toward cooler climates have been evidenced by oxygen isotope
records both in the Atlantic ocean (Miller et al., 1991) and Mediterranean area
(Turco et al., 2001). In late Quaternary, major clathrate dissociation events
have been related to abrupt climate change; sea-level and water temperature
variations during glacial and interglacial periods favour gas-hydrates
destabilization and extensive mass-wasting processes (Kennett et al., 2000;
Maslim et al., 2004). It is envisaged that climatic induced gas-hydrates
destabilization were active in the Salsomaggiore Ridge during late Serravallian.
Thus, in the Salsomaggiore Ridge case study, the tectonics and climate seem
to act concomitantly in creating the seep-carbonate deposits: tectonic pulse
and climatic oscillations are both generating/enhancing mass-wasting
processes. The outlined evolution is common to ridges of other accretionary
wedges where the interplay and feed-back between tectonics and climate is
still to be accurately defined. The precise timing and interplay between
tectonics and climate are key points to understand accumulation and depletion
of gas-hydrates in continental margins.
References
Conti S., Artoni A., Piola G., in press. Seep-carbonates in a thrust-related
anticline at the leading edge of an orogenic wedge: the case of the middle-late
Miocene Salsomaggiore Ridge (Northern Apennines, Italy). Sed. Geol.
Kennett J., Cannariato K.G., Hendy I.L., Behl R.J., 2000, Carbon isotope
evidence for methane hydrate istability during Quaternary interstadials.
Science, 288, 128-133.
Maslim M., Owen M., Day S., Long D., 2004. Linking continental-slope failures
and climate change: testing the clathrate gun hypothesis. Geology 32, 53-56.
Miller K.G., Feigenson J.D., Wrigt J.D., Clement, B.M., 1991. Miocene isotope
reference section, Deep Sea Drilling Project, Site 608: an evaluation of isotope
and biostratigraphic resolution. Paleoceanography 6, 33-52.
Turco E., Hilgen F.J., Lourens L.J., Shackleton N.J., Zachariasse W.J., 2001.
Punctuated evolution of global climate cooling during the late middle to early
late Miocene: high-resolution planktonic foraminiferal and oxygen isotope
records from the Mediterranean. Paleoceanography 16, 405-423.
T02-5 Orale
Lucente, Claudio Corrado
THE MONTARDONE MELANGE IN THE NORTHERN APENNINES:
EVIDENCE OF MUD-DIAPIRISM.
CONTI Stefano 1, FONTANA Daniela 1, LUCENTE Claudio Corrado 2
1 - Univesità di Modena e Reggio-Emilia - Modena
2 - Regione Emilia-Romagna
Key terms: melange; mud diapir; authigenic seep-carbonate; methane-rich
fluid; northern Apennines
The Montardone melange (MM) is a chaotic unit consisting of polygenic breccias
in a shale matrix (olistostrome texture) outcropping in the core of the E-W
trending Montebaranzone syncline in the northern Apennines. The MM occurs
mainly at the top of the Termina Formation, a Serravallian-Tortonian unit
belonging to the Epiligurian succession; minor, lens-shaped bodies of MM occur
at lower stratigraphic positions. The Termina Formation consists mainly of
marlstones and includes lens-shaped sandstones and bodies of authigenic
seep-carbonates (13C-depleted). Reworked blocks and slabs of the Termina
marls are found within the MM.
The succession is interpreted here as the filling of a tectonically active slope
basin characterized by topographic constrains (lateral confinement) as testified
by pinch-out, onlapping, and lateral facies changes to sandstone lobes.
The main body of the MM covers the entire syncline with strong lateral
thickness changes, making it possible to distinguish two different sectors of the
syncline. In the eastern sector the MM achieves the maximum thickness of
more than 200 meters. In the western sector it reduces to 40 meters,
becoming progressively thinner westwards. In the eastern sector the MM shows
a vertical contact with the hosting Termina marls. Bodies of authigenic
carbonates occurs close to the contact within the hosting marls, and at the
base of the melange. These carbonates, located in the southern flank of the
Montebaranzone syncline, have systematic polygenic breccias at the base, with
the same composition as the MM. Seep-carbonates occurring in the northern
flank do not have these basal polygenic breccias.
Previous interpretations suggested a gravity-driven emplacement for the MM,
recognized as a large olistostrome. We propose here an alternative hypothesis
interpreting the main body of the MM as a mud diapir on the basis of the
following evidence: 1) distribution and geometry of the melange; 2) the
vertical, abrupt contact with the hosting marls; and 3) the occurrence of basal
polygenic breccias characterizing the seepage-carbonates close to the main
diapiric body, along the southern flank of the syncline.
Most likely, the surface expression was a mud volcano or a mud ridge affected
by diffuse slope-instability with the emplacement of coalescent debris flows
(olistostromes) also involving blocks of authigenic carbonates. Alternatively,
the minor lens-like bodies of MM at different stratigraphic levels could be
explained as sill-like intrusions of diapiric material.
Mud diapirism and the formation of a mud volcano/mud ridge are attributed
here to tectonic loading by overthrusting and the generation of a large amount
of methane-rich fluid in the source rocks, i.e. a large older olistostromal body.
The occurrence of methane-rich fluids, testified by authigenic carbonates,
contributed to generate overpressured shales ascending along sin-sedimentary
faults.
T02-6 Invitato
Jin, Young Keun
DETECTION OF GAS HYDRATE-RELATED STRUCUTRES ON NE SAKHALIN
CONTINENTAL MARGIN, THE SEA OF OKHOTSK
JIN Young Keun 1, SHOJI H. 2, MAZURENKO L.L. 3, OBZHIROV A. 4, CHAOS
Scientific Party 5
1 - Korea Polar Research Institute (KOPRI), KORDI, 503 Get-Pearl Tower,
Songdo Techno Park, 7-50 Songdo-dong, Yeonsu-gu Incheon, 406-840, Korea
2 - New Energy Resources Research Center, Kitami Institute of Technology,
165 Koen-cho, Kitami 090-8507, Japan, e-mail:[email protected]
3 - All-Russian Research Institute for Geology and Mineral Resources of the
SESSIONE T02
Ocean, 1 Angliyskiy Avenue, 190121, Saint-Petersburg, Russia, e-mail:
[email protected]
4 - Pacific Oceanological Institute FEB, RAS, 43 Baltiyskaj St., Vladivostok,
694100, Russia, e-mail: [email protected]
5 - CHAOS Scientific Party
Key terms: BSR; gas hydrate; fluid occurrence; tectonics; Okhotsk
The Sea of Okhotsk is a well-know place in the world where gas hydrate is
widespread and thick pure gas hydrate (~50 cm thick) was sampled in 2005
CHAOS cruise. We conducted high-resolution geophysical survey using the
equipments with various frequencies. Side-scan sonar with 5 kHz SBP, sparker
seismic, hydroacoustic data reveal that large-scale marine channel structure
from the northern boundary of gas venting area. Gas hydrate BSR is getting
deep with water depth of seafloor. The BSR touches at the seafloor at 300 m of
water depth, indicating the top of gas hydrate stability zone in the area is 300
m. In the area shallower than about 1000 m of water, gas venting structure
area is defined depth and circular-shape gas venting structures are uniquely
developed. In the deeper area, mud-diapir structures form high bathymetric
expressions. Gas flares in the water column occur large range of water depth
between 110 m and 1220 m. The maximum height of the flares is up to 750 m,
reaching to 150 m of water depth. This implies that some amounts of methane
gas released from subbottom could be safely delivered into atmosphere
through the water column.
Major findings of the CHAOS cruise are as followings: 1) Seafloor expressions:
Side-scan sonar mosaic shows many seafloor structures like pockmarks in the
NE Sakhalin slope. The diameters of some structures are up to 500 m, 2)
BSRs: Depths of the BSRs are getting shallow as water depth decrease and
reach at the seafloor at 300 m in water depth, indicating that the top of the gas
hydrate stability zone is about 300 m in the study area, 3) Gas flares in the
water column: A lot of flares emitted from the seafloor were newly compiled.
Some flares rise up to about 800 m meters from the seafloor to the sea
surface. The flares occurred mainly on the rim of the gas venting structures, 4)
Gas hydrate occurrences: Some of hydrate-bearing cores contain big amount of
gas hydrates. Remarkable pure gas hydrate layer up to 35 cm thick was
recovered at the KOPRI structure. Gas hydrates sampled at 390 m in the water
depth in the Gisella structure are likely to be the shallowest one among
reported ones in the world so far. 5) Chimney structures in the gas
hydrate-bearing sediments: Sparker profiles reveal two groups of the chimneys
showing different seismic characteristics; (1) narrow wipeout (little or no
coherently reflected seismic energy) gas hydrate filling-chimneys, (2) wide
(more than 500 m) dark-colored (enhanced reflection) gas filling-chimneys.
T02-7 Orale
Loreto, Maria Filomena
ANALYSIS OF GAS HYDRATE RESERVOIR BY INTEGRATED
GEOPHYSICAL DATA ROCESSING, SOUTH TO ELEPHANT ISLAND.
LORETO Maria Filomena 1, TINVELLA Umberta 1, ACCAINO Flavio 1
1 - Istituto Nazionale di Oceanografia e Geofisica Sperimentale - Trieste
Key terms: BSR; fluid escape; mud volcanoes; overpressure; tectonics
Sediments of the accretionary prism, present along the continental margin of
the Peninsula Antarctica SW of Elephant Island, are filled by gas hydrates as
evidenced by a strong Bottom Simulating Reflector (BSR). The BSR, produced
by the impedance acoustic between hydrate and free gas layers, was identified
between 61° and 61.5° S using seismic sections acquired during the Austral
summers 1996/1997. A multidisciplinary geophysical dataset represented by
seismic data, multibeam, chirp profiles, CTD and core samples was acquired
during the Austral summer 2003/2004, onboard of R/V OGS-Explora in the
frame of the Progetto Nazionale di Ricerche in Antartide (PNRA). The seismic
data acquired during the last cruise allowed us to better characterize the area
where the BSR is present.
The estimation of gas hydrate and free gas concentrations is based on the
P-wave velocity analysis. So, we need to extract a detailed and reliable velocity
field; for this purpose we have developed an ad hoc procedure. Our method
uses the pre-stack depth migration to determine, iteratively and with a layer
stripping approach, the velocity field and a depth-migrated seismic section. The
final velocity field is translated in terms of gas hydrate and free gas amounts
by using theoretical approaches.
Several seismic sections are been processed in the investigated area, three of
that parallel oriented to the margin and one of that dip oriented. The final
velocity sections have been interpolated to produce a 3D image of the area and
translated in gas phase concentration sections, considering the gas distribution
within sediments both uniform and patchily distributed. The free gas layer is
only locally presents; consequently, the relative base of the free gas reflector
(BGR) was identified in some lines or part of them. The hydrate layer shows
important lateral variation with strong decrease of hydrate concentration in
correspondence of faults, which favour the fluid escape, or close to mud
volcano system. In fact, we expect that the presence of mud volcano modifies
the temperature of sediments, becoming higher than the surrounding area, and
produces a thinning of the hydrate layer and relative increase of pore pressure.
Finally, we observed that where fold propagation fault systems deform
sediments the gas hydrate concentration could locally increase and free gas
decrease.
Multibeam data allowed us to recognize several important features, such as
tectonic lineaments, mud volcanoes, collapse troughs and recent slides from a
mud volcano ridge. One CTD profile acquired close to a mud volcano, indicated
a significant positive thermal and salinity anomaly above the sea floor,
probably correlated with an episodic fluid expulsion event. This evidence is also
consistent with the sub-bottom profile acquired across the area, that reveals
the presence of several fluid expulsion plumes in the water column through the
faults at the border of the gas hydrate reservoir. The integrated geophysical
data analysis and the estimated depth of the BSR allowed us to extrapolate the
average thickness of the gas hydrate layers on regional scale, evaluating the
theoretical depth of the BSR.
The integrated analyzes of all available data is in progress, nonetheless the
preliminary results allow to propose a reasonable explanation on the origin,
migration and accumulation of the methane present along the margin. The
regional analysis of the area filled by gas (free or hydrate) suggests that the
hydrate layer stability is strongly influenced by the tectonic activity and by the
59
circulation of hot fluids and relative thermal field.
T02-8 Orale
Cruz
Vargas Cordero, Ivan De La
EVIDENCES OF GAS HYDRATE PRESENCE ALONG THE SOUTH CHILEAN
MARGIN
VARGAS CORDERO Ivan De La Cruz 1, TINIVELLA Umberta 2, ACCAINO Flavio 2,
FANUCCI Francesco 3, LORETO Maria Filomena 2
1 - Università degli Studi di Trieste/Istituto di Oceanografi e Geofisica
Sperimentale (OGS)
2 - Istituto di Oceanografi e Geofisica Sperimentale (OGS)
3 - Università degli Studi di Trieste
Key terms: accretionary prism; BSR; fluid escapes; tectonics
The south Chilean margin, between 38° and 45° S, is shaped by interaction of
the Nazca plate with south American plate. An accretionary complex,
characterized by trench-prism-forearc basin system, is constructed by the
oblique subduction of the Nazca plate. The accretionary style changes along the
margin as so the volume of the prism. In the northerm part of the investigated
area, the entire prism is affected by faults activity that determine the peculiar
deformational style, while, in the southern part, the intense frontal accretion is
realised thought many inverse faults.
The seismic data, here analysed, were acquired during the Conrad (1988) and
Sonne (2001) geophysical cruises by American and German team respectively.
The seismic data processing is performed by using the Seismic Unix software.
The processing sequence is characterized by a standard sequence to produce a
stacked section and a post-stack Kirchoff depth migration by using the
interpolated and smoothed stack velocity field.
Seismic reflection profiles are characterized by the presence of remarkable
Bottom Simulating Reflector (BSR) showing reverse phase with respect to the
sea bottom and a very high-amplitude. The BSR is produced by the impedance
acoustic contrast due to hydrates and free gas trapped below the hydrate
stability zone. To better define the seismic character of the hydrate bearing
sediments, we selected parts of the seismic line to perform a detailed velocity
analysis by using iterativelly the pre-stack depth migration. In this way, we can
extrapolate the amount and the distribution of the hydrates along the margin.
The RV161-35 seismic line, located close to 39° S, shows an irregular trend of
the BSR; around it, the seismic image evidences fluid escapes and possible
mud volcanoes formation; whereas southward the RC2901-734 seismic line,
located close to 44° S, reveals a strong and continuous BSR. Northward of the
studied area, the BSR is recognized in the lower slope at about 3000 m depth,
while southward the BSR is located in the upper slope at about 1000 m depth.
As aspected, the gas hydrate layer results thinner along the upper slope than
the lower slope. The intense tectonic activity affecting the accretionary prism
and associated fluid escapes suggest that the hydrate zone could be related to
the deformational style.
T02-9 Orale
Macelloni, Leonardo
MISSISSIPPI CANYON 118 HYDRATES MOUND, A COMPLEX HYDRATES
STRUCTURE IN THE NORTHERN GULF OF MEXICO.
MACELLONI Leonardo 1, CARUSO Simona 1, MCGEE Thomas Martin 1, LUTKEN
Carol Blanton 1, BOSMAN Alessandro 2, SLEEPER Kennet 1, WOOLSEY Robert
James JR. 1
1 - Center for Marine Research and Environmental Technology, University of
Mississippi
2 - Dipartimento Scienze della Terra, La Sapienza Universita di Roma
Key terms: hydrates vent; sea floor maps; acoustic images; sea floor video
survey; hydrates outcrop
Gas hydrates are solid structures composed of gas molecules encased in cages
of frozen water. Most interesting to the energy community are hydrates that
contain hydrocarbon gases. In the northern Gulf of Mexico, hydrates of this
type form in water depths greater than 450 m and often occur in mounds
located where faults intersect the seafloor. Typically, these hydrates consist of
seawater from which the salt has been excluded and gases that have migrated
up faults from buried hydrocarbon reservoirs.
In addition to hydrates, the mounds contain large amounts of calcium
carbonate and various other minerals precipitated by microbes that extract
energy from hydrocarbon fluids. It has been observed that microbial activity is
an order of magnitude greater in the vicinity of mounds containing hydrate
outcrops than elsewhere on the seafloor. The proliferation of microbes around
gas hydrate sites is not coincidental; it is the result of a synergistic relationship
between hydrocarbon gas hydrates and microbes; i.e., the carbon-rich gases
within hydrates provide sustenance for the microbes, and biosurfactants
produced by the microbes enhance the formation of hydrates.
A permanent multi-sensor sea-floor observatory is being installed by the Gulf of
Mexico Hydrates Research Consortium to monitor, more or less continuously, a
mound in Mississippi Canyon Block 118. Baseline studies of the vicinity of the
mound include acoustic imagery from an Autonomous Underwater Vehicle
(AUV), and seismic-reflection profiling using the surface-source/deep-receiver
technique (SSDR). Ground-truth is provided by shallow sediment cores, video
survey, sea-floor photographs and samples collected by manned submersible.
The acoustic imagery includes 100% high resolution swath bathymetry
coverage, 100% acoustic backscatter imagery, and 200% side-scan sonar
coverage. Resolution of sea-floor features is on the order of 3-5 meters for the
bathymetry map and under 1 m for the side scan sonar mosaic.
The seismic reflection data comprise a grid of profiles intended to provide a
psuedo-3D image of the mound's interior and shallow geologic structures in its
vicinity.
Video survey, sea floor photographs and samples collected by manned
submersible as well as shallow sediment cores, provide valuable ground-truth
to correlate-calibrate the acoustic data set.
At MC 118, at least three circular vent structures are present on the mound.
SESSIONE T02
60
Each of these is actually composed of several small craters. The acoustic
back-scatter imagery and the side-scan sonar mosaic show high backscatter
anomalies that form five separate roughly circular patterns, three of which
align well with the vent structures. Video survey and sea-floor photographs
clearly show many processes associated with gas hydrate mounds that may be
contributing to the textural contrast identified by the acoustic anomalies; these
include biological and authigenic carbonate accumulation, gas hydrate
formation, remarkable hydrates outcrops, bacterial mats, and both surface and
subsurface disturbances related to cessation of fluid-venting.
Shallow-source deep-receiver (SSDR) seismic profiles image the mound in
stark contrast with the surrounding closely spaced horizontal reflectors in the
rest of the block. Over the vents, energy penetration became very modest, and
high amplitude "patch" alternatively with wipe-out areas are localized
immediately below the sea floor. The patch can represent the seismic image of
the authigenic carbonate accumulation, probably buried during the vent
evolution. A strong deeper reflector (300 ms below the sea bottom),
characterized by clear negative polarity, has been mapped over an extend area
beneath the mound. A preliminary 3-D model suggests this reflector may
represent the seismic expression of the limit of the hydrate stability zone.
Analyses are ongoing in an attempt to model all the seismic horizons and the
fault pattern in the subsurface at this gas hydrates location.
T02-10 Poster
Accaino, Flavio
A METHOD TO ESTIMATE GAS HYDRATE FROM SEISMIC DATA.
ACCAINO Flavio 1, TINIVELLA Umberta 1, LORETO Maria Filomena 1
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS)
Key terms: gas hydrates; seismic velocity; gas hydrate concentration
Gas hydrates in marine environments have been mostly detected from analysis
of seismic reflection profiles, where they produce a remarkable Bottom
Simulating Reflector (BSR). Generally, the BSR is a very high-amplitude
seismic reflector that is associated with a phase reversal. This phase reversal
may indicate that sediments above the BSR are extensively filled with gas
hydrates and lower sediments below it are filled with free gas in the pore
space. The base of the free gas zone can be locally detected as a seismic
reflector called BGR, as revealed in several studies.
The scientific community is investing much effort to in studying sediments
containing gas hydrates to characterize the hydrate reservoir and to quantify
the gas trapped within sediments from seismic data analysis. We developed a
procedure where the gas hydrate and free gas concentrations, in the pore
space, can be estimated by seismic velocity anomalies. This is possible
applying a theoretical model based on Gassmann's equation with an explicit
dependence on differential pressure and depth. The model is valid for three
different situations;(i) full water saturation; (ii) water and gas hydrate in the
pore spaces; and (iii) water and gas in the pore spaces.
The first step, for the evaluation of the gas hydrate and free gas concentration,
is to determine the velocity field accurately. It can be obtained using two
procedures: tomographic inversion of the reflected/refracted events; iterative
analysis of the semblance of common image gathers obtained by pre-stack
depth migration. Then, using as reference curve a velocity profile of the
investigated sediments without gas hydrate, the obtained velocity field can be
translated in terms of gas hydrate and free gas concentrations. Alternatively,
the reference curves, i.e. the physical parameters versus depth for water
saturated sediments, can be extracted using the Hamilton curves, or from
information obtained by drilling.
The proposed method was applied in various areas where BSR is present. In
particular, it is applied in an area where a BSR was identified by OGS (Antarctic
Peninsula). In this area, a grid of seismic lines were acquire during three legs.
The velocity field obtained by the seismic information allow to construct a 3d
velocity field and to translate it in terms of gas hydrate and free gas
concentration sections.
T02-11 Poster
Del Negro, Paola
BIOGEOCHEMICAL PROPERTIES OF ANTARCTIC SEDIMENTS INVOLVED
IN METHAN HYDRATES PRODUCTION
PREDONZANI Sergio 1, DEL NEGRO Paola 2, DE VITTOR Cinzia 2, CATALETTO
Bruno 2, ACQUAVITA Alessandro 1, FABBRO Cinzia 2, CELUSSI Mauro 2, TINIVELLA
Umberta 3
1 - A.R.P.A. Friuli Venezia Giulia, Osservatorio Alto Adriatico, P.zza Collalto 15,
I-33057 Palmanova (UD)
Trieste
3 - OGS- Dipartimento di Geofisica della Litosfera, Borgo Grotta Gigante 42/C,
I-34010 Sgonico (Trieste)
Key terms: methan hydrates; biogeochemical processes; antarctic sediments
During 2003 Italian-Antarctic expedition along the South Shetland Margin
(Antarctic Peninsula) a strong signal suggesting the presence of a gas hydrate
rich zone was recorded by means of Bottom Simulating Reflector (BSR). In this
area a mud volcano was present, hence a core (GC01) was collected using a
gravity corer in order to confirm the enrichment in gas hydrate.
The core was submitted to X-ray radiography and Computerized Axial
Tomography analysis to investigate the presence of gas within the sediment
pockets or the presence of low density zone. Low density areas were perforated
by means of a steel need connected to vacutainer. The gas (C1-C6) were
analysed by gas chromatography (GC) with FID detector. In addition, detection
of gases in fresh sediment was performed on discrete levels of the core
obtained from longitudinal sections (thickness=1 cm), collected in close vessels
and subsequently thermodesorbed (T=60°C). Biogeochemical analyses
(organic carbon, labile organic matter, CHNS, Al, Fe) were performed on
sediment homogenized and lyophilised, while bacteria were determined in fresh
sample.
The most abundant hydrocarbon found in free gases was methane, conversely
only traces of C2-C6 alkanes were detected. These evidence was confirmed
also in core sections, even though the presence of C2-C6 alkanes was in the
same order of magnitude of methane contents.
The biochemical composition of sedimentary organic matter was used in order
to obtain information about the origin of the deposited material. Biopolymeric
carbon, which was expressed as sum of proteins, lipids and carbohydrates,
represented a relatively high percentage of organic carbon (on average of 11,5
%); in detail proteins represented the dominant biochemical class of these
organic compounds.
Among lithogenic elements both Al and Fe contents showed no peculiar trends
along the core depth. Al concentration was less variable than Fe concentration
with average values of 6,6 + 0,3% and 3,1 + 0,2 % respectively.
Each sediment level was characterized by a typical bacterial community
probably related to different gas production. The identification of methanogenic
strains is in progress.
T02-12 Poster
Natalicchio, Marcello
CARBONATE CONCRETIONS IN UPPER MIOCENE SEDIMENTS OF THE
TERTIARY PIEDMONT BASIN: VESTIGES OF AN ANCIENT GAS
HYDRATES STABILITY ZONEDELA PIERRE Francesco 1, FESTA Andrea 1, MARTIRE Luca 1, NATALICCHIO
Marcello 1, PETREA Catalin 1, CLARI Pierangelo 1
Key terms: carbonate concrections; gas hydrates; Tertiary Piedmont Basin
Several carbonate concretions have been recognized in the SE sector of the
Tertiary Piedmont Basin (TPB), close to the Villalvernia-Varzi line. They are
enclosed in Tortonian to lower Messinian slope deposits (Sant'Agata Fossili
Marls=SAF), which are followed, through the Intramessinian unconformity, by
upper Messinian chaotic deposits (Complesso Caotico della Valle Versa).
Preliminary
C data (-15,11 to -59,64 0/00 PDB) indicate that carbonate
13
precipitation was induced by bacterial degradation of methane. The positive 18
O values (from +1,56 to +8,11 0/00 PDB) suggest that methane was sourced by
gas hydrate destabilisation.
Carbonate concretions can be grouped as follow:
a) cemented mud breccias rich in chemosymbiotic macrofauna ("chemoherm").
These rocks, enclosed in the lower part (Tortonian) of SAF, represent the sea
floor products of an ancient venting site and allow to date the fluid emission
phase.
b) Stratiform concretions, 20 to 60 cm thick and up to 20 m wide. They occur
in the upper part (lower Messininan) of the SAF, 10-15 m below the upper
Messinian chaotic deposits. Some concretions are brecciated and are
characterized by mm to cm - sized angular clasts separated by different types
of carbonate cements. Others show septarian-type cracks, incompletely filled
with sediments and carbonate cements.
c) Cylindrical concretions, showing a maximum height of 120 cm and a
diameter ranging from 5 to 70 cm; a common feature is the occurrence of an
axial portion of about 1 cm across. This kind of concretions crops out at
different levels of the SAF, both below and above the chemoherm.
d) Decimeter-sized ellipsoidal concretions, resulting from the extensive
cementation of the hosting fine-grained sediments. They are located in the
upper part of the SAF.
Lack of chemosymbiotic fossil remains and of traces of exposure on the sea
floor suggest that concretions b, c and d originated below the seafloor, at a
depth that is still difficult to evaluate. Stratiform concretions are related to the
formation of gas hydrates in the sediment pore spaces and their succesive
destabilisation. In particular, the brecciated concretions resemble the collapse
breccias which, in present day settings, are frequently reported in areas where
gas hydrates are forming. Cylindrical concretions corresponds to ancient fluid
conduits originated by the localized cementation of sediments by focused
methane rich-fluids, sourced by gas hydrates destabilisation and ascending
toward the seafloor. Their distribution is controlled by a network of mesoscopic
fractures and faults sub-perpendicular to bedding that represent a preferential
pathway in controlling the upward migration of CH4 rich-fluids. Further studies
are needed to clarify the genesis of ellipsoidal concretions.
The described concretions are a reliable evidence of the past formation of gas
hydrates in the sedimentary column, of their destabilisation and of the
migration of the resulting hydrocarbon-rich fluids toward the seafloor.
Moreover, their stratigraphic relationships indicate that at least two phases of
methane flow occurred in the Late Miocene and are associated to trascurrent
movements along the Villalvernia-Varzi Line. During the first one the
methane-rich fluids reached the sea floor, giving rise to the chemoherm
embedded in the Tortonian part of the SAF. Cylindrical concretions located
below the chemoherm mark the ascending pathways of the fluids in the
subsurface. The second one is testified by stratiform, cylindrical and ellipsoidal
concretions enclosed in the lower Messinian part of the SAF. These subsurface
products, which may have acquired their lithified state at any time after
sediment deposition, mark a portion of the sedimentary column originally
localized within the gas hydrate stability zone. Gas hydrate destabilisation
could have also triggered mass wasting events, resulting in the formation of
the overlying upper Messinian chaotic deposits.
T02-13 Poster
Praeg, Daniel
HYDRAMED: GAS HYDRATE STABILITY AND PROSPECTIVITY IN THE
MEDITERRANEAN SEA
PRAEG Daniel 1, UNNITHAN Vikram 2, CAMERLENGHI Angelo 3
Trieste, Italy
2 - Jacobs University Bremen (JUB), Germany
3 - Istitució Catalana de Recerca i Estudis Avançats (ICREA), c/o Universitat de
Barcelona, Spain
Key terms: hydrate; stability; salinity; temperature; Mediterranean
SESSIONE T02
Gas hydrates have been proven at one location in the Mediterranean Sea (in
mud volcanoes of the Anaximander Mountains), but their wider occurrence
remains unknown. The EC-funded HYDRAMED project was designed to examine
the potential gas hydrate system in the Mediterranean Sea as a whole, over the
timescales of glacial-interglacial change. The hydrate stability zone (HSZ) was
modelled using gridded parameters for pressure (water depth), bottom water
temperature and geothermal gradient, assuming a range of pore water
salinities and gas compositions. For pure methane in seawater, the HSZ is
present throughout the Mediterranean in depths >1 km (due to bottom waters
of 12-14°C), but in thicknesses >200 m only in the east (which is geothermally
cooler). Gas compositions including higher hydrocarbons yield a thicker and
shallower HSZ; however, higher pore water salinities have an opposite and
stronger effect, such that the HSZ is not present in the Mediterranean for
salinities of 20% or more. Pore water salinities at deep-sea drillsites vary from
3.5% to >30% above the Messinian salt, reflecting processes of diffusion and
advection that represent a first-order control on hydrate stability in the
Mediterranean. Hydrate stability has also been influenced by changes in
temperatures since the last glacial stage, when the effects of lowered sea level
(-125 m) were outweighed by bottom waters estimated to have been at least
4°C cooler, corresponding to a HSZ up to 50% thicker and hundreds of metres
shallower. A dramatic reduction in hydrate stability is implied for the glacial to
interglacial transition, with implications both for slope stability along basin
margins and for the functioning of cold seep systems associated with hydrates
(e.g. Anaximander Mountains).
Correlation of areas where the HSZ is thicker (>100 m) with areas of known or
potential flux of gas to seabed (e.g. biogenic gas from Plio-Quaternary
depocentres, thermogenic gas from accretionary prisms or areas beyond the
Messinian salt seal) allows the identification of several areas of interest for
possible hydrate occurrence. Within these areas, the modeled HSZ has been
used to guide a search for indicators of hydrates in existing datasets, both
geochemical (deep-sea drillsites) and geophysical (BSRs, using a regional
multichannel seismic dataset held in archive by OGS). The most prospective
areas lie in the eastern Mediterranean Sea, and include the Nile Fan and the
inner basins of the Calabrian Arc accretionary prism.
Acknowledgement: The HYDRAMED project was funded at OGS from
2004-2006 by a Marie Curie Intra-European Individual Fellowship held by D.
Praeg, within the European Community 6th Framework Programme (contract
MEIF-CT-2003-501814).
T02-14 Poster
Praeg, Daniel
GEOPHYSICAL EVIDENCE OF GAS HYDRATES ON THE NILE DEEP SEA
FAN
PRAEG Daniel 1, GELETTI Riccardo 1, MASCLE Jean 2, UNNITHAN Vikram 3,
WARDELL Nigel 1
Trieste, Italy
2 - Géosciences Azur, Villefranche-sur-Mer, France
3 - Jacobs University Bremen (JUB), Germany
Key terms: hydrate; BSR; seismic; slope stability; glacial-interglacial
Bottom simulating reflectors (BSRs) that may indicate the base of a zone of
hydrate-bearing sediments have never been documented in the Mediterranean
Sea, although gas hydrates have been proven at seabed at one location (SE of
Greece). The wider extent of gas hydrates in the Mediterranean Sea was
explored by the EC-funded HYDRAMED project (see separate poster), which
showed that the theoretical hydrate stability zone (HSZ) is present throughout
the Mediterranean Sea in water depths >1000-1200 m and identified several
areas of interest for possible hydrate occurrence. Prominent among these is the
Nile Fan, where abundant cold seeps record the escape of gas to seabed,
through the theoretical hydrate stability zone.
Here we present evidence of a BSR on the western Nile Fan, based on targeted
reprocessing of multichannel seismic reflection data held in archive by OGS.
The MS lines were acquired in 1973 using Flexotir sources fired every 100 m,
recorded over a 2.4 km long 24-channel cable, resulting in CDPs of 12 fold
coverage. Despite the relatively low data fold and spatial resolution, targeted
reprocessing resulted in stacked and migrated sections of good quality of parts
of two lines across the western Nile Fan. The sections include a reflector of
inverse polarity that lies subparallel to and within 300 ms of the seabed and in
places cross-cuts the (discontinuous) reflectors of the upper Nile Fan. The
reflector extends over a depth range of at least 2000-2800 m and over a
horizontal distance >80 km. Comparison with the theoretical stability zone for
methane hydrate in seawater indicates the reflector to be consistent with the
base of a shallow zone of hydrates up to 250 m thick. The upper limit of the
theoretical HSZ extends upslope beyond the observed BSR, to c. 1200 m.
Modelling of hydrate stability for conditions representative of the last glacial
stage, when sea levels were lower (-125 m) and bottom waters cooler (by at
least 4°C), indicates that the HSZ would have been up to 50% thicker and its
upper limit some 300 m shallower. Deglaciation therefore resulted in a
dramatic reduction in hydrate stability, with implications for slope stability
along the shifting upper limit of the HSZ (in water depths of c. 900-1200 m),
as well as for the functioning of cold seeps linked to hydrate reservoirs across
the depth range of hydrate occurrence. The recurrent release of free gas from
hydrates during glacial-interglacial cycles of climate may have had a strong
impact on the sedimentary record of the Nile Fan and the adjacent Herodotus
Basin, both of which contain evidence of large-scale slope failure.
Acknowledgement: The HYDRAMED project was funded at OGS from
2004-2006 by a Marie Curie Intra-European Individual Fellowship held by D.
Praeg, within the European Community 6th Framework Programme (contract
MEIF-CT-2003-501814).
SESSIONE T04
La laguna di Venezia: un laboratorio naturale di ricerche
interdisciplinari
T04-1 Invitato
61
Carbognin, Laura
LAND SUBSIDENCE IN THE VENICE LAGOON (ITALY)
CARBOGNIN Laura 1
1 - Institute of Marine Sciences-National Research Council, Venice, Italy
Key terms: Venice lagoon; Mechanical land subsidence; Geochemical land
subsidence; Monitoring network; SIMS mapping
In its life one-and-a-half millennium long, Venice saw an apparent subsidence
of many dozens centimeters. Considering the last century, we can attribute the
elevation loss of 23 cm to just land sinking and the real sea level rise; Venice
lives in a lagoon and it is with respect to water level that she has to limit
herself.
Land subsidence is anyway a process that has involved the entire lagoon area
since its origin, and not only the city of Venice.
Causes of real subsidence are natural and anthropogenic. Compaction of
sediments (average rate of 1.3 mm/yr) has been primary in historical times,
while in geological times also tectonic processes (less than 0.5 mm/yr) played
an important role. Modernization over the 1900, including land reclamation and
oxidation of organic soils, groundwater overexploitation for industrial uses, has
seriously accelerated the compaction process (more than 2,5 mm/yr).
Presently the city of Venice can be assumed to be stable; compaction induced
by groundwater pumping is stopped and the natural one is going on at a very
low rate. In terms of real subsidence (without considering the rising sea) the
prediction is reassuring.
But land subsidence has always been and still is occurring differentially in
space and time. To date subsidence rates from 1 to 5 mm/yr are recorded over
the northern sector and in the southern catchment and surroundings.
A complete analysis of the phenomenon during the last decades was performed
by combining high precision levelling, remote sensing measurements and tide
gauge records.
T04-2 Invitato
Di Giulio, Andrea
NATURAL SUBSIDENCE OF VENICE: A DEEPLY ROOTED NEVERENDING
STORY
DI GIULIO Andrea 1, BARBIERI Chiara 1, MASSARI Francesco 2
1 - Dipartimento di Scienze della Terra, Università di Pavia, Italy
2 - Dipartimento di Paleontologia, Geologia e Geofisica, Università di Padova,
Italy
Key terms: Venice; Natural Subsidence; Sedimentation; Geohistory; Cenozoic
Integrated geohistory analysis performed on high resolution stratigraphy of
Venezia 1 and Lido 1 wells (Quaternary-Pliocene interval) and low resolution
stratigraphy of a simulated well extending Lido 1 down to the base of Cenozoic
(Paleocene-Miocene interval) is used to reconstruct the interplay between
subsidence and sedimentation occurred in the Venice area (eastern Po Plain)
during the last 60 Myr, and to discuss the relationships between calculated
subsidence rates and time resolution of stratigraphic data.
Both subsidence and sedimentation are mostly related the tectonic evolution of
the belts that surround the Venice basin, influencing the lithosphere vertical
motions and the input of clastic sediments through time. In particular, two
subsidence phases (0.13 mm/yr and 0.14 mm/yr) are recorded between
40-33.5 Myr and 32.5-24 Myr, coeval with tectonic phases in the Dinaric belt.
Vice versa, during the main South-Alpine orogenic phase (middle-late
Miocene), quiescence or little uplift (-0.03mm/yr) reflects the location of Venice
area close to the peripheral bulge of the South-Alpine foreland system. Early
Pliocene evolution is characterised by a number of subsidence/uplift events,
among which two uplifts (-0.4mm/yr and -0.2mm/yr) occurred between 5-4.5
and 3-2.2 Myr and can be correlated with tectonic motions in the Apennines.
During the last Myr, the Venice area was initially characterised by uplift
(-0.6mm/yr rising to -1.5mm/yr between 0.4 and 0.38 Myr) eventually
replaced by subsidence at a rate ranging between 1.6 and 1.0 mm/yr up to
0.12 Myr and then decreased to 0.4mm/yr, as an average, up to present.
Our results allows to evaluate the contribution of compaction of deep (>0.5
km) sediments to recent subsidence, and highlights that time resolution of the
stratigraphic dataset deeply influences the order of magnitude obtained for the
calculated subsidence rate. This last point is due to the fact that natural
subsidence seems to have worked through short-lived peaks (at least in the
order of 100 kyr, but even shorter duration cannot be excluded), alternated
with long relatively quiescent intervals. This suggests caution when
components of subsidence are deduced by subtracting long-term to short-term
subsidence rate.
T04-3 Invitato
Gambolati, Giuseppe
CAN VENICE BE RAISED BY INJECTING FLUIDS (SALTWATER OR CO2)
INTO DEEP SALINE AQUIFERS UNDERLYING THE LAGOONGAMBOLATI Giuseppe 1
1 - DMMMSA-UNIVERSITA' DEGLI STUDI DI PADOVA
Key terms: ANTHROPOGENIC LAND UPLIFT; FLUID INJECTION; VENICE
UPHEAVAL; LAND SUBSIDENCE; SAVING VENICE
The frequency of flooding in Venice has much increased over the last 50 years
as a major consequence of natural and anthropogenic land subsidence, mean
sea level rise, and a more active lagoon hydrodynamics induced by the
deepening of the largest navigation canals. The endless debate on the most
appropriate solution for saving the city seems to have recently come to a halt
with the official approval of MOSE, an impressive engineering project consisting
of 79 mobile barriers planned to close the lagoon inlets during the most severe
storms, thus preventing the Adriatic Sea from flooding the city. However,
MOSE has still many strong opponents, including the Venice Mayor, who do not
believe this huge and complex structure can effectively preserve both the city
SESSIONE T04
62
and the lagoon ecosystem, and keep on debating and advancing other
alternative solutions. We present here one such solution that has none of the
environmental consequences and technical shortcomings charged to MOSE.
This is concerned with injecting seawater (or subordinately anthropogenic
CO2) into a brackish sandy aquifer lying at 600-800 m below Venice and
raising the city. The technology of underground fluid injection is currently
available from oil industry. A prediction of Venice upheaval to be expected is
performed with the aid of much advanced numerical fluid-dynamical and
geo-mechanical models based on new information recently gained about the
setting and the properties of the Northern Adriatic basin. Preliminary results
show that 12 vertical injection wells, strategically located within the lagoon
area, may raise Venice from 15 up to 40 cm, with a most likely value of 25-30
cm, over a 10 year time, thus offsetting or substantially mitigating the vast
majority of the high tides that occasionally plague the city. To test the
feasibility of the idea a pilot project of injection of seawater, properly treated
for geo-chemical compatibility, is designed and advanced with the aim at
investigating the anthropogenic uplift that can actually occur, over a small yet
representative area selected on purpose within the lagoon or close to the
lagoon margin.
T04-4 Orale
Tosi, Luigi
SALT WATER CONTAMINATION IN THE SOUTHERN COASTAL VENETIAN
PLAIN: AN OVERVIEW
TOSI Luigi 1, CARBOGNIN Laura 1, RIZZETTO Federica 1, TEATINI Pietro 2, RORAI
Cecilia 2, BASSAN Valentina 3, GASPARETTO-STORI Giuseppe 4, VITTURI Andrea 3
Italy
2 - Dipartimento di Metodi e Modelli Matematici per le Scienze Applicate,
Università di Padova, Italy
3 - Provincia di Venezia, Settore Protezione Civile e Difesa del Suolo, Servizio
Geologico, Venezia, Italy
4 - Consorzio di Bonifica Adige Bacchiglione, Conselve (Pd), Italy
Key terms: saltwater intrusion; Venice Lagoon; Bacchiglione-Brenta river
mouth; ISES monitoring network
The salt water contamination process in the Venice watershed between the
southern edge of the Venice Lagoon and the Adige River was investigated by
hydrogeological and geophysical surveys and a new monitoring network of
surface water and shallow groundwater (Carbognin and Tosi, 2003). The
results show that: i) the presence of saline water extends up to 20 km inland
from the coast; ii) the depth of the fresh/salt-water interface varies from
ground level to 30 m depth and exhibits a significant, mainly seasonal, time
variation; iii) the contaminant plume penetrates from 10 even to 100 m depth
in the subsoil (Carbognin and Tosi, 2003; Carbognin et al. 2005a); iv) the
dynamics of soil salinization process is especially sensitive to the changes in
the river discharge, water levels of the drainage network regulated by a
number of pumping stations, and climatic conditions (Rizzetto et al., 2003,
Carbognin et al., 2005b). Furthermore riverbed seepage of sea water,
encroaching from river mouths, seriously contributes to the salt contamination.
In summer 2003, characterized by a severe drought, salt water flowed up the
Brenta and Bacchiglione rivers for about 20 km (Carbognin et al., 2005b). The
presence of geological and geomorphologic features can favour or mitigate the
contamination process. For example, in the Chioggia littoral, the system of
sand dune ridges contains a reservoir of freshwater up to 15 m thick, whereas
paleo-river beds occurring in the catchment and intersecting the southern
lagoon margin, expand landward the saltwater intrusion. The saline
contamination is particularly severe in reclaimed areas characterized by ground
elevation up to 4 m below the sea level and where land subsidence, mainly due
to peat soil oxidation, has induced an elevation loss greater than 1 m over the
last few decades (Tosi et al., 2000, Teatini et al. 2005, 2007). Soil salinization
and land subsidence have increased the risk of scenarios of soil desertification.
Aknoledgements
We acknowledge ISES, BRENTA and Co.Ri.La. 3.1b-3.10-3.16 Projects to make
available data.
References
Carbognin, L., Tosi, L., Il Progetto ISES per l'analisi dei processi di intrusione
salina e subsidenza nei territori meridionali delle Province di Padova e Venezia.
Progetto ISES, Grafiche Erredici, Padova, 2003.
Carbognin, L., Teatini, P. & Tosi, L., Land Subsidence in the Venetian area:
known and recent aspects. Giornale di Geologia Applicata, 1, pp. 5 -11, 2005a.
Carbognin, L., Rizzetto, F., Tosi, L., Teatini, P. & Gasparetto-Stori, G.,
L'intrusione salina nel comprensorio lagunare veneziano. Il bacino meridionale.
Giornale di Geologia Applicata, 2, pp. 119-124, 2005b.
Rizzetto, F., Tosi, L., Carbognin, L., Bonardi, M. & Teatini, P., Geomorphological
setting and related hydrogeological implications of the coastal plain south of
the Venice Lagoon (Italy). Hydrology of the Mediterranean and Semiarid
Regions, eds. E. Servat et al., IAHS Publ. n. 278: Wallingford, UK., pp.
463-470, 2003.
Teatini, P., Tosi, L., Strozzi, T., Carbognin, L., Wegmüller, U., Rizzetto, F.,
Mapping regional land displacements in the Venice coastland by an integrated
monitoring system. Remote Sensing of Environment, 98: 403-413, 2005.
Teatini, P., Strozzi, T., Tosi, L., Wegmüller, U., Werner, C., Carbognin, L.,
Assessing Short- and Long-time displacements in the Venice Coastland by SAR
Interferometric Point Target Analysis. J. Geophysical Research, 112, F01012,
2007.
Tosi, L., Carbognin, L., Teatini, P., Rosselli, R., Gasparetto-Stori, G., The ISES
Project subsidence monitoring of the catchment basin south of the Venice
Lagoon (Italy). In: Carbognin L, Gambolati G, Johnson AI (eds) Land
subsidence, La Garangola, Padova (Italy), II, pp 113-126, 2000.
T04-5 Orale
De Franco, Roberto
MONITORING THE SALTWATER INTRUSION BY TIME LAPSE
ELECTRICAL RESISTIVITY TOMOGRAPHY: THE CHIOGGIA TEST SITE
(VENICE LAGOON, ITALY)
DE FRANCO Roberto 1, BIELLA Giancarlo 1, TEATINI Pietro 2, TOSI Luigi 3,
CHIOZZOTTO Barbara 4, CLAUDE Christelle 5, MAYER Adriano 1, BASSAN Valentina
6
, GASPARETTO-STORI Giuseppe 7
1 - IDPA-CNR
2 - DMMSA-Università di padova
3 - ISMAR-CNR
4 - Morgan Rilievi Srl
5 - CEREGE-Aix en Provence
6 - Provincia di Venezia-Servizio Geologico
7 - Consorzio di Bonifica Adige-Bacchiglione- Conselve (PD)
Key terms: Time lapse electrical resistivity tomography; saltwater intrusion
dynamics; Venice Lagoon
An electrical resistivity tomography (ERT) time lapse experiment aimed at
monitoring the dynamics of the saltwater intrusion in the coastland bounding
the southern Venice Lagoon, near the city of Chioggia (Italy), is presented. The
experiment, operated for about one year from November 2005 to September
2006, was carried out by means of an apparatus developed ad hoc. Some
preliminary test and calibration acquisitions allowed the final setup of the
experimental parameters. The system acquired 10 apparent resistivity
tomograms per day, five of which with high resolution by a 97.5 m long ERT
line with a 2.5 m electrode spacing and five by a 300 m long and 5 m electrode
spacing ERT line, suitable to monitor the intrusion process down to 50-60 m
depth. A 50 m deep exploratory borehole drilled near the test site identified a
shallow phreatic aquifer and two confined aquifers within the depth of interest
and allow to constrain the electro-stratigraphy obtained by the resistivity
tomography. The collected data point out a different time behavior of the
salinization process in the upper aquifer with respect to the deeper ones. The
shallow aquifer, located between 3 and 15 m depth below mean sea level, is
the most contaminated by the salt intrusion with a minimum resistivity
formation value of 0.8 ohm*m. For the upper 2-3 m depth the experimental
data reveal a seasonal resistivity fluctuation with a minimum salt intrusion in
March-April and a maximum in the dry summer season. An opposite behavior
was experimented by the lower part. The deeper aquifers are characterized by
a resistivity ranging from 3.0 ohm*m to 10 ohm*m and show a resistivity rise
at the beginning of the summer time probably due to an increasing contribution
of fresh water from sub-regional aquifers. The data collected by the
experiment have been correlated with a number of environmental variables,
i.e. tidal regime, rainfall, groundwater table, and water levels in the
watercourses close the monitoring site. In particular, a correlation is found
between the resistivity in the upper 5 m of the phreatic aquifer and the
rainfalls, and between the water level in the adjacent main channel and the
resistivity down to about 10 m depth. This relation is indicative of the
draining/feeding influence exerted by the channel probably only to the first
aquifer. Moreover a quite clear negative correlation with the tidal regime is
observed at seasonal time scale, while at daily time scale the tidal oscillation
doesn't affect the resistivity behaviour in the phreatic aquifer.
T04-6 Invitato
Christelle, Claude
THE QUANTIFICATION OF SUBMARINE GROUNDWATER DISCHARGE ON
COASTAL ZONES VIA RADIOACTIVE TRACERS: THE CASE OF TWO
MEDITERRANEAN AREAS
CHRISTELLE Claude 1, GATTACCECA Julie 1, MAYER Adriano 2, OLLIVIER Patrick 1,
RADAKOVITCH Olivier 1, VALLET-COULOMB Christine 1, HAMELIN Bruno 1
1 - CEREGE
2 - IDPA-CNR
Key terms: Submarine Groundwater Discharge; radium; radon; Venice; Gulf of
Lion
Submarine groundwater discharge (SGD) is now recognized as a major
pathway for nutrients and contaminants. In the past ten years, many studies
focused on the importance of SGD on coastal processes. SGD consists of
terrestrial fresh groundwater and seawater recirculating across the aquifer ocean interface. A number of methods can be applied for measuring SGD, such
as hydrological modelling based on piezometric head measurements, direct
seepage measurements, geophysical tracers such as groundwater temperature
or electrical tomography, pore water investigations and application of
submarine wells, and steady-state mass-balance models using geochemical
tracers such as Ra and Rn. Among these methods, the short-lived natural
radionuclide tracers are particularly useful tools to quantify SGD, since their
radioactive activities can be directly translated into fluxes. Two Mediterranean
sites, in South of France and in North-Eastern Italy, have been studied in this
context. In both site, we used a water balance method approach completed by
a multi-element study, with a special interest in radium (226Ra and 228Ra)
and radon (222Rn) isotopes analysis. 226Ra activities measurements were
performed by isotope dilution and thermal ionization mass spectrometry on
small samples (0.5L). Very small variations in 226Ra can be resolved by this
technique, thanks to the high precision that is attainable (1 to 5% on 20 to 200
fg radium). 222Rn activities were measured by in-situ continuous-monitoring
-counting technique with a precision of 10%. Estimations of SGD in the Gulf
of Lion (France) using 226Ra data from coastal waters and groundwaters
sampled in the main aquifer of the Rhone delta, reaches a maximum of 4.5 x
107 m3/d. In the Camargue delta, (France), the groundwater discharge in the
principal pond (Vaccares) was estimated from 222Rn mass budgets. It is
around 1.1 x 103 m3/d, in very good agreement with those based on
hydrological and salt budget. In the South basin of the Venice Lagoon, Italy,
(Co.Ri.La. project), the subsidence of the basin prevents the fresh groundwater
discharge induced by the hydraulic gradient. Our work is thus focused on the
characterization of the recirculated saline groundwater discharge (location,
speed, induced changes in water chemistry). This discharge appears mostly
driven by tide in the Mediterranean area. 226Ra and 222Rn activities are
significantly higher in the lagoon samples (2.3-5.3 and 26-82 Bq/m3
respectively) than in the open Adriatic Sea (2.2 and 10 Bq/m3 respectively).
Mass balance models taking into account riverine inputs, diffusion from
sediments, loss, production and decay of the isotopes, do not explain the
lagoon excesses and suggest the existence of another source of 226Ra and
222Rn in the lagoon. Groundwater from the semi-confined aquifer (0-30 m)
connected with lagoon waters presents significant enrichment in 226Ra and
SESSIONE T04
222Rn (c.a. 35 Bq/m3 and 1300 Bq/m3), and may be considered as an
additional source to generate the required excess. Groundwater fluxes
necessary to explain the observed excess in the lagoon is 2.9x105 and
3.15x105 m3.d-1, based on 226Ra and 222Rn mass balance respectively.
Other similar works are in progress in Minorca island (Spain). Parameters that
may explain the observed differences in magnitude of SGD in various
Mediterranean environments are not yet well understood. Explaining discrepant
SGD estimations according to different methods still require some
investigations.
T04-7 Orale
Del Negro, Paola
CARBON FLUXES IN THE WATERS OF THE LAGOON OF VENICE: IS THE
PLANKTOIN SYSTEM NET AUTOTROPHIC OR HETEROTROPHICPUGNETTI Alessandra 1, DEL NEGRO Paola 2, GIANI Michele 3, ACRI Francesco 1,
BERNARDI AUBRY Fabrizio 4, BERTO Daniela 3, LARATO Chiara 2
1 - CNR - Istituto di Scienze Marine (ISMAR), Castello 1364/A, I-30122 Venezia
Trieste
3 - ICRAM - Brondolo, I-30015 Chioggia (VE)
4 - CNR - Istituto di Scienze Marine (ISMAR), Castello 1364/A, I-3012 Venezia
Key terms: plankton; carbon fluxes; Venice Lagoon
In this work we analyze the most important carbon processes of the plankton
community (primary production, bacterial production and community
respiration) in the waters of the Lagoon of Venice, with the main objective of
defining the importance and the significance of the planktonic and
microbial-mediated carbon fluxes and their seasonal variations. In particular we
aim at elucidating: (i) the prevalent autotrophic or heterotrophic nature of the
base of the planktonic food web; (ii) the net metabolism of the plankton
system (iii) the strength of the phytoplankton-bacteria coupling (iv) the
relations between organic carbon and bacterial activity. Seasonal samples at
three plankton-dominated sites have been carried out during 2005, in the
framework of the II CORILA Research Program (2004-2006). Our results
evidenced the importance of the heterotrophic compartment in the functioning
of the plankton system in the lagoon. Indeed, bacteria production has a similar
or even higher importance than primary production and, therefore, the base of
the planktonic trophic web may be prevalently heterotrophic. Moreover, the
plankton community respiration is mostly prevalent over phytoplankton
production and the planktonic system represents, therefore, a source rather
than a sink of CO2. The non-planktonic dissolved organic carbon is necessary
for the whole planktonic community since bacteria carbon requirements are
only very partially satisfied by phytoplankton production. The bacteria
metabolism appears, indeed, mainly addressed towards enzyme production and
catabolic activity. The organic carbon that may be mobilized from the dissolved
and particulate pools through bacterial exoenzymatic activity seems sufficient
to meet their C requirements for maintenance and growth. We estimated that
the bacteria community, on the average, could recycle the pool of DOC in three
days.
The prevalence of a net-heterotrophic metabolism of the plankton system
agrees with the estimate carried out for the whole lagoon in the framework of
the LOICZ (Land-Ocean Interactions in the Coastal Zone) activities and based
on the nutrient budget. All the studies carried out on the autotrophic
components of the lagoon evidenced, in the last 20 years, marked changes in
the biomass and production of the whole autotrophic compartment and, in
particular, the reduction in the frequency and intensity of phytoplankton
blooms. These changes could be attributed to an increase in water turbidity,
related to increased sediment resuspension, by clam harvesting and sediment
management. In these conditions the relative importance of the heterotrophic
processes might have increased. Most aspects concerning the heterotrophic
compartment and the qualitative and quantitative aspects of the organic carbon
are, at present, largely neglected in the on-going lagoon monitoring activities
and management plans. The currently measured parameters (chlorophyll a and
microphytoplankton abundance), although of basic importance, leave largely
incomplete the information necessary to define the trophic state of the lagoon
and its natural and anthropogenic evolution.
T04-8 Orale
Azzoni, Roberta
BIOGEOCHEMICAL PROCESSES AND WATER QUALITY IN TWO CANALS
IN THE URBAN CENTRE OF VENICE
AZZONI Roberta 1, NIZZOLI Daniele 1, BARTOLI Marco 1, MARCOMINI Antonio 2,
VIAROLI Pierluigi 1
1 - Dipartimento di Scienze Ambientali Università degli Studi di Parma
2 - Dipartimento di Scienze Ambientali Università Cà Foscari di Venezia
Key terms: organic matter; sediment; nutrient recycling; sulphate reduction;
denitrification
Canals in the urban centre of Venice receive an high untreated sewage load
from the surrounding human settlements. Organic and nutrient loadings are
expected to influence biogeochemical processes occurring in the sediment and
in the water column, with further impacts on water quality.
This study aimed at analysing physical and chemical characteristics of water
column and sediments in two canals, under different tidal conditions in summer
and winter. The biogeochemical transformation and reduction of the organic
load were also assessed. Dissolved inorganic and organic nutrient
concentrations in the water column were determined over a day-night cycle.
Organic carbon mineralization, denitrification (Dt), nitrate ammonification
(DNRA) and sulphate reduction (SRR) rates and inorganic nutrients fluxes were
measured both in the water column and at the water-sediment interface.
The great sedimentary organic matter fuelled high bacterial mineralization
rates (up to 8 mmol C m-2 h-1), mainly through anaerobic metabolism. SRR
accounted for up the 95% of total mineralisation rates, whilst Dt and DNRA
represented only a small fraction of organic carbon respiration. The relative
importance of Dt and DNRA differed between season, with DNRA resulting in up
to 60% of nitrogen recycling in summer. Overall sediment metabolism
63
accounted for about 60% of organic matter mineralization of the whole system
(sediment and water column) but had a low capacity to dissipate the nutrient
load which was mainly recycled to the water column as ammonium and
reactive phosphates.
T04-9 Orale
Rizzetto, Federica
GEOLOGICAL SETTING OF THE VENICE LAGOON AND ITS
SURROUNDINGS
RIZZETTO Federica 1, TOSI Luigi 1, BRANCOLINI Giuliano 2, ZECCHIN Massimo 2,
DONDA Federica 2, BARADELLO Luca 2
Italy
2 - Dipartimento di Geofisica della Litosfera - Istituto Nazionale di Oceanografia
e di Geofisica Sperimentale - OGS, Sgonico (Trieste), Italy
Key terms: Geological evolution; stratigraphic setting; Late Pleistocene;
Holocene; Venice Lagoon
The knowledge of geological and depositional setting, sedimentological and
stratigraphic characteristics, and geomorphological features of the Venice
Lagoon has been updated using data recently acquired in the framework of
CARG and Co.Ri.La. 3.16 Research Line Projects. In particular, the
investigations allowed the geological mapping of the lagoon, the nearby
mainland, and the littoral sector and pointed out the reconstruction of their
evolution.
Deposits down to 100 m deep, referred to the Late Pleistocene and the
Holocene, were investigated and according to the rules established by the
Agency for Environmental Protection and Technical Services the Unconformity
Bounded Stratigraphic Units were used to classify the Venetian Units (Rizzetto
et al., 2006). The most ancient recognized stratigraphic unit is the Correzzola
Unit that corresponds to the uppermost part of the Venice Supersynthem and
identifies the last Tyrrhenian marine transgressive event. An unconformity,
dated about 110 kyr BP, evidences the transition to the overlying alluvial
deposits of the Mestre Supersynthem, accumulated until the end of the Last
Glacial Maximum. The top of the Mestre Supersynthem, dated about 18 kyr BP,
is marked by a regional unconformity due to deposition-starved conditions,
occurred between the Upper Pleistocene and the Lower Holocene and
responsible for a stratigraphic gap spanning from 8 to 13 kyr; at the top of this
unit the finding of an overconsolidated silty-clay layer (caranto) is frequent.
The Po Synthem, representing the Holocene sequence composed of alluvial,
deltaic, littoral, and shelf sediments, shows the typical wedge-shaped
architecture containing transgressive and highstand deposits.
The Po Synthem is divided into two units, the Torcello Unit and the Malamocco
Unit. The Malamocco Unit represents the most ancient part of the Po Synthem.
Basal deposits are composed of marine sediments in the central-east area and
alluvial-deltaic in the western one. The former reflect the landward migration of
the coast due to the Post Glacial transgression and the related presence of a
back-barrier lagoon, whose deposits interdigit with layers of fluvial/deltaic
environment toward the mainland. Transgressive sediments are buried under
those from coastal progradation related to sea level highstand. Transgressive
and prograding units generate a sandy-clayey body that thins out towards the
NW. Seaward, littoral-shelf transition facies are present; they are completely
replaced by shelf sediments offshore. The top layers of the Malamocco Unit are
of Late Roman Age and show evident signs of pedogenesis, indicating
conditions of subaerial exposure. The Torcello Unit, corresponding to the
uppermost and most recent part of the Po Synthem, refers to the post-Roman
sedimentation, started from V-VI century A.D. and ended with the present. Its
base reflects deteriorated climatic conditions that, from IV-VI century A.D.,
caused a significant increase in rainfall, and therefore in flooding, and probably
even a sea level rise responsible for a partial submersion of the lagoon area.
This occurrence is often proved by the presence of lagoon deposits lying above
the anthropogenic levels of the Roman Age. In the mainland the bottom
boundary of the Torcello Unit coincides with yellowish-brown and
reddish-brown soils, characterized by partial or total decarbonatation in surface
horizons and accumulation of carbonates in the deeper ones.
Acknoledgements
CARG (Veneto Region, APAT) and Co.Ri.La. 3.16 Research Line Projects are
acknowledged.
References
RIZZETTO F., TOSI L. & TOFFOLETTO F. (2006) - The new stratigraphic units of
the Venice Lagoon Geological Map. Proceedings of the 5th European Congress
on Regional Geoscientific Cartography and Information Systems, Barcelona,
June 13th to 16th, 2006, vol. 2, 143-145.
T04-10 Orale
Brancolini, Giuliano
PRELIMINARY RESULTS OF VERY HIGH RESOLUTION SEISMIC
SURVEYS IN THE VENICE LAGOON
BRANCOLINI Giuliano 1, TOSI Luigi 2, BRADELLO Luca 1, BRATUS Antonio 1, DONDA
Federica 1, RIZZETTO Federica 2, ZECCHIN Massimo 1
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale
2 - Istituto di Scienze Marine-CNR
Key terms: Venice; Lagoon; Seismic; Holocene; Sediments
New Very High Resolution Seismic (VHRS) surveys, integrated with available
coring data, have been used to investigate the recent (Late Pleistocene and
Holocene) setting of the Venice Lagoon in the frame of the Co.Ri.La. research
line 3.16. The survey was carried out in the most representative areas:
a)The shelf off the Lido inlet, well characterized by the Trasgressive Systems
Tract (TST) at the base of the Holocene and the overlying Highstand Systems
Tract (HST) prograding toward the open sea. Seismic grid off the Lido inlet
detected and characterized a like-delta shape morphological feature that has
been interpreted as an ebb-tidal delta, produced by sediments eroded from the
lagoon and transported through the inlet by the tide. The internal geometry
and the elongate shape of the ebb-tidal delta testify the interplay between the
tide and the North Adriatic along-shore current. Comparing maps of the
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64
ebb-tidal delta produced by the seismic survey with some historical
bathymetric maps, we calculated a depositional rate of 5 cm/year for the last
120 year.
b) Lido and Chioggia inlets. An highly dynamic environment is testified by the
active erosion that has produced trenches more than 40 m deep in the inner
part of the inlets and by the asimmetry of the Holocene deposits inside the
inlets. The Lido and Chioggia inlets underwent important human interventions
starting from the end of the XIX century. The thickness of the recent sediments
in the Lido inlet shows a relevant asymmetric distribution: more than 12 m
near the northern side of the inlet and less than 1 m, up to zero, in the
southern side. The setting of Holocene deposits in the Chioggia inlet is exactly
the opposite: the higher thickness has been measured in the southern side (up
to 7 m), whereas sediments are eroded or not deposited on the northern side
of the inlet.
c) The lagoon shallows, carachterized by lateral variability of the deposits,
mainly produced by the tidal channels migration. Based on the new data, it has
been possible, for the first time, to represent and map the three main phases
that characterize the formation and the evolution of the lagoon: i) the marine
ingression between 10,000 and 6,000 years B.P. that produced the submersion
of the previous alluvial plane by the Adriatic Sea; ii) the following high stand of
the sea level, that records the predominance of sediment supply from rivers
that caused the progressive advance of the coastline toward the sea; and
finally iii) the predominance of the erosion and transport of sediments from the
lagoon to the sea, consequence of the rivers diversion operated by humans
since historical time.
These distinct phases are associated to sedimentary deposits with different
geotechnical, sedimentological, and geochemical characteristics, that play
different roles in the erodibility of the sea floor and in the hydrogeological
regime, as testified by the sub-merged littoral belts in the southern lagoon,
already recognized from the bathymetric surveys, but much better defined in
the new seismic images, or by the paleo-channel network, filled by more recent
sediments.
T04-11 Orale
Donnici, Sandra
ACOUSTIC SURVEY IN VERY SHALLOW WATER: PALEOENVIRONMENTAL
RECONSTRUCTION IN THE VENICE LAGOON
DONNICI Sandra 1, MADRICARDO Fantina 1, LEZZIERO Alberto 2, DE CARLI
Federica 2, BERTANI Barbara 3, BIOTTO Giancarlo 3
1 - Consiglio Nazionale delle Ricerche - Istituto di Scienze Marine
2 - Pharos sas
3 - Magistrato alle Acque, Consorzio Venezia Nuova, Servizio Informativo
Key terms: acoustic survey; very shallow water; core sampling;
geomorphological reconstruction
During the last three years, an extensive acoustic survey was carried out on
geo-archaeologically interesting areas in the central and northern Venice
Lagoon. The purpose of the project, called ECHOS, was to explore the
Holocenic sedimentary record that includes origin and development of the
Venice Lagoon. ECHOS is part of a Magistrato alle Acque project in these
lagoon areas which includes the archaeological project ALPHA and the archive
project CLIO.
More than 45 km2 in the central and northern part of the lagoon were explored
with high resolution for the first 5-7 meters of depth in the subbottom. Such an
extensive acoustic investigation of lagoon sediments has been systematically
carried out for the first time in extremely shallow water, with water levels
ranging from about 0.5 m to about 5 m. A total of 2200 km of survey tracks
were covered. For this purpose, a traditional 30 KHz echo sounder was
modified for use in very shallow water. Although we sometimes operated with
50 cm of water level or less, experimental proofs show that the far field
approximation is accurate. To obtain the greatest detail within the capability of
the instrumentation employed, the survey field was organized in parallel lines
using a dedicated software.
The acoustic method used gave indications of the subbottom layer content over
wide areas and provided an extremely useful guide for selection of sample sites
for coring. Mapping of the acoustic anomalies provided information for the
palaeoenvironmental reconstruction of the entire area.
In order to acquire palaeoenvironmental information about the morphological
structures identified by the acoustics, ground truth sediment cores were
extracted. Their geographic positions were determined through a DGPS system,
while their lengths varied between 8 and 9.1 m, for all the structures identified
by the acoustic data to be intersected. Cores were drilled inside and outside the
morphological structure identified. Descriptions of the stratigraphic succession
and sedimentary structures, micropalaeontological analysis and 14C analysis
were employed for the reconstruction of the environmental development of the
area.
The geological data confirmed the results of the acoustic investigations. The
paths of buried lagoon canals and the extension of several palaeosurfaces were
identified by correlating the acoustic and geological data. Core analysis showed
anthropic traces in some of the identified paleosurfaces.
All acoustic anomalies, the identified morphological structures and survey
tracks have been imported in a GIS (Geographic Information System) and
implemented with specific attributes. The GIS environment is extremely useful
to correlate all the data coming from the different projects ECHOS, ALPHA and
CLIO.
T04-12 Orale
A direct implication of this simple morphological rule is that the wide variability
of aeolian coastal forms in a same geographical context (as blowouts, parabolic
dunes, etc.) can be easily used to infer the accretionary or retreating history of
the shoreline. The time-scale of application is broad, from one year to thousand
years, but not so much is know about the influence of wind regime, mainly
when significant variation can occur in wind strength, responsible for the
sediment transport towards the dunes. The northern Adriatic sandy coast was
significantly affected by human activities such as reclamation, tourist
settlements and construction of long jetties at the inlets and river mouths.
What remains of the ancient dunes along with historical documents testify that
recent foredunes are generally of reduced size in comparison with those
reported in the first half of the last century. Causes are firstly due to the
sedimentary negative budget which has being affected this coastal zone
following fluvial inputs reduction. In addition, a progressive decrease of high
energy ENE Bora wind frequency seems to have contributed to the observed
morphological changes. Decrease of wind transport capability has been
predicted as one of the main factors affecting the limited development of the
present dunes, not exceeding 4-m-height. Experimental data on dunes
morphology from an accretionary area (Ca' Roman, Venice lagoon) seem to
confirm this hypothesis. The Ca'Roman beach is located at the southern tip of
Pellestrina island and is characterized by a parallel series of dune ridges, with a
important vegetation succession for the geographical context, recently included
in pSIC. The present morphological structure is the result of a continuous
beach accretion, documented since the end of the first phase of the
construction of the jetties of the Chioggia inlet, in 1911. The wind regime
appears particularly favourable as the exposure is onshore with respect to Bora
wind. The direct human impact is considerably reduced, above all because of
the natural isolation of the area. The beach area and the dunes have been
subject to a monitoring field survey during one year, including a detailed
topographical and morphological survey along 4 transects, the anemological
data analysis, the comparison of historical maps and aerial photographs. The
data collection and analysis have allowed to reconstruct the dune system
evolutionary history: 8 foredunes formed since 1955, with an overall
decreasing trend of the dune crest seawards. Each dune can be easily dated at
the time of its formation, by shifting the present shoreline-dune crest distance
at the different former position, until the superimposition with the ancient form
is obtained. Each position was further controlled using historical maps and
air-photos. Wind data from Cavanis Institute, Venice were also used to obtain
the time-series of eolian transport potential (Qpot), calculated by the product
of frequency and cubic speed (Fv 3). The cumulative Qpot calculated from the
formation of each dune until the appearance of a new foredune seaward, can
represent an useful index of the aeolian activity, responsible for the growth of
the dune.
Data indicate that the ratio Qpot/shoreline accretion is well correlated to the
dune elevation and volume. Despite a significant accretion of the beach, the
ancient dunes grew up to 6 m, according to the high cumulative Qpot recorded
until the end of 1980's.
Considering the different evolutionary trend of the northern Adriatic beaches,
and the secular wind time-series, the highest elevation of the ancient dunes
can thus be associated mainly to a stronger wind regime. As a general rule,
reciprocal effects of Qpot and beach accretion rate should be taken into
account in order to infer the potential of dune construction.
T04-13 Orale
Sarretta, Alessandro
SEDIMENTOLOGICAL VARIABILITY AND BATHYMETRIC CHANGES OF
THE LAGOON OF VENICE IN THE LAST 30 YEARS
SARRETTA Alessandro 1, MASIOL Mauro 2, PISTOLATO Mario 2, MOLINAROLI
Emanuela 2, GUERZONI Stefano 1
1 - CNR - Istituto di Scienze Marine, Venezia
2 - Università Ca' Foscari, Venezia
Key terms: sediment; bathymetry; lagoon; venice; grain size
A detailed comparison of the textural variations of sediments with bathymetry
was done, by comparing the grain size compositions of bottom sediment
collected in the Lagoon of Venice in the years 1970 (GEOMIN) and 2000
(UNISMAR). In this 30-year period the whole Lagoon underwent significant
bathymetric variations, with an average deepening of ~0,15 m. Input and
navigation channels were not included in the comparison, that was done on
samples collected in Lagoon beds only. The average depth of GEOMIN samples
was 0.8 m (range 0.2/1.8) whilst UNISMAR sediments were collected at water
depths between 0.2 and 2.2 m of (average 1 m).
Sediment samples from 1970 showed a very low percentage of sand (5-25%)
in the northern part and in two areas along the inner part of the central and
southern Lagoon. On the contrary, the sediments from 2000 showed higher
percentage of sand (50-75%) mainly in the southern Lagoon. Silty fraction
from 1970 to 2000 decreased in the whole Lagoon, particularly in the southern
part and in the central one, near the city of Venice. A textural classification of
the sediment, following Flemming (2000), highlighted that the sediments of the
whole Lagoon shifted from prevailingly muddy and slightly sandy mud to
muddy sand and slightly muddy sand in the latest sampling.
In order to obtain a more detailed comparison of grain-size data the entire
Lagoon has been divided into four groups, according to bathymetric variations,
as follows: (1) strong erosion (difference 2000-1970 = dz -0.5 m); (2)
moderate erosion (-0,5m<dz<-0,1 m); (3) stability (-0,1m<dz<+0,1 m); (4)
Bezzi, Annelore
FOREDUNE GROWTH AND IMPLICATION FOR BEACH MORPHODYNAMIC
STAGES AND DECENNAL WIND REGIME VARIATION
FONTOLAN Giorgio 1, BEZZI Annelore 1
1 - Università degli Studi di Trieste, DISGAM, Coastal Group
Key terms: foredune; wind regime; accretionary beach; north Adriatic; Venice
The classical model for beach-dune interaction indicates that foredune volume
is strongly related to the beach sedimentary budget.
moderate sedimentation (dz +0,1 m). The average dz of the four groups
were -0.8 m, -0.25m, -0.01m and +0,25 m, respectively. Strong and
moderate erosion affected mainly the central Lagoon, stability was found in the
northern part and sedimentation occurred in various areas around eroded
marshes and in the inner (confined) part of the Lagoon. The comparison of
various sediment type within the four groups showed evidences that all groups
were depleted in fine-grained fractions (silt and clay) and resulted to be
-conversely- enriched in sand fraction. On average, there was a loss of ~ 8 %
of silt (63-4 µm) and 2-3 % of clay (<4µm) and the enrichment of the sandy
part (>63 µm) was 10-11 %. Within the silt the most "mobile" fractions
resulted the fine part (4-22 µm) for "moderate erosion" and "stability" groups
and the coarse one (15-63 µm) in the part of the Lagoon with the highest
SESSIONE T04
bathymetric differences between 1970 and 2000. The mechanism proposed to
explain the textural variations is the loss of all fractions for the group 1 and of
the fraction < 22µm for group 2. Stability occurred in group 3 by replacement
of 10% of fine-grained silt with sand, whilst the sedimentation was mainly due
to marshes erosion.
Budget calculations were tentatively done in order to estimate the amount of
sediments displaced inside the Lagoon, together with the part definitively lost
in the studied period, but the sampling density (1 sample every 2-3 km2)
prevented the possibility of providing detailed figures. In general, data have
been published with average yearly annual sediment loss of 500-1000 +10^6
m3, which are compatible with our budget calculations of an intertidal
compositional change of 20, 50 and 30% of sand, silt and clay respectively. A
deeper and sandier Lagoon was thus produced, with significant effects on
habitat composition and basin ecology.
T04-14 Orale
Lezziero, Alberto
GEOARCHAEOLOGICAL INVESTIGATIONS IN VENICE LAGOON:
PALAEOENVIRONMENTAL RECONSTRUCTION OF THE NORTHERN BASIN
IN ROMAN AND LATE ANTIQUITY AGE.
LEZZIERO Alberto 1, FOZZATI Luigi 2
1 - PHAROS s.a.s., Venezia
2 - NAUSICAA - Soprintendenza Archeologica per il Veneto, Venezia
Key terms: roman archaeological sites; palaeoenvironmental reconstruction;
geoarchaeology; Venice Lagoon; antique sea level oscillations
Geoarchaeological investigations was carried out in the city of Venice and in
Venice Lagoon during the last decades with the aim of reconstructing
environmental changes that controlled human settlement in the area.
The presence of buried archaeological sites in the sea subbottom is therefore
correlated to particular marine environmental situations, so their detection and
unearthing also help to improve the knowledge of the geomorphological
evolution of the area as well as to yield new evidence on trends in sea-level
change for the Lagoon of Venice. In fact, The great availability of
archaeological data permitted to study relative sea level oscillations during
about the last 2000 years by evaluating how much ground level had to be
modify following the mean sea level rise trough the centuries.
Archaeological studies gave as a result hundreds of ancient sites found and
antique remains can be buried in lagoon deposits at different depth or, in some
cases, they can lie on the lagoon bottom or on the surface of islands.
The sediments found in these sites were studied by quaternary geology
methods in order to discover the ancient environment and the
post-depositional processes that controlled their buring dynamics.
In particular, core sampling executed in roman or late antiquity sites in
Northern Basin and sedimentological, palaeocological and 14C analyses
demostrate that the lagoon landscape was different from the recent
environment. Salt marshes and salt swamps occupied the area that now
represents the lagoon inner margin and the emerged sites occupied wider
areas in the whole northern basin. In the study area the roman period was
proper to human settlements because of the suitability of emerged lands.
These statements are confirmed by historical data.
At the end of the roman imperial/late antiquity age the whole studied sites are
covered by lagoon deposits that indicates a period of positive sea level
oscillation and a human settlements gap.
The basin circulation was deeply modified by human intervention in the
following centuries, in particular starting from XIV century, till the present days
and that artificial process causes increases of land sinking. These sites are now
buried by a few meter thick lagoon deposits and represent an important
archaeological marker for the northern Venice Lagoon basin.
T04-15 Poster
Cossarini, Gianpiero
POTENTIAL IMPACTS OF VARIATIONS IN PRECIPITATION REGIMES
CAUSED BY CLIMATIC CHANGES: EFFECTS ON THE BIOGEOCHEMICAL
PROPERTIES OF THE LAGOON OF VENICE
COSSARINI Gianpiero 1, LIBRALATO Simone 1, SALON Stefano 1, SOLIDORO
Cosimo 1
1 - OGS
Key terms: biogeochemical model; Climate change; Venice lagoon
Nutrient loadings are among the most influential forcing in coastal and
estuarine ecosystems. Climatic changes can induce variations of precipitation
patterns and might substantially modify river runoff and nutrient loading.
Changes in terms of amount and timing can affect water quality of coastal
ecosystems. This study aims at assessing the potential impact of changes on
seasonal precipitation pattern on biogeochemical proprieties in the lagoon of
Venice, where spatial distributions and time variability of biogeochemical
proprieties are clearly influenced by river runoff and lagoon-sea exchanges.
We implemented a downscaling experiment, which involves four components: a
regional climate model (RegCM) providing inputs for two statistical models that
gave boundary conditions for a coupled transport-biogeochemical model (TDM)
of the lagoon.
Outputs of the RegCM provided high-resolved meteo data for the drainage
basin of the Venice lagoon organized in three multidecadal data sets, relative to
a present-day climate (1961-1990, RF), and two future scenarios (2071-2100,
A2 and B2). RF data relative to the area of interest were validated against
several climatologies. A statistical logarithmic regression model between annual
nutrient loads and observed precipitation was calibrated using historical data
and was used to provided annual loads from RegCM output. A climatological
annual evolution of nutrients and phytoplankton concentrations at the
lagoon-sea boundaries was modulated according to seasonal precipitation of
RegCM output and a regression model based on historical data. Finally TDM
was used to simulate trophodynamics in the lagoon. The model state variables
are inorganic nutrients, phytoplankton and zooplankton concentrations and N,
C and P contents in detritus and in sediment. Transport is described in term of
65
pure turbulent diffusion, inhomogeneous and anisotropic diffusion tensors
parametrize the tidal mixing. Model boundaries are taken from the two
statistical models and directly from RegCM output for meteorological
conditions. The TDM model was corroborated using experimental data of
2001-2003 period.
The projections of future climate simulated by the two RegCM scenarios, A2
and B2, show both a strengthening of the seasonal dynamics, resulting in more
precipitation during the rainy season (autumn) and in less precipitation during
the dry season (summer) with respect to the present-day situation (RF).
The impact of these variations on biogeochemical proprieties was assessed
comparing the present-day TDM forced by RF run, with TDM A2 and B2-forced
scenarios. Changes of the rain regime implied a seasonal variation of nutrient
loads characterized by a mean decrease in spring and summer (more intense in
A2 than in B2), and an increase in winter and autumn. As a consequence, the
mean level of DIN (sum of NH4 and NOx) during winter and autumn was higher
in future scenarios than in the present-day run. Such a surplus of nutrients was
not utilised in the system and resulted in an increase of nutrients export to
Adriatic Sea.
In spring and summer the decrease of nutrient loads implied a decrease of
nutrient concentrations in the system. Under A2 scenario such reduction
caused a widespread decrease in the productivity of system. The number of
years characterized by very dry summer increased of about 20% with respect
to the RF run. In B2 scenario, the decrement of nutrient content did affect
neither mean seasonal phytoplankton biomass nor primary production, but had
a strong impact on secondary production, that decreased by 10% during
summer.
Climate predictions showed a strengthening of seasonal dynamics and the
decrease of summer precipitation would affect biogeochemical proprieties of
the systems: and a productivity reduction of the system would be expected.
Such an effect was amplified and more easily recognized in the higher trophic
level of the ecosystem.
T04-16 Poster
Teatini, Pietro
LAND SUBSIDENCE IN THE VENICE LAGOON BY ERS AND ENVISAT SAR
INTERFEROMETRY ON NATURAL AND ARTIFICIAL POINT TARGETS
TEATINI Pietro 1, STROZZI Tazio 2, TOSI Luigi 3, WEGMÜLLER Urs 2, WERNER
Charles 2, CARBOGNIN Laura 3, CECCONI Giovanni 4, ROSSELLI Roberto 5
1 - Dept. of Mathematical Methods and Models for Scientific Applications,
University of Padova,Padova, Italy
2 - Gamma Remote Sensing, Gümligen, Switzerland
3 - Institute of Marine Sciences, National Research Council, National Research
Council
4 - Consorzio Venezia Nuova, Servizio Ingegneria, Venice, Italy
5 - Sistema Informativo, Venice Water Authority, Venice, Italy
Key terms: Land subsidence; Venice Lagoon; Interferometric Point Target
Analysis; ERS; ENVISAT
The Venice Lagoon, Italy, is a unique worldwide environment which is presently
vulnerable due to loss in surface elevation as a result of land subsidence
referred to the mean sea level.
Land displacements in the Venice coastland have been determined over time by
traditional monitoring techniques (i.e., spirit leveling and GPS). Recently,
SAR-based analyses have been used to complement the ground-based
methods. Interferometric analysis on persistent point targets (IPTA) (Werner et
al. 2003; Wegmülle et al., 2004) has been proved to be very effective in
detecting land displacement in the Venetian coastal environment (Teatini et al.,
2005; 2007; Tosi et al., 2002).
ERS SAR and ENVISAT ASAR images spanning the time period 1992-2005 and
2003-2006, respectively, processed at regional and local scale and on "natural"
as well as "artificial" reflectors provided an updated image of the vertical
movements of the Venice Lagoon. Unfortunately, there are some parts of the
Venice Lagoon where anthropogenic structures completely lack (e.g., in the
inner lagoon). In order to fill this gap of IPTA application, about 50 artificial
square trihedral corner reflector (TCR) have been established in the first
semester of 2007.
The natural processes and the human interventions in the Venice Lagoon may
induce in the near future time dependent land movements at the local and
lagoon scales which will require a highly accurate monitoring. The continuity of
the ENVISAT functioning is of paramount importance to supply a future reliable
land subsidence monitoring service in the Venice coastland.
Acknowledgments
This study is supported by the Venice Water Authority.
References
Teatini, P., Tosi, L., Strozzi, T., Carbognin, L., Wegmüller, U. & Rizzetto, F.
(2005). Mapping Regional Land Displacements in the Venice Coastland by an
Integrated Monitoring System, Remote Sens. Environ., 98(4), 403-413.
Teatini, P., Strozzi, T., Tosi, L., Wegmüller, U., Werner, C. & Carbognin, L.
(2007). Assessing Short- and Long-time Displacements in the Venice Coastland
by Synthetic Aperture Radar Interferometric Point Target Analysis, J. Geophys.
Res., 112, F01012, doi:10.1029/2006JF000656.
Tosi, L., Carbognin, L., Teatini, P., Strozzi, T. & Wegmüller, U. (2002).
Evidence of the Present Relative Land Stability of Venice, Italy, from Land, Sea,
and Space Observations, Geophys. Res. Lett., 29(12),
doi:10.1029/2001GL013211.
Werner, C., Wegmüller, U., Strozzi, T. & Weismann, A. (2003). Interferometric
Point Target Analysis for Deformation Mapping. In 'IGARSS 2003', Vol. VII, pp
4362-4364.
Wegmüller, U., Werner, C., Strozzi, T. & Wiesmann, A. (2004). Multi-temporal
Interferometric Point Target Analysis. In 'Analysis of Multi-Temporal Remote
Sensing Images' (Eds. P. Smits & L. Bruzzone), World Scientific, Series in
Remote Sensing, Vol. 3, pp 136-144.
T04-17 Poster
Rizzetto, Federica
THE SHEETS 128 "VENEZIA" AND 148-149 "CHIOGGIA-MALAMOCCO"
OF THE NEW GEOLOGICAL MAP OF ITALY
SESSIONE T04
66
TOSI Luigi 1, RIZZETTO Federica 1, BONARDI Maurizio 1, DONNICI Sandra 1,
SERANDREI BARBERO Rossana 1, TOFFOLETTO Federico 2, CAMPANA Riccardo 2
Italy
2 - Regione del Veneto, Direzione Regionale Geologia e Attività Estrattive,
Venezia, Italy
Key terms: Geological maps; UBSU; Venice and Mestre Supersynthems; Po
Synthem; Venice Lagoon
The new geological survey and mapping of the areas included in the Sheets
128 "Venezia" and 148-149 "Chioggia-Malamocco" of the 1:50,000 scale
topographic map series were recently realized within the framework of the
CARG Project, led by the Agency for Environmental Protection and Technical
Services (APAT, formerly Italian Geological Survey) and aimed to investigate
and show age, distribution, sedimentological characteristics, and depositional
environments of the stratigraphic units outcropping and buried in the whole
Italian territory.
The Geological Maps result from the analysis and interpretation of thousands of
geological, geomorphological, sedimentological, mineralogical, paleontological,
and geophysical data and information obtained from multidisciplinary
investigations. In particular, photo-interpretation, remote sensing, geological
and geomorphological in situ surveys (including hundreds of drillings from 1 to
100 m deep), very high resolution seismic investigations, and laboratory
analyses on the collected samples (detailed stratigraphic descriptions,
micropaleontological and mineralogical analyses, radiocarbon dates) were
performed exclusively for this Project.
Core samplings were mainly focused within the upper 20-30 m of subsoil,
representative of units deposited at the end of the Last Glacial Maximum (LGM)
and during the Holocene. Anyhow, interpretation of data deriving from two new
100 m-deep drillings and their correlation with those obtained from other
existing very deep cores allowed a view of the stratigraphic setting and
sedimentological characteristics of the Upper Tyrrhenian deposits.
According to the rules established by APAT to represent the Quaternary
deposits, the "Unconformity Bounded Stratigraphic Units", defined on the
presence of two evident, demonstrable, and significant discontinuities, were
used to classify the different sedimentary bodies, distinguished on the basis of
their age, grain size, depositional environment, and bounding unconformities.
The Mestre Supersynthem, whose top is dated about 18,000 years BP, is the
most ancient stratigraphic unit mapped on the 1:50,000 scale Geological Maps
and represents the Upper Pleistocene alluvial deposits accumulated until the
end of the Last Glacial Maximum.
The Po Synthem, composed of Holocene sediments of alluvial, deltaic, lagoon,
beach, and shelf environments, lies on the Mestre Supershyntem and is
separated from it by an unconformity representative of a period of much
reduced sedimentary supply or "non depositional" conditions, occurred before
the beginning of the Holocene transgression. This hiatus between the Late
Pleistocene and the Holocene sedimentation ranges from 8,000 to 13,000 years
because the age of the Po Synthem bottom varies from about 10,000 to 5,000
years BP.
On a chronological basis the Po Synthem has been divided into two units, the
Torcello Unit, composed of post-Roman deposits accumulated from V-VI
century A.D. to the present, and the underlain Malamocco Unit, whose lower
boundary corresponds to that of the Po Synthem.
The Geological maps give also evidence of the main geomorphological features
that characterized the examined territory, in particular abandoned riverbeds,
ancient beach ridges, old lagoon channels and inlets, and fluvial ridges.
Noticeable grain size variability characterizes all the surface and deep deposits:
therefore only four lithologic classes were mapped, i.e. sand, silt, clay, and
peat; sediments having mixed composition were ascribed to one of them on
the basis of their prevailing component.
All these different kinds of information were reproduced using both different
symbols and colours in order to allow a simple and clear comprehension of the
Geological maps.
Acknowledgements
This work was performed in the frame of the CARG Project, with financial
supports from APAT and Veneto Region.
T04-18 Poster
Tosi, Luigi
CHARACTERIZATION OF THE PO SYNTHEM BASE IN THE SHEETS 128
"VENEZIA" AND 148-149 "CHIOGGIA-MALAMOCCO" OF THE NEW
GEOLOGICAL MAP OF ITALY
RIZZETTO Federica 1, TOSI Luigi 1, BRANCOLINI Giuliano 2, BARADELLO Luca 2,
DONDA Federica 2, FANZUTTI Francesco 2, ZECCHIN Massimo 2, TOFFOLETTO
Federico 3, CAMPANA Riccardo 3
1 - Institute of Marine Sciences, National Research Council, Venice, Italy
2 - National Institute of Oceanography and Experimental Geophysics, Sgonico,
Trieste, Italy
3 - Veneto Region, Department of Geology and Extraction Activities, Venice,
Italy
Key terms: Po Synthem base; Venice Lagoon; Geological Map; VHRS survey;
Pleistocene/Holocene boundary
The base of the Po Synthem in the Venetian coastal plain represents the
stratigraphic boundary between the Pleistocene and the Holocene deposits. In
the sheets 128 "Venezia" and 148-149 "Chioggia-Malamocco" of the new
Geological Map of Italy it was represented at 1:50,000 scale (Tosi et al. 2006a,
2006b, 2006c).
The mapping of the Po Synthem bottom resulted from the analysis of hundreds
of stratigraphic, sedimentological, and radiochronological data from cores
aimed to identify the boundary it from the underlain Mestre Supersynthem; the
investigations were supplemented by the interpretation of more than 400 km of
very high resolution seismic survey carried out in the Venice lagoon channels
and near/offshore.
Dataset analysis revealed an irregular distribution of available information
because the most of the collected cores were located in sites of interest for
restoration works and safeguarding of the lagoon, in particular littoral strips,
inlets, and islands. Furthermore, regional and local variability of the depth of
the Po Synthem base was evidenced. The former is mainly related to the
morphological setting of the Pleistocene alluvial plain, whereas local variability
to the presence of paleo-riverbeds and ancient tidal channels that eroded the
Po Synthem base.
For this reason the mapping required data filtering first and then an
interpolation using a regular grid. Finally, a few adjustments were done where
the comparison with dataset and interpolated data showed high differences.
An overview of the setting of the Po Synthem related to the two maps is below
reported.
In general in the northern-western sectors of the sheets "Venezia" and
"Chioggia-Malamocco" the Po Synthem is absent (the Mestre Supersynthem is
exposed) or very thin (1-2 m thick). The Po Synthem base deepens from the
lagoon margin, 4-10 m b.s.l., to the littoral steeps, 10-20 m b.s.l.. Offshore, at
a depth of about 22 m, the Mestre Supersynthem is exposed again.
The maps show a number of linear depressions, with NE-SW and NW-SE
directions, caused by erosion due to ancient rivers. Some of these features
coincide with actual tidal channels, revealing that part of them was
superimposed on the old fluvial network, such as those located from the Lido
inlet to the Valle del Cavallino through the Treporti-San Felice Channel and
from Treporti Channel to the mouth of the Dese River throught the Burano
Channel.
The presence of zones elevated with respect to surrounding areas,
characterized by lobate shapes and attributed to ancient fluvial ridges, is also
evidenced in the maps. In some cases, they are in relation to abandoned
riverbeds found in the mainland (Motte di Volpego-Alberini; Torson di
Sotto-Litorale di Pellestrina-San Pietro in Volta-S. Antonio; Valle Pierimpiè-Valle
Millecampi-Cà Roman).
Finally, examples of high resolution seismic profiles, validated by
sedimentological investigations and showing the reflector representing the
Mestre Supersynthem - Po Synthem boundary, are provided in the maps.
Acknowledgements
This work was performed in the frame of the CARG Project, with financial
supports from APAT and Veneto Region.
References
Tosi L., Brancolini G., Baradello L., Donda F. & Rizzetto F. (2006) - Very high
resolution seismic surveys in the lagoon and gulf of Venice shallow waters.
Proc. 5th Eur. Cong. on Reg. Geo. Cart. and Info. Syst., Barcelona, 2006, 2,
156-158.
Tosi L., Rizzetto F., Bonardi M., Donnici S., Serandrei Barbero R., Toffoletto F.
(2006) - Note illustrative della Carta Geologica d'Italia alla scala 1:50.000. 128
- Venezia. APAT, SystemCart, Roma, 164 pp.
Tosi L., Rizzetto F., Bonardi M., Donnici S., Serandrei Barbero R., Toffoletto F.
(2006) - Note illustrative della Carta Geologica d'Italia alla scala 1:50.000.
Foglio 148-149 "Chioggia-Malamocco". APAT, SystemCart, Roma, 162 pp.
T04-19 Poster
Zecchin, Massimo
ANATOMY OF THE HOLOCENE SEQUENCE IN THE SOUTHERN VENICE
LAGOON SHOWN BY VERY HIGH RESOLUTION SEISMIC DATA
ZECCHIN Massimo 1, BRANCOLINI Giuliano 1, TOSI Luigi 2, RIZZETTO Federica 2,
BARADELLO Luca 1
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS,
Sgonico (TS)
2 - Istituto di Scienze Marine - Consiglio Nazionale delle Ricerche, Venezia
Key terms: Venice; Holocene; Sequence stratigraphy; Very high resolution
seismic profiles
The Venice area is part of a foreland region located between the northern
Apenninic and the eastern South-Alpine chains. The Holocene deposits of the
Venice area document the transgressive and highstand phases that followed
the Last Glacial Maximum. Three main seismic units (H1-3), separated key
stratal surfaces, were recognized in the Holocene succession accumulated in
the southern Venice lagoon.
Unit H1 is the lowermost unit of the Holocene succession, and is bounded at
the base by the Pleistocene/Holocene (Pl/Hol) boundary, which consists of a
surface of subaerial exposure. Unit H1 is formed by two sub-units (H1a and
H1b). Unit H1a is composed of curved to irregular and inclined reflectors, and
is typically characterized by an extreme thickness variability (from 0 to 12 m)
along both depositional strike and dip. The unit is interpreted as a the result of
the deposition in a lagoonal to estuarine environment. Unit H1b is recognizable
only in the seaward part of the Holocene succession, above Unit H1a, and
pinches-out landwards. Unit H1b is composed of curved and inclined reflectors
that display both onlap and downlap relationships with the H1a/H1b boundary.
The unit is interpreted as a transgressive marine deposit.
Unit H2 is placed above Unit H1, and is composed of two sub-units (H2a and
H2b) showing different seismic patterns. The top of the unit locally may
correspond with the floor of the deeper, modern tidal channels. Unit H2a is
present in the landward sector of the study area, and is composed of irregular,
curved and hummocky reflectors that may be locally similar to those present in
Unit H1a. The unit has been interpreted as the result of the deposition in an
environment that oscillated between a lagoon and a delta plain incised by
distributary channels. Unit H2b is located seaward with respect to Unit H2a,
and their lateral transition is indistinct. Unit H2b is composed of
seaward-inclined reflectors that downlap onto the H1/H2 boundary, and shows
a thickness increase from 5 to 10 m southwards. Irregular and deformed
reflectors are also present. Unit H2b is interpreted as a prograding delta front
to shoreface.
Unit H3 corresponds with the modern and recent lagoonal deposits. Unit H3
typically consists of tidal channel deposits incised in the previously accumulated
Holocene sediments, especially near the modern inlets and the barrier island.
Various inclined and irregular reflectors are recognizable within these
channelized deposits. Tidal channel deposits are shallower and less represented
landward, where they pass laterally into the tidal and subtidal flats of the
modern lagoon.
The Holocene succession of the southern Venice lagoon, therefore, shows a
discrete complexity, and its architecture is the result of the early Holocene
transgression and the following highstand phase. Unit H1 is interpretable as a
TST, placed above a sequence boundary amalgamated with a transgressive
surface. The surface that separates Units H1a and H1b is a wave ravinement
surface, that marks the base of the marine ingression. Units H1 and H2 are
separated by the maximum flooding surface, which testifies the maximum
SESSIONE T04
marine ingression (about 6 kyr B.P.); therefore, Unit H2 is interpreted as the
HST of the Holocene sequence. Unit H3 is mostly the product of a
human-induced transgression, due mainly to river diversions and limited to the
lagoon area, during the late Holocene highstand.
T04-20 Poster
Donda, Federica
THE EBB-TIDAL DELTA OF THE LAGOON OF VENICE (ITALY)
DONDA Federica 1, BRANCOLINI Giuliano 1, TOSI Luigi 2, KOVACEVIC Vedrana 1,
BARADELLO Luca 1, GACIC Miro 1, RIZZETTO Federica 2
1 - Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS)
2 - Istituto di Scienze Marine (Venezia)
Key terms: Holocene; Lagoon of Venice; High resolution seismic; tidal inlets
Tidal inlets occur along a major part of the world's sediment coastlines and
represent highly dynamic areas in terms of hydrodynamics and sediment
transport. Sediments eroded from the inlet and supplied by littoral drifts
accumulate in tidal deltas on the landward and the seaward side, constituting
the flood- and ebb-tidal delta respectively. An ebb-tidal delta is an
accumulation of sand and fine shell gravel deposited primarily by the ebb-tidal
current on the seaward site of the tidal inlet (Hayes, 1980; Davis and Hayes,
1984).
The formation of the Venice Lagoon started about 6000 years ago. Up to about
1000 A.D., its evolution was influenced by the activity of the main tributary
rivers (Adige, Bacchiglione, Brenta, Sile, and Piave), that supplied large
amounts of freshwater and sediments to the lagoon. In the last centuries, the
Lagoon's evolution was primarily induced by human interventions, in particular
fluvial diversions and channel dredging aimed at preserving the lagoon
environment. The tides are presently responsible for more than 90 % of the
total current variability in the inlet, where the maximum current amplitude may
reach 1.5 m s-1. The semi-diurnal M2 component has a major axis amplitude
of about 0.70 m s-1 (Gacic et al. 2004) accounting for more than 55 % of the
total variance. Considering the sediment transport during peak tidal events, a
clear predominance of sediment loss from the lagoon towards the sea has been
documented (Amos et al. 2005).
Several geophysical surveys have been carried out in the Venice Lagoon by
OGS in the framework of the CARG Project (Geologic map sheets 128 "Venezia"
and 148-149 "Chioggia-Malamocco") and Co.Ri.La (Consorzio per la gestione
del Centro di Coordinamento delle Attività di Ricerca Inerenti il Sistema
Lagunare di Venezia) subproject 3.16 "New very high resolution seismic
methods to study the Venice Lagoon subsoil" with a boomer system. About 140
km of very high resolution seismic profiles have been acquired in the area
located offshore the Lido inlet.
The ebb-tidal delta developed within the Holocene seismic sequence. Such
body is about 8 km long and a maximum of 4 km wide. Internally, it is
constituted of low to medium amplitudes, seaward dipping reflectors,
downlapping onto a regional unconformity, called S2 reflector. It is imaged as a
convex-upward body, particularly well developed offshore the Lido inlet. The
ebb-tidal delta appears to be slightly asymmetric, with the seaward flank being
steeper than the landward one. In the cross-section, parallel to the coast, the
ebb-tidal delta reveals also an asymmetric profile, with the northeastern flank
being slightly deeper than the southwestern one.
The isopach map reveals that the maximum thickness of the ebb-tidal delta
deposits (about 6 m) occurs just offshore the Lido inlet, but also that they are
distributed approximately in a E-W direction. No core data are available in the
study area, and thus the lithological characterization and the age of the
ebb-tidal delta are still speculative.
The comparison between the seismic profiles and historical bathymetric maps
dating back to 1886 AD reveals that the ebb-tidal delta of the Lido inlet formed
at around the end of the XIX century. It then represents a very recent feature
compared to the general evolution of the lagoon of Venice and formed as a
response of net transport of sand from the lagoon through the Lido inlet, as a
consequence of the construction of the two jetties, that have bound the inlet
from 1886 to the present day.
T04-21 Poster
Colizza, Ester
NEW STRATIGRAPHIC INFORMATION ON UPPER PLEISTOCENE IN THE
VENICE AREA: THE CH1M CORE AT MALAMOCCO INLET
FONTOLAN Giorgio 1, SCHIOZZI Laura 2, COLIZZA Ester 1, BEZZI Annelore 1,
MELIS Romana 1, PILLON Simone 1, LENAZ Davide 3, MARINONI Luigi 4, FONDA
Giulia 5
1 - DiSGAM, UNIVERSITA' DI TRIESTE
2 - ARPA, REGIONE FVG
3 - DST, UNIVERSITA' DI TRIESTE
4 - DST, UNIVERSITA' DI PAVIA
5 - DMPOB, UNIVERSITA' DI MODENA
Key terms: core stratigraphy; upper Pleistocene; Tyrrhenian; Venice Lagoon
A 82-m-long core has been recently collected by MAV-Consorzio Venezia Nuova
at Malamocco inlet, reaching 100 m below m.s.l. Nine depositional macro units
were recognized. These units correspond to different environments from Middle
Pleistocene (upper part of Ionian) to Upper Pleistocene. A relevant data is the
identification of the Tyrrhenian (MIS 5.5) transgressive event dated back to
125 kys BP, corresponding to the second last interglacial phase. This event lies
between 86 and 69 m below present msl. Bio-stratigraphic analysis (fossil
micro-fauna assemblage) has permitted to its identification. Estimating that ca.
15-m-thick bottom sediments are certainly pre-Tyrrhenian (Ionian), we can
suppose that the whole sampled sequence covers a time span of at least 140
kys.
The upper Ionian is represented by three continental macro units, with
sediments ranging from alluvial plain to swamp. The progressive flooding of
the alluvial plain is testified by the occurrence of marine macro- and
micro-fauna that characterizes the overlying macro unit 4. Facies is typical of
semi-enclosed inter-distributary bay, and marks the beginning of the
transgressive MIS 5.5 cycle. Maximum flooding is testified by the deepest
67
laminated siltey sand facies of outer delta front / inner prodelta (macro unit 5).
A coarsening upward sequence indicates subsequent regression, culminated
with emersion at ca. 69 m below m.s.l. (end of Tyrrhenian).
The overlying sediments represented a lithological alternation of continental
sandy and muddy facies. The post-Tyrrhenian sedimentation is given by delta
sands of macro unit 7; peat lacustrine-swamp deposits lie immediately above
(macro unit 8). An alternation of sand layers and muddy deposits distinguish
the overlying alluvial plain facies of macro unit 9.
Sediment sequence is truncated at the top, thus testifying the present current
erosion inside the tidal inlet. Holocene is virtually absent since only a small
amount of contemporary shell detritus has been collected.
From a compositional point of view dolomite represents a marker of fluvial
influence areas. The dolomite clearly predominates calcite. The high dolomite
contents found in the sand matrix are mainly due to the Brenta-Bacchiglione
river system. On the other hand, the low carbonate values and the
quartz-feldspar increase are linked to Adige and Po rivers influence. Therefore
area has been influenced by different terrigenous inputs due to alternate or
concomitant supplies from eastern and central-western alpine origin rivers.
T04-22 Poster
Marotta, Leonardo
GEOMORPHOLOGICAL AND LANDSCAPE QUANTITATIVE INDICATORS:
AN APPLICATION TO VENICE LAGOON
MAROTTA Leonardo 1, GUERZONI Stefano 2, MOLINAROLI Emanuela 3, SARRETTA
Alessandro 2
1 - Entropia Snc, Recanati, Italia
2 - CNR - Istituto di Scienze Marine, Venezia, Italia
3 - Università Ca' Foscari, Dipartimento di Scienze Ambientali, Venezia, Italia
Key terms: Quantitative Geomorphology; Landscape analysis; Fractals; Lagoon
of Venice
Quantitative geomorphology and landscape ecology can be used to determine
the spatial properties of wetlands and to assess the impacts of anthropogenic
activities. The proposed general methodology is based on identification of
different space and time scales of processes within the environmental units in
order to understand geomorphology and ecology of the Lagoon of Venice.
Measuring morphological features and ecological diversity in land- and
sea-scapes means evaluate the spatial configuration and composition of
geomorphological and landscape elements (habitats, ecotopes), diversity in
lagoon play an important role in the ecological functionality and biological
diversity. Fractals can be used to determine the geometric and spatial
properties of wetlands and can be correlated with sedimentological and
hydrologic process. Fractal dimension of patches is calculated in all the lagoon
with 2 different methods.
Landscape diversity has two components: richness and evenness. Richness
refers to the number of patch types (compositional component) and evenness
to the area distribution of classes (structural component).
The Shannon Diversity Index quantifies the number of different patch types
and the proportional area distribution among patch types.
All the indices are evaluated for the entire lagoon as sum and as average
(weighted with the areas of relative basins), with a multi-temporal approach.
Global results indicate a general diminution of fractal dimension, that means a
diminution of Ecotones in the lower fringe of tidal and an increase of salt
marshes border line, this can be correlated with erosion phenomena. The
results shows a general loss of diversity, Simpson indices stresses the
increasing of relative dimension of open lagoon morphology and the loss of
inter-tidal morphologies and patches.
T04-23 Poster
Bondesan, Aldino
THE IMAGO PROJECT. A DATA BASE OF THE HISTORICAL
CARTOGRAPHY OF THE LAGOON OF VENICE
BONDESAN Aldino 1, FURLANETTO Paola 2, LEVORATO Chiara 3, ROSSELLI Roberto
4
, BERTANI Barbara 4
1 - University of Padova
2 - AKEO - Padova (Italy)
3 - Adastra srl - Torre di Mosto (Venezia, Italy)
4 - Magistrato alle Acque - concessionario Consorzio Venezia Nuova
Key terms: Historical Maps; Lagoon; Venice
The IMAGO Project relates to a purpose-built data base concerning the
historical cartography of the Lagoon of Venice and its border to the hinterland.
The project is funded by the Magistrato alle Acque- Concessionario Consorzio
Venezia Nuova (Venice Water Authority - Concessionary Consortium "Venezia
Nuova") through a Memorandum of Understatment with the Archivio di Stato di
Venezia (Archive of State of Venice). About 400 maps were chosen among
more than 2000 ordered by author, century, area, purpose and intrinsic
factors. Each record of the data base contains the raster image of the map;
each map is described through nine sections containing different data sets
concerning the map itself. This data base fully meets the requirement of a
traditional archive, including cataloguing and inventorying of maps, even
according to the rules of the Centro di Documentazione per il Catalogo dei Beni
Archivistici (Documentation Center for the Catalog of Archival Heritage). More
important, it also includes some descriptive sections with list of toponyms,
hydronyms, soil use etc. regarding the map and an interpretative part in which
the map is read, described and interpreted analyzing and comparing it with
present maps and with the geomorphological outline. Most important and
representative maps were georeferenced and digitalized.
The data base is complete with the geographical localization of the historical
map; bibliographic references and hypertextual link with original texts
complete the information.
The project started in 2001 and was organized in different steps. After the first
and the second step (called IMAGO 1 and IMAGO 2), in which cataloguing and
analysis of each maps were performed, the third step (IMAGO 3) regarded an
advanced cartographic research in order to draw the geographical and
paleo-hydrographical framework of the lagoon area and the surrounding plain
SESSIONE T04
68
during the XVI and XVII century. A second data base, called FORMA and linked
with IMAGO, describes the most important geological and geomorphological
elements whose natural and man-induced evolution is analyzed and discussed.
The IMAGO data base became in this way a powerful tool for gathering
information about changes occurred during the last 500 years when major
artificial interventions took place.
At present the areas between Tagliamento river and Livenza river, between
Piave river and Sile river and the northern part of the Venice lagoon were
studied in their landscape evolution.
This presentation will illustrate the geomorphological changes affecting the
northern stretch of the lagoon of Venice as they were identified through an
integrated map analysis from 1500 to 1700 A.D.
T04-24 Poster
Marani, Marco
BIOLOGICALLY-CONTROLLED MULTIPLE EQUILIBRIA OF TIDAL
LANDFORMS AND THE FATE OF THE VENICE LAGOON
MARANI Marco 1, D'ALPAOS Andrea 1, LANZONI Stefano 1, CARNIELLO Luca 1,
RINALDO Andrea 1
1 - Università di Padova
Key terms: Venice lagoon; wetlands; climate change
Looking across a tidal landscape, can one foresee the signs of impending shifts
among different geomorphological structures? This is a question of paramount
importance considering the ecological, cultural and socio-economic relevance of
tidal environments and their worldwide decline. In this Letter we argue
affirmatively by introducing a model of the coupled tidal physical and biological
processes. Multiple equilibria, and transitions among them, appear in the
evolutionary dynamics of tidal landforms. Vegetation type, disturbances of the
benthic biofilm, sediment availability and marine transgressions or regressions
drive the bio-geomorphic evolution of the system. Our approach provides
general quantitative routes to model the fate of tidal landforms, which we
illustrate in the case of the Venice lagoon (Italy), for which a large body of
empirical observations exists spanning at least five centuries. Such
observations are reproduced by the model, which also predicts that salt
marshes in the Venice lagoon may not survive climatic changes in the next
century if IPCC's scenarios of high relative sea level rise occur.
T04-25 Poster
SESSIONE T05
Traccianti geochimici ed isotopici di processi superficiali in ambiente
marino e continentale
Faccioli, Andrea
INTEGRATION OF INTERFEROMETRIC BATHYMETRY, LASERSCANNER
AND SIDE SCAN SONAR FOR A 3D IMAGING OF SHALLOW WATER
ENVIROMENTS UNDER AND ABOVE WATER SURFACE.
FACCIOLI Andrea 1
1 - Codevintec Italiana
Key terms: 3D imaging; interferometric bathymetry; 3D laser scanner; side
scan sonar
Examples of high resolution 3D surveys in shallow waters.
3D Laser Scanner images integrated with Bathymetry correlated with SideScan
sonar imagery.
Laser Scanner and interferometric bathymetry represent the cutting edge of
environmental survey technology. Integration of these two methodologies was
tested carrying out a number of high resolution surveys in Venice, Po river and
some Italian harbors.
Bathymetric surveys has been conducted with SEA SWATHplus-H
Interferometric Wide Swath Sonar. Its main features are: Swath widths of 10
to 15 times water depth, Beam width of 300°, Small, light and portable
system, Easily mobilized on small (3m) to medium (30m) vessels, Side Scan
Sonar images co-related to bathymetry, Depth capabilities of to 50cm-300m
(depending on the transducer).
For attitude correction a CodaOctopus F180 sensor was used.
The F180 is a combined position, heading and attitude sensor using dual GPS
antenna and motion sensing technology. It has inertial sensing capabilities for
a fully integrated single solution for positioning, orientation and motion. The
dual frequency (L1/L2) system when aided by RTK corrections can provide very
accurate height information that can be used to provide 'real-time tide'. The
F180 for the trial was RTK corrected with corrections being provided from a
Thales Z-max GPS.
The areas above sea level have been acquired with Optech ILRIS-3D Terrestrial
Laser Scanner. ILRIS is a small instrument (not very different from a motorized
total station) that acquire everything is in the visual field up to a distance in
excess of 1000m (depending on the reflectance of the acquired material) with
milli-metric precision. The resolution is in the order of 20 millirad, that means a
dot every 2 millimeters at a distance of 100m
In addition to supplying a accurate x,y,z point cloud, both the instruments
(Laser Scanner and Interferometric Multibeam) measure the signal intensity of
the target surface. From this information an useful 3D black and white image of
the surveyed area can be created. For Laser Scanner this image it's a pseudo
photo based on the response to the infrared of the different materials, for
Swath Plus it's the intensity produced from a real side scan image.
The similarity of the data provided by the two systems (point cloud and
intensity value) has made possible the integration of the two surveys trough
the commercial software Polyworks.
The final product is a single 3D model made up of bathymetry and above water
surface topography, to this it is possible to add on it digital camera images for
a 3D photorealistic view of the surveyed area.
T04-26 Poster
Key terms: coastal management; physiographic unit; handbook
The Manual "Geological-Hydraulic Upheaval Phenomena on Slopes" was written
in order to provide a complete picture of the most significant natural
phenomena that causes geological-hydraulic upheaval on slopes, i.e.
gravitational movements, erosion phenomena generated by run-off water, and
avalanches. Several human activities such as agricultural use, the management
of woods, grazing, quarrying, elements that could also have a sizeable impact
on the dynamics and equilibrium of slopes, are also described in the Manual.
On the national scene, a document gathering these themes together, and
describing them in a simple and easily understandable way did not appear to
be available. This manual is therefore addressed to a wide range of users, with
particular regard for Local Authority specialists and Administrators.
The manual is divided into two parts. The first part provides a systematic
classification of the main phenomena of geological-hydraulic upheaval on
slopes, together with a general description of each phenomenon and the
above-mentioned human-related activities. Its aim is to highlight their typical
characteristics, accompanied with various explanatory images and by one or
more outline models that underline their main morphological and evolutionary
features.
The second part contains a detailed index of the symbols used for the
representation on maps not just of the phenomena of geological-hydraulic
upheaval on slopes and the above-mentioned human activities, but also the
civil engineering works most frequently used to prevent and safeguard the
Italian territory from such geological-hydraulic upheavals. It is our suggestion
that this index be integrated with existing literature and thereby make up for
any deficiency especially in the applicative field.
It is to be hoped, therefore, that this manual become an operating handbook,
easy to consult, and constitute a useful aid and reference work for
understanding the phenomena responsible for geomorphological instability on
slopes. Consequently the manual would serve in the evaluation of the causes
and mechanisms of upheavals and in the activities connected with the defense
of the land. It would be used for forecasting, preventing and mitigating the
hydro-geological risks, the correct planning on the use of the land, the
management of natural resources and the collection and processing of the
relevant data and information.
Brustia, Elisa
AN HANDBOOK FOR INTEGRATED COASTAL MANAGEMENT
LUCARINI Mauro 1, BRUSTIA Elisa 1, DOMENICO Ligato 1
1 - APAT (Agenzia per la Protezione dell'Ambiente e per i Servizi Tecnici)
T05-1 Invitato
Cidu, Rosa
TRANSPORT OF TRACE ELEMENTS IN RIVER WATER: INFLUENCE OF
THE FINE PARTICLES
CIDU Rosa 1
1 - Università di Cagliari, Dipartimento Scienze della Terra
Key terms: river water; trace elements; Sardinia
To investigate the influence of the solid load on the mobility of trace elements
35 water samples were collected from rivers flowing in Sardinia (Italy).
Sampling of river waters was carried out in 2003 under high-flow (January) and
low-flow (June) conditions. Aliquots of non-filtered and acidified water were
collected for the determination of total amounts. Aliquots of filtered (0.4 µm
and 0.015 µm) and acidified water were collected for the determination of
dissolved amounts. Trace elements were analyzed by ICP-MS.
Sardinia was a good test area due to its peculiarities in climate (arid summers,
mild and humid winters) and geology (Paleozoic granitic and metamorphic
rocks; Mesozoic carbonate rocks; Tertiary-Quaternary conglomerate,
sandstone, carbonate and marl sequences, and volcanic rocks). Moreover, the
occurrence of mineral deposits (mainly Pb, Zn, Ag, Fe and Cu sulphide
minerals), exploited intensively from 1880 to 1980, may represent potential
sources of several trace elements.
Concentrations of B, Li, Rb, Sr, Ba, Mo and U increase with salinity and are
higher in June under low-flow condition; small differences were observed
between total and dissolved amounts. These elements are mainly transported
in solution and appear related to the intensity of water-rock interaction
processes, which are enhanced when the rain contribution to the rivers is low.
Concentrations of Fe, Al, Pb, Zn, Cu, Ni, Cd, Co, Th, Y and rare earth elements
(REE: La-Lu) are higher in the river waters sampled at high-flow condition.
Since the abundance of fine materials in any particular river, as well as along
the river course, may vary significantly, a large variation in the contents of
these elements was observed. Lower dissolved concentrations are generally
observed in the <0.015 µm fraction as compared with the <0.4 µm fraction.
Concentrations decrease significantly under low-flow condition, when a low
turbulence allows the settlement of the fine particles. Large differences in total
and dissolved (<0.4 µm) concentrations of many trace elements were observed
between the waters sampled both in January and June; this might be explained
by the different hydrological conditions that control the amount of fine particles
present in the river water.
The elements Pb, Zn, Cu, Ni, Cd, Co, Th and REE showed good correlation with
Al and Fe; they might be adsorbed on a variety of metal-bearing oxide and
hydroxide minerals at near-neutral pH, as well as on clay particles. This
process causes their removal from solution and is more marked at low-flow,
when the low turbulence favors the settlement of fine materials. Taking into
account that the load of fine materials in a river may vary significantly, mostly
depending on the amount of rain and runoff, and that this fraction may host
some toxic elements, the sampling season should be carefully considered in
studies devoted to the assessment of the quality of river waters.
A significant number of water samples show dissolved Al, Fe, Mn and Pb above
the Italian limits established for drinking water. Considering those waters
collected both in January and June, samples above limit occur more frequently
at high-flow condition than at low-flow. Dissolved Pb and Mn exceed Italian
regulation in 20% of samples under high-flow condition. Among the highly toxic
SESSIONE T05
heavy metals, dissolved Cd is found above the Italian limit (5 µg/L Cd) in two
samples draining important mining districts. The weathering of mine wastes,
and the discharge of urban wastes into rivers, is likely the main source
responsible of pollution.
T05-2 Invitato
Vetuschi Zuccolini, Marino
HEAVY METALS CHARACTERIZATION AT LARGELY VARIABLE SPATIAL
SCALES: ELEMENTS AND ISOTOPES TRACEABILITY FOR
ENVIRONMENTAL INVESTIGATIONS
VETUSCHI ZUCCOLINI Marino 1
1 - Laboratorio di Geochimica, DIPTERIS, Università di Genova
Key terms: Geochemistry; PHEs; Isotopic fractionation; Geostatistics
Tracing a physical-chemical property of geological materials (seen as part of
the natural environment) requires very different and complementary
approaches due to the extreme variability in dimensionality and condensation
state.
Two topics will be shown, deemed to represent limiting cases of the wide
spectrum of geochemical investigations: the first one is a spatial (scale- and
time-independent) approach and the second one is a "first-principle" molecular
method.
They can be assimilated to the two distinct aspects of the intrinsic nature of
phenomena which rule geochemical interactions: statics and dynamics.
By "static approach", we mean here the picture of an environmental reality
taken somewhere in the time scale and considered at equilibrium for a certain
period of time. This is often the only way to describe large parts of
geographical extensions where superposition of phenomena prevents a
deterministic solution.
The rehabilitation of an area subjected to mining activities or other kinds of
pollution requires a good definition (in statistical sense) of the knowledge of
the local extent of contamination to define budget and techniques of
intervention.
Some constraints derived primarily from theory, and from a close analysis of
the nature of the variable lead to improved predictions, and, in general to
better optimization of budget and time resources.
At the atomic scale, mediated magnitudes have no meaning but in an
homogeneous system at equilibrium it is possible to define, through "first
principles" the fingerprint of chemical species. We will discuss, as an example,
traceability of isotopic fingerprints and exchanges among heavy metal species
in geological materials under various state of aggregation.
T05-3 Invitato
De Vivo, Benedetto
GEOCHEMICAL ATLAS OF ITALY
DE VIVO Benedetto 1, LIMA Annamaria 1, BOVE Maria Anna 1, ALBANESE Stefano 1,
CICCHELLA Domenico 2, SABATINI Giuseppe 3, DI LELLA Luigi Antonio 3,
PROTANO Giuseppe 3, RICCOBONO Francesco 3, FRIZZO Pietro 4, et al.
1 - Università degli Studi di Napoli "Federico II"
2 - Università degli Studi del Sannio
3 - Università degli Studi di Siena
4 - Università degli Studi di Padova
Key terms: Atlas; Geochemistry; Environment; Italy; Multifractal IDW
In recent years, the increasing interest from the public opinion regarding the
environmental issues pushed National governments and the European Union to
develop laws and policies directed to protect the environment.
Since basic geochemical cartography is considered nowadays one of the most
useful tool to implement environmental intervention plans, it became evident,
both for the scientific community and the politicians, that there was the need
for geochemical data coherent and uniform on an international scale.
Researches started in 1998 in the framework of the International Geochemical
Mapping Project (IGCP 259), highlighted a lack of uniformity and the
insufficient availability of geochemical data at an European scale, due to the
use of different sampling procedures, analytical methodologies or
incompleteness of the existing datasets.
Hence, a series of standardized procedures for sampling and analysis (to be
conducted in selected laboratories) were established, through which create a
geochemical database based on a global sampling grid (GRN, Global Reference
Network), that would allow to compare national and regional geochemical
datasets.
In 1994 the FOREGS became the European subcommittee of the IGCP 360.
Each of the 26 nations of the FOREGS project contributed to the Geochemical
European Atlas, collecting national geochemical data.
The Italian Geochemical Atlas addresses the need for a large scale geochemical
mapping based on FOREGS standards. In the framework of the GTN (Global
Terrestrial Network), Italy has been divided in eight 160 x 160 Km square cells.
Stream water (W), stream sediments (S), floodplain sediments (F), topsoils (T)
and subsoils (C) samples have been collected in two phases in 58 locations,
homogeneously distributed along Italy. For FOREGS purposes, we sampled 50
sites all over Italian territory; these data have been used for the compilation of
the Geochemical Atlas of Europe (Salminen et al., 2005; 2006. Geochemical
Atlas of Europe, Part 1 and Part 2. Geological Survey of Finland, Espoo). Later
on, between April and September 2005, further samples have been collected in
eight new sites, to improve sampling homogeneity for the southern Italy
territory.
In both phases we strictly implemented FOREGS sampling and sample handling
procedures. Every sample site has been documented by two photographs
collected in an appropriate database.
Soil and sediment samples have been dried at 40°C with infrared lamps,
crushed in agate mortar, and sieved (< 0.063 mm fraction), before being
analyzed.
The geochemical data used for the FOREGS project and the new data from
sub-cells of southern Italy have been processed using ArcView GIS TM, and a
new Multifractal IDW method available in the software GeoDAS TM (Cheng et al.,
2001. The 20th Intern. Geochem. Explor. Symposium (IGES). Santiago de
69
Chile, 6/5-10/5, 2001, 42-43.; Lima et al., 2003. Applied Geochemistry, 18
(12), 1853-1865; Cicchella et al., 2005. Geochemistry: ExplorationEnvironment - Analysis, 5, 1-12; Albanese et al., 2007. Journal of Geochemical
Exploration, 93, 21-34).
Finally, a total of 360 geochemical maps, showing elemental distributions for
the whole Italian territory, have been produced to be published in the
Geochemical Atlas of Italy (De Vivo et al., in press. Aracne Editrice, Rome)
Geochemical maps show that, even, at large scale, distribution patterns of
some elements clearly depend on the nature of outcropping rocks and on the
major geo-lithological structures and lineaments. In particular, the
Roman-Neapolitan alkaline volcanic province is very well individuated along the
Tyrrhenian sea by K, Pb and some Rare Earths Elements. Some maps also
highlight mineralized areas in southern Sardinia.
T05-4 Invitato
De Vivo, Benedetto
URBAN GEOCHEMICAL MAPPING IN THE CAMPANIA REGION
DE VIVO Benedetto 1, LIMA Annamaria 1, ALBANESE Stefano 1, CICCHELLA
Domenico 2, FEDELE Luca 3, GREZZI Giuseppe 1
2 - Università degli Studi del Sannio
3 - Virginia Polytechnic Institute and State University
Key terms: Urban soils; Heavy metals; Pollution; Geochemical mapping; Site
characterization
Five atlases were produced to present the geochemical maps compiled using
topsoil samples collected in the metropolitan and provincial area of Napoli and
of the cities of Avellino, Benevento, Caserta and Salerno (Campania, Italy) .
Due to the constant human presence in these areas for many centuries, it is
reasonable to expect that most of the elements concentrations have been
affected by anthropogenic activities.
These atlases, beside the distribution pattern of chemical elements in urban
soil, aimed at the determination of the geochemical baseline values (or
backgrounds, depending on local conditions) of each analyzed element (38) by
means of a a recently developed geostatistical tool, GIS based, called GeoDAS TM
(Cheng et al., 2001. The 20th Intern. Geochem. Explor. Symposium (IGES).
Santiago de Chile, 6/5-10/5, 2001, 42-43.).
As consequence, the produced atlases can be considerated as a reliable tool to
assess toxic and harmful elements pollutions levels threatening ecosystem and
human health and to provide a sound basis for policy makers and legislators
who need to address the public concerns regarding environmental issues.
In each atlas 7 categories of map have been included:
° Dot maps showing single elements distribution;
° Maps illustrating the interpolated data distribution;
° Maps showing baseline/background values distribution;
° Maps showing anomaly values distribution;
° Maps showing regional variability of factor scores of elemental associations
resulting from R-mode factor analysis;
° Risk maps for some selected elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb,
Se, Tl, V, Zn) using the trigger and action levels set by the Italian Law (D.M.
471/99);
° Maps showing radioactivity values distribution.
We collected 1620 soil samples over a total area of about 1471 km2 with a grid
of 0.5 x 0.5 km in the urbanised areas and a grid of 1,5 km x 1,5 km in the
suburban areas. Approximately 3 kg of soil were collected, between 0 and 15
cm below the surface. The samples were dried, crushed in an agate mortar,
and sieved to the <100 mesh fraction (150 m) to collect 30 g for chemical
analysis. Before and after sieving, the samples were homogenised and
quartered.
Analyses were carried out by Acme Analytical Laboratories Ltd (Vancouver,
Canada), accredited under ISO 9002. Each sample was digested in a modified
aqua regia solution and analysed by ICP-MS and ICP-ES both for major
elements (Al, Ca, Fe, K, Mg, Na, P, Ti) and for Ag, As, Au, B, Ba, Bi, Cd, Co, Cr,
Cu, Ga, Hg, La, Mn, Mo, Ni, Pb, S, Sb, Sc, Se, Sr, Te, Th, Tl, U, V, W, Zn.
Concentrations of Pt, Pd and Rd were determined on the 20% of the total
amount of collected soil samples. Radioactivity surveys have been carried out
on 400 sites, covering the 5 studied areas, using a portable Scintrex GRS-500
that measures partial and total radioactivity.
Univariate and multivariate statistical analyses were carried out in order to
show the single-element geochemical distribution and the distribution of
elemental association factor scores resulting from R-mode factor analysis.
Factor analysis was used to identify different groups of chemical elements with
approximately share the same geochemical distribution pattern.
For geochemical maps compilation we applied a recently developed multifractal
IDW interpolation method and a fractal filtering technique (S-A method) using
the GeoDAS TM software.
Generally, produced maps highlighted the environmental impact of human
activities on urban areas strongly polluted by harmful elements such as Pb, Zn,
Cd and Cu (Albanese, in press. Geochemistry: Exploration- Environment Analysis)
Besides, geochemical maps of Pt and Pd showed how use of cathalitic
converters (mandatory since 1990, in Italy) on autovehicles determined a new
form of pollution in urban soils (Cicchella et al, 2003. The Science of the Total
Environment, 308, 121-131; Cicchella et al., in press. Geochemistry:
Exploration- Environment - Analysis).
T05-5 Orale
Sacchi, Elisa
THE RAMET PROJECT: A REGIONAL SURVEY ON HEAVY METALS
CONTENT IN CULTIVATED SOILS FROM LOMBARDY
SACCHI Elisa 1, BRENNA Stefano 2, FORNELLI GENOT Stefania 1, SETTI Massimo 1,
SALE Vanna Maria 2, AZZOLINA Laura 2, LEONI Maria Alessandra 2
2 - Dipartimento dei Servizi all'Agricoltura, ERSAF Lombardia
SESSIONE T05
70
Key terms: heavy metals; cultivated soils; diffuse pollution; agricultural
practices; baseline concentrations
Soils are critical environments where rock, air and water interface. Heavy
metals in soils are always present at a background level of non-anthropic
origin, their input in soils being related to weathering of parent rocks and
pedogenesis. In the last decades, the natural content has been exceeded by
the human input (Alloway, 1995). Major anthropogenic sources for heavy
metals to soils are metalliferous mining and smelting, agricultural materials,
sewage sludge, fossil fuel combustion and industries. Currently, according to
the European Environment Agency, contamination by heavy metals is one of
the more relevant soil contamination problems from diffuse sources (EEA,
2003).
The Lombardy plain is characterised both by intensive agriculture and by a
strong anthropic pressure exerted by industrial and urban settlements. The
RAMET Project, which was completed by ERSAF and the University of Pavia in
2006, aims at investigating diffuse pollution in cultivated soils which can be
attributed to agricultural practices. The project was co-funded by the Regional
Direction for Agriculture (Regione Lombardia) and by the Ministry of University
and Research (PRIN 2004).
About 1000 soil profiles were selected from the ERSAF collection, created in the
last decades for the elaboration of the pedological map of Lombardy
(1:50.000). Heavy metals analyses (Cd, Cu, Ni, Pb, Zn and Mn) were
conducted by aqua regia digestion and Atomic Absorption Spectrometry on two
samples per soil profile, one representative of the A horizon, and the second
corresponding approximately to a depth of 100 cm (generally belonging to a C
horizon).
Results were statistically treated in order to obtain background concentrations
for all the parameters. Distribution maps of each element were compiled. An
advanced statistical treatment was performed which allowed the reduction of
variables and their attribution to precise pollution sources and processes.
Results indicate that, in cultivated soils, heavy metals contents are generally
well below the regulatory limits, with the exception of Cu in vineyard soils.
Nevertheless, especially south of Milan and other urban areas, an enrichment
in the top soil for Cd, Cu, Pb and Zn is observed, which can be attributed to an
anthropic input. On the other hand, the Ni content, often exceeding regulatory
standards, is associated to Mn and its distribution with depth points to a
natural origin. The study highlights that, although an input from agricultural
activities certainly exists, especially in vineyards and intensively cultivated
areas, this is largely exceeded by the input due to industrial pollution and road
traffic.
Three particular land use and practises were investigated in detail by
excavation of dedicated soil profiles. In the Oltrepo' area, the most important
regional vine growing area, the distribution of Cu and associated metals with
depth and the metal transfer to surface and groundwater were investigated. In
Lomellina, a vast flat area dedicated to rice cultivation, the effects of field
flooding on the distribution of heavy metals in soil profiles were observed. In
the Cremona plain, where intensive farming and crop raising are practised,
heavy metal accumulation in soils following several years of sewage sludge and
farm manure spreading was evaluated.
The results of this study are published in a monograph (Regione Lombardia,
2007) and are collected in a database aiming to serve as a basis for long term
monitoring of cultivated soil quality.
References
Alloway B.J. (Ed.), 1995. Heavy metals in soils. II Edition. Blackie Academic &
Professional, London
European Environment Agency EEA, 2003. Europe's environment: the third
assessment. Summary. Office for Official Publications of the European
Communities, Luxembourg, 61.
Regione Lombardia, 2007. Analisi del contenuto in rame ed altri metalli nei
suoli agricoli lombardi. Quaderni della Ricerca n. 61, Milano, 120 pp.
T05-6 Orale
D'Antona, Marco
IDENTIFICATION OF THE SOURCE AND FATE OF NITRATE
CONTAMINATION OF THE PONTINA PLAIN GROUNDWATERS USING
STABLE NITROGEN AND OXYGEN ISOTOPES
D'ANTONA Marco 1, BRILLI Mauro 2, CORTESE Maria 3, MASI Umberto 1,
ZAMPILLONI Sandro 4
1 - Università degli Studi "La Sapienza" di Roma
2 - Istituto di Geologia Ambientale e Geoingegneria (CNR), Sez. La Sapienza,
Roma
3 - Arpalazio, Sez. Prov. di Latina
4 - Dipartimento Territorio, Regione Lazio
Key terms: NITRATE; GROUNDWATER; CONTAMINATION; NITROGEN AND
OXIGEN ISOTOPES
Nitrate contamination is one of the most important issues concerning the
quality of natural waters; nitrate concentrations have exceeded acceptable
levels in several areas in Italy.
The source and fate of nitrate contamination of natural waters may be
identified, using isotopic techniques, by comparing the nitrogen and oxygen
isotope contents of dissolved nitrate with those of potential sources. It has
been demonstrated that nitrate nitrogen isotopes discriminate between nitrified
soil organic nitrogen, nitrogenous fertilizers and animal and sewage wastes;
oxygen isotopes effectively distinguish different types of fertilizers (synthetic
and organic) and nitrate from meteoric waters. Positive co-variation of the two
variables indicates that denitrification is in progress, since fractionation of this
process alters the original isotope ratios, depleting the heavier isotopes (15N
and 18O) in the reaction products and enriching the residual NO3-.
The isotopic technique was used to study nitrate pollution in the Pontina Plain
groundwaters. This area is a large plain located between the Lepini and Ausoni
mountains to the east and the Tyrrhenian coastline to the west. Geologically it
consists of quaternary deposits composed of clays, sands that host an aquifer
at a shallow depth and isolated perched aquifers, almost all of which are
entirely dependent on intergranular permeability.
The Pontina region is subject to intense agricultural exploitation and contains a
high concentration of livestock farms; the combination of these activities and
the shallow groundwater levels renders groundwater highly vulnerable to NO3contamination. In some areas, pollution due to pharmaceutical factories is a
further hazard.
The present study is based on the sampling of about 20 wells uniformly
distributed between Cisterna di Latina e Terracina. The water samples were
collected during the winter 2006, a period in which fertilization is absent. The
results were obtained from the surface aquifer, whose main supply of water
consists of meteoric precipitation, as indicated by the oxygen isotope
composition which is on average -5.14 0/00 and corresponds to the annual
average composition of meteoric waters in the region.
The chemical data show that nitrate concentrations vary greatly depending on
the borehole site, reaching values as high as 240mg/l. Isotopic nitrate values
range from +4.72 0/00 to +16.37 0/00 for delta 15N, and from +4.34 0/00 to +18.08 0
/00 for delta 18O. These results indicate that the main nitrate contamination
source is animal waste; approximately half of the samples have a nitrogen
isotope composition that falls within the normal range for nitrified soil organic
nitrogen. Although the majority of the region is intensively cultivated, there is
no evidence of mineral fertilizers, whose delta 18O is generally higher than +17
0 00
/ ; only one sample has delta 18O of +18.08 0/00. The absence of mineral
fertilizers may be due to the fertilization-free period of vegetative quiescence in
which the sampling was conducted (i.e. winter), though it is also possible that
the fertilizers NO3- have exchanged with soil N and, consequently, have an
isotopic value similar to that of nitrified soil organic nitrogen.
No denitrification process was observed, probably owing to a scarce water
self-softening capability of the soil, which is an important point to be
considered when addressing the issue of nitrate contamination of the
groundwater in this area.
T05-7 Orale
Rango Godebo, Tewodros
WATER QUALITY IN THE MAIN ETHIOPIAN RIFT - NEW INSIGHT ON
THE FLUORIDE PROBLEM
RANGO GODEBO Tewodros 1, BIANCHINI Gianluca 1, BECCALUVA Luigi 1
Key terms: Ethiopia; Rift valley; groundwater; water quality; fluoride problem
The Ethiopian rift area is suffering severe water quality problems, as
groundwaters are often characterized by anomalously high fluoride (F) content
that induces an endemic disease (fluorosis) in the local population.
Our survey, focused in the Ziway-Shala lakes district, indicates that the F
content is higher than the tolerance limit prescribed by WHO (1.5 mg/l) in
many important wells (up to 20 mg/l), with the more extreme F concentration
(up to 95 mg/l) in some thermal springs.
The new analyses, compared with the available literature data, indicate that
ground and surface water from the highlands, typically characterized by low
TDS (Total Dissolved Solids) and Ca(Mg)-HCO3 hydrochemical facies, do not
show high F content.
The subsequent interaction of these waters with the lithologies outcropping in
the rift valley - i.e. rhyolitic ignimbrites and lacustrine sediments derived by
their weathering - induces a general increase of the water TDS, a variation of
the chemical signature toward Na-HCO3 compositions, as well as enrichment of
F.
In these interactions the rhyolite parageneses (mainly consisting of volcanic
glass, alkaline feldspar, amphibole, biotite), reacting with water and carbon
dioxide (juvenile?), are progressively converted into a "secondary" clay-bearing
mineral assemblage, with release of alkalis, fluoride and boron, as well as
bicarbonate in the interacting water. The resulting waters, typically
characterized by high pH (7.5-10.0) are also affected by cation exchange
softening with the neo-formed clay minerals (i.e. Ca-Mg uptake by the aquifer
matrix, with release of Na in the groundwater).
These are plausibly the main mechanisms that explain the high F content of the
local groundwater, as evidenced by positive correlation between F, pH, and
Na, and inverse correlation between F and Ca (Mg). In these conditions,
fluoride can not precipitate as fluorite (CaF2), and it is replaced by OH- in
clay-minerals.
Therefore, the high F content observed in groundwaters does not necessary
require the involvement of deep (F-rich) juvenile fluids, and could be explained
as the result of complex water-rock interaction processes.
T05-8 Orale
Amadori, Michele
BORON AND SULFATE ISOTOPES AS TRACERS OF ENVIRONMENTAL
POLLUTION IN SURFACE WATERS (POSSERA CREEK, LARDERELLO,
TUSCANY)
AMADORI Michele 1, CORTECCI Gianni 1, GRASSI Sergio 1, PENNISI Maddalena 1
1 - ISTITUTO DI GEOSCIENZE E GEORISORSE, CNR, PISA
Key terms: BORON; POLLUTION; STABLE ISOTOPES; STREAMWATER;
LARDERELLO
The Possera creek, a left tributary of the Cecina River, is affected by boron
pollution that reaches up to 20 mg/L nearby to the Larderello village. In this
area, heavily exploited in the past for the geothermal resource, B-rich spent
fluids from the power plants and muddy by-products from the colemanite
industrial processing were released along the Possera creek up to late
seventies. Recent investigations carried out on the creek waters have
highlighted a good correlation (R = 0.98) between boron and sulfate in the
water, even though no evaporites are present in the basin.
The aim of this study is to characterize the pollutant source/s by determining
the isotopic compositions of boron ( 11B) and sulfate ( 34S) in the creek, and in
the expected pollutants. Hypotheses on the pollution of the Possera creek were
first focused on the borogypsum, that represents the by-product of the boric
acid industrial process. From 1950 to 1980 industrial boric acid was produced
at Larderello, by dissolving in sulphuric acid the colemanite minerals imported
from Turkey. Colemanite (2CaO3*B2O3*5H2O) contains 15.6% of elemental
boron, and is one of the most important boron minerals used industrially. The
recovery of boric acid by treatment of the colemanite with sulphuric acid was
between 65 to 95%. The borogypsum residue was discharged in the
environment. As a consequence, the boron content in the Possera creek
SESSIONE T05
reached 420 mg/L boron in 1974.
The isotopic analysis on possible pollutants were addressed to the colemanite (
B = -13 / and
11
0 00
S = 1 / ), the borogypsum (
34
0 00
B = -13.3 / and
11
/00) and the geothermal fluids from exploited wells (12 0/00 <
5.4 0/00 <
0 00
S = 1.4
34
0
B < 15 0/00 and
11
S < 7.4 0/00). The results, along with those on surface water samples
34
along the Possera (-5 0/00 < 11B < 11 0/00 and 5.4 0/00 < 34S < 7.4 0/00) led to a
model by which the pollutants of the creek are mainly the borogypsum still
occurring in the aquifer skeleton, and subordinately a geothermal component.
The latter determines a notable shift of the isotopic signature of the sulfate
dissolved in the creek upstream of the Larderello village, followed downstream
by dissolution of borogypsum.
T05-9 Orale
Dinelli, Enrico
GEOCHEMISTRY OF STREAMS SEDIMENTS FROM THE RIVERS
DRAINING THE APENNINES IN THE EMILIA-ROMAGNA REGION
DINELLI Enrico 1, LUCCHINI Federico 1
1 - Università di Bologna-Dipartimento di Scienze della Terra e
Geologico-Ambientali
Key terms: stream sediment; geochemistry; provenance; pollution
The geochemistry of river sediments represent an important tool in
environmental studies, since this matrix reflects the composition of country
rocks, and thus enable the evaluation of baseline and background values
fundamental in any sound land use policy. They can also indicate critical areas
related to natural or anthropogenic sources, but in this sites stream sediment
can become a potential source of secondary contamination if the sediment
undergoes physico-chemical changes. This work presents the results of a
geochemical survey carried out on stream sediments of the rivers draining the
Apennines within the territory of the Emilia-Romagna Region, from the Tidone
River to the Marecchia River, in their final part of the course in the Po River
Plain area. The aims of the work are to identify regional trends in element
distribution, define possible provenance indicators and locate critical areas.
A total of 187 samples were collected between 2000 and 2004 from the active
bed of all the major rivers draining the Apennines, samples were directly sieved
in the field and the fraction < 180 mesh (177 m) retained for analysis. Total
chemical composition of the samples was evaluated by XRF spectrometry on
pressed powder pellets. The elements considered are Si, Ti, Al, Fe, Mn, Mg, Ca,
Na, K, P, S, Sc, V, Cr, Co, Ni, Cu, Zn, As, Rb, Sr, Y, Zr, Nb, Ba, La, Ce, Pb, Th,
S. Univariate, bivariate and multivariate statistics were performed on this
data-set to help in the interpretation.
Results indicate that exist regional trends in the geochemistry of river
sediments that directly reflects the geology and lithology of the mountain
chain, and generally there are no major variation along their course. On the
basis of multivariate analysis some broad features can be outlined: the rivers
draining the Romagna Apennines are characterized by larger concentrations of
elements related fine-grained sheet silicates and by the relative importance of
elements such as Mg, K and S, whereas those from the Emilia Apennines are
generally richer in elements associated to carbonates and are almost all
characterized by enrichments in elements related to ophiolitic successions (Cr,
Ni, Co, Mg). The Reno River but also the Idice-Savena Rivers and the Panaro
and Secchia rivers are all characterized by high SiO2 concentrations with
intermediate to low CaO concentrations. Given these results it is possible to
identify several geochemical indexes useful to discriminate sediment
provenance related to geological substrate in the mountain chain.
There are significant anomalies for Zn, Pb, Cu, and P that generally tend to
increase downstream for the Emilia Rivers, prior to their confluence in the Po
River, and close to the mouth into the Adriatic Sea for Reno, Fiumi Uniti,
Bevano, Rubicone.
T05-10 Poster
Mameli, Paola
CRETACEOUS VERSUS MESSINIAN ALTERITES ON THE MESOZOIC
CARBONATE SHELF OF SARDINIA: MINERALOGICAL AND
GEOCHEMICAL EVIDENCES
MAMELI Paola 1, MONGELLI Giovanni 2, OGGIANO Giacomo 1, PODDA Annamaria 1
1 - Università degli Studi di Sassari
2 - Università degli Studi della Basilicata
Key terms: CLAYS; WEATHERING; PROXY; SARDINIA
In north-western Sardinia alterites overlaying Mesozoic carbonate rocks occur
in two different stratigraphic and palaeogeographic contests. The older alterites
lay below some karstic bauxites of mid-Cretaceous age whereas the younger
ones are referred to Messinian time and occur as paleosoil within an alluvial fan
to braided river deposit. The palaeoclimatic conditions that led to the formation
of the alterites associated to the bauxite are well constrained. As a fact NW
Sardinia and Provence before the Miocene drift of the Corsica-Sardinia Plate
pertained to the same south European realm characterized by a monsoonal
climate. Nevertheless some open questions concern the provenance of the
parental material that first evolved into the alterites and than into bauxite.
Conversely, the provenance of the Messinian alterites is well localized in the
Variscan metamorphic basement of NW Sardinia but no univocal data concern
the palaeoclimatic conditions during their formation.
From the comparison of the mineralogical and geochemical features between
the two alterites further data can be attained:
1) about the provenance of the bauxite parent material;
2) about the alteration conditions during the Messinian time in western
Mediterranean.
The Cretaceous alterites are mostly composed by kaolinite, subordinate illite,
minor Fe-oxyhydroxide and boehmite. The Messinian alterites are composed
by illite and kaolinite in equal proportion, with minor content of
Fe-oxyhydroxide and gibbsite.
71
As concerns chemical data both subsets have been normalized to the Gloss
standard (Plank and Langmuir, 1998) in order to stress their features relatively
to average upper continental crust composition.
As for major elements the Cretaceous Subset (CS) is strongly enriched in Ti
and Al (2-5 x Gloss) and, to a minor extent, in Fe (2-4 x Gloss) whereas
relevant depletion (<1 x Gloss) is observed for Si and especially Mn, Ca, Na, K,
and P. The Messinian Subset (MS) is moderately enriched (1-2 x Gloss) in Ti,
Al, Fe, and K.
As for trace elements, some transition metals, includind Sc, V, Cr, and Ni, and
some high field strenght elements, including Y, Zr, Hf, Nb, and Th, are enriched
in CS samples, whereas in the MS samples their contents are close to those of
the Gloss.
Chondrite-normalized REE patterns show homogeneous and typical UCC
pattern for MS samples with average Lach/Ybch = 9,6 and average Eu/Eu*=
0,72. Chondrite-normalized REE patterns of CS samples show fractionation
effects likely due to intense weathering, in agreement with CIA values and
A-CN-K ternary plot, including Ce-anomalies and scattered Lach/Ybch values
(from 2 to 17). It is interesting to observe that the conservative provenance
Eu/Eu* proxy has average value (0,72) very similar to that of the MS subset.
In order to assess the source(s) from which the clays derive we coupled the
Eu/Eu* index with the TiO2/Al2O3 ratio which also is conservative during
weathering. In the Eu/Eu* vs TiO2/Al2O3 binary plot samples from both subsets
form an homogeneous array close to the UCC average composition and
pointing toward a mafic end member.
The data obtained may suggest that subsets share a common source area in
which occurred also mafic protoliths and that alteration during Messinian
occurred under less dry condition as supposed.
T05-11 Poster
Manfra, Luigia
HEAVY METALS IN THE SUBMERGED OMBRONE RIVER DELTA
(CENTRAL TYRRHENIAN SEA - ITALY)
CONFORTO Luisa 1, MANFRA Luigia 1
1 - Sapienza Università di Roma
Key terms: Heavy Metals; Marine Sediments; Tyrrhenian Sea;
Paleoenvironment; Anthropic influences
Heavy metals (Fe, Mn, Pb, Zn, Cu, Cd, Ni, Co, Cr) concentrations from the Last
Glacial Maximum to about 1000 years BP and their present distribution are
reported. Samples were collected during two campaigns carried out by the CNR
in 1994 and 1996 in the submerged Ombrone River delta. In a previous work
paleoclimatic and paleoenvironmental changes that occurred during the last 26
Kyr have been investigated in 6 cores by isotopic and micropaleontological
studies supported by Radiocarbon age determinations. In this work metals
concentrations in the cores are measured using an ICPAES to state the local
background in geological times before anthropic influences and their trends are
related to paleoenvironmental changes. The last 50 years concentrations trends
and their areal distributions are measured in 12 box-cores previously dated by
Cs and Pb methods. Those values, compared to the historical background,
could help to evaluate present environmental conditions of the basin.
Our results show that all the more significant elements measured in cores
generally have similar variation trends correlated to the main paleoclimatic
features. During glacial times concentrations reach their lowest values
according to scarce precipitations and low rivers contributions, whereas they
increase since the Holocene onset because of changed environmental
conditions (enhanced temperature, rainfalls and rivers supply). In some levels
Pb shows much enhanced concentrations probably linked to anossic
environment because of well stratified water column conditions with low salinity
layer in the surface waters. This feature is particularly pronounced in the most
distal core (about 22 Km from the coast, 150 m under the sea level) where this
element has its greatest increase, peaking in the level dated 6200 BP,
corresponding to the Sapropel S1 Phase, recognized in the eastern
Mediterranean but not yet found in the western area.
Co, Zn, Cu and particularly Pb reach enhanced concentrations in younger
samples, (about 3000-500 years BP) and this feature probably suggests an
anthropic origin, since higher values are found in levels corresponding to main
human activities periods. These elements, largely employed in many hand
made goods as glasses, pottery, coins, aqueducts pipes, were available in the
metallurgic Tuscan region. We can recognize the Etruscan, Roman and the
Renaissance ages, whereas in the early Middle Age (VI century D.C.), when
human activities were poorly developed and the mines were nearly
unexploited, metals concentrations fall to background mean values.
Box-cores data show that present elements concentrations are almost similar
to the background ones, the main difference concerning some Mn values found
in top levels spanning from 1986 to 1993. Two main Mn concentration belts are
evidenced following a NW-SE alignment; the outer belt (25-10 Km from the
coast) includes values ranging from 1000 to about 3500 ppm , while the inner,
nearer to the coast, has values (500 - 900 ppm.), similar to the background.
This Mn increase in the more recent levels could be explained by an anthropic
supply in the last years as there are many activities that could cause Mn
environmental dispersion. Moreover, Mn anomalies disposition along the coast
could be due to marine currents flowing through the Giglio Island and the
Argentario Mount, following a SE-NW course. This feature suggests that the
Mn-rich sediments could rather come from an alloctonous source from the
South than from the Ombrone River basin, as evidenced from recent
sedimentological and seismic studies. Nevertheless, these different
concentrations could be due to the geochemical Mn behavior linked to the pH
and Eh conditions changing from the coast to the open sea and from the
deeper sediment to the surface. Further studies are needed to solve this issue.
T05-12 Poster
Nisi, Barbara
GROUND-AND STREAM-WATER GEOCHEMISTRY FROM THE CHIANA
VALLEY (EASTERN TUSCANY. CENTRAL ITALY).
VASELLI Orlando 1, TASSI Franco 1, NISI Barbara 1, ROSSETI Ilaria 1, RAMALDI
Elena 1, DELGADO HUERTAS Antonio 2, BUCCIANTI Antonella 1, BICOCCHI
Gabriele 1, MONTEGROSSI Giordano 3
SESSIONE T05
72
1 - Department of Earth Sciences Florence (Italy)
2 - CSIC - Estacion Experimental de Zaidin Granada (Spain)
3 - CNR-Institute of Geosciences and Earth Resources Florence (Italy)
Key terms: Chiana Valley; central Italy; stream and ground waters;
geochemistry; stable isotopes
Intensive agriculture and agrozootechnical activities play an important role in
affecting and spoiling the water quality of rivers and shallow aquifers, in spite
of increasing efforts to minimize their effects. From this point of view, the
NNW-SSE-oriented Chiana Valley (eastern Tuscany, Italy), whose origin is
referred to the Plio-Pleistocene extensional event after the Apenninic
compressive phase, is one of the most productive areas so that anthropogenic
sources, such as fertilizers, sewage effluents and mainly hog, cattle and poultry
manure, seriously affect the water resources. In this context, the original
chemical composition of water is often completely masked and the
nitrogenated species achieve concentrations several orders of magnitude above
those found in unpolluted areas. In the present work, the results obtained
during an extensive geochemical survey on surface and ground waters carried
out all over the Chiana Valley are discussed in order to asses which are the
portions of the valley more prone to agriculture and agrozootechnical pollution.
More that 120 springs and wells and 25 stream waters, the latter being
collected monthly for one year along the main course (Chiana Channel) and its
tributaries, have been analyzed for main, trace (Br and F) and nitrogenated
(ammonium, nitrite and nitrate) species as well as and oxygen and hydrogen
isotopes. More than one third of the ground waters has resulted to be
unsuitable for human consumption being characterized by high contents of
dissolved species, e.g. the values of Total Dissolved Solids (TDS) are up to
4,000 mg/L, and particularly high ammonium and nitrate contents (18 and 300
mg/L, respectively). Besides, the high variability in terms of geochemical facies
(from calcium bicarbonate to sodium chloride), especially for those wells
bottoming up to 100 m, suggests the presence of deep-seated inputs of fluids
related to the complex geological structure of the area, these wells being
located along the main tectonic lineaments of the Chiana Valley. More than
50% of the running waters, likely affecting the ground waters when wells close
to the streams and bottoming at 5-20 m are taking into account, is persistently
exceeding the limits imposed by the Italian law for ammonium, nitrite and
nitrate contents (0.5, 0.1 and 50 mg/L, respectively) for waters intended to
human consumption. Also the stream waters have a highly variable chemical
composition ascribable to human activity with a clear geographical zoning.
Waters from the southern part (upper reaches) indeed vary in composition
from calcium sulfate to sodium chloride, whereas those flowing in the northern
part (lower reaches) are calcium(Mg) bicarbonate. The improvement of the
surface water quality to the North is likely resulting by the numerous, almost
unpolluted springs and stream discharging into the final part of the Chiana
Channel before it enters the Arno River, one of the most important Italian
rivers.
Oxygen and hydrogen isotopes eventually indicate that the shallow aquifers are
partly fed by the surface waters, whereas deeper aquifers are recharged by the
topographic highs (up to ca. 800-1000 m) that surround to the West and to the
East the Chiana Valley.
T05-13 Poster
Petrini, Riccardo
HYDROGEOCHEMISTRY AND SR ISOTOPES FOR THE
CHARACTERIZATION OF MULTIPLE SOURCES IN THE CLASSICAL KARST
AQUIFER (ITALY-SLOVENIJA BOUNDARY)
ZINI Luca 1, VALENTINUZ Federico 1, FRANCESCHINI Giuliana 1, SLEJKO
Francesca 2, PETRINI Riccardo 2, CUCCHI Franco 1
1 - DISGAM-Universita' di Trieste
2 - DST-Universita' di Trieste
Key terms: karst aquifer; geochemistry; Sr isotopes
The study of the different hydrological compartments is a prerequisite for the
monitoring of the elemental fluxes, to evaluate the environmental changes in
an ecosystem due to anthropogenic disturbance, and ultimately to preserve the
most vulnerable ground-waters from contamination and degradation. In many
karst domains in the Mediterranean areas, ground-water and surface water
constitute a single system, as the result of numerous solution features that
facilitate the exchange of water between surface and subsurface. A detailed
description of the hydrology in these type of aquifers and the definition of the
groundwater input and output balance has become urgent, due to their high
vulnerability.
The Classic karst covers an area of about 900 km2 extending from the SE of
Isonzo river to Slovenija, and its water resources serve at present more than
half a million people. The aquifer is hosted into deposits of the carbonatic
platform, divided into six chronologically different units, ranging in age from
Cretaceous to lower Eocene. These are overlapped by flysch deposits (Eocene)
characterized by a mineral assemblage of quartz, feldspar and micas. The
major springs have an average discharge capacity of 40 m3s-1 and a
maximum of 175 m3s-1, and are related to the Timavo river, to the Doberdo'
and Pietrarossa lakes. A number of minor springs are distributed along the
coast line and off-shore in the Trieste gulf. It is so far believed that the inputs
to groundwater circulation come mostly from the Timavo river and directly
from rainwater infiltration, even if in low water-table periods inputs from the
Vipacco and Isonzo rivers have been postulated. The latter river would be also
responsible for the input of potentially toxic elements, including mercury and
fertilizer-derived products.
In January 2007, a survey for the monitoring of selected springs and surface
waters was started. Geochemical data indicate that waters have a Ca-HCO3
and Ca-Mg-HCO3 character. Water-rock interaction and mass balance
calculations indicate that ground-waters evolve through different extent of
dolomite dissolution, and are near to equilibrium or slightly undersaturated in
calcite and quartz. Sr-isotope data allow to distinguish springs which
equilibrated with Cretaceous or Eocene limestones during their flow; higher
87Sr/86Sr ratios measured in some of the surface- and ground-waters record
mass transfers from silicate lithologies, attributable to the contributions of
Isonzo and Reka river to the water bodies.
T05-14 Poster
Nisi, Barbara
DETERMINATION OF NITROGEN AND OXYGEN ISOTOPES IN
DISSOLVED NITRATES IN DOMESTIC AND PUBLIC-SUPPLY WELLS
FROM CECINA VALLEY (TUSCANY, CENTRAL ITALY)
NISI Barbara 1, DELGADO HUERTAS Antonio 2, VASELLI Orlando 1, CAPECCHIACCI
Francesco 1, DOUENCE Cedric 2, FRULLINI Riccardo 1, PRANZINI Giovanni 1
1 - Department of Earth Sciences Florence (Italy)
2 - CSIC - Estacion Experimental de Zaidin Granada (Spain)
Key terms: Nitrate pollution; Cecina Valley; Oxygen and nitrogen isotopes;
Analitycal methods; Central Italy
Human activity has altered the nitrogen cycling in terrestrial and aquatic
ecosystems. The increasing use of nitrogen-bearing organic and inorganic
fertilizers along with the high deposition of atmospheric nitrogenated
compounds is enhancing nitrate fluxes in soil solutions, groundwater and
surface waters. Most urban and agricultural areas of Italy are facing the
problem of nitrate pollution in both surface and ground waters. Despite the
increasing efforts to reduce nitrate inputs from intensive agriculture at national
and European (EC Directive 91/676/CEE) levels, nitrate is still one of the main
contaminants. In this respect, isotopic techniques such as those set up for
nitrogen and oxygen isotopes in nitrates (e.g. Silva et al., 2000, Casciotti et
al., 2002) are particularly useful to define the main pollution sources (e.g. Nisi
et al., 2005).
This work, carried out in the framework of a PRIN project (Working Unit of
Florence: Resp. G. Pranzini), describes the analytical procedure for determining
nitrogen and oxygen isotopes in nitrate according to Silva et al. (2000), partly
modified in the Laboratories of Stable Isotope Geochemistry of Granada and
Florence. The method has been applied in an explorative way to selected
domestic and public-supply wells from the hydrologically complex area of
Cecina valley (Tuscany, central Italy).
Water samples were collected from wells distributed throughout the valley in
urban and agricultural areas. Nitrate contents range from 15 to 200 mg/L. For
each site 1000 mL of water were filtered with 0.45 micrometers polycarbonate
membranes to avoid microbial reduction-oxidation reactions. Nitrate was
collected by anion exchanging resin columns after eluting anions with 3M HCl
that was neutralized by adding Ag2O. The AgCl precipitate was removed by
filtration leaving Ag-NO3 in solution and solid AgNO3 was obtained by
freeze-drying. Nitrogen isotope ratios were determined by thermal
decomposition of AgNO3 into tin capsules by a Carlo Erba 1500 NC elemental
analyzer connected to a Finningan Delta Plus XL mass spectrometer. For
oxygen isotope analysis all oxygen-bearing compounds and dissolved organic
matter must be removed. Therefore, barium chloride was added to the aliquots
of the neutralized eluent to precipitate sulfate and phosphate. The suspension
was filtered and then passed through a cation exchange column to remove the
excess Ba, re-neutralized with Ag2O, filtered again and finally agitated with
activated carbon to remove dissolved organic matter. The nitrate solution was
then freeze-dried and the oxygen isotope ratios were obtained by combustion
into silver capsules with a Finningan TC pyrolysis device connected to the Delta
Plus XL mass spectrometer. The nitrogen isotope ratios (using the delta
notation) in the Cecina valley water samples are from -2.8 to + 14.9 0/00 (AIR),
whereas those of the oxygen isotope ratio vary from +10.1 0/00 to +22. 6 0/00
(V-SMOW). Most of the wells have a nitrogen and oxygen isotopic signature
typically associated with an origin of nitrate from synthetic nitrate fertilizers.
However, denitrification processes and/or residual water effluents of
agrozootechnical and/or urban origin cannot be ruled out and consequently,
more detailed investigations are needed to further constrain the potential
source of nitrogen pollution.
REFERENCES
CASCIOTTI K.L., SIGMAN D.M., GALANTER HASTINGS M., BÖHLKE J.K. AND
HILKERT A., 2002. Measurement of the oxygen isotopic composition of nitrate
in seawater and freshwater using the denitrifier method. Analytical Chemistry
74, 4905-4912.
NISI B., VASELLI O., BUCCIANTI A. & SILVA S.R.. 2005. Sources of nitrate in
the Arno River Waters: constraints d15N and d18O. GeoActa, 4, 13-24.
SILVA S.R., KENDALL C., WILKISON D.H., ZIEGLER A.C., CHANG C.C.Y.,
AVANZINO R.J., 2000. A new method for collection of nitrate from fresh water
and the analysis of nitrogen and oxygen isotope ratios. J. Hydrol., 228, 22-36.
T05-15 Poster
Sacchi, Elisa
NITRATE CONTAMINATION OF THE PO VALLEY PHREATIC AQUIFER: AN
ISOTOPIC REGIONAL SURVEY
SACCHI Elisa 1, PILLA Giorgio 2, GERBERT-GAILLARD Laure 3, ZUPPI Gian Maria 4
1 - Dipartimento di Scienze della Terra, Università di Pavia e CNR-IGG, sezione
di Pavia
3 - ISO4 s.s.
4 - Dipartimento di Scienze Ambientali, Università Ca' Foscari di Venezia
Key terms: nitrate; groundwater pollution; stable isotopes; phreatic aquifer
Nitrate concentration in surface and groundwater is an environmental concern.
Nitrate pollution may be attributed to point sources, such as landfills, septic
tanks or factory farming. Agricultural regions commonly suffer diffuse water
pollution, which, in contrast, cannot be attributed to a precise source. Rather, it
is the cumulative effect of day to day activities over large areas, including
application of synthetic fertilisers, manure spreading and sewage sludge
disposal.
Distinction between different sources of nitrates in groundwater can be made
using hydrochemistry or/and by determining the isotopic signature of oxygen
and nitrogen in the nitrate molecule. While the first approach may be useful in
simple cases such as point source pollution, the combination of 15N and 18O
data in nitrate allows to evidence cumulative effects in regional contamination
problems and, in addition, to recognise nitrification and denitrification
processes.
The Po plain hosts a multilayer alluvial aquifer, of Quaternary age, is
SESSIONE T05
constituted by gravels and sands with interbedded clay layers. The thickness of
the sedimentary sequence is strongly conditioned by the presence of buried
structures of the marine substratum, which are dislocated and affected by
Alpine and Apennine thrusts. Groundwater flow direction in the phreatic aquifer
is oriented N to S in the pre-alpine sector and S to N in the Apennine one. The
area covered by this study is of approximately 3,600 km2, crossing the Po plain
from N to S in correspondence to the Piedmont-Lombardy administrative
boundary (Novara, Alessandria and Pavia provinces). Agricultural land use
includes corn, wheat and rice fields.
Sample selection for hydrochemical and isotopic characterisation was
performed based on available data from groundwater quality monitoring
programmes. About 100 monitored wells and natural outflows were considered,
including also rivers and irrigation channels, all with nitrate concentration
exceeding 10 mg/l.
This study dramatically evidences the impact of intense agriculture activities
over groundwater resources. Contamination from synthetic fertilisers is
widespread and nitrate accumulation is a threat to large groundwater supplies.
Peak concentrations are instead associated to point source pollution and can be
attributed to leakage of the sewage network. Nitrate concentrations being
higher than 10 mg/l, the isotopic compositions in the compositional field of soil
organic matter likely correspond to a mixed contribution from both synthetic
fertilisers and manure spreading.
The distribution of groundwater contamination is closely related to:
1. the hydraulic characteristics of the unsaturated zone: clay rich soils reduce
infiltration and favour denitrification through the establishment of anoxic
conditions
2. the agricultural input: corn and wheat cultivation seems to be mostly
responsible for nitrate contribution to groundwater
3. irrigation practices: the artificial recharge associated with rice cultivation
also represents a preferential pathway for input of exotic substances to
groundwater, but in this case, the input of nitrogen compounds is partially
reduced by denitrification, as it is observed in the Casale and Lomellina areas.
The isotopic composition of nitrates confirms the hydrogeologic model of the
phreatic aquifer. In the Po plain, the depth of the denitrification zone is
strongly conditioned by the presence of buried structures and associated saline
waters: it may be as shallow as 15 m below surface, like in the Oltrepo region,
or deeper than 100 m, like in the Alessandria plain. Therefore stable isotopes of
the nitrate molecule may also represent a useful tool to evidence aquifer
overexploitation associated with high withdrawal rates.
T05-16 Poster
Sacchi, Elisa
TRACING NITRIFICATION AND DENITRIFICATION PROCESSES IN A
PERIODICALLY FLOODED SHALLOW SANDY AQUIFER (LOMELLINA,
NORTHERN ITALY)
SACCHI Elisa 1, PILLA Giorgio 2, GUALLINI Marcella 2, ALLAIS Enrico 3, ZUPPI Gian
Maria 4
1 - Dipartimento di Scienze della Terra, Università di Pavia e CNR-IGG, Sez. di
Pavia
3 - ISO4 s.s.
4 - Dipartimento di Scienze Ambientali, Università Ca' Foscari di Venezia
Key terms: flooded soil; heavy metals; nitrate isotopes; groundwater pollution;
redox
The Lomellina region is characterised by an elevated potential infiltration and
intensively cultivated with, mainly, rice and corn fields. A severe recharge of
the phreatic aquifer takes place from seepages of channel network and from
rice ponds. Therefore, the phreatic aquifer often contains waters of poor
quality: high salinity, high nitrate, sulphate and chloride contents and, locally,
detectable amounts of heavy metals and pesticides. Soils are arenosols and
luvisols, with acidic pH, mainly constituted by quartz and feldspars. A strong
depletion of Mn and Fe in the topsoil is often observed in rice paddies, together
with the formation, at a depth greater than 80 cm, of Fe and Mn precipitates
and nodules.
Eleven very shallow wells were selected in a limited area for water level,
hydrochemical and isotopic monitoring. The water table depth was measured
daily at the centre of the investigated area. Groundwater sampling closely
followed the agronomical practices and was performed approximately once per
month, from March 2006 to January 2007. Analyses included: pH, Eh,
temperature, conductivity, major ions, trace metals, and stable isotopes of
dissolved nitrates.
After field waterlogging, the water table level steeply increased of 1.6 m, rising
the piezometric surface to about 1.5 m below the surface. Data collected from
local irrigation agencies allowed calculating for the entire season a recharge of
about 38,000 m3/ha, highly exceeding natural recharge from precipitation. The
seasonal variation of groundwater quality includes a rise in temperature and
conductivity, and a decrease in pH, a typical evolution for shallow groundwater.
On the other hand, Eh is highly variable from well to well, indicating the
presence of localised oxido-reduction phenomena.
Based on hydrochemical characteristics and seasonal evolution two groups of
waters were be distinguished:
- Group 1 wells show, after soil flooding, a progressive decrease in Eh and
dissolved nitrates, and an increase in alkalinity and Fe content. Mn is always
low and Zn content may rise up to 2.6 mg/l. The isotopic composition of
dissolved nitrates range from +4 to +13 0/00 in 15N, and several samples fall
in the compositional field of soil organic matter. This seasonal evolution is
easily interpreted as a denitrification, operated via the oxidation of the
dissolved inorganic matter and producing an increase in alkalinity. During
denitrification, the increase in Fe content is probably due to the destabilization
of Fe oxi-hydroxides rather than to pyrite oxidation.
- Group 2 wells show an increase in Eh, dissolved nitrate and Mn contents, a
decrease in Fe, low Zn and very high K contents (up to 60 mg/l). The seasonal
evolution of the nitrate isotopic composition follows the slope of the
denitrification trend, but in the opposite direction, and could therefore be
interpreted as a mixing process between a residual and a "fresh" nitrate
source. Nevertheless, samples with the highest nitrate concentrations have an
enriched isotopic composition which cannot be readily attributed to any precise
source. Given the close relationship observed between dissolved nitrate and Mn
73
content in these samples, it is suggested that their enriched isotopic
composition is derived by nitrification of residual ammonium using MnO2 as an
oxygen source.
These seasonal differences are likely related to land use. In fact, samples from
group 2 are located within or close to rice paddies, while land use is more
variable elsewhere. Flooded rice paddies provide a unique environment where,
in ideal conditions, nitrification and denitrification processes can be traced and
rates calculated. This was not possible at the end of this monitoring year,
because the cycle was not completely closed by a return to the initial
conditions. This is attributed to the exceptionally warm winter experienced this
year, allowing the biological activity in soils to persist.
SESSIONE T06
Fibre minerali naturali: rischio ambientale ed effetti sulla salute
T06-1 Key Lecture
Gunter, Mickey E.
THE ROLE OF THE MINERALOGIST IN ASBESTOS-RELATED ISSUES
GUNTER Mickey E. 1
1 - Geological Sciences, University of Idaho, Moscow Idaho, 83844-3022, USA
Key terms: Asbestos; non-regulated asbestos; Libby, Montana USA;
non-commercial asbestos; El Dorado Hills, California USA
Over the past 100 years as the world became industrialized, over 180 million
metric tons of asbestos were mined and used world-wide, peaking in the
mid-1970s to approximately 5 million tons per year. During this time, asbestos
was used in thousands of products, especially textiles and insulating materials.
World production dropped to approximately 2 million tons by 2003, but this
mineral commodity still amounted to approximately $500 million (US) in 2003.
Of the seventeen countries that still produced commercial asbestos, Russia,
China, and Canada were the leaders, while China, India, and Kazakhstan were
the leading three countries in asbestos use. Currently, the majority of
asbestos is used in asbestos-cement products.
The use of asbestos declined in the late 1970's as health concerns arose among
asbestos miners and millers. The associated diseases were asbestosis, lung
cancer, and mesothelioma. Also during this time, members of the
mineralogical community pointed out that there appeared to be a relationship
between these diseases and the different asbestos minerals, with the
less-commonly used commercial amphibole varieties, crocidolite (i.e.,
asbestiform riebeckite) and amosite (i.e., asbestiform grunerite) presenting
more of a health risk than the more commonly used chrysotile (a fibrous form
of serpentine). Three other asbestiform varieties of amphibole are worth
noting: anthophyllite, tremolite, and actinolite; these varieties were never
mined in large amounts and there are no specific names to differentiate their
asbestiform and non-asbestiform varieties.
Issues surrounding asbestos had waned in the United States until the fall of
1999, when the news media reported on asbestos diseases of the former
miners of the closed vermiculite mine in Libby, Montana, USA. The vermiculite
deposit contained trace amounts of amphiboles assumed to be tremolite.
Characterization on these samples showed them to be predominantly the
non-regulated amphiboles winchite and richterite. While there is little
disagreement on the species names of these amphiboles, or the fact that all
asbestiform amphiboles should be regulated, there is at issue the distinction
between asbestiform and non-asbestiform varieties of non-commercial
amphiboles. Some researchers claim that less than one-third of the samples
from Libby are asbestiform, while others claim almost of all them are. The
issue becomes how to distinguish a fiber of an amphibole from a fragment.
And while this is a regulatory concern, the underlying debate is that fibers may
be more harmful to health than fragments, and there is disagreement on this
issue among scientists.
El Dorado Hills, California, USA, is a growing community in central California
located in a geologic environment where amphiboles occur. Concern arose
there about asbestos exposure to school children as well as the residents. The
phrase "naturally occurring asbestos" has been used in this region to
distinguish between commercially produced asbestos and the amphiboles that
occur naturally in rocks and soils. Also at issue in this community, and many
other areas of the US and world where amphiboles are major constituents of
the rocks, is how to distinguish between fibers and fragments of amphiboles.
Clearly, assistance of the mineralogical community is needed to characterize
these materials to aid in health-based studies, as well to help establish some
common-sense regulations. It is fairly easy for us to provide precise structural
and compositional information on these minerals, while it is more difficult to
quantitatively distinguish between fibers and fragments; however, we are in
the best position to make this distinction. We also can assist in providing the
geological context for the occurrence of these minerals. Last, we should play
more of an active role in assisting those who make public policy decisions when
dealing with non-anthropogenic exposure to earth materials.
T06-2 Invitato
Groppo, Chiara
METAMORPHIC VEINS FROM THE SERPENTINITES OF THE PIEMONTE
ZONE, WESTERN ALPS: A REVIEW
GROPPO Chiara 1, COMPAGNONI Roberto 1
1 - Dept. of Mineralogical and Petrological Sciences, Univ. Torino &
Interdepartmental Centre "G. Scansetti" for Studies on Asbestos and other
Toxic Particulates, Univ. Torino, Italy
Key terms: Piemonte Zone; natural hazard; serpentinites; fibrous minerals
In the Western Alps only three of the six minerals defined as "asbestos" by the
D.L. 15/08/91 occur in the Piemonte Zone, namely chrysotile, tremolite and
actinolite. However, in the past decades, a large variety of fibrous minerals not
SESSIONE T06
74
regulated by the current legislation were discovered in the serpentinites of the
Piemonte Zone. Among them the most abundant are: antigorite, diopside,
carlosturanite and balangeroite (Compagnoni et al., 1983, 1985; Belluso &
Ferraris, 1991; Belluso et al., 1997; Compagnoni & Groppo, 2006; Groppo &
Compagnoni, 2006, 2007), whereas sepiolite, brucite, brugnatellite, olivine and
Ti-clinohumite are rare (Belluso et al., 1997).
Preliminary chemical and biochemical data (Gazzano et al., 2005; Groppo et
al., 2005; Turci et al., 2005) suggest that balangeroite is a potentially harmful
fibrous mineral, with toxicity effects similar to those of crocidolite. Being the
health effects of most non regulated fibrous minerals still unknown, the
detailed analysis of their occurrences in the natural environment is of
paramount importance for the definition of an asbestos natural hazard.
In this light, a detailed petrologic study of the metamorphic veins occurring in
serpentinites from the Piemonte Zone was performed, which allowed to
recognise six different vein generations containing fibrous minerals, developed
at different P-T-X conditions.
° The first vein generation consists of fibrous balangeroite + magnetite +
FeNi-alloys (+ fibrous chrysotile replacing balangeroite) and formed during the
serpentinite prograde evolution. These veins are limited to the serpentinized
portion of the Lanzo Ultramafic Massif.
° The second vein generation, consisting of diopside + Ti-clinohumite +
olivine + antigorite + Mg-chlorite, is related to the high pressure peak
metamorphic event and is widespread in the Internal, eclogite-facies, Piemonte
Zone. Diopside and less frequently Ti-clinohumite and olivine may occur with a
fibrous habit.
All the other vein generations developed during the retrograde serpentinite
evolution, at different P-T conditions:
° Types 3 veins, consisting of carlosturanite + antigorite + diopside + garnet
(+ fibrous chrysotile and brucite replacing carlosturanite) formed at moderate
P-T conditions and are present in the serpentinites from the Internal Piemonte
Zone. Carlosturanite, diopside and garnet all occur with a fibrous habit.
° Type 4 veins, consisting of fibrous antigorite + diopside, formed at low P-T
conditions. These veins are ubiquitous in both the Internal and External
Piemonte Zone.
° Veins of type 5 and type 6 consist of chrysotile and fibrous tremolite +
calcite, respectively, and formed at very low P and T conditions. Chrysotile
veins are widespread in both the Internal and External zone, whereas tremolite
veins are localized in fractures characterized by circulation of a CO2-bearing
fluid.
References
Belluso & Ferraris (1991). European Journal of Mineralogy, 3, 559-566.
Belluso et al. (1997). In: Minoia C., Scansetti G., Piolatto G & Massola A.
(Eds.): "L'amianto: dall'ambiente di lavoro all'ambiente di vita. Nuovi indicatori
per futuri effetti", Fondazione Maugeri, 167-174.
Compagnoni & Groppo (2006). Rendiconti Società Geologica Italiana, 3, Nuova
Serie, 21-28.
Compagnoni et al. (1983). American Mineralogist, 6, 214-219.
Compagnoni et al. (1985). American Mineralogist, 70, 767-772.
Gazzano et al. (2005). J. Toxic. Environ. Health , 68, 41-49.
Groppo & Compagnoni (2007). Periodico di Mineralogia (in press)
Groppo et al. (2006). European Journal of Mineralogy, 18, 319-329.
Groppo et al. (2005). J. Toxic. Environ. Health, 68, 1-19.
Turci et al. (2005). J. Toxic. Environ. Health , 68, 21-39.
T06-3 Invitato
Mazziotti Tagliani, Simona
MINERALOGICAL CHARACTERIZATION OF FIBROUS AMPHIBOLES OF
ENVIRONMENTAL INTEREST.
MAZZIOTTI TAGLIANI Simona 1, ANDREOZZI Giovanni Battista 1, BALLIRANO
Paolo 1, PACELLA Alessandro 1, BRUNI Biagio Maria 2, BURRAGATO Francesco 1,
GIANFAGNA Antonio 1, PAOLETTI Luigi 2
1 - Dipartimento di Scienze della Terra, Sapienza Università di Roma, Piazzale
A. Moro, 5 - 00185 Roma Italy
2 - Dipartimento di Tecnologie e Salute, Istituto Superiore di Sanità, V.le R.
Elena, 299 - 00162 Roma Italy
Key terms: Fibrous amphiboles; Fluoro-edenite; Tremolite; Crystal chemistry;
Biological environment
Fibrous amphiboles have been recognized as highly oncogenic upon inhalation,
due to their morphology, structural features and chemical composition. Severe
and widespread environmental contamination by amphibolic fibers requests a
detailed study of these minerals.
Both mineral asbestos sensu stricto (Burragato et al., 2001) and the new
mineral fibers not classified as asbestos have been studied for years at the
Department of Earth Science, Sapienza University of Rome.
The new fibrous amphibole fluoro-edenite, of ideal formula NaCa2Mg5(Si7Al)O22F2
, was found in the volcanic products of Biancavilla (Sicily, Italy) and was
recognized as the responsible of an anomalously high incidence of malignant
pleural mesothelioma.
Up to now Biancavilla is the first known occurrence of amphibole asbestos in a
volcanic area. Mineralogical and environmental investigations led to the
identification of the fluoro-edenite (Gianfagna and Oberti, 2001) and in
particular of the fibrous amphibole as a secondary product in the volcanic
formations around the "Il Calvario" locality.
Chemical data obtained on both the fibers and the mineral assemblage of the
samples show that the fibrous amphiboles derive on the fluids that locally
metasomatize the benmoreitic products. These fluids were enriched in F, REE,
and incompatible elements, which allowed the crystallization of fibrous
amphiboles and other fluorine-rich minerals. By combining micro-chemical,
Mössbauer and structural data the fibrous amphiboles from Biancavilla are
classified as fluoro-edenite, even if very subordinate tremolite, winchite, and
richterite compositions are also present (Mazziotti-Tagliani, 2007).
Preliminary crystal-chemical results on tremolite fibers, mainly coming from
Italian sites with presence of ophiolites and "green stones" (Piemonte, Lazio,
Basilicata and Calabria), are less heterogeneous with respect to the
fluorine-edenite fibers from Biancavilla. In particular, tremolites show minor
compositional variations prevalently related to the Fe, Al, and Na contents
(Pacella et al., 2007).
From the toxicological point of view, both in vivo and in vitro tests confirmed
the strong influence of both chemical composition and iron species. In fact, a
content of Fe 2+ higher than that of Fe 3+ in the fibers corresponded to a greater
toxicity both in cellular and tested animals. These results show that the Fe 2+/Fe
3+
ratio is an important parameter playing a crucial role in the development of
cancer. Further investigation will be focused on this particular aspect to check
the real toxicity of the fibers in the biological environment.
Burragato F., Ballirano P., Fiori S., Papacchini L., Sonno M. (2001) Segnalazione di tremolite asbestiforme nel Lazio. Il Cercapietre. Notiz. Gruppo
Mineralogico Romano. Vol. 1/2, 2001.
Gianfagna A., Oberti R. (2001) - Fluoro-edenite from Biancavilla (Catania,
Sicily, Italy): crystal chemistry of a new amphibole end-member. Amer. Miner.,
86, 1489-1493.
Mazziotti-Tagliani S. (2007) - Gli anfiboli fibrosi nell'area vulcanica di
Biancavilla: un particolare approccio metodologico. Convegno Nazionale
"Anfiboli fibrosi:nuove problematiche relative al rischio ambientrale e
sanitario". Roma, 27-28 Aprile 2007. Volume Atti, pp. 43-46.
Pacella A., Andreozzi G.B., Ballirano P., Gianfagna A., Mazziotti Tagliani S.,
Bruni B.M. (2007) - Caratterizzazione cristallochimica di fibre di anfibolo di
interesse ambientale. Convegno Nazionale "Anfiboli fibrosi:nuove
problematiche relative al rischio ambientale e sanitario". Roma, 27-28 Aprile
2007. Volume Atti, pp. 160-161.
T06-4 Invitato
Belluso, Elena
LOCAL ENVIRONMENTAL BACKGROUND OF MINERAL FIBRES BY
SENTINEL ANIMALS
BELLUSO Elena 1, BELLIS Donata 2, CAPELLA Silvana 3, FORNERO Elisa 4,
FERRARIS Giovanni 1, COVERLIZZA Sergio 5
1 - Dip. di Scienze Mineralogiche e Petrologiche, Università di Torino; CNR IGG
- Sez. di Torino; Centro Interdip. per lo Studio degli Amianti e di altri Particolati
Nocivi "G. Scansetti", Univ. di Torino
2 - Serv. di Anatomia, Istologia Patologica e Citodiagnostica ASL4 Torino Nord
Emergenza S.G. Bosco; Centro Interdip. per lo Studio degli Amianti e di altri
Particolati Nocivi "G. Scansetti" Univ. Torino
3 - Dip. di Scienze Mineralogiche e Petrologiche, Università di Torino; Centro
Interdip. per lo Studio degli Amianti e di altri Particolati Nocivi "G. Scansetti" Univ. di Torino
4 - Dip. di Scienze dell'Ambiente e della Vita, Università del Piemonte Orientale,
Alessandria; Centro Interdip. per lo Studio degli Amianti e di altri Particolati
Nocivi "G. Scansetti", Univ. di Torino
5 - Serv. di Anatomia, Istologia Patologica e Citodiagnostica ASL4 Torino Nord
Emergenza S.G. Bosco
Key terms: MINERAL FIBRES; SENTINEL ANIMAL; LOCAL ENVIRONMENTAL
BACKGROUND; BREATHABLE MINERAL MONITORING
In last decades many fibrous minerals have been found in outcropping rocks of
different Italian areas, e.g. in serpentine rocks of Piedmont, Basilicata and
Calabria, and in volcanic rocks of Sicily. In Piedmont, asbestos chrysotile,
tremolite and actinolite and other fibrous minerals not asbestos classified (e.g.
balangeroite and carlosturanite) have been found in large quantity. In Sicily,
some different fibrous amphiboles, among fluoro-edenite fibres, are abundant
in autochthon lava rocks. At Balangero (Turin) the biggest mine of crysotile in
Europe was operative for long time. Moreover Piedmont has a territory with
large industrial presence; at Casale Monferrato (Alessandria) the corrugated
asbestos-cement roofs have been the most manufactured product; a lot of
infrastructures have been built using serpentine rocks. At Biancavilla the
volcanic rock containing fibres were locally used as building material until few
years ago. Everywhere, human activities and weather actions like wind and
rainfall have relevance as well, operating both on anthropic and natural sources
and producing air dispersion of fibres of different dimensions, also breathable.
Recent publications show the advantage in using animal populations (Sentinel
System Animals) as indicator of airborne and breathable pollutants (e.g.
asbestos). Therefore our investigations have been carried out in lung samples
of some animals species lived in different Piedmont areas and near Biancavilla
(Sicily), opportunely chosen:
- 20 lungs of cows from Susa Valley (VS), Piedmont;
- 19 lungs of cows from Lanzo Valleys (VL), Piedmont;
- 6 lungs of cows from Sesia Valley (VC), Piedmont;
- 6 lungs of wild animals from Varaita Valley (VV), Piedmont;
- 28 lungs of wild animals from Regional Park "La Mandria" (M), Piedmont;
- 12 lung of sheep and 1 of goat from Biancavilla (BV), Sicily;
- 12 lungs of cows from Asti (AT), Piedmont, as control group.
After chemical digestion every sample have been investigated by MO and
SEM-EDS in order to detect ferruginous bodies (Fb) and identify and quantify
the mineral fibres species and synthetic inorganic fibres respectively.
Histological section examination has been carried out by OM to evaluate
inorganic lung burden too.
Fb has been detected in all animal groups except in VC group with a frequency
of 16% in VL samples, 20% in VS samples, 33% in VV and M samples, 35.7%
in BV samples and 50% in At samples.
Many different inorganic fibres have been detected in lungs of Piedmont
animals: asbestos tremolite, actinolite, crocidolite, grunerite and chrysotile; not
asbestos natural and synthetic silicates (e.g. diopside, vitreous fibres); titanium
dioxide.
In animal lungs from Biancavilla area (Sicily) the following inorganic fibre
species have been detected: inosilicates (amphiboles and pyroxenes),
sheet-silicates (mainly clay minerals), feldspars and titanium dioxide.
These results are been compared with those of animals' lung samples from Asti
(Piedmont), area geologically free of asbestos (control case).
In decreasing order the inorganic fibres lung burden has been observed in
100% of BV, in 95% of VS samples, in 84% of VL samples, in 32% of M
samples, in 25% of VV samples, in 17% of VC samples and in 8% of AT
samples.
Our results confirm the advantage of using lungs of SSA to monitor the
background level of breathable inorganic fibres in natural environment.
Aims of this work is to begin the creation of a map of burden of Fb and
breathable inorganic fibres in the different Italian areas.
T06-5 Invitato
SESSIONE T06
Tomatis, Maura
ASBESTIFORM MINERALS IN THE NATURAL ENVIRONMENT:
LOCALISATION, IDENTIFICATION, POTENTIAL HAZARD AND POSSIBLE
INACTIVATION ROUTES. A MULTIDISCIPLINARY APPROACH IN A
JOINT PROJECT CENTRO SCANSETTI-REGIONE PIEMONTE
TOMATIS Maura 1, GROPPO Chiara 2, DAGHINO Stefania 3, FAVERO-LONGO Sergio
Enrico 3, FORNERO Elisa 4, GAZZANO Elena 5, TURCI Francesco 1, COMPAGNONI
Roberto 2, GHIGO Dario 5, FUBINI Bice 1
1 - Dip. Chimica IFM e Centro "G. Scansetti" per lo Studio degli Amianti e degli
altri Particolati Nocivi-Università di Torino
2 - Dip. Scienze Mineralogiche e Petrologiche e Centro "G. Scansetti" per lo
Studio degli Amianti e degli altri Particolati Nocivi-Università di Torino
3 - Dip. Biologia Vegetale e Centro "G. Scansetti" per lo Studio degli Amianti e
degli altri Particolati Nocivi-Università di Torino
4 - Dip. Scienze dell'Ambiente e della Vita-Università del Piemonte Orientale "A.
Avogadro" e Centro "G. Scansetti" per lo Studio degli Amianti e degli altri
Particolati Nocivi
5 - Dip. Genetica, Biologia e Biochimica e Centro "G. Scansetti" per lo Studio
degli Amianti e degli altri Particolati Nocivi-Università di Torino
Key terms: asbestiform minerals; potential hazard; inactivation
Asbestiform minerals occur in several natural environment. The Piemonte Zone
(Italian Western Alps) is rich in asbestos, mainly chrysotile (serpentine) - the
Balangero chrysotile mine, the largest one in Europe, is in fact located in the
Lanzo Ultramafic Massif -and tremolite (amphibole). Besides this two regulated
asbestos, other less common fibrous minerals (e.g. balangeroite and
carlosturanite), not regulated by the current legislation, are also present. This
minerals may be as hazardous as the well-known asbestos forms. The
commercially use of asbestos has been banned in Italy in 1992, so, from
occupational issue, they have now become mostly an environmental problem.
The presence of such fibrous minerals may constitute a potential risk to the
local population if the fibers become airborne fibers and are inhaled, following
antropic activities. However, while strict regulations in most of the Western
Countries, which have banned the use of asbestos, control the conditions to be
fulfilled by workers acting in the presence of asbestos, there is a lack of
information and regulations on asbestos in the environment. There are no
indications on the protocol to follow during rock removal in construction works,
no information on the toxicity of asbestos fibers exposed for long periods of
time to weathering nor of the other asbestiform minerals, not regulated by the
current legislations.
In order to evaluate asbestos risk in this area the Regione Piemonte has
established a collaboration with the Interdepartmental Center "G. Scansetti" for
Studies on Asbestos and other Toxic Particulates of the University of Torino,
aiming to tackle the problems by means of a multidisciplinary study, involving
expertise from geology and chemistry to toxicology and epidemiology. The
study involves the following steps:
i) localization of asbestos mineralisation in serpentinites, characterization and
identification of both conventional and non regulated asbestos; ii) evaluation of
fibers in air, in the organs of nearby standing animals and in the exposed
population; iii) chemical and biochemical investigations on the toxicity of the
new asbestiform minerals whose interaction with animal tissues and impact on
human health have never been studied; iv) effect of weathering, of growth of
fungi or lichens on the fibers composition and reactivity, in view of possible
bioremediation routes.
T06-6 Invitato
Belpoggi, Fiorella
FIRST EXPERIMENTAL EVIDENCE OF MESOTHELIOMAS INDUCED BY
FLUORO-EDENITIC FIBRES PRESENT IN THE LAVA STONE OF THE ETNA
VOLCANO. THE CARCINIGENICITY OF DIFFERENT KIND OF NATURAL
FIBRES.
SOFFRITTI Morando 1, BELPOGGI Fiorella 1, TIBALDI Eva 1, LAURIOLA Michelina 1,
MANSERVIGI Marco 1
1 - Fondazione Europea Ramazzini, Bologna
Key terms: mesothelioma; fluoroedenite; Biancavilla
Subsequent to the detection of an increased mortality for malignant pleural
neoplasms (4 observed versus 0.9 expected) in the town of Biancavilla (about
20,000 inhabitants), situated on the south-west slope of the Etna volcano
(Sicily, Italy), 17 cases (10 males and 7 females) of pleural mesothelioma were
ascertained from 1980 to 1993. An occupational exposure to asbestos was
considered possible in only 2 of these, and could not be completely excluded in
5 other cases. For the remaining 10 cases it was reasonable to consider
possible environmental exposure. On the basis of this finding, a careful
mineralogical and environmental study was started in the area of Biancavilla,
where incohesive volcanic materials have been widely used for the building
industry and for road paving, particularly in the 1960s and 1970s. This
research led to the identification of fluoro-edenitic prismatic crystals and
asbestiform fibres [with a chemical formula NaCa2Mg2(Si7Al)O22F2],
prevalently composed by a calcium amphibole, associated with microgranular
feldspars, haematite and pyroxenes. In order to acquire more detailed
information on the possible causal relationship between the exposure to these
materials and the onset of mesotheliomas, an experimental study has been
started in our laboratory to evaluate their carcinogenicity. The experiment has
been performed on Sprague-Dawley rats, 8 weeks old at start. The asbestiform
fluoro-edenitic fibres have been tested by a single intraperitoneal or
intrapleural injection on groups of 80 rats (40 males and 40 females) at the
dose of 25 mg in 1 cc of water; the prismatic fluoro-edenitc fibres has been
tested by a single intraperitoneal injection on one group of 30 rats (15 males
and 15 females) at the dose of 25 mg in 1 cc of water; 1 cc of water was
administered by intraperitoneal injection to 80 rats (40 males and 40 females)
(controls). The results of this study indicate that fluoro-edenitic fibres induce
peritoneal and pleural mesotheliomas, with an incidence comparable to that
obtained with asbestos fibres, in particular crocidolite.
T06-7 Orale
Lesci, Isidoro Giorgio
75
QUANTITATIVE ANALYSIS OF CHRYSOTILE IN
ANTIGORITE-SERPENTINITE USING THERMAL AND SPECTROSCOPIC
ANALYSIS
COMPAGNONI Roberto 1, CORALLO Antonio 2, FORESTI Elisabetta 2, GROPPO
Chiara 1, LESCI Isidoro Giorgio 2, ROVERI Norberto 2
1 - Dept. of Mineralogical and Petrological Sciences, Univ. Torino, Italy and
Interdepartmental Centre "G. Scansetti" for Studies on Asbestos and other
Toxic Particulates, Univ. Torino, Italy
2 - Dept. Chemistry "G.Ciamician" - University of Bologna - via Selmi, 2 I-40126 Bologna (Italy)
Key terms: chrysotile; quantitative analysis; FTIR spectroscopy; TGA-DTA
analysis
Most serpentinites derive from hydration of mantle peridotites and are
widespread in mountain belts. They mainly consist of serpentine minerals
(lizardite Lz, antigorite Atg and chrysotile Ctl ) and magnetite, diopside,
tremolite, chlorite.
In Italy, Lz-serpentinites mainly occur in the non- or slightly metamorphic
Apenninic ophiolitic units, whereas Atg-serpentinites are typical of the
meta-ophiolites of the Alps. Since both Lz and Atg serpentinites may contain
Ctl asbestos veins and the matrix Lz and Atg are compositionally and
structurally very similar to Ctl, the quantitative determination of Ctl is not a
trivial problem.
In this work we suggest a new method for the quantitative determination of Ctl
in Atg serpentinites by means of both FTIR spectroscopy and TGA-DTA
analysis.
A very pure Ctl sample from John's Manville mine (Canada) and a pure fibrous
Atg sample from serpentinite near Lanzo (Italian western Alps) have been
selected for the study. Their IR spectra were acquired in the range 4000-370
cm-1 at 2 cm-1 resolution, by using a Bruker IFS66 spectrometer operating
with a DTGS detector. In the examined Ctl and Atg samples, the stretching
vibrations of the inner OH occur at 3690 cm-1 and 3678 cm-1, respectively.
The stretching vibrations of the outer OH occur at 3646 cm-1 for Ctl, while it is
little evident for Atg. Atg is also characterised by a shoulder at 3699 cm-1 and
a large band at 3570 cm-1.
Ctl-Atg mixtures have been used to simulate natural Atg serpentinite rocks in
the whole range of composition from Ct0Atg100 to Ctl100Atg0. The spectra
were fitted using 6 evident peaks or shoulders of either Ctl or Atg spectra at
3699, 3690, 3678, 3670, 3646 and 3570 cm-1; the 3670 cm-1 band has been
used to better fit the asymmetric right side of the Atg peak at 3678 cm-1.
The integrated area of the band at 3690 cm-1 plotted as a function of the Ctl
amount in the mixture, shows a linear correlation between the two parameters.
The straight line fit has been obtained from a least squares analysis with an
R2-factor of 0.9926.
Differential thermal analysis has been used successfully in this work to
distinguish and quantify Ctl from Atg. The thermal decomposition of serpentine
minerals is thought to take place in two main steps, as evidenced by the two
main reaction peaks. An endothermic area from 620 °C to 720 °C corresponds
to the loss of hydroxyl water and is accompanied by the collapse of the crystal
structure. The sharp exothermic peak at 810°C indicates the recrystallization of
the remaining amorphous anhydrous materials into forsterite (Mg2SiO4) and
enstatite (MgSiO3). The samples used for the calculation of calibration curves
were prepared by adding a suitable amount (10-90 wt%) of chrysotile to the
starting antigorite and by homogenizing the mixtures.
Differential Thermal Analysis-Thermo Gravimetric Analysis were carried out
using a SDT Q600 by TA instrument. Heating was performed in an alumina
crucible in a nitrogen flow (20 cm3 min-1) at a rate of 10 °C min-1 up to 1000
°C. The samples weights were in the range 18-25 mg.
The results show that the FTIR spectroscopy and TG-DTA analysis allow, not
only to distinguish the different serpentines minerals, but also to quantify the
amount of chrysotile in antigorite serpentinites.
T06-8 Orale
Fedoryshyn, Oleksandr
ACOUSTIC CONTROLL METHOD OF CONCENTRATION AND SIZES OF
SOLID
PARTICLES IN AIR
FEDORYSHYN Oleksandr 1
1 - Istituto di geofisica, sezione di Carpazi, Lviv, Ucraina
Key terms: solid particles; elastic waves; scattering
For an estimation of influence on health of fibrous materials a reliable and
operative method of control behind their presence in an environment are
necessary. For the express estimation of presence of solid particles in air or in
water it is offered to use the acoustic control method, which is based on
dispersion of elastic waves by these particles. In not polluted environment the
elastic wave propagating from a radiator to the receiver, will be spherical, and
the amplitude will be will change in inverse proportion to distance:
where R
- distance from a radiator to the receiver.
If in the medium there are solid particles the elastic wave on them will
scattern. For a finding of amplitude of the scattern wave in such media with
success it is possible to use the theory of turbulence[1]. According to this
theory dependence of amplitude of a coherent wave on distance will such:
where - quantity of particles on unit of volume,
- section of
scattering. The method of an estimation of concentration of solid particles
consists in registering amplitude of a coherent wave on different distances from
a radiator, and then on the basis of the developed mathematical model to
define the average size of particles and their quantity on unit of volume.
1. Ishimaru A. Wave propagation and scattering in random media. Academic
Press New York 1978
T06-9 Orale
SESSIONE T06
Gualtieri, Alesssandro
76
THE TEMPERATURE INDUCED TRANSFORMATION OF
CEMENT-ASBESTOS SLATES IN VIEW OF A SAFE RECYCLING IN
STONEWARE TILE MIXTURES
GUALTIERI Alesssandro 1
1 - Dipartimento di Scienze della Terra, Università di Modena e Reggio Emilia
Key terms: asbestos; cement-asbestos; temperature; inertisation; recycle
Cement-asbestos is the main asbestos containing material still found in most of
the European countries such as Italy. Man- and weathering-induced
degradation of the cement-asbestos slates makes them a source of dispersion
of asbestos fibres and represents a priority cause of concern. This concern is
the main prompt for the actual policy of abatement and disposal of asbestos
containing materials in controlled wastes. An alternative solution to the
disposal in dumping sites is the direct temperature induced transformation of
the cement-asbestos slates into non-hazardous mineral phases. As a matter of
fact, law nr. 248 - D.M. 19/07/2004 is a road map in Italy for the management
and treatment of asbestos wastes. It legitimates the crystal-chemical
transformation of asbestos containing materials (ACM) throughout thermal,
mechanical, or chemical treatments and the recycle of the transformation
product. Because of the scarcity of waste plants devoted to the confinement of
ACM on the Italian territory, the reorganization of the existing ones in a more
restrictive legislative scheme, and the consciousness of the intrinsic risks of
asbestos dispersion during the dumping operations and in the long term, after
the disposal in controlled wastes, this law was a prompt to ultimately solve the
so called asbestos problem.
This contribution outlines of the reaction path taking place during the firing of
cement-asbestos slates up to the complete transformation temperature, 1200
°C. The reaction sequence was investigated using different experimental
techniques such as optical and electron microscopy, in situ and ex situ qualiquantitative X-Ray powder diffraction. The understanding of the complex
reaction path is of basic importance for the optimization of industrial heating
processes leading to a safe recycling of the transformed product.
For the recycling of asbestos containing materials, the Italian laws require that
the product of the crystal chemical transformation of asbestos containing
materials must be entirely asbestos-free, and should not contain more than
0.1% weight fraction of the carcinogenic substances such as cristobalite.
Moreover, if fibrous phases other than asbestos (with length to diameter ratio
> 3) are found, they must have a geometrical diameter larger than 3 mm. It
will be shown that using an interplay of different experimental techniques, it is
possible to safely verify the complete transformation of asbestos minerals in
this temperature induced process. The product of transformation of cement
asbestos has a phase composition similar to that of a natural or a low
temperature clinker with the exception of having a larger content of aluminium,
iron and magnesium. This product can be safely recycled for the production of
stoneware tile mixtures. The addition of 3-5 wt% of the transformation does
not bear significant variations to the standard parameters of white porcelain
tile mixtures.
T06-10 Poster
Manuella, Fabio Carmelo
PRELIMINARY STUDY OF ASBESTOS OBSERVED IN SOME
ULTRAMAFIC-MAFIC XENOLITHS FROM HYBLEAN DIATREMES
(SOUTHEASTERN SICILY, ITALY)
MANUELLA Fabio Carmelo 1, CILIBERTO Enrico 2
1 - Dipartimento di Scienze Geologiche, Università degli Studi di Catania,
Sezione di Mineralogia, Petrografia, Geochimica e Vulcanologia, C.so Italia 57,
95129 Catania, tel. 095/7195742 fax 095/7195760,
2 - Dipartimento di Scienze Chimiche, Università degli Studi di Catania, V.le A.
Doria 6, 95125 Catania, tel. 095/7385054, [email protected].
Key terms: serpentine; tremolite; xenoliths; Hyblean diatremes;
serpentinization
Recent studies on ultramafic-mafic xenoliths from Hyblean Miocenic diatremes
have suggested that the inaccessible lithospheric basement consists of a fossil
oceanic core-complex tectonically exposed at sea-bottom, and afterward
covered by the regional Meso-Cenozoic carbonatic succession (Scribano et al.,
2006a). Hence, serpentinization of mantle peridotites has been considered a
major process for the evolution of the Hyblean basement. In fact, pervasive,
long lasting hydration of mantle ultramafics can be accounted for the
"crustalization" of the upper mantle, since serpentinite is considered a crustal
rock in terms of density and seismic waves velocity. In addition, lithospheric
stresses due to volume increase after serpentinization of peridotite have had
important bearing on regional tectonic evolution, therefore the exothermic
nature of the serpentine-forming reactions has probably triggered and
sustained the long-lasting hydrothermal circulation inferred by Scribano et al.,
2006b.
In spite of above remarked importance of serpentinization process, no study
was carried out on asbestos from Hyblean xenoliths to date. These minerals
occur in the alteration shell of moderately large xenoliths, fill veins crosscutting
the relatively fresh cores of the same, and almost entirely form a number of
microxenoliths disseminated in the tuff-breccia deposits from Carlentini
Formation (Upper Miocene). We begin the characterization of these minerals
analyzing the thick alteration rind of eight fist-sized harzburgite, one websterite
and one altered gabbro xenoliths from Valle Guffari tuff-breccia deposits. XRF,
XRD, FT-IR and SEM-EDS are employed to provide mineralogical data base for
further discussion on hydration process of ultramafic rocks in the Hyblean
basement.
All samples were initially ground and treated with an aqueous solution
containing 0,1 % of sodium dioctylsulfosuccinate in order to extract asbestos.
Bulk analysis of some powdered samples were made by means of XRF. XRD
patterns were used to identify serpentine polytypes and tremolite, hence to
calculate cell parameters. These minerals are here reported in descending
order of abundance: tremolite, orthochrysotile, clinochrysotile, lizardite, and
antigorite. Moreover mineralogical associations of ortho- and clinochrysotile
with tremolite, antigorite and lizardite with tremolite, and orthochrysotile
associated to lizardite were recognized in different samples.
By the assumption that these minerals were formed in an oceanic ridge
environment, thermal conditions can be deduced from temperatures of
formation of antigorite, chrysotile and lizardite (Wenner et al., 1971; Bonatti
et al., 1984) respectively at 235, 180 and 125°C, and of tremolite at
350-500°C (C. Mével, 2003; H. Paulick, 2006).
Furthermore the interpretation of FT-IR spectra confirmed the presence of
chrysotile and tremolite in some samples.
References:
Bonatti et al., EPSL, 1984, 70, 88-94.
Mével, C. R. Geoscience, 2003, 335, 825-852
Paulick et al., Chem. Geol., 2006, 234, 179-210.
Scribano et al., Min. and Petr., 2006, 86, 63-88.
Scribano, Ofioliti, 2006, 31 (2), 161-171.
Wenner et al., Contr. Mineral. and Petrol., 1971, 32, 165-185.
T06-11 Poster
Paglionico, Antonio
POTENTIAL SOURCES OF ASBESTOID MINERALS: THE CALABRIAN
METAOCEANIC CRUSTAL ROCKS
PAGLIONICO Antonio 1, FESTA Vincenzo 1
1 - Dipartimento Geomineralogico - Università degli Studi di Bari
Key terms: metaophiolites; asbestos; calabria
The Calabria-Peloritani range is characterised by tectonic units stacked during
the Alpine orogenesis. These units consist, from the top, of: a) Hercynian
continental crust basement-rocks, with or without remnants of sedimentary
cover, b) rocks belonging to the Jurassic - Lower Cretaceous Tethyan oceanic
crust, c) rocks belonging to the Mesozoic carbonate platforms. Metaophiolitic
bodies belonging to oceanic crust, Alpine tectonic units are widespread in the
Catena Costiera and Sila Massif. The cropping out oceanic crust of Calabria is
generally characterized by metagabbros, mafic exstrusive and ultramafics.
Mafics and ultramafics constist of metabasalts represented by pillow-lavas and
pillow-breccias; tremolite and crocidolite dikes cut serpentinized peridotitic
rocks. Their growth was favoured by retrograde metamorphism with
development of shear zones, veins, faults and fractures, from blueshists to
greenshists facies conditions.
The asbestos minerals in the ultramafic rocks become dangerous when
rock-bodies are interested by weathering phenomena. Owing to their
microfribrous structure, the asbestos minerals are easily veihcolable in the air,
and consequently dangerous for the human health. The rocks of the Calabrian
oceanic crust are largely subjected to weathering favoured by: i) their complex
metamorphic and tectonic evolution (i.e. grain size reduction, fracturation and
fragmentation), ii) climatic conditions (i.e. thermal range), and iii) human
transformation for agricoltural using. In particular, eluvial and colluvial deposits
lieing on weathered oceanic crust rocks, in which asbestos minerals could be
reasonably present, locally reach several metres of thickness. In addition, large
areas, where oceanic crust rocks, alluvial and colluvial deposits crop out, are
urbanized or characterized by agricoltural activities. Consequently,
metaophiolitic bodies represent potential asbestoid sources. In addition, the
asbestos risk could be enlarged also to those zones reached by fibrous minerals
deriving from the aforesaid sources areas after easly erosion and transport
processes by natural or human activities. The presence of the exposed
serpentinized ultramafics have been locally indicated in some published
research works aimed to study the tectono-metamorphic evolution of the
Calabria-Peloritani range. To obtain preliminary indications on the potential
asbestos risk in Calabria, the following steps have been taken into account in
the first phase of this research study: 1) localization, on the basis of
bibliographic data, of the metaophiolitic bodies cropping out in the Catena
Costiera and Sila Massif; 2) localization, on the basis of bibliographic
indications, of the exposed serpentinized ultramafics; 3) characterization by
satellite images of the soil use by human activities of those area where
serpentinized ultramafics are exposed; 4) collection of demographic data in the
potential asbestoid mineral source areas. On the basis of the aforesaid data,
the following additional steps are here suggested to obtain a complete
monitoring of the asbestos risk in northern Calabria: a) localization by of the
exposed serpentinized ultramafics using the MIVIS; b) detailed geological
mapping of the potential asbestos sources localized by MIVIS; c) sampling of
rocks an soils deposits containing asbestos minerals; d) monitoring of the air
particulate in the neighbouring of the main urbanized areas where
serpentinized ultramafics crop out.
In conclusion, a similar research is carring out by the CNR-IMAA in the
Calabria-Basilicata boundary area. Preliminary results suggest a correlation
between potential sources of asbestos minerals and epidemiologic data
regarding the population living in areas which are locally characterized by
weathered oceanic crust rocks.
T06-12 Poster
Di Benedetto, Francesco
THE NATURAL PRESENCE OF ASBESTOS IN TUSCANY
DI BENEDETTO Francesco 1, BAFARO Enzo 2, BIONDINI Stefano 3, FORNACIAI
Gabriele 2, MONZALI Silvano 4, NEMO Alessandro 5, SILVESTRI Stefano 6
1 - Museo di Storia Naturale,Università di Firenze
2 - Dipartimento Provinciale di Firenze, ARPAT
3 - Regione Toscana, D. G. Diritto alla Salute e Politiche di Solidarietà
4 - Regione Toscana, D. G. delle Politiche Territoriali ed Ambientali
5 - U.F. PISLL, Azienda USL 6 Livorno
6 - Centro per lo Studio e la Prevenzione Oncologica, Firenze
Key terms: Asbestos minerals; ophiolites; mesothelioma; Tuscany
The knowledge of the presence of asbestos minerals in Tuscany is one of the
requirements for the risk assessment for general population exposure due to
naturally released fibres. A complete investigation of the presence of asbestos
minerals over the regional territory has not yet been entirely achieved.
However, crysotile, tremolite, antophyllite and actinolite have been reported to
occur in at least twelve sites, most of which representing ophiolite outcrops. In
addition, the Regional Mesothelioma Registry, records two events concerning
workers which operated in the iron and talc mining industry for several years.
SESSIONE T06
77
To date, no cases have been instead recorded within ophiolite extraction
workers since 1988.
On these bases, a deep recognition of the available data about the Tuscan
ophiolites has been undertaken, in agreement with the Asbestos Mapping
Programme, promoted by the Italian Ministry of the Environment. This
Programme, in fact, involves both the civil and occupational environment. The
present study reports the preliminary results of a mapping campaign
performed by the Tuscan Regional Administration, the Local Environmental
Agency (ARPAT), the Institute for Research and Prevention of Cancer (CSPO)
and the Natural History Museum of the University of Florence. This study aims
to ascertain the presence of fibres and asbestos-related minerals, identifying
their mineralogical nature and the possible presence of airborne asbestos fibres
affecting workplaces like mines and quarries and the general environment.
Most of the active, inactive and abandoned quarries as well as unbenefited
outcrops were monitored by specific site surveys. Investigated parameters
were on one hand the mechanical characteristics of the ophiolite rocksand on
the other the quantification of asbestos minerals as contaminants. The
collection of the data concerning the workers operating in ophiolitic quarries
since 1950 is in progress and the cohorts will be submitted to epidemiological
analysis in order to better define the presence of asbestos related diseases
besides mesothelioma. The exploitation of the ophiolite outcrops dates back in
Tuscany to the Medieval centuries, mainly for the use in monumental buildings,
while a relatively small volume of "green stones" characterises the modern and
contemporary activity. Nowadays the main use of the extracted materials
concerns the road- and railway backgrounds. Only small-to-medium companies
operate extractive activities with prevalently local destination.
The preliminary results confirm a wide distribution over the regional territory of
asbestos-related mineral occurrences within the ophiolitic natural outcrops and
quarries; the presence of asbestos minerals, chrysotile and amphiboles, has
been indirectly singled out through the information collected interviewing two
patients affected by mesotelioma previously employed in a talc and iron mines
respectively. These two mines results actually abandoned and the
characterization of the contaminants is in progress.
Key terms: Fibrous amphibole; fluoro-edenite; Santa Maria di Licodia; Mount
Etna
The Santa Maria di Licodia area, located on the lower southwestern flanks of
Mt. Etna volcano, suffers an environmental contamination by fluoro-edenite, a
new calcic fibrous amphibole responsible of malignant pleural mesothelioma.
The first occurrence of fluoro-edenite amphibole, NaCa2Mg5(Si7Al)O22F2
(Gianfagna and Oberti, 2001) in a volcanic environment, was recognised in
Biancavilla benmoreitic lava dome and dyke complex (0.015 Ma), exposed a
few kilometres NW of Santa Maria di Licodia (Burragato et al., 2005). Fibrous
fluoro-edenite is highly oncogenic upon inhalation, due to its shape, very small
size and, possibly, composition (Comba et al., 2003).
Preliminary volcanological and mineralogical investigations carried out in the
Santa Maria di Licodia area revealed the presence of fluoro-edenite crystals
associated with volcanic products, outcropping in the Anime del Purgatorio
locality, analogous in age and composition to the Biancavilla case. The host
rock-type consists of benmoreitic lava dome and dyke complex and associated
autoclastic breccias which have been quarried extensively for building
activities. In particular, in the Santa Maria di Licodia area, micrometric
fluoro-edenite crystals, detected by SEM-EDS microanalysis techniques, occur
within friable material from altered lava and breccia and show both prismatic
and fibrous morphologies. In addition to the fluorine-rich amphibole, the
mineral assemblage includes: feldspars, clinopyroxene, ortopyroxene,
hematite, fluorapatite. Different from Biancavilla, macroscopic mineralization of
fluoro-edenite in the lava fissures has not been found.
The new finding of fibrous fluoro-edenite around Santa Maria di Licodia
indicates a widespread environmental contamination of hazardous
mineralization. Detailed geological survey and mineralogical investigation
focused on the characterisation of mineral fibers and host rock-types. Research
in progress addresses the peculiar genetic process involving F-rich fluids, which
allowed crystallisation of fluoro-edenite and coexisting fluorine-rich and
anhydrous mineral assemblage, along with the evaluation of the areal extent
and concentration of the mineral fibers in the southwestern etnean area in
order to reduce risks to human health.
T06-13 Poster
Burragato, F., Comba, P., Baiocchi, V., Palladino, D.M., Simei, S., Gianfagna,
A., Paoletti, L., Pasetto, R. (2005) - Geo-volcanological, mineralogical and
environmental aspects of quarry materials related to pleural neoplasm in the
area of Biancavilla, Mount Etna (Eastern Sicily, Italy). Environ. Geol., 47,
855-868.
Comba P., Gianfagna A., Paoletti L. (2003) - Pleural mesothelioma cases in
Biancavilla are related to a new fluoro-edenite fibrous amphibole. Arch.
Environ. Health, 58(4), 229-232.
Gianfagna A., Oberti R. (2001) - Fluoro-edenite from Biancavilla (Catania,
Sicily, Italy): crystal chemistry of a new amphibole end-member. Amer. Miner.,
86, 1489-1493.
Plescia, Paolo
MORPHOLOGICAL AND STRUCTURAL CHARACTERIZATION OF
CHRISOTILE FIBERS OF NEW FORMATION IN SERPENTINE MINERALS:
INDICATIONS ABOUT THE MECHANISMS OF FORMATION OF
CHRISOTILE IN SERPENTINE MINERALS AND ABOUT THE DANGEROUS
OF THIS MATERIALS
MUSTO Daniela 1, PAOLONI Giuseppe 2, PLESCIA Paolo 2, TOCINO Maria 2, SOTTILE
Rosaria 3
1 - Science and Technology Information Institute "Alessandro Faedo" Research
Area CNR of Pisa
2 - Institute for the Study of. Nanostructured Materials. Research Area of CNR
Roma
3 - ARC Laboratory - ASSING SpA
Key terms: chrisotile; nanotubes; serpentine minerals
In this study, characterization data of some serpentine minerals from the
"Roccheta of Vara" area, in "La Spezia" province are shown. These materials
present particular structures, constituted by cover materials with a low degree
of crystallinity and are associated with tectonic movements.
Such structures are particularly interesting for the pollution problems of
asbestos fibers since they often become the center of fiber serpentine mineral
formation.
The analyses of the surfaces subject to the tectonic activity have been
performed with the X-ray Diffraction(XRD), Scanning Electron
Microscopy(SEM), Infrared Spectrophotometry(FTIR) and Thermogravimetry
analysis. A great diference between the primary
materials(serpentine-antegorite type)and the new formation
materials(amorphous or low degree of crystallinity material)has been identified.
Through the integration with the other techniques of analysis in the following
phases, showed in genetic sequence, haven been recognised:
- serpentine antigorite
- serpentine lizardite
- an amorphous glassy phase magnesium silicate composition rich in superficial
deposits of chrysotile.
- a crystal superficial phase with a high quantity of chrysotile.
Between lizardite and the following phases, a growth of iron and manganese
oxides crystallization, particularly in the dendritical and massive forms is
observed.
Inside the amorphous phase the presence of very small geodes(dimensions:
0,5-1 mm)is observed, inside which the presence of a dense felt of chrysotile
crystals with dimension between a few microns to 500 can be noticed.
Outside of the geodes the presence of sphere cave of silicon has been
observed, also observed under SEM and under the spheres nanotubes appear
with magnesium silicate composition and morphology attributable to chrisotile.
The most interesting thing is represented by the new fibrous formation form on
the surface of glide, in correspondence with the points of maximum attrition.
The results point out that the serpentines of "Rocchetta of Vara" after attrition
change their morphology forming a new material that has a low grade of
crystallinity in which chrysotile is crystallied with morphology and dimension
which allow them to be classified among the nanofibres material, part of which
grow parallel to the other forms of serpentine and in such a way that they are
hardly identificable.
T06-14 Poster
Mazziotti Tagliani, Simona
FIBROUS AMPHIBOLES IN THE SANTA MARIA DI LICODIA AREA
(MOUNT ETNA, ITALY)
MAZZIOTTI TAGLIANI Simona 1, SIMEI Silvia 1, GIANFAGNA Antonio 1,
PALLADINO Danilo Mauro 1
1 - SAPIENZA UNIVERSITA' DI ROMA, P.le A. Moro 5, 00185 Rome, Italy
T06-15 Poster
Iezzi, Gianluca
AMPHIBOLE ASBESTOS FROM LIBBY (MONTANA, USA):
MINERALOGICAL DATA FOR TOXICOLOGICAL APPLICATIONS
IEZZI Gianluca 1, DELLA VENTURA Giancarlo 2, DI GIOACCHINO Mario 3,
BELLATRECCIA Fabio 2, VERNA Nicola 3, GUNTER Mickey 4, DI SABATINO Bruno 1
1 - Dip. Scienze della Terra, UdA, Chieti
2 - Dip. Scienze Geologiche, Uni. Roma3, Roma
3 - CeSI, UdA, Chieti
4 - Earth Science Dep., Uni. Idaho (USA)
Key terms: amphibole; asbestos; XRPD; FTIR; cation ordering
Among the different natural and industrial materials, asbestos are still retained
to be significantly dangerous for the human health and in the majority of
countries their uses and manipulations are ruled out by laws (Plumlee et al.,
2006). The term asbestos is generally used to describe minerals that either
occur as long silky fibres or can be easily split so as to become such. The
asbestos minerals are currently sub classed into two main groups: (i)
serpentines (e.g. chrysotile) and (ii) amphiboles (e.g., tremolite, riebeckite). It
is now retained that fibrous amphiboles are significantly more dangerous than
fibrous serpentines (McDonald and McDonald, 1997; Plumlee et al., 2006).
Therefore it is extremely important to characterise the fibrous amphiboles
(natural and industrial) occurring in the environment as airborne dust,
particularly with respect to their chemistry. However despite of a relatively
large amount of medical and biochemical studies devoted to the toxicological
effects of asbestos (especially on amphiboles), the mineralogical
characterisation of the fibrous minerals was normally little constrained.
Several parameters can in fact be supposed responsible for their biological
hazard, and these include the Fe content of the fibres, the absolute dimensions
and aspect-ratio of the crystallites, the electrical surface potential, the solubility
as a function of pH, and the hydrophobicity vs. hydrophilicity (van Oss et al.,
1999); all these properties are notably dependent on their chemistry, and thus
their knowledge is of capital importance for any investigations dealing on
amphibole asbestos.
A rather rapid, complete and accurate crystal-chemical investigations of
(fibrous) amphiboles can be carried out by the combination of SEM, XRPD and
FTIR OH-stretching data. We checked this analytical protocol on a set of
asbestos amphiboles from the Libby quarry, Montana (USA). These samples
were previously studied and characterized by EPMA, Mössbauer and single
crystal XRD. Our crystal-chemical results well matched with those reported in
literature. This definitively indicates that the spectroscopic (FTIR) methods
offer a very fast tool for a proper characterization of fibrous amphiboles in
environmental monitoring.
References:
McDonald, J.C., McDonald, A.D. (1997). Annals of Occupational Hygiene, 41(6),
699-705.
Plumlee G.S., Morman S.A., Ziegler T.H. (2006). Reviews in Mineralogy and
Geochemistry, vol. 64:5-57.
van Oss, C.J., Naim, J.O., Costanza, P.M., Giese, R.F. Jr., Wu, W., Sorling, A.F.
(1999). Clays and Clay Minerals, 47, 697-707.
T06-16 Poster
SESSIONE T06
Pacella, Alessandro
78
CRYSTAL-CHEMICAL CHARACTERIZATION OF TREMOLITES OF
ENVIRONMENTAL AND HEALTH INTEREST.
PACELLA Alessandro 1, GIANFAGNA Antonio 1, ANDREOZZI Giovanni Battista 1,
BALLIRANO Paolo 1, MAZZIOTTI-TAGLIANI Simona 1, BRUNI Biagio Maria 2,
FOURNIER Jeanine 3, STIEVANO Lorenzo 3
1 - Dipartimento di Scienze della Terra,"Sapienza" Università di Roma, Piazzale
A. Moro, 5, 00185.
2 - Dipartimento Tecnologie e Salute, Istituto Superiore di Sanità, V.le Regina
Elena 299, 00162 Roma.
3 - Laboratoire de Réactivité de Surface, UMR 7609 - CNRS, Université Pierre
et Marie Curie 4, place Jussieu - 75252 - Paris - France.
Key terms: fibrous tremolite; amphiboles; chrystal-chemistry; biologycal
activity
In addition to the mineralogical interest, crystal-chemical characterization of
fibrous tremolites results relevant for environmental and health aspects.
Toxicological studies evidenced that interactions between fibrous material and
biological environment are strongly dependent on both geometry and crystal
chemistry of mineral fibers.
Crystal chemistry of the prismatic variety of amphiboles has been described in
many works, instead the corresponding fibrous varieties have not been well
characterised so far because of the difficulties in the methodological approach.
Only recently was reported some works on fibrous amphiboles (Gianfagna et
al., 2003; Gianfagna et al., 2007; Andreozzi et al., 2006).
Present work reports new chemical and structural data on fibrous tremolites
obtained with a tested multi-analytical approach.
Analysed samples prevalently came from various Italian serpentinites
(Piemonte, Calabria, Basilicata and Lazio) and from Jamestown (CA, USA).
Chemical composition has been obtained through EMPA microanalysis. ICP-MSA
was used as a further check of the microanalytical data. Mössbauer
spectroscopy was used to quantify Fe 3+/Fetot ratios.
Powder diffraction data were collected and evaluated by the Rietveld method.
Cell parameters, fractional coordinates for all the atoms, and site scattering for
M1, M2, M3, M4, and A, were refined.
Tremolite fibers showed different iron content (2 < FeO% < 5) and Fe 3+/Fetot
ratios. Moreover, small variations in Si/Al and Ca/Na ratios were found (Pacella
et al., 2007). These are correlated to the small structural differences observed
( angle parameter and cell volume).
Photoelectron Spectroscopy Analysis (XPS) are in progress in the Laboratoire
de Réactivité de Surface de Paris VI in order to determine the surface
chemistry of the fibers and to correlate it with the biological activity.
References:
Andreozzi G., Ballirano P., Belardi G. (2006) - Crystal chemical and structural
characterization of fibrous tremolite from Val di Susa (Italy). XXXV Congresso
dell'Associazione Italiana di Cristallografia, Ferrara, 21-23 Settembre 2006.
Gianfagna, A., Andreozzi G.B., Ballirano, P., Mazziotti Tagliani S., Bruni B.M.
(2007) - Chrystal chemistry of the new asbestiform fluoro-edenite amphiboles
of volcanic origin from Biancavilla, Sicily, Italy. Canadian Mineralogist, 45,
249-262.
Gianfagna, A., Ballirano, P., Bruni, B., Paoletti, L. and Oberti, R. (2003) Characterization of amphibole fibres linked to mesothelioma in the area of
Biancavilla, Eastern Sicily, Italy. Mineral. Magaz., 67, 1221-1229.
Pacella A., Andreozzi G.B., Ballirano P., Gianfagna A., Mazziotti Tagliani S.,
Bruni B.M. (2007) - Caratterizzazione cristallochimica di fibre di anfibolo di
interesse ambientale. Convegno Nazionale "Anfiboli fibrosi: nuove
problematiche relative al rischio ambientale e sanitario". Roma, 27-28 Aprile
2007. Volume Atti, pp. 160-161.
T06-17 Poster
Cavallo, Alessandro
ASBESTOS IN ORNAMENTAL GREENSTONES- A COMBINED ANALYTICAL
APPROACH
CAVALLO Alessandro 1
1 - Università degli Studi di Milano - Bicocca
Key terms: asbestos; greenstones; ornamental stones; SEM-EDS; XRPD
The commercial term "greenstones" is referred to a lot of different green to
dark-green rock types, of mafic/ultramafic composition, such as serpentinites,
talc-chlorite schists, talc-olivine fels and chlorite schists. The "hard" varieties
(serpentinites) are suitable for flooring, covering and roof slabs, whereas the
"soft" varieties (talc and/or chlorite bearing rocks) are typically used for jars,
pots, barbecue slabs and stoves, because of their easy workability and
fire-resistance. The mineralogical composition of these rocks is characterized
by variable amounts of serpentine, olivine, talc, chlorite, amphiboles and
carbonates, and sometimes small quantities of chrysotile and fibrous
amphiboles (asbestos) may be present. In order to investigate the
mineralogical composition, the microstructures and the incidental presence of
asbestos fibers, 20 different commercial varieties of Italian and foreign
greenstones were analyzed, using optical microscopy (OM), X-ray powder
diffraction (XRPD) and SEM-EDS, both on stony and crushed samples. The
performed investigations evidenced a marked lithological heterogeneity,
ranging from antigorite schists, chlorite schist to talc-amphibole-carbonate
bearing rocks (soapstone). The serpentinites have generally
non-pseudomorphic textures, and the rock-forming minerals are serpentine
(antigorite), olivine, pyroxene (usually diopside), chlorite and magnetite.
Chrysotile asbestos is extremely rare, localized in small veins or fractures:
because of the reduced adhesion to the rock, this mineral is practically absent
in manufactured products. The identification of chrysotile by XRPD is almost
impossible in these rocks, due to the very low concentration, the polymorphism
problem and the typical structural disorder of serpentine minerals. For these
reasons, only SEM-EDS investigations on crushed and stony samples are able
to identify small chrysotile fibres and discriminate them from
antigorite/lizardite splinters. The chlorite and talc-chlorite schists are
characterized by different microstructures (from massive to foliated), and the
prevailing minerals are chlorite and talc, with small amounts of serpentine
(antigorite/lizardite) and tremolite-actinolite. Talc-olivine fels and soapstones
exhibit the greatest textural and mineralogical variability: olivine, talc,
carbonates (calcite, dolomite, magnesite), chlorite, serpentine, and sometimes
remarkable amounts of amphibole (tremolite-actinolite and anthophyllite). The
XRPD and EDS analyses allowed the identification of the amphiboles, whereas
OM and SEM determined the accurate crystal size, the habit and the length to
diameter ratio: these investigations excluded the presence of asbestiform
varieties. Nevertheless, the amphibole crystals may be occasionally splitted and
fragmented in acicular/asbestiform splinters, in consequence of mechanical
processing (dressing, turning, drilling, etc). This problem was evidenced by
SEM-EDS investigations on processing debris and powders, and some
asbestiform amphiboles were identified. This research evidences the usefulness
of a combined analytical approach for the investigations of "greenstones",
characterized by wide mineralogical-microstructural variability: the best swift
analytical technique depends on the lithology. The identification of incidental
asbestiform minerals requires great care, especially the distinction from the
common non-asbestiform amphibole varieties and the detection of small
chrysotile amounts in serpentinites.
T06-18 Poster
Della Ventura, Giancarlo
THE ANALYSIS OF FIBROUS AMPHIBOLES BY FTIR SPECTROSCOPY IN
THE OH-STRETCHING REGION
DELLA VENTURA Giancarlo 1, BELLATRECCIA Fabio 1, IEZZI Gianluca 2,
REDHAMMER Guenther 3, ZELLI Francesco 1, PEZZO Giuseppe 1, TESTI Dorina 1
1 - Università Roma Tre
2 - Università G. d'Annunzio, Chieti
3 - Institute of Crystallography Aachen, Germany
Key terms: Amphiboles; fibrous; FTIR spectroscopy; Mossbauer; composition
The mechanism through which fibrous amphiboles may give rise to
mesothelioma is still not completely understood. Several factors have been
taken into account, and these include the morphological aspect (length:width
ratio), the chemical composition, and a variety of surface properties which are
ultimately responsible for the mineral-cellule interactions (e.g. van Oss et al.,
1999). Studies in vitro demonstrate that the morphology of the fiber has a
strong role in determining its biological danger, because very thin and long
crystallites are hardly eliminated by the alveolar macrophages. However, a
second factor which seems to influence the biological attack of a fiber is its Fe
content; iron can in fact be involved in complex biochemical reactions with
oxygen and cause DNA damages. It follows that the rapid determination of the
chemical composition of a fiber, and of its Mg/Fe ratio in particular, is
extremely important in environmental studies. The direct analysis can be
achieved only by micro-chemical tools such as by EDS- or WDS-equipped
electron microscopes. However, these techniques are extremely expensive and
often unsuitable when dealing with extremely fibrous (diameter < 3 µm)
materials. Therefore a rapid and easily accessible method is highly desirable in
large scale environmental monitoring. The best alternative to EMPA is provided
by FTIR spectroscopy, a technique which can be used on both single crystals
(down to few µm in dimension) and powders. Here we present the results of a
new calibration based on the analysis of a large set of well-characterized
fibrous and prismatic natural amphiboles spanning a very large variety of
chemical compositions and geological occurrences. All samples were previously
studied using X-ray diffraction and EMPA. FTIR spectra in the principal
OH-stretching region were collected on KBr disks prepared with a
mineral:matrix = 5:150 mg ratio. Most spectra show four prominent bands
which can be assigned to the combination of Mg and Fe 2+ at the OH-coordinated
M(1,3) sites (Della Ventura et al. 1996, 1997, Iezzi et al. 2005). The digitized
spectra were fitted by interactive optimization followed by least-squares
refinement; all bands were modelled as symmetric Gaussians. Della Ventura et
al. (1996, 1997) showed that the binary site-occupancies at M(1) and M(3) in
the amphibole structure are related to the observed intensities of the four (A to
D) components in the principal IR OH-stretching spectrum. Using the original
equations of Burns and Strens (1966):
M(1,3)
Mg = 3IA + 2IB + IC and M(1,3)M 2+ = IB + 2IC + 3ID (with M 2+ = Fe 2+)
where IA-ID are the intensities measured for the corresponding A to D bands,
one can derive the (Mg, M 2+) site populations at M(1,3) with a high degree of
confidence. This method is particularly suitable for asbestiform materials which
cannot be properly characterized by EMP. The present work shows that the
above spectroscopic tool can be applied to a large variety of amphibole types.
For species were significant (Mg, Fe) are present at M(4) (i.e. anthophyllite
-cummingtonite - grunerite) an additional information (e.g. Mössbauer) is
however required for a complete characterization of the sample.
References
Burns, R.G. and Strens, R.G.J. (1966) Science, 153, 890-892.
Della Ventura, G., Robert, J.-L., Hawthorne, F.C. (1996) Geochimica and
Cosmochimica Acta, vol. spec. 5, 55-63.
Della Ventura, G., Robert, J.-L., Raudsepp, M., Hawthorne, F.C., Welch, M.
(1997) American Mineralogist, 82, 291-301.
Iezzi, G., Della Ventura, G., Hawthorne, F.C., Pedrazzi, G., Robert, J.-L.,
Novembre, D. (2005) European Journal of Mineralogy, 17, 733-740.
van Oss, C.J., Naim, J.O., Costanza, P.M., Giese, R.F. Jr., Wu, W., Sorling, A.F.
(1999) Clays and Clay Minerals, 47, 697-707.
T06-19 Poster
Rinaudo, Caterina
MICRO-RAMAN SPECTROSCOPY APPLIED TO FIBROUS MINERALS
CAIRO Simona 1, FORNERO Elisa 1, RINAUDO Caterina 1, BELLUSO Elena 2
1 - DISAV-Università del Piemonte Orientale A.Avogadro-Alessandria
2 - DSMP-Università di Torino
Key terms: micro-Raman; fibrous minerals; carlosturanite; fluoro-edenite
The study of the fibrous minerals is normally carried out by techniques (X-Ray,
SEM-EDS, TEM-AEM) for which careful preparation of the samples, with also
risks of creating artefacts, is necessary. The µ-Raman spectroscopy has an
undoubted advantage: it needs no samples preparation and, to obtain a Raman
spectrum is sufficient to place the specimen in the path of the spectrometer's
SESSIONE T06
laser beam. Moreover, thank to the optical microscope annexed to the
spectrometer, the laser can be aimed at a specific region of the sample. It is
thus possible to obtain the Raman spectrum from various parts of a specimen,
revealing differences in heterogeneous samples. As recently demonstrated, this
technique allows a rapid identification of the fibrous minerals defined by law as
"asbestos", even when they are in association with other mineral phases [1-4].
In this work we applied Raman micro-spectroscopy to fluoro-edenite and
carlosturanite [5], minerals until now not still considered by the law "asbestos".
Nevertheless being fibrous, their toxicity on human health is actually under
study.
All the samples were previously characterized by using the classic XRPD,
SEM-EDS, TEM-AEM methods in order to be sure of the mineralogical
characteristic of the fibers studied by the spectroscopic method. After, a
µ-Raman study has been performed on single bundles of fibers placed with
different orientation with respect to the laser incident beam. The µ-Raman used
is a spectrometer HR800 LabRam Jobin Yvon equipped with a CCD air-cooled
detector, an Olympus BX41 microscope, a television camera and a 20 mW
HeNe laser working at 632.8 nm. In order to compensate for noise, the spectra
were registered using 10 cycles of 60 scans each, resolution 1 cm-1. The
correct calibration of the instrument was verified by measuring the Stokes and
anti-Stokes bands and checking before every run the position of Si band at ±
520.6 cm-1. During this work it was be possible to identify the vibrational
modes of the different groups constituting the crystalline structure in the two
minerals under study. Also samples which resulted by TEM-EDS study
constituted by different minerals are undergo micro-Raman analysis and the
bands ascribed to the different phases constituting the mineral associations are
easily identified. Moreover, our results confirm the earlier findings of our
group: Raman spectroscopy is a powerful tool for the identification of mineral
phases once the Raman spectrum of to the pure phase has been determined.
References
[1] Rinaudo, C., Gastaldi, D., Belluso, E. (2003): "Characterization of
chrysotile, antigorite and lizardite by FT-Raman spectroscopy". Can. Mineral.,
41, 883-890.
[2] Rinaudo, C., Belluso, E., Gastaldi, D. (2004): "Assessment of the use of
Raman spectroscopy for the determination of amphibole asbestos". Min. Mag.,
68(3), 455-465.
[3] Rinaudo, C., Gastaldi, D., Belluso E., Capella, S. (2005): "Application of
Raman Spectroscopy on asbestos fibre identification". N.J. Miner. Abh, 182/1,
31-36.
[4] Groppo, C., Rinaudo, C., Cairo, S., Gastaldi, D., Compagnoni, R.(2006):
"Micro-Raman spectroscopy for a quick and reliable identification of serpentine
minerals from ultramafics". Eur. J. of Miner., 18, 319-329.
[5] Belluso, E., Fornero, E., Albertazzi, G., Cairo, S., Rinaudo, C. (2006): Use
of micro-Raman spectroscopy to distinguish carlosturanite from the serpentine
minerals, Can. Min. (accepted)
T06-20 Poster
Vettori, Silvia
MAPPING OF ASBESTOS-CEMENT ("ETERNIT"-TYPE) ROOFING SHEETS
BY HYPERSPECTRAL DATA ANALYSIS
VETTORI Silvia 1, BENVENUTI Marco 1, CHIARANTINI Leandro 2, COSTAGLIOLA
Pilario 1, MONTANARI Mauro 3, MORETTI Sandro 1, TICCI Fabio 4, ALPARONE
Luciano 5
1 - Dipartimento di Scienze della Terra, Univ. Firenze
2 - Galileo Avionica S.p.A., Società di Finmeccanica
3 - Ufficio SIT, Comune di Follonica (GR)
4 - Ufficio Ambiente, Comune di Follonica (GR)
5 - Dipartimento di Ingegneria Elettronica, Univ. Firenze
Key terms: Asbestos; roofing; Hyperspectral data; mapping
Asbestos is the name of a group of fibrous silicates which have outstanding
physical properties (high tensile strength, chemical and thermal stability, high
flexibility, low electrical conductivity, and large surface area), but,
unfortunately, a carcinogenic nature as well. Since January 2005, the use and
production of asbestos is prohibited within Italy (Law No.257/92) and the
whole European Union. About 32*106 tons of asbestos materials are reside still
in "Eternit", a brand of roofing and panelling material made of asbestos fibres
and cement widely used for decades in many Italian urban and industrial areas.
Detailed mapping of asbestos-containing roofs from industrial and private
buildings has been promoted by Italian Law (D.M. 101/2003) and is currently
undertaken by regional environmental protection agencies. Application of
hyperspectral imaging for urban area analysis and mapping appear to be
particularly intriguing in terms of efficiency and cost reduction.
The present study proposes a systematic procedure to recognize Eternit-type
(i.e., containing Asbestos fibres + Cement, AC) roofing sheets and to evaluate
their deterioration status. We applied hyperspectral data imaging to distinguish
AC-made roofs from other types. For this purpose we employed the Multisensor
Hyperspectral System (SIM-GA), recently assembled by Galileo Avionica S.p.A..
SIM-GA is a modular avionic hyperspectral system, mainly composed of two
electrooptical heads (EOH) in VNIR and SWIR spectral range (from 0.4 mm to
2.5 mm) and a digital acquisition system with a four times better resolution
than instruments currently available (eg. MIVIS). In this "modular" approach
the two EOHs are physically separated but co-aligned on a common plate. This
concept allows a flexible application-specific configuration of the instrument
and therefore the possibility to use it on different platforms (including
Unmanned Air Vehicles and ultralight aircrafts). The system has been
embarked for the first flight on Dec 15, 2005 on a CASA 212 plane. The flight
plan included the coastal region of Tuscany, in particular over the urban and
industrial area of Follonica (Grosseto). Contemporary on-ground reference
measurements (e.g.: spectral radiance and reflectance) have been made for
post-flight data verification and calibration.
Laboratory analyses of AC samples representing various levels of deterioration
were performed by means of a portable spectroradiometer ASD FielSpec FR
(Full-Range Analytical Spectral Devices by FieldSpec Pro) which allows to
collect reflectance spectra (350-2500 nm range) performing spot analyses.
These spectral measurements have been used to built up a spectral library
needed for the validation of airborne data calibration as well as for a
preliminary evaluation of instrumental limits of detection of asbestos fibers.
We compared different methods used in the literature for the analysis of
hyperspectral (PCA, ICA, SAM, etc.). Unmixing algorithms to obtain the
79
abundances of the component of interest have been tested for the
identification/mapping and the quantitative estimate of asbestos fibers in AC. A
fast non-iterative procedure is proposed to solve the unmixing problem: the
non-negative abundance vector of each spectral pixel is found in a finite
number of operations. This procedures allowed to obtain a preliminary AC
mapping of the Follonica area.
T06-21 Poster
Bloise, Andrea
SYNTHESIS OF ASBESTOS TREMOLITE
BLOISE Andrea 1, BELLUSO Elena 1, BARRESE Eugenio 2, RINAUDO Caterina 3
1 - Unito
2 - Unical
3 - Unipmn
Key terms: asbestos tremolite; synthesis; standard sample; SEM/EDS,
TEM/EDS, XRPD, µ-Raman, DSC/TG
Tremolite Ca2Mg5Si8O22(OH)2 is a well kwon end-member of the calcic
amphibole usually growing with elongated or flattened bladed prismatic crystals
but also columnar or fibrous.
Tremolite fibres with length > 5 µm, width < 3 µm and aspect ratio > 3 are
classified as asbestos (2003/18/CE) and responsible of producing pathological
effects for human health. Actually it is known that toxicity and pathogenicity of
asbestos tremolite are correlated to morphology, bio-persistence and chemical
composition of the fibres [3]. In last decades several papers have been
published to describe the synthesis of tremolite [1, 2]. Length and width of the
obtained tremolite, when described and relatively to synthesis conditions, are
of the order of 2 and 0.5 µm respectively. This amphibole has been obtained by
various methods (externally or internally heated pressure vessel and
piston-cylinder presses), and various starting materials (gels, oxides, natural
tremolite); different aqueous solution, and ratios of H2O/reactants. These
experiments, performed in order to investigate the intergrowth of tremolite
with other phases under different synthesis parameters and to establish the
better synthesis conditions, showed that synthesized tremolite is not
stoichiometric (over 10% of Mg). It is not yet understood if this excess is
caused by chain-multiplicity defects [5], cummingtonite substitution [4], or
both. The present study was devoted to synthesize fibres of tremolite as unique
phase under hydrothermal condition and to characterize the obtained material.
The mineralogical study of starting material and final products was performed
by XRPD, SEM/EDS, TEM/EDS, thermal and µ-Raman studies.
A fixed quantity of finely powdered starting mixture according to an ideal
stoichiometric tremolite plus distilled water were put within a sealed platinum
capsule. The hydrothermal synthesis, performed in externally heated pressure
vessel, was carried out at 780° C, 1.7 Kbar and a run duration of 120 h.
The final product is fibrous tremolite as main product, quartz and talc as minor
phase (< 5%). The XRPD spectrum showed tremolite, the observed peaks
matching well the spectrum reported by JCPDS for monoclinic natural tremolite.
The medium length and width of fibres is 15 and 0.16 µm, as measured by
SEM and TEM on many fibrils. SAED images show very high cristallinity.
EDS/TEM analyses revealed the following average composition (oxide wt %):
SiO2= 61.59, MgO= 26.80, CaO=11.60. On the spectra registered using
micro-Raman spectroscopy the observed bands match well the wavelengths of
the bands registered on natural samples of tremolite. Finally the TG curve for
synthetic tremolite showed weight loss about 4 % corresponding to the
endothermic peaks at 928 °C on the DSC trace.
The synthetic and well characterized fibres can be used as standard sample in
several investigations. Chemically and morphologically controlled asbestos
tremolite is useful for in vitro and in vivo studies in order to understand the
role of these fibres in the pathological effects. Synthetic tremolite may be
compared with natural tremolite to test if can give different cellular answers.
References
[1] Bozhilov K. N., Jenkins D. M. and Veblen D. R. (2004) Am. Min., 89, 74-84
[2] Della Ventura G., Hawthorne F. C., Robert J. L., Iezzi G. (2003) Eur. J.
Mineral., 15, 341-347
[3] Dumortier, P., Rey F., Viallat J. R., Broucke I., Boutin C. and De Vuyst P.
(2002) Occup. Environ. Med. 59, 643-646
[4] Jenkins D. M. (1987) Am. Min.,72, 707-715
[5] Maresch W. V., Czank M. And Schreyer W. (1994) Con. to Min. and Petrol.,
118, 297-313
SESSIONE T07
Geologia e salute
T07-1 Invitato
Cortecci, Gianni
GEOLOGY & HEALTH: MAN, AN IMPORTANT GEOLOGICAL FACTOR
CORTECCI Gianni 1
1 - Institute of Geosciences and Earth Resources-CNR - Pisa
Key terms: Geology; Health; Androsphere
Geology & Health is an emerging science dealing with the relations between
geological environment and health, disease, pathology and death of humans,
animals and plants. It is focused on geology and its interdisciplinary
relationship to medicine, biology, chemistry and other sciences. Geology &
Health is substantially different from Medical Geology and Environmental
Medicine. The former investigates the influence of natural geological factors on
health of man and animals, and the latter the health risks posed by
contaminants in the home, workplace and outside ambient. Geology & Health
addresses all living beings (man, animals, plants), investigating both the
natural and anthropogenic hazards, but also the therapeutic properties of
geological materials. All three sciences contribute in different ways to health
SESSIONE T07
80
issues, and thus to the development of public health policy, with the result that
this interdisciplinary field is expected to assume an increasingly greater role in
education and to society at large. The "International Year of Planet Earth
2007-2009" (a triennium, subtitled Earth Sciences for Society), proclaimed by
the IUGS, and the UN Year of Planet Earth in 2008, declared by the General
Assembly of the United Nations, testify to an acclaimed awareness that is time
for the scientific community to focus on the relationship between mankind and
Planet Earth, thereby acknowledging that geoscientists are key players in
creating a local, national, and international sustainable future for both.
Ultimately, the initiative was promoted to sensitize the politicians,
decision-makers, media and general public to the Earth sciences and their
influence on many aspects of the everyday life.
In this presentation I would like to emphasize the impact of man as a
geological element (like a rock, water, volcanic eruption) on planet health.
Human activity (androsphere), among other things, redistributes metals,
contributes exotic compounds and promotes unnatural geologic processes,
usually with negative results. As with nature, man can cause flooding,
landslides and shore erosion. Metals (essential, non-essential, and toxic) are
redistributed from fairly harmless sites to places where they can have a
detrimental effect on human, animal and plant health. Even essential trace
elements (such as F, Si, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Mo, I, W) can be
detrimental if ingested in abnormal quantities. Acidification of rocks and soils
by acid rains from a contaminated atmosphere will accelerate the metal
distribution process, thus making it more easy for toxic metals (As, Cd, Hg, Pb)
to enter the food chain. Hg, Cd and Pb are harmful to plants, animals and man
alike.
The goitre caused by iodine deficiency, the dental caries caused by a
deficiency, or dental and skeletal fluorosis by an excess of fluoride, anaemia
due to iron deficiency, and muscular dystrophy due to selenium deficiency are
all classic examples of diseases related to natural geological factors. On the
other hand, acid rains, the greenhouse effect and the hole in the ozone are
basically the by-products of the human "volcanic" activity, which introduces
huge amounts of gases and particulate matter into the atmosphere. The fine to
ultra-fine particulates emitted by vehicular traffic and heating systems
represent another serious health problem, particularly in densely populated
cities, as particles retain heavy metals and polycyclic aromatic hydrocarbons
(PAH), the latter being almost exclusively anthropogenic. The carcinogenic and
atherogenic properties of PAHs are well documented.
I'd like to recommend a book that highlights the importance of geology in
health problems. The title is "Essentials of Medical Geology-Impacts of the
Natural Environment on Public Health" (ISBN: 0-12-636341-2), which was
published in 2005 by Elsevier Academic Press.
T07-2 Invitato
De Vivo, Benedetto
TOXIC METALS DISTRIBUTION, NATURAL RADIOACTIVITY AND
EPIDEMIOLOGY IN THE CAMPANIA REGION (ITALY).
DE VIVO Benedetto 1, LIMA Annamaria 1, ALBANESE Stefano 1, DE LUCA Maria
Luisa 1
Key terms: Geochemistry; Epidemiology; Geochemical mapping; Natural
radioactivity; Geochemical backgrounds
In the Campania region (southern Italy), studies on the distribution of metallic
harmful elements and radioactivity have been carried out, both on stream
sediments, at a regional scale, and on soils, at a local scale (urban areas). Lima
et al. (Appl. Geochem., 20, 611-625, 2005) demonstrated that high U, Th and
K values in stream sediments correspond well with the occurrence of volcanic
rocks in the central-western part of the region, whereas low values characterize
sedimentary deposits in the rest of the region. Gamma-ray spectrometry maps
produced for 40K, more useful than 238U and 232Th, show particularly high
radioactivity levels which corresponds with all the eruptive centers
(Roccamonfina, Campi Flegrei and Somma-Vesuvius, including the fissure
sources of Campania Ignimbrites). In these areas, concentrations of harmful
elements, such as Pb, Zn, Cd, Cu, etc., are generally above the regional
average, as well (Albanese et al., J. of Geochem. Expl., 93, 21-34, 2007).
The atlas of cancer mortality for the Campania residents during the period
1982-2001 shows that especially in the north-western sector of the region, the
standardized mortality ratio (SMR) on the overall regional population for all
neoplasms, expressed as a percentage, is always above 110 (Pizzuti et al.,
Reg. Camp. - Oss. Epid. Reg., 119 pp., 2006). These higher risk areas roughly
correspond to the zones where radioactivity and harmful element
concentrations are higher than the rest of the regional territory, implying that
the naturally occurring radioelements and the intense anthropogenic pressure
on the environment could be possible causes of increased cancer risk. Since
SMR is higher mostly in the provincial area of Naples, where a detailed
geochemical soil survey has been carried out (Cicchella et al., Geochem.:
Explor., Environ., Analysis 5, 29-40, 2005), further studies are in progress to
relate SMR to harmful element distribution in the soils of the area. Knowledge
of the epidemiology integrated with a detailed elemental study of soil will be
important to assess the risks related to various potential causes.
T07-3 Orale
Valera, Paolo
RELATIONSHIPS BETWEEN HEAVY METALS AND HEALTH IN SARDINIA:
A PRELIMINARY STUDY
MUNTONI Elisabetta 1, VALERA Paolo 1, DEIANA Andrea 1, MUNTONI Sandro 2
1 - DIGITA - Department of Geoengineering and Environmental Technologies Faculty of Engineering - Cagliari University, Italy
2 - Department of Toxicology - Oncology and Molecular Pathology Unit Cagliari University, Italy
Key terms: Geochemical Data; Health; Stream sediment; GIS; Risk Index
In 1948, the World Health Organization (WHO) defined "health" as "a condition
of complete mental, social physical well-being, not only determined from the
absence of diseases". Genetic and environmental factors (mainly economic and
social) contribute to this condition. Thus, a multidisciplinary approach to study
human health is suggested. Such an approach, requires the involvement of
various disciplines and experties, in order to investigate human health and
quality of life interactions.
The "Geomedicine", defined as the relationship between the geological
environment, and human health, is acquiring important meanings in the
development of medical and epidemiological information. The Department of
Geoengineering and Environmental Technologies (DIGITA), of the Faculty of
Engineering - Cagliari University - since several years, is involved in sampling
of several environmental matrix supports (rocks, soils, stream sediments) and
their geochemical analysis.
Up to now, the sampling and analytic surveying is accomplished, and a new
geochemical mapping is starting up, at 1:100.000 scale of all Sardinia, which is
based on the stream sediment database.
In a preliminary analysis of this database we found high values of well known
dangerous elements, such as Cd, As, Pb, Hg. These unexpected findings
suggest us to set up a study on possible correlations between geochemical data
and some chronic diseases existing in Sardinia, through spatial distribution of
chemical elements, their migration mechanisms, geochemical background in
the lithologies and biodisponibility of heavy metals.
The study involves a team of environmental engineers, GIS (Geographic
Information System) experts, geologists from the Engineering Faculty Department of Geoengineering and Environmental Technologies, and medical
researchers from the Medicine Faculty - Department of Toxicology, both from
Cagliari University.
This study, is being carried out through the following steps:
- Regional mortality data collection, georeferring and digitalizing (just
started);
- GIS development, expectably open source, like GRASS, where medical,
geochemical and lithological data, will be analysed;
- Choice of a pilot area with high mortality for pathologies connected with
heavy metals exposure;
- Morbidity and mortality data analysis of the pilot area population (hospitals,
regional health agencies);
- A detailed geochemical prospection and geostatistical study of the area;
- Speciation and biodisponibility analysis of some elements;
- Investigate the presence of the heavy metals in other matrices, like soil,
vegetables or insects like bees and/or their products;
- Organization and insertion of all the informations into the GIS
- Data processing analysis;
- Statistical analysis of correlations between morbility /mortality and
geochemical data, in order to identify reliable coefficients and to obtain a Risk
Index for the human health;
In conclusion, this model can be considered not only an important source of
information regarding gene-environment interactions in Sardinia, but also a
validated method for further geochemical/medical analysis and territorial
planning worldwide.
T07-4 Orale
Ciotoli, Giancarlo
SIMULATION OF HEAVY METAL AND SULPHATE TRANSPORT IN
GROUNDWATER FROM FLY-ASH DEPOSIT IN THE AREA OF THE
"NIKOLA TESLA B" THERMO-POWERPLANT, (OBRENOVAC, SERBIA)
CIOTOLI Giancarlo 1, CELIKOVIC Igor 2, LOMBARDI Salvatore 1, MORONI Monica 3,
ZUNIC Zora 2
1 - Dipartimento di Scienze della Terra, Università di Roma "La Sapienza"
2 - VINÈA Institute of Nuclear Sciences, Belgrade, Serbia
3 - Dipartimento di Idraulica, Università di Roma "La Sapienza"
Key terms: fly-ash; heavy metal; groundwater; transport simulation
The seepage of solutes from waste disposal industry is an important
environmental concern; examples include seepage from fly-ash deposits
derived from coal burning power plant. The dominant focus of studies on these
sites, generally, regards physical movements of the solute and their chemical
behavior in groundwater. The investigation of transport behavior in
groundwaters provides useful information for both groundwater protection and
remediation of coal-ash repository sites. In particular, dispersion, diffusion,
recharge to the aquifer, and chemical reactions as well as radioactive decay,
should be taken into account to obtain reliable prediction on transport of
radionuclides and of inorganic pollutants.
Emission and deposition of coal ash represent major environmental problems,
due to the large amount of ash obtained. During coal combustion, the organic
component becomes oxidized, while inorganic components mostly remain in
the ash. The variability of inorganic constituents is influenced by biological,
hydrological and geochemical factors and their association forms govern their
behavior and their technological and environmental impact. The environmental
impact of ash is due to the leaching of microelements (including heavy metals
such as Pb, Cr, Cd, Co, Cu, Zn, As, V), but also major cations (Ca) and anions
(SO4) from ash by atmospheric and surface waters. The presence of metals in
groundwater and soils can pose a significant threat to human health and
ecological systems. The chemical form of the metal contaminant influences its
solubility, mobility, and toxicity in ground-water systems. Typically metals are
relatively immobile in subsurface systems as a result of precipitation or
adsorption reactions.
This work presents 3D reactive and non-reactive transport models of
contaminants in groundwaters employing MODFLOW and MT3D codes. This
simulation was carried out by using literature and field data collected in the
area of the "Nikola Tesla B" thermo-power plant (TENT B), (Obrenovac, Serbia)
in the framework of INTAILRISK CE project.
The TENT B area is located on the bank of the Sava river, near the Obrenovac
village, about 40 km upstream from the Belgrade city (Serbia & Montenegro).
This plant is producing about 4.5 x 10 9 kg of coal-ash per year. Ash is
transported to the dump after being suspended in the water taken from the
Sava river, in the approximate ratio 1:10. The dump of the power plant "Nikola
Tesla B" has an area of about 6 km2.
The primary environmental concern associated with this disposal site is the
potential groundwater contamination. Hydrochemical data of waters from wells
collected during the field surveys highlights high mineralization (i.e. 1200 mg/l)
and a high content of SO42- (up to 450 mg/l) and Cl- (up to 70 mg/l)
contributing to the hypothesis of a potential pollution from the fly ash deposit.
SESSIONE T07
The transport model was built by solving in 3D the Advection-Dispersion
Equation in the shallow aquifer.
In order to build the model, geological, hydrogeological and hydrochemical
data from wells located both in the source area (fly ash deposit) and in the
surrounding agricultural land were employed, as well as mineral springs located
at the boundary of a fluvial terrace about 2 km south. In particular, the
transport model was implemented by using reactive, soluble sulphates, as well
as heavy metals as contaminant. The main goal of the study was: (i) to model
the groundwater flow in the TENT B area; (ii) to build a conceptual model
describing transport of heavy metals within the groundwater assuming
precipitation or adsorption reactions; (iii) to understand the transient impact of
soluble compounds (sulphates) derived from fly ashes on the quality of
groundwater assuming retardation due to interaction with the soil.
T07-5 Orale
Giannossi, Maria Luigia
BASILICATA (ITALY) EPIDEMIOLOGICAL NEPHROLITHIASIS PROJECT
AND STONE ANALYSIS:CORRELATION TO ENVIRONMENTAL RISKS
FACTORS (PRELIMINARY DATA)
GIANNOSSI Maria Luigia 1, SUMMA Vito 1, TATEO Fabio 2, MONGELLI Giovanni 3
1 - Istituto di Metodologie per l'Analisi Ambientale - CNR - Italy
2 - Istituto di Geoscienze e Georisorse - CNR, c/o Dip. Geoscienze- Italy
3 - Dipartimento di Scienze Geologiche - Università degli studi della Basilicata Italy
Key terms: epidemiology; kidney stone; environmental factors
Epidemiological data on the occurrence of nephrolithiasis appears to be
gradually increasing but it remains poorly defined. Precise data on the
epidemiology of this disease can only be determined if geographical position,
race, age and sex, climate, nutrition and other environmental factors are also
taken in consideration.
There are no population based data on the incidence or prevalence of kidney
stones in Italy and in particular in Basilicata (southern Italy). Previous studies
show that kidney stones are uncommon before the age of 20 years, their
incidence rises between the age of 20 and 30 years and then remains relatively
constant until the age of 70 years, after which the incidence falls again. Men
are at greatest risk of developing kidney stones with incidence and prevalence
rates between two and four times that of women. Men were at greater risk of
producing calcium oxalate stones and uric acid stones. Women were at greater
risk of infection stones. The frequency of some type of stone vary significantly
throughout the year, with an increase during summer and autumn (uric acid
stones), instead for other stone the frequency did not vary.
The main purpose of our study is to acquire useful information on
nephrolithiasis in Basilicata and to perform the chemical and mineralogical
analysis of stone, to examine regional variation in the incidence rate of kidney
stones, to know the pattern of chemical and mineralogical composition of stone
and to determine epidemiological and environmental risk factors for stone
formation in Basilicata. We must assume that hospital discharge rates reflect
stone incidence rates.
Study has been carried out in collaboration with doctors of Potenza (Italy)
Hospital, for multidisciplinary character of the research. The epidemiological
analysis was based on data from regional institution of the Basilicata resident
population ( 597000) that was hospitalized for nephrolithiasis in regional and
external hospital structures. Additional data have been obtained from
interviews of patients. Questionnaires include personal details (gender, age,
marital status, address, educational level) and socio-economic (type of work,
etc.) and medical history data (weight, height, personal and family anamnesis,
eating habits, etc.).
In particular for eating habits, all respondents were asked how much liter of
water-based beverage they consumed per day, and how much of their water
was consumed from municipal or commercial supply. Patients were asked how
often they had consumed some kind of food (as vegetable rich in oxalate) and
where they were cultivated, to evaluate possible chemical elements in the soil
promoting kidney stones. Dietary habits, life-style, climate and socio-economic
status, and also water chemistry, soil geochemistry and mineralogy, are
peculiar epidemiological characteristics of renal stone formers, and probably
may explain the geographic distribution of calcium nephrolithiasis. All the
information has been stored in a data base available for consultation during
research.
An high prevalence of the disease from 9.2 to 15.1 out of 1,000 inhabitants has
been observed in some regional area; most patients are men and the peak age
for the development of stones is between 40 and 60 years. The incidence rate
is significantly greater in the northern Apennine Basilicata zone and tend to
decrease in the southern Basilicata Bradanic Foredeep. In view of the
correlation between composition of patients stone and environmental factors
(as water chemistry, average annual temperature, and soil geochemistry and
mineralogy), careful morphologic and constitutional analysis of stone should
not be neglected.
Understanding the epidemiology of stones disease is important to determine
the significance of the disease at a community level, the associations and risk
factors for individuals and the likelihood of stone recurrence.
T07-6 Invitato
Valdrè, Giovanni
DNA CONDENSATION, ORDERING AND SPONTANEOUS
CONFORMATIONAL CHANGES ONTO LAYER SILICATES
VALDRÈ Giovanni 1
1 - UNIVERSITA' di BOLOGNA, ITALY
Key terms: Phyllosilicates; DNA; Biosurfaces; Biomineralogy
The main purpose of this project is to characterize the surface potentials of
various layered minerals for the control of DNA, nucleotides and cells
adsorption. A critical aspect of imaging biomolecules and biomolecular
processes is the nature of the substrate on which the molecules are adsorbed.
In the past the underlying assumption, derived from current models of
biomolecules' adsorption, is that the substrate surface plays a "passive" role in
81
the process and functionalization is required during the deposition. Several
techniques have been developed to tailor the adsorption of biomolecules
according to different experimental requirements. These include the
functionalization of the surface with self-assembled monolayers, the use of
ligand-receptor complexes and the regulation of the buffer conditions.
Following our experiments it became immediately clear that the above
assumption is not completely correct for layer silicates because very similar
atomic flat crystals, as in the case of muscovite and biotite, showed very
different affinity to DNA adsorption.
Furthermore, it was found that chlorites have the ability to nanoconfine the
deposition of DNA molecules in particular areas (brucite-like) of the surface.
This effect became even more interesting when it was noted that some DNA
strands could be stretched between two brucite areas. The stretching was
shown to be produced by the anisotropy of the surface potential and it is
therefore an active process induced by the surface. The molecules were also
shown to be "suspended" between the two brucite areas with very small
interaction with the underlying surface.
The possibility to manipulate DNA molecules on a flat surface, as in the case of
chlorite, has great potential, in biological, medical and health sciences, for
example to exploit its use (and that of similar layer silicates) to study
DNA-enzyme complexes, cellular behaviour and biochemical assays.
T07-7 Invitato
Setti, Massimo
MUDS FOR PELO-THERAPY
SETTI Massimo 1
1 - Dipartimento Scienze della Terra Università di Pavia
Key terms: peloid muds; clay minerals; maturation treatments; mineral water
effects
There is a long tradition in using clays as empirical medicine, also noticed by
legends, beliefs, rituals and ethnological records. Clay minerals (kaolinite,
smectite, sepiolite and palygoskite) are used in the preparation of
pharmaceutical products and animal feed, as active chemo-sorbents for
protective coatings of stomach, intestine and skin (cosmetics, dermatology,
burns treatment, etc.) and as adsborbents of toxins, bacteries and even
viruses. "Pelo-therapy" is the local or generalized application of thermal muds
(hot cataphlasmas called "peloids") for recovering rheumatism, arthritis and
bone-muscle traumatic damages. SPA centres in northern Italy use clayey
admixtures for the formulation of muds to be used in pelo-therapy. The basic
ingredient, "virgin" clay, is a dressed bentonitic geomaterial. The peloid muds
are obtained by maturation of the virgin clay with mineral waters gushing out
in-situ which have different geochemistry: sulphureous, Ca-sulphate,
Ca-Mg-sulphate and Br-I-salty. The maturation treatment is varying with
respect to mixing procedure and lasting time. Many parameters
(physico-chemical and rheological behaviour) can change during the
maturation treatments with respect to virgin clay: mineralogical composition,
clay fraction, CEC, pH, soluble salts, water retention, swelling index, activity,
consistency parameters (WL, WP and PI), thermal behaviour and cooling
kinetics.
A need of regulation (standard procedures) is suggest to certificate the clay
geomaterials suitable for pelotherapy, and also for drugs formulation.
T07-8 Orale
Tateo, Fabio
DILTIAZEM.HCL - BENTONITE COMPLEX FOR HEALING APPLICATIONS
TATEO Fabio 1, GIARETTA Aurelio 1, MEDICI Luca 2, SUMMA Vito 2
1 - IGG-CNR
2 - IMAA-CNR
Key terms: bentonite; drug delivery system; clay mineralogy
Geologic materials have been widely used for pharmaceutical preparations and
clay minerals in particular experienced a prolonged commercial success in this
field because they have been used both as excipient and as active principle
(Carretero, 2002 and references therein). These two different purposes are
obviously in contrast each other because the inert behaviour of an excipient is
hardly compatible with the biological effect of a pharmacological active
principle. The recent feeling about this topic is much more based on the
mineralogical considerations than in the past, because the different behaviour
of different clays minerals is taken into account (Droy-Lefaix & Tateo, 2006,
Carretero et al., 2006; Aguzzi et al., 2007; Viseras et al., 2007).
Smectite minerals are highly suitable for sustained release of cationic drugs
because of their high cation exchange capacity (CEC), but also low CEC
minerals, such as halloysite, have been used to this purpose, owing to the
microtubular habit of the crystals and multiple layering of different substance
to provide adequate ligands to the drug (Levis & Deasy, 2003).
Diltiazem.HCl is a cationic drug with good solubility in water. These features of
the drug and its therapeutic value in the treatments of different pathologies
such as hypertension and angina, make it an interesting opportunity for test
advanced uses of clay minerals for healing uses.
Two natural bentonites, one composed mainly of dioctahedral smectite (with
some illite), and the other by trioctahedral smectite have been used for drug
interaction. An amount of the drug equivalent to about 4 times the nominal
CEC of smectite (1 meq/g) has been dissolved in water with 1 g of bentonite.
After 2 hours the suspension was washed 3 times by centrifuge.
The water interaction between diltiazem.HCl and the analysed smectites caused
a clear expansion of the interlayer space from about 1.5 to about 1.9 nm
indicating that the organic molecule entered into the interlayer space,
expanding it. Such an arrangement represent a nano-holder of the drug, that
may prevent the rapid degradation of the active principle.
The amount of diltiazem sorbed was evaluated by CNS measures, ranging from
about 19.5% (dioctahedral sample) to 19.9% (trioctahedral sample). The
entrance of the drug into interlayer spaces, decrease the water content of the
mixtures, from about 18% to 12% (dioctahedral sample) and from about 17%
to 11% (trioctahedral sample).
The significant concentration of the drug into the bentonite matrix makes the
SESSIONE T07
82
smectite-diltiazem complex a valuable carrier of the drug.
Aguzzi C., Cerezo P., Viseras C., Caramella C., 2007. Use of clays as drug
delivery systems: Possibilities and limitations. Applied Clay Science, 36: 22-36.
Carretero M.I., Gomes C.S.F. and Tateo F., 2006. Clays and human health. In:
F. Bergaya, B.K.G. Theng and G. Lagaly (eds) Handbook of Clay Science,
Developments in Clay Science, Vol. 1, Chapter 11.5: 717-741.
Droy-lefaix M.T. and Tateo F., 2006. Clays and clay minerals as drugs. In: F.
Bergaya, B.K.G. Theng and G. Lagaly (eds) Handbook of Clay Science,
Developments in Clay Science, Vol. 1, Chapter 11.5: 743-752.
Levis S.R. & Deasy P.B., 2003. - Use of coated microtubular halloysite for the
sustained release of diltiazem hydrochloride and propranolol hydrochloride.
International Journal of Pharmaceutics, 253: 145-157
Viseras C., Aguzzi C., Cerezo P. and Lopez-Galindo A., 2007. Uses of clay
minerals in semisolid health care and therapeutic products. Applied Clay
Science, 36: 37-50
T07-9 Orale
Peruzzo, Luca
SILICON IN THE HUMAN BODY AND THE ODD OCCURRENCE OF
MICROCRYSTALLINE QUARTZ IN PATHOLOGICAL SYNOVIAL FLUIDS
PERUZZO Luca 1, OLIVIERO Francesca 2, FRALLONARDO Paola 2, TAURO Leonardo 3
, SFRISO Paolo 2, SCANU Anna 2, RAMONDA Roberta 2, PUNZI Leonardo 2
1 - Istituto di Geoscienze e Georisorse - CNR Padova
2 - Divisione di Reumatologia, Dipartimento di Medicina Clinica e Sperimentale
- Università di Padova
3 - Dipartimento di Geoscienze - Università di Padova
Key terms: silica; quartz; synovial fluid; arthritis
In the course of our research on pathogenic crystals in the synovial fluid (SF),
unexpected SiO2 particles have been detected.
Many crystal species are common in SF of patients affected by rheumatic
disorders, osteoarthritis (OA) in the specific instance.
Under the polarized light optical microscope the search for crystals like
monosodium urate (MSU) and calcium pyrophosphate dihydrate (CPPD) is the
main object of the early laboratory investigations, but other particles may be
seen including basic calcium phosphate (BCP) and other crystals (cholesterol,
oxalate, corticosteroid, lipid), different types of cells, hemoglobin, hematoidin,
starch from gloves, dust, etc.
MSU, CPPD and BCP crystals, are certainly related to specific diseases
(respectively: gouty arthritis; pseudogout, articular chondrocalcinosis,
polyarthritis; calcific periarthritis, inflammatory osteoarthritis, soft tissue
inflammation). Although the exact significance of their presence in
osteoarthritic SF is still unclear, it has been observed that they correlate with
disease severity and higher radiographic grades. Therefore, the detection and
correct identification of crystals represent an important step in patient
management.
In clinical practice, however, analysis of SF based on optical microscopy
frequently leads to the finding of other types of crystals that cannot be
identified with complete certainty, often because of their small size. Scanning
electron microscopy was used in this study to better characterize all the types
of crystals and look for their possible clinical significance in the setting of OA.
The identification of SiO2 in 10 out of 24 samples drove us to deepen the
investigation on these particles, consisting of sharp-edged micron size grains.
Silicon-containing particles in SF have been previously described only two times
and ascribed to artifacts produced by technical procedures.
The best care taken of avoiding pollution during any step of our experiment,
together with the use of disposable materials in total absence of glass and the
analysis of blank samples, tend to exclude any form of external contamination.
Furthermore, X-ray powder diffraction obtained from some selected samples
displayed unequivocally the spectrum of a crystalline phase corresponding to
quartz.
At this point, agreed that those particles reasonably can be microcrystalline
quartz, the question is: where does it come from?
If the hypothesis of sample contamination is to be discarded, it's nearly but not
completely excluded the possibility of an external origin, for example by
inhalation (dusts), ingestion (drugs, food) or other form of introduction (drugs,
prostheses). Nevertheless, it is more challenging to explore the alternative
possibility that the crystals formed within the articular capsule (synovial fluid,
synovial tissue, cartilage or bone).
Silicon, after iron and zinc, is the third most abundant trace element in the
human body and is especially associated with connective tissues such as in
bone, tendon, cartilage, skin and blood vessels. Several ex vivo and in vitro
studies reported the beneficial effects of silicon supplementation on bone and
cartilage development, even if the mechanisms are not completely understood.
On the other hand, it's common knowledge that in the biological world many
organisms (sponges, diatoms, radiolaria, plants and mollusks) are able to
produce silica-based structures also from undersaturated solution, peri-neutral
pH and low temperature and pressure.
Supporting the hypothesis of microcrystalline quartz formed in the SF it's of
interest to consider that silica exhibiting crystalline texture has been prepared
by some researchers from aqueous solution at room temperature and pH 7, in
the presence of biomolecules.
The research currently in progress aims to establish if and how SiO2 crystals
form in the synovial environment and whether they may have long-term
consequences with respect to OA progression.
T07-10 Invitato
Huertas, F. Javier
INTERACTION OF CLAY MINERALS AND ORGANIC ACIDS:
GEOCHEMICAL, ENVIRONMENTAL AND HEALTH IMPLICATIONS
HUERTAS F. Javier 1, FIORE Saverio 2
1 - Estacion Experimental del Zaidin - CSIC Granada, Spain
2 - Istituto di Metodologie per l'Analisi Ambientale - CNR Tito Scalo (PZ), Italy
Key terms: Environments; Lung deseases; Dissolutions; Adsorption; Organic
acids
Organic matter plays a key role in a number of geochemical and environmental
processes in the biosphere, as soil formation, plant nutrition, groundwater
chemistry, transport of solutes and pollutants, weathering of minerals, etc.
Soils and groundwaters contain low molecular organic acids, as acetate,
oxalate, formiate, salicylate, citrate, etc., in concentrations that vary between
tens to thousands of micromole per liter. They may interact in-situ with
minerals interface or may be transported and react elsewhere.
Vertebrates, as a part of the global environment, constitute a particular case of
the mineral/ligand interactions. They, especially humans, are continuously
exposed to minerals through the skin and respiratory and digestive systems.
Fluids containing a great number of organic molecules are released in response
to a foreign object. Organic molecules react with the mineral surface in order to
neutralize (encapsulate or dissolve) it and to prevent diseases and pathologies.
For example, asbestos and quartz have been recognized as hazardous if the
can reach the alveolar cavities. However, World Health Organization has
alerted that many other materials in the airborne dust can be potentially
dangerous under certain conditions of exposure. Few things are known about
the possible effect of the minerals added to food or used in healing treatment
and natural medicine. Although many treatments with "healing minerals" have
made for long in many cultures, their use in modern medicine should be
investigated to asses the benefits and potential risks.
It is has been demonstrated that organic acids enhance dissolution of
(hydr)oxides and silicates. The organic acids may modify the rate of alteration
and weathering processes by several mechanisms, such as production of
acidity, alternative reaction paths and reduction of the solution saturation by
complex formation and transport of cations. This study concerns the role of low
molecular weight organic acids on the dissolution rate of smectite, by surface
adsorption and scomplexation in solution. Clays are one of the main
components of fine fraction of soils, sediments and airborne dust. Organic acids
as oxalic, salicylic, citric or lactic contains phenol and carboxylic functional
groups that can interact with the clay surface and form soluble complexes.
These acids are common in ground water and body interstitial fluids.
K-montmorillonite was treated in flow-through reactors with solutions containig
organic acids, in background electrolite solutions at 25°C and in synthetic lung
fluids at 37°C. The pH was adjusted at ~3-4 and 6-7.5. The output solution
was collected every 24 h to monitor pH and concentrations of organic acids, Si,
Al, Mg and Fe. The smectite dissolution rates were derived from Si
concentrations at steady state conditions. Batch adorption experiments were
perform to quantify the adsorption of the organic acids on the smectite surface.
The results indicate that the presence of organic acids may contribute to
degradation of the smectite by dissolution and complexation reactions at pH~7
(interstitial fluids). However, at pH 3 (lysosomal fluids) organic acids contribute
to dissolution reaction producing acidic conditions (proton promoted
mechanism). Further investigation will be required in order to deepen our
understanding of the mechanism of organic matter interactions with mineral
surfaces under earth surface and human body conditions.
T07-11 Orale
Gullo, Maria
ASBESTOS HAZARD: IMPACT, DIMENSION AND IMPLICATIONS IN THE
AOSTA VALLEY (ITALY)
GULLO Maria 1
1 - INAIL Direzione Regionale Piemonte - CONTARP
Key terms: asbestos; work; diseases; environmental; hazard
The asbestos mineral is common in the territory of the Aosta Valley as result of
the industrial production as well as the geologic and petrographic setting of this
region. The mineral is present in several outcrops and has been object of ore
exploitation.
Based on the above considerations the study of the asbestos-connected
occupational diseases on the Valle d'Aosta district has been carried out tacking
into consideration the ten year period 1994-2003. Aim of the study was a
better understanding of the impact factors in different working cycles in order
to estimate the expected amount of charge for diseases, to evaluate the
evolutionary trend and the relationships between environmental context and
asbestos-related occupational diseases.
The dataset has been provided by the INAIL data bank, by enquiry carried out
by the Consulenza Tecnica Accertamento Rischi e Prevenzione, by the
Dipartimento Prevenzione - SPRESAL USL (Aosta) and by previous works.
Preliminary results of this study suggest a positive (increasing) trend of the
asbestos-related diseases in the Aosta Valley. Among the neoplasias the pleural
mesothelioma prevail. On the base of the mesothelioma lengths we hypotesize
that the incidence peak has not been recorded till now. Moreover the
comparison of our data with those available from the Aosta USL, support a gap
between certified and expected occupational diseases. The latter, so called "lost
diseases", are extimated on the base of statistic-epidemiologic evaluations
(Annual Report 2002 INAIL).
The comparative analyses between workers reporting occupational
asbestos-related diseases and the curricula of workers asking for a declaration
on asbestos exposure in conformity to the Law n. 257/92 (and subsequent
modification) support the increase of these diseases among the steelworkers,
one of the most prominent job opportunity in the district.
The asbestos hazard concern also the domestic environment as well as the
housing. A number of 354 reclamation works have been carried out in the
1993-2004 decade.
Moreover an increase of the environmental hazard in the Aosta Valley is
provided by the geologic-petrographic features. For example in the Emarèse
area asbestos exploitation was carried out as from1872 and ceased on 1939.
However the regulations concerning the reclamation work for this area were lay
down recently (Decreto Ministero dell'Ambiente 2611/2002).
In conclusion the dataset analysis indicate that the asbestos-related diseases
mainly depends on working exposure. We cannot exclude the impact of
different sources considering the lost diseases.
T07-12 Orale
Perniola, Donato
MINERALOGICAL RISK EVALUATION INDUCED BY NATURALLY
SESSIONE T07
OCCURRING ASBESTOS IN BASILICATA (SOUTHERN ITALY)
FIORE Saverio 1, BELVISO Claudia 1, BOCHICCHIO Andrea 1, BONELLI Giovanni 1,
CAVALCANTE Francesco 1, GIANCRISTIANO Franchino 1, LETTINO Antonio 1,
MEDICI Luca 1, PERNIOLA Donato 1, RAGONE Pietro 1
1 - CNR - Istituto di Metodologie per l'Analisi Ambientale - Tito Scalo (PZ)
Key terms: asbestos; loose rocks; massive rocks; air; water
In order to identify risk areas in which residents in Basilicata (Italy) are
potentially exposed to outcropping rocks containing asbestos, a study has been
carried out on the environmental systems (stony and loose rocks, the air and
surface waters).
The area of investigation, situated along the Calabria-Basilicata border, covers
750 km2 and includes many towns and villages in the Pollino National Park.
The study was carried out according to the following phases of investigation:
- Geological mapping, with the support of a MIVIS observations, integrated
with geomorphologic mapping and land use;
- Petrographic characterization of massive rocks (by optical microscopy and
microXRD) and their weathered surface (by SEM/EDS);
- Mineralogical characterization of the loose rocks (XRD and SEM/EDS) and
microXRD);
- Environmental analyses relative to asbestos in the air (SEM/EDS) and in
water (XRD, SEM/EDS);
- Evaluation of the capacity of stony rocks to release asbestos fibres.
The results of the geologic/petrographic investigations show that in the studied
area there outcrop 36.8 Km2 asbestos-containing rocks. The most abundant
asbestos mineral is tremolite; chrysotile occurs subordinately.
Analytical investigations have allowed to ascertain the presence of asbestos
fibres in friable rocks, on the surface of stony rocks, in the air and in river
water. In some cases, it has been measured amounts to 10% wt.
The high-risk areas are those object of human activity (building and
agriculture) and to changes in the natural order (landslides or surface
alterations) which are capable of moving the materials.
The results have been implemented in a GIS which is able to gather, link,
elaborate and share analytical and geographic data.
This system allows us to relate the state of contamination of the environmental
matrixes to the demographic and epidemiologic data.
The algorithm to evaluate the mineralogical risk indicated by the Italian law is
manifestly useless.
T07-13 Orale
Torri, Giorgia
NEW FINDINGS ON THE REAL RISK OF EXPOSURE TO AIRBORNE
MINERAL FIBERS IN OUTDOOR LIFE AND PROFESSIONAL
ENVIRONMENT IN ITALY
TORRI Giorgia 1, GUALTIERI Alessandro 1, MANGANO Dario 1, RICCHI Anna 2,
FORESTI Elisabetta 3, LESCI Giorgio 3, ROVERI Norberto 3, MARIOTTI Mauro 4,
PECCHINI Giovanni 5
Reggio Emilia
2 - Dipartimento di Sanità Pubblica, Azienda USL Modena Città
3 - Dipartimento di Chimica "G. Ciamician" Alma Mater Studiorum, Università di
Bologna
4 - Dipartimento di Sanità Pubblica, Azienda USL Bologna Città
5 - ARPA, Sezione Provinciale Reggio Emilia
Key terms: Asbestos; Monitoring; Outdoor
Air-dispersed particulate material, and especially asbestos fibres represent a
hazard for the human health. It is of paramount importance to monitor the
presence of particulate not only in air but also in other media such as water
and soils (the so called fall-out particulate) to carefully assess the real levels of
exposure risk in life and work environments.
The long term project granted by the Fondazione Cassa di Risparmio di Modena
(Modena, Italy) which involves the University of Modena and Reggio Emilia,
ARPA Reggio Emilia, ARPA Bologna, University of Bologna deals with the
monitoring of asbestos and other inorganic mineral fibre particulate (with a
special care to PM10 particulate) in life and professional environments of
selected Italian sites.
Work and life environments with different characteristics were selected within
the Bologna, Modena and Reggio Emilia Provinces (Italy) and kept monitored
for about one year to investigate the activity of the asbestos fibres and other
inorganic particulate during different seasons and environmental/climate
conditions. For each monitoring site selected for its potentiality to be a source
of particulate dispersion in air, a corresponding blank (presumably with zero or
low probability of particulate dispersion) site has been monitored in order to
collect also the background dispersion values.
Monitoring was conducted in continuous mode for 1 week and is repeated 4
times a year (spring, summer, autumn, and winter time). The monitoring of
the airborne dispersed particulate was possible using an especially modified
high flux volumetric (ca. 1 m3 per min) area air sampler and large cellulose
filters (A4 paper size). The fall out particulate is collected in a 1 m2 wide
collector filled with water which simulate a water source. Samples of the
surface soil are also collected in the proximity of the monitoring sites to assess
the nature and concentration of the particulate deposited in a long term. The
analysis of the collected samples was possible using bulk (the Rietveld method
and FTIR) and microscopic techniques (optical microscopy, SEM, and TEM) in
the attempt to determine the nature, meso-microstructure and density of the
inorganic particles. Only the specimens that have shown the presence of
asbestos fibres were further investigated with SEM, for the quantitative
evaluation of the asbestos fibres in bulk and filters following the instructions
suggested by DM 6/09/1994.
The nature of the crystalline phases present in the various media and relative
origin during the four monitoring shifts has been revealed. Some of these
phases are considered carcinogenic (i.e. quartz), others have clearly a fibrous
habit (i.e. anatase) although their are not considered hazardous. As a matter of
fact, a number of fibrous phases other than asbestos have been discovered in
the airborne particulate and other media.
Despite the nature of the collected sample, the outcome of this study points to
a very low concentration of asbestos fibres in the outdoor environment.
Considering the literature data on the dispersion of asbestos fibres in air in
83
urban and industrial areas, the results are quite surprising because the
calculated amount of asbestos fibres in air from our study is negligible. On the
other hand, although not fully consistent, literature data seems to point to a
generalized high concentrations of airborne asbestos fibres. Although outdoor
working and life sites have been investigated, the comparison with the allowed
concentration of asbestos fibres in working environment (100 ff/l according to
the recent law Decreto 257/2006) indicates that the concentration found in this
work are by far much lower than the concentration limits imposed by the law.
In view of this finding, the alarming scenario of a diffuse asbestos exposition in
outdoor environment should be reconsidered.
T07-14 Orale
Bevilacqua, Rosanna
RECENT DEVELOPMENTS ON OCCUPATIONAL QUARTZ HAZARD: THE
ITALIAN SITUATION
BEVILACQUA Rosanna 1, COCCHIONI Mario 2
1 - INAIL - DIREZIONE REGIONALE MARCHE
2 - UNIVERSITA' DI CAMERINO
Key terms: SILICA; SILICOSIS; DUST; CANCER; HAZARD
Recent studies show epidemiological evidence of a relationship between
exposure to airborne silica dusts, silicosis and lung cancer. The causal agent of
the disease is free crystalline silica breathed through inhalation of airborne
dusts, usually at work. Silica dusts are generated and dispersed in air during
operations like the cracking, moving and grinding of rocks, sand, cement and
of some minerals. Dust concentrations today, when measured, still show high
levels during many industrial activities and expose workers to the risk of
silicosis, which is only an initial stage of the disease that may evolve into lung
cancer and autoimmune pathologies. Silica is a chemical compound widely
diffused in nature, both amorphous and crystalline. In 1997 IARC, on the basis
of a large number of epidemiological survey results, evaluated as sufficiently
evident the carcinogenicity for crystalline silica (quartz and crystobalite). Both
toxicity of free crystalline silica and cellular response depend on the character,
origin and state of the particulate minerals and their surface properties and on
the contamination with other substances that may activate the cancer process.
The only way to prevent the negative health effects of silica is to limit air
diffusion of dusts and their inhalation, reducing air concentration of respirable
dust. In 2000 the American Conference of Governmental Industrial Hygienists
fixed 0,05 mg/m3 of quartz in respirable dust as the Threshold Limit Value TWA for crystalline silica. This is also the limit for compulsory insurance against
silicosis for all Italian workers. In this paper recent developments on silica risk
assessment and on the reliability of measurements of silica in air are discussed
and analyzed, as well as epidemiological aspects of silicosis in the various
regions of Italy, comparing the present and past century. The results of
analytical surveys on occupational exposure to airborne respirable silica dusts
both in the Marche region and throughout Italy, conducted among workmen in
factories using air sampling instruments, show a great variety of occupational
exposure levels; high concentrations of airborne respirable silica dusts were
observed in some factories, such as cast iron foundries and the ceramic
industry.
T07-15 Orale
Moroni, Beatrice
GEOLOGICAL VS ANTHROPOGENIC INPUTS OF PARTICULATE
POLLUTANTS IN DIFFERENT URBAN CONTEXTS IN UMBRIA
MORONI Beatrice 1, BARCHERINI Luca 2, SCARDAZZA Francesco 2, CAPPELLETTI
David 2
1 - Dipartimento di Scienze della Terra - Università di Perugia
2 - Dipartimento di Ingegneria Civile ed Ambientale - Università di Perugia
Key terms: PM10-PM2.5; ICP-AOS; UV-VIS; SEM-EDS; image analysis
This work is focussed on the characterization of atmospheric particulate matter
from different sites in Umbria with final aim to evaluate the impact of natural
and anthropogenic sources on the composition of the fine aerosol. PM10 and PM
2.5 samples on PTFE filters were collected in Perugia and Terni by low volume air
sampler coupled with PM10 and PM2.5 selective-inlet head impactors. Nearly 200
samples were collected, spanning a time period from May 2006 to April 2007
and analyzed using different analytical techniques. Bulk chemical analyses
were performed by means of ICP-AOS, IC and UV-VIS techniques, whereas
single particle morphological and chemical analyses were achieved by SEM-EDS
coupled with image analysis techniques. Morphological and chemical data were
elaborated in order to find out possible correlations between size and
composition of the particles. Bulk and single particle chemical compositions
were compared in order to establish branching ratios of chemical elements in
the different classes of particles.
Considerable morphological and compositional differences among the samples
from Perugia and Terni were evidenced. These differences delineate two
different emissive contexts in Perugia and Terni, the former being strongly
influenced by motor traffic and the latter resulting from a mixing of natural,
roadside and industrial inputs. In addition, potential sources and modes of
distribution of fine aerosol in the environment were outlined. These results
gave a significant contribution to the evaluation of the effectiveness of local
abatement strategies of particulate pollutant emissions.
T07-16 Poster
Canessa, Anna
A GEOLOGIC ITINERARY FOR THE CALVANA MOUNTS (PRATO, ITALY)
CANESSA Anna 1, BASTOGI Marco 2, GEI Fiorenzo 2, MAETZKE Federico 3
1 - Sigea, GISland.it
2 - Club Alpino Italiano
3 - Università di Palermo
Key terms: Geosites; Environment; Geological Heritage
SESSIONE T07
84
Characterisation of Geosites is in the aims of Sigea (Environment & Geology
Italian Society): in this framework, the volume is dedicated to the
environmental safeguard of the Calvana Relief, where 8 different Geosites were
individuate along the 10 km itinerary.
Mapping and boarding were carried out (the 8 boards are documented in the
Italian Geosites Census) in order to emphasize the importance of the Calvana
Relief in the geologic heritage. Natural calcareous caves were detailed and
described in the contest of the carsic zone of the Central Appennine Geology.
The zone is covered by an anomaly of radon gas content: sampling the radon
ratio in the geochemistry laboratory of "Forra Lucia" cave, the provenience of
radon was correlated at the volcanic substrate (Ofioliti), carried to the surface
by the deep cave system.
In the contest of several geological educational training courses, field
investigations were carried out by GPS techniques so that geosites position is in
geographical coordinates; the volume also includes GIS cartography, photos,
sampling - tests and a comprehensive bibliography.
T07-17 Poster
Cantelli, Alessandro
IMPROVING RISK ASSESSMENT AT A TPHS CONTAMINATED SITE BY
USING HDPE AND CONCRETE SLAB LINERS
CANTELLI
Alessandro 1, PUPPINI Umberto 1, REMONTI Michele 1, RAINERO Alberto
1
1 - ESI Italia srl
Key terms: Contamination; TPHs; Indoor vapour; HDPE features
The contaminated site is in Milan. Many different soil and groundwater
monitoring samples were collated during site investigation to achieve site
specific information on the contamination, aimed for a human health and
groundwater risk assessment for industrial land use.
Soil investigations were run through many years (from 1993 up to April 2006),
looking for TPH C<12 and C>12 occurrence while the groundwater sampling
was carried out in past two years. High TPHs (C<12 and C>12) concentrations
exceeding standard values affect both unsaturated and saturated soil. The risk
assessment was run with Giuditta 3.1 and RISC 4.0, based on RBCA and
CONCAVE protocols. According to APAT Guide Lines the contaminated soil
source size is considered to be 50 x 50 meters wide and 20 meters thick (0-20
m b.g.l). Groundwater contamination was recognised and the source size was
even defined 50 x 50 meters wide starting from 10 meters depth.
These conditions lead to recognise risks for all of the receptors. To improve the
performance of the risk assessment it was assumed to realise a surface
containment of the site, made by using HDPE liners coupled with a
reinforced-concrete slab. Through a comprehensive literature research, life
cycle features (size, weathering, durability etc.) of the HDPE layer were
defined.
Both HDPE liner and reinforced-concrete slab thicknesses were changed testing
different solutions to achieve a 'no-risk' condition for workers. A reduction of
the indoor vapours risk was reached eventually with a conservative hazard
index value HI= 0,818.
T07-18 Poster
Ginesu, Sergio
TERRITORY, NATURAL RADIOACTIVITY AND HEALTH IN SOME PLACES
OF SARDINIA
LUMBAU Aurea 1, GINESU Sergio 2, CARBONI Donatella 3, CHESSA Giacomo 1
1 - Dipartimento di Odontostomatologia - Università di Sassari
2 - Istituto Scienze Geologico Mineralogiche - Università di Sassari
3 - Dip. Teorie e Ricerche dei Sistemi Culturali - Università di Sassari
Key terms: Uranium; Radiometric anomalies; Human theet; Man and territory
The radioactive pollution in Sardinia, has been in the recent years matter of a
considerable debat in the scientific literature. At the present time however, the
complex problem of possible interaction between environmental and human
activity in a long suitable period is still awaiting a adequate interpretation. At
the end of 70' years, the Italian Nuclear AGIP survey has been carried out
detailed researches on U ore deposits linked to the fast sedimentation
processes in lacustrine environments associated to the post-collisional events
during the paenipleining process of Sardinia chain. Particularly, researches
focused on siltites and sandstones levels belonging to the post-collisional
covers referred to the Permian-Carboniferous time span outcropping in several
areas of Sardinia island. Collected data indicate important radioactive
anomalies localized in Ogliastra and Sarcidano regions in the central and
southern Sardinia. These areas are characterized by a high natural background
radioactive values; suitable knowledge elements are offered by the comparison
between data collected in the present work in the Escalaplano and
Perdasdefogu areas with those of Nuclear AGIP during the 70' years.
Further relationships between human activity and environment will be indicated
by data collected on dental apparates because they record the interaction of
the organism with pollutant substances. As a consequence, it is expected the
possibility to reconstruct history and length of interaction processes with
pollutant substances, because during the formation of dental germs the
vascularisation favoured the mobility of chemical elements which successively
are fixed in the mineral fraction of teeths.
The scenario has reconstructed on account of a precise evaluation of human
pollution and linked to the recent complex socio-economical history of
investigated areas. Moreover, will be studied the human impact on
environment to and the possible radioactive anomalies in the investigated
areas.
T07-19 Poster
Delle Rose, Marco
HUMAN HEALTH RISKS RELATED TO WATER RESOURCES MANAGEMENT
AND URBAN POLLUTION (SALENTO, SOUTHERN ITALY).
DELLE ROSE Marco 1
1 - Consiglio Nazionale delle Ricerche, IRPI, Bari
Key terms: organic pollution; gastroenteritis exposure; urinary bladder cancer;
hypo-chlorination
Recent epidemiological studies focused that the Salento people have an higher
exposure to gastroenteritis in comparison to Italian population and the
exposure to urinary bladder cancer is particularly high. This paper supports the
hypothesis that the aforementioned health risks can be related to the present
water resources management and urban pollution.
The Salento peninsula, where Quaternary calcarenites and clays overlie Tertiary
and Cretaceous carbonates, is characterized by karst morphologies. It hosts
discontinuous shallow aquifers, locally used for irrigation, and a huge deep
coastal karst aquifer intensively exploited for human purposes. Since the first
settlements, landscapes were modified to drain the surface waters and
discharge floods. The oldest wells excavated to draw groundwater go back
even to the Bronze Age and testify archaic know-how about the water
supplying. The Salento is presently crossed by a number of network of artificial
and fluvial karst channels strongly modified owing to the urbanisation of
territory. The main channels system, the Asso network, was joined to the
Parlatano water sink and to other five minor karst sinks about 75 years ago, to
solve the secular malaria scourge. To start from the 1991, this man-made
fluvial-karst system have been used to discharge municipal and industrial
wastewater from treatment plants. This use was encouraged by the necessity
to restore the poor reserve of the deep aquifer. Actually, the terminal sinks of
the Asso fluvial-karst system absolved the functions of: storm water drainage
wells, aquifer remediation-related wells and underground injection regulated
wastewater disposal systems.
Urbanisation profoundly affects groundwater recharge and groundwater quality
and, as revealed a recent literature, the depth and the rate at which
contamination penetrate urban aquifer remain poorly understood.
Physic-chemical and bacteriological features of flowing water through the
Parlatano water sink and groundwater drain by the Guardati hydraulic structure
of Lecce were monitored during the last two years. At the same time, the
tectono-stratigraphic arrangement of the sites was studied.
About the Parlatano, the analysed waters presented high bacterial amount with
Escherichia coli MPN/100 mL higher than the value established by law. High
nitrate concentrations and significative nitrite and ammonia concentrations are
also detected. A geological survey of the water sink, allowed the recognition of
a fault dissecting the pre Quaternary substratum that can determine direct
injections of wastewater in the deep aquifer.
Concerning the waters sampled at the Guardati structure, variable amount of
fecal pollution as well as nitrate concentration were measured. Occasionally,
nitrites had detected too. Comparing this data with the rain heights recorded
by the university meteorological station, a clear direct correlation is
established. A pervasive network of kastified fractures inside the local Miocene
calcarenites, recognized during the geological survey, allow fast infiltrations,
namely in order of few hours or at most some days. So, the pollutants dispelled
through sewer conduits can contaminated the groundwater also in occasion of
usual rainfalls.
To reduce the risks of the human health due to the high amount of organic
pollutant systematically injected into the Salento aquifers, hypo-chlorination
procedures of the water are ponderously realized. However, the impossibility of
the total inactivation of some pathogenic virus by hypo-chlorination is largely
exposed by a specific literature, whereas other researches stressed the elevate
risk to urinary bladder cancer of the peoples drinking such treated waters. So,
the water resources management is an hard task, being both the discharges
into karst sinks and the escapes through sewers of wastewater, at enmity with
the safeguard aquifers by pollutant displacements and the need to protect the
public health.
T07-20 Poster
Giannossi, Maria Luigia
EXPERIMENTAL PREPARATION OF MUDS FOR PELOTHERAPY:
PRELIMINARY GRAIN-SIZE AND CHEMICAL DATA
SUMMA Vito 1, TATEO Fabio 2, GIANNOSSI Maria Luigia 1, MEDICI Luca 1
1 - Istituto di Metodologie per l'Analisi Ambientale - CNR - Italy
2 - Istituto di Geoscienze e Georisorse - CNR, c/o Dip. Geoscienze - Italy
Key terms: clay material; mud preparation; maturation process; grain size
data; chemical data
Mud therapy (or pelotherapy, or lutotherapy) is one of the oldest examples of
healing use of clays and the main concept of mud preparation has not changed
much after Roman times: it involves mixing a natural clay with saline water for
a sufficiently long time (months) as to acquire special characteristics. Such a
time of prolonged interaction is called "maturation". Following this procedure,
three critical parameters can affect the compositional features of the
therapeutic mud: the initial composition of the clay, the composition and
temperature of water and the maturation procedures that enable a biologic
community of micro- and macro-organisms to develop, according to
environmental conditions in the maturation pond. Nevertheless, the reasons for
such a long time success of pelotherapy are still under debate and both
chemical and physical processes have been mentioned, as well as
biologically-mediated features developed in the mud before rubbing on
patients. For a very long time the increase of local and systemic body
temperature was considered the most important factor produced by
pelotherapy, with well-known effects. However, the most suitable clay type for
delaying heat dispersion (smectite) is sporadically used in spa centers, mainly
when smectite raw materials are easy available. Such a consideration supports
the idea that other parameters are involved in the clinic success of
pelotherapy.
A different approach to establish the optimum maturation parameter is based
on the occurrence of organic substances produced by micro-organisms living
near the mud-water interface. They are mainly diatoms and cyanobacteria that
bring different types of organics, part of which have well known
anti-inflammatory effects.
An other effect of mud rubbing deals with the chemical exchange between the
mud and the skin, because the increase of temperature and sweating enhance
the opening of cutaneous barrier. This exchanging feature is mostly unknown,
but the experience of other previous studies indicate that skin is permeable to
SESSIONE T07
inorganic cations during pelotherapy.
In order to evaluate the effects of the mud composition on the maturation
process, 8 little ponds have been placed in the maturing area of a spa centre
(southern Apennines, Italy) and filled with different clay materials and the with
mineral water used by the spa (alkaline-sulphate mineral water). The ponds
have been sampled monthly, and preliminary data are reported (3 months).
To gain insights of the peculiar properties of peloid muds prepared, the
following analyses will be carried out: granulometry, mineralogy, chemistry,
and physicochemistry (pH, exchange capacity and exchangeble ions). The
obtained data concerning the maturated muds will be compared with those of
the ''virgin'' clay geomaterials and mineral water.
Six raw materials have been selected because are very rich in clay minerals as
smectites and kaolinite, although illite. Calcite, quartz, feldspars, sometimes
are present as minor minerals. Two clays are polymineralic and are from
Basilicata (southern Italy), represent Plio-Pleistocene deposits; one of them is
used in the same spa centre.
Preliminary granulometrical data indicate that maturation induces significant
grain size variations. The crumbling and stirring in the basins of maturation and
the prolonged rock-water interaction produce an increase of the fraction < 8
µm (with the exception of polymineralic clays) and a decrease of 8-32µm
components. The decrease of grain size in bentonites is coupled with the
increase of exchengebla Na of muds, mainly related to smectite minerals,
whose 001 distance shorten to about 1.25nm in air-dryed smectites. The
increse of Na as solvating cation in smectites likely produce an expansion of
the diffuse double layer arount clay particle.
T07-21 Poster
DICLOFENAC-BEARING HYDROTALCITE AS EXTENDED-RELEASE
SYSTEM AND SUN ERYTHEMAS INHIBITOR
BONINA Francesco Paolo 1, GIANNOSSI Maria Luigia 2, MEDICI Luca 2, PUGLIA
Carmelo 1, SUMMA Vito 2, TATEO Fabio 3
1 - Università di Catania
2 - CNR - IMAA
3 - CNR - IGG
Key terms: diclofenac; hydrotalcite; release experiments
During the last decades, the extensive use of pharmaceuticals has highlighted
the need to reduce their wastefulness and extend through the time their
efficiency by slow reactions between drug and human organism. Recently a lot
of studies have used cationic and anionic clays for pharmaceutical preparations,
moving the role of clays from just an inert matrix, to more active functions
aimed to protect the active principle or to achieve special goals. The aim of this
work is to test different mineral substrate in order to improve the
extended-release system available for widespread anti-inflammatory drug such
as diclofenac and to compare its local efficiency as sun erythemas inhibitor
alone and in anionic-clay form.
Alcoholic and hydroalcoholic solutions of the anti-inflammatory drug diclofenac
were prepared and mixed with two anionic-clay hydrotalcite phases, untreated
and heated at 500°C. Hydrotalcite pretreated at 500°C showed more
adsorption capacity of diclofenac. Diclofenac-bearing clay samples were used
for in vitro release experiments to evaluate the percutaneous absorption of
diclofenac, using sets of eight Franz cells with membranes of stratum corneum
epidermis obtained from human skin; a 2% diclofenac-bearing hydroalcoholic
gel was used as comparison sample. The results highlighted that hydrotalcite
pretreated at 500°C is less suitable for release procedures, despite its higher
uptaking capacity, whereas diclofenac adsorbed from alcoholic solution by
untreated hydrotalcite forms the most efficient sample and shows the best
permeation profiles: this sample was selected for the in vivo experiments.
Ten healthy volunteers were informed and used for the in vivo experiments.
Cutaneous erythemas were produced by a UV lamp. Six cutaneous sites on the
center of the forearm were marked and irradiated; two skin sites were not
further treated and used as control, three ones were treated by 300 mg of clay
samples and one was treated by the 2% diclofenac-bearing gel; the erythemas
were supervised by a X-Rite 968 reflectance spectrophotometer; the spectra
obtained for each cutaneous site have permitted to calculate the values of
erythema index (EI), and the efficiency of the diclofenac-bearing samples was
assessed by the percentage of inhibition of the erythema (PIE). The
diclofenac-bearing clay sample appeared to be useful for an efficient application
on human skin as inhibitor of the UV-induced erythemas, also better than
comparison gel sample. The meaningfulness of the more efficiency of drug-clay
formulation is confirmed by statistical analysis.
T07-22 Poster
presence of CO2 concentrations above the OSHA workplace limit (0.5% for
prolonged exposure) and very high radon activity (average of 36000 Bq m-3)
contributing to a very high dose rate. According to the D.Lgs. n. 241
26/05/2000, in Italy two action levels are considered for radon in the
workplace:
° 500 Bq m-³ per year (average value);
° Above this level the limit is defined as absorbed dose rate in 3 mSv/y.
This level corresponds to an average of 500 Bq m-³ for 2000 hours of exposure
per year. Due to this scenario, a ventilation chimney was opened in the
catacomb to reduce Rn concentrations. In 2003 two further surveys, conducted
before and after the opening of the chimney, highlighted a strong decrease
(about 50%) of the concentrations of both gases, supporting the hypothesis
that the opening of more chimneys and/or other suitable types of mitigation
could reduce gas concentrations below the legal limits allowing the presence of
workers and/or visitors. The good results obtained using this type of
remediation are highly relevant because it has not modified the micro-climate
in the catacombs that contributes to the preservation of the rare paintings in
some of the major tombs. Furthermore, the application of discrete and/or
continuous monitoring surveys using portable devices at this site shows that
these methods can be used as post-mitigation tests of the effectiveness of the
remediation system, and to control the air quality both during public visits and
after long period of closure. Moreover, with an automatic radon monitoring
system the time remaining to reach the maximum annual dose recommended
could be automatically updated.
T07-23 Poster
Medici, Luca
Ciotoli, Giancarlo
INDOOR AIR QUALITY IN AN ARCHEOLOGICAL SITE: THE VILLA
TORLONIA JEWISH CATACOMBS (ROME, ITALY)
ANNUNZIATELLIS Aldo 1, BACCANI Anna 1, BARBERA Maria Rosaria 2, BEAUBIEN
Stanley Eugene 1, CIANCETTI MAGNANI Marina 2, CIOTOLI Giancarlo 1, LOMBARDI
Salvatore 1
1 - Dipartimento di Scienze della Terra, Università di Roma "La Sapienza"
2 - Soprintendenza Archeologica di Roma
Key terms: radon; carbon dioxide; catacombs; remediation
Some measurements of indoor radon and carbon dioxide concentrations were
conducted in the Jewish catacomb in Villa Torlonia (Rome, Italy), excavated in
the volcanic sequence (tuffs and pozzolana) linked to the Sabatini Volcanoes
activity. Before this study the Soprintendenza Archeologica of Rome sent notice
that it was not possible to visit the Villa Torlonia Catacombs, even for research
purposes, because of the presence of noxious gases (CO2 and Rn).
Furthermore, a project to open the catacombs to the public was delayed
because the poor air quality prevented the possibility to work for the
conservation of paintings and other artifacts.
This study was carried out to evaluate the possibility of opening this interesting
archaeological site, both for restoration of the historically important paintings
and for public visits. A preliminary survey, conducted in 1998, confirmed the
85
Moroni, Beatrice
MORPHOCHEMICAL CHARACTERIZATION OF FINE PARTICULATE
MATTER USING ELECTRON MICROSCOPY TECHNIQUES: SOME
INDUSTRIAL HYGIENE APPLICATIONS
DELLA PENDA Emma 1, MORONI Beatrice 2
1 - INAIL - Direzione Regionale Umbria - Consulenza Tecnica Accertamento
Rischi e Prevenzione
2 - Dipartimento di Scienze della Terra - Università di Perugia
Key terms: SEM; TEM; image analysis; EDS; industrial hygiene
Investigation of the morphochemical characteristics of fine particulate matter
involves a large number of industrial activities where the production and/or the
manipulation of different, sometimes not well identified materials expose
workers to the risk of occupational diseases. The mode of interaction and the
degree of toxicity of the particles mostly depend on the chemistry and the
surface reactivity which, on turn, are the result of the structure and texture of
materials.
Electron microscopy techniques offer a wide range of applications to micro and
nanostructural investigations of particulate matter. SEM and TEM imaging
coupled with image analysis supply a wide range of morphological parameters
on a statistical population of particles. SEM-EDS elemental mapping is a simple
tool to distinguish chemical phases within a complex matrix, whereas SEM- and
TEM-EDS spot microanalysis allow a detailed investigation of single phases at
different analytical resolution. Cathodoluminescence microscopy and/or
spectroscopy can successfully evidence chemical inhomogeneities and
structural defects within the particles. Electron diffraction by TEM provides
information on the structural state (defects and dislocations, amorphous and
crystalline fields) of the particles. In all cases the small grain size prevents
complex manipulation of the particles with great advantage in sample
preparation.
In this paper some applications of SEM and TEM techniques to the study of a
variety of industrial materials including welding fumes, crystalline silica dust
and refractory ceramic fibers are reported and discussed.
SESSIONE T09
Stratigrafia delle pianure alluvionali e sedimentologia degli acquiferi
T09-1 Invitato
Amorosi, Alessandro
AQUIFER ARCHITECTURE IN THE PO PLAIN: CYCLICITY, CONTROLS
AND FACIES
AMOROSI Alessandro 1
1 - Università di Bologna
Key terms: Sequence Stratigraphy; Aquifer; Cyclicity; Quaternary; Po Plain
Increasing demand of groundwater for municipal and agricultural use during
the last decades has shifted applied sedimentology in focus toward detailed
reservoir and hydrostratigraphic characterization. This study shows how
accurate reconstructions of stratigraphic architecture in alluvial plains can help
significantly in developing conceptual models that can be used to portray the
geometry, boundary characteristics and heterogeneity of aquifers and aquifer
systems in a regional context. Specifically, the hierarchy of stratigraphic units
resulting from the application of sequence stratigraphic concepts can provide a
framework from which aquifer models can be developed, allowing predictions of
regional reservoir architecture.
Ten years of sedimentological and stratigraphic studies of Middle-Late
Quaternary fluvial to shallow-marine deposits in the Po Plain, based upon new
stratigraphic boreholes performed by the Geological Survey of Regione
Emilia-Romagna, have documented the linkage between alluvial and coeval
nearshore deposits, revealing distinctive cyclic changes in lithofacies and
channel stacking patterns, falling in the Milankovitch and sub-Milankovitch
bands. The transgressive surfaces (TSs) represent the most readily identifiable
features within the Po Basin fill, allowing stratigraphic subdivision of
Middle-Late Quaternary deposits into a series of Transgressive-Regressive
(T-R) sequences (subsynthems), each spanning an interval of approximately
SESSIONE T09
86
100 ka. The TSs constitute basinwide stratigraphic markers that show greater
extent and correlation potential than sequence boundaries or maximum
flooding surfaces.
The lower parts of T-R sequences correspond to thin transgressive systems
tracts (TST), showing coastal-plain aggradation and rapid shoreline
transgression, and reflecting the rapid backstepping of barrier-lagoon-estuary
systems. Transgressive deposits are overlain by thicker shallowing-upward
successions, interpreted to reflect delta and strandplain progradation during
highstand conditions (highstand systems tracts). In the highly subsiding Po
Basin, subsequent long phases of sea-level fall are recorded by exceptionally
thick (up to 60 m) successions of interbedded alluvial and coastal-plain
deposits (falling-stage and lowstand - LST - systems tracts). At the basin scale,
laterally extensive sand and gravel bodies within T-R sequences are inferred to
represent regional hydrostratigraphic units.
Base-level and palaeoclimatic fluctuations (glacial/interglacial cycles) exerted
the major control on stratigraphic architecture in the coastal area. Upstream,
where alluvial processes are dominant, variations in discharge and sediment
supply are increasingly important.
This study shows that sequence stratigraphy can be a powerful tool for
delineating aquifer geometry. Alluvial fan gravels, close to the basin margin,
and fluvial-channel sand bodies (Po River channel belts) in the depocentre
constitute the major aquifer systems of the Po Plain. These occur invariably in
the upper part of T-R sequences (LST), their tops approximately corresponding
to the TSs. These lowstand fluvial deposits, formed at time of maximum
regression and marking a sharp increase in sediment supply at the turnaround
between glacial and interglacial conditions, show a high degree of
interconnectedness, which is reflected by sheet-like geometries with an overall
"jigsaw puzzle" internal organization. On the other hand, transgressive
sedimentation marks the change to increasingly isolated, ribbon-shaped fluvial
bodies, with a peculiar "labyrinth" style. Beneath the coastal plain,
high-permeability sediment bodies are mostly represented by the nearshore
coastal sands overlying the TSs. These laterally extensive sand bodies are
elongated parallel to the present shoreline and typically wedge out toward the
alluvial plain.
T09-2 Invitato
Irace, Andrea
THE DEEP FRESH-WATER ACQUIFERS IN PLIOCENE-HOLOCENE
SUCCESSIONS OF THE WESTERN PO PLAIN: INTEGRATED
STRATIGRAPHIC ANALYSIS AS A TOOL FOR THE RESOURCES
MANAGEMENT.
IRACE Andrea 1, TRENKWALDER Stefania 1, NATALICCHIO Marcello 1, CLEMENTE
Paolo 1, OSSELLA Luca 1, MOSCA Pietro 1, POLINO Riccardo 1, DE LUCA Domenico
Antonio 2, VIOLANTI Donata 2, GOVERNA Maria 3, et al.
1 - C.N.R., Istituto di Geoscienze e Georisorse, Sezione di Torino
3 - Regione Piemonte, Direzione Pianificazione Risorse Idriche
Key terms: Western Po Plain; synthems; aquifer group; fresh/saltwater
interface; recharge-areas
A tridimensional, 1:250.000/ 500.000 scaled, geologic model is here presented
which allows to define the geometry and the structure of deep fresh-water
acquifers in Pliocene-Holocene successions buried under the Western Po Plain
(NW Italy). This area is characterized by km-scale accumulations of terrigenous
deposits in three adjoining basins, that share an overall "regressive" evolution:
the Savigliano and the Alessandria basins to the South, and the Padane
Foredeep basin to the North. The integration of surface data, deep well data
and available seismic reflection lines permits to subdivide the
Pliocene-Holocene succession of each basin into large-scale synthems and to
identify the distribution of both major depositional systems and lithofacies
changes.
In this work each synthem is conceptually considered as an "aquifer group" and
corresponds to a sedimentary body that, owing to its peculiar large-scale
features (gross distribution of facies associations, internal and external
geometries, overall internal stacking pattern, cementation and compaction
degree) shows a distinctive behaviour, in response to the regional water flow
system. Each aquifer group is further subdivided into lower rank units, here
called "hydrogeologic units", corresponding to single lithofacies associations
and showing homogeneous hydrogeologic features.
The main results of this work are: 1) reconstruction and mapping of each
aquifer group; 2) reconstruction and mapping of the approximate geometry of
the surface (facies change) that separate continental-transitional
sandy-gravelly (with medium-high permeability) deposits, from marine
clayey-sandy (with low permeability) deposits (surface "A"); 3) reconstruction
and mapping of the freshwater/brackish-saltwater interface (surface "B"); 4)
identification of main groundwater flow directions and their relative
recharge-areas.
The "A" surface is a diachronous and articulate plane, that often crosses the
boundaries of aquifer groups. It shows increasing depths from present-day
margins towards central portions of Savigliano and Alessandria basins, whereas
it is constantly buried and it decreases in depth from present-day margins of
the Padane Foredeep basin (except the southern one) towards its central
sector.
The "B" surface also crosses the boundaries of aquifer groups, even if it is
mainly located into fine-grained marine deposits. Its present-day geometric
configuration results from several processes that were effective from the time
of deposition of the studied successions, such as the regressive migration of
the coastline, the substitution of connate saltwaters by fresh meteoric waters in
the uplifted portions of aquifer groups and the heterogeneous tectonic
deformation. The depth from the ground level of this surface usually ranges
from 50 to 1400 m.
The integration of reconstructed "A" an "B" surfaces allows to recognize the
areal distribution and the cumulative thickness of potentially exploitable deep
aquifers and, consequently, to identify their usable volumes (intended as
thicknesses of permeable sediments with freshwater). Minimum thicknesses of
these sediments are of about 50 m while, among maximum thicknesses, are
recorded values of about 800 m respectively for the Savigliano and the
Alessandria basins, and of 1000 m for the Padane Foredeep.
At regional scale, the recharge-areas of deep aquifers correspond to narrow
belts of alluvial plains, bordering mountain and hill areas. The recharge seems
to take place with two modalities: direct (infiltration of meteoric waters or from
superficial water bodies) and indirect (infiltration through others, overlaying,
aquifer groups). Direct recharge-areas are located where Pliocene sandy
aquifer groups crop out. Indirect recharge-areas are instead placed in high
plain zones, where the occurrence of very thick permeable deposits allows the
downflowing of superficial groundwaters towards deeper aquifer groups.
T09-3 Orale
Berra, Fabrizio
ARCHITECTURE OF THE MILANO SUBSURFACE DEPOSITS FROM WELL
AND CORE DATA: DEFINITION OF MAJOR DEPOSITIONAL SURFACES
AND RECONSTRUCTION OF SEDIMENTARY BODIES
ROSSELLI Silvia 1, BERRA Fabrizio 2, FELLETTI Fabrizio 2, PICCIN Andrea 1
1 - Regione Lombardia
2 - Dipartimento di Scienze della Terra "A. Desio", Università degli Studi di
Milano
Key terms: subsurface deposits; major depositional surfaces; reconstruction of
sedimentary bodies
In the frame of the CARG project-Sheet 118 Milano, more than 600 wells (on
2200 available in the sheet) have been analysed and interpreted in order to
reconstruct the subsurface geology of an area of about 570 square km. The
wells, from 60 to more than 200 m deep, were drilled for water supply and
their stratigraphy was described during drilling. Descriptions are generally
based on the grain size of the deposits. The available description have been
processed in order to outline the existence of important grain-size changes that
have been used for the definition of main facies changes. In order to define the
sedimentological evolution and the organization of the subsurface deposits,
four cores (about 200 m each) have been drilled. The obtained cores evidenced
the presence of several shallowing-upward cycles: on account of this
observation, the presence of shallowing upward trends have also been inferred
for the well logs. Furthermore, magnetostratigraphic analyses (Muttoni, 2003)
allowed to define the age and to correlate a main surface that represents a
major regressive event (coarse on fine-grained deposits) correlated to the
onset of the Quaternary glaciations.
The stratigraphic frame and the interpretation of the well logs allowed to
identify some major surfaces in the upper 100-120 meters of the subsurface
deposits, that have been traced all across the Milano CARG Sheet.
The stratigraphy of the studied wells has been organized in a GIS database.
The geometry of the main surfaces have been reconstructed by means of
geostatistical elaboration of the collected data: comparisons among surfaces
and the present-day topography allowed to document that the thickness of the
sedimentary bodies roughly increases from north to south, recording a
difference in subsidence rates form north (lower) to south (higher subsidence).
More in detail, difference in dip orientation of the bounding surfaces of the
main depositional bodies (from South to East-South-East) have been outlined.
The stratigraphic approach to the study of the subsurface of alluvial subsurface
deposits can represent an important frame for the hydrogeologic
reconstruction: the identification of major discontinuities (i.e. time lines)
represent an important frame that can be completed with the distribution of
the grain-size of the deposits and thus with the reconstruction of the
hydrogeologic system.
Muttoni G., Carcano, C., Garzanti E., Ghielmi M., Piccin, A., Pini, R., Rogledi S.,
and Sciunnach D. (2003) - Onset of major Pleistocene glaciations in the Alps.
Geology 31, 989-992.
T09-4 Orale
Muttoni, Giovanni
MAGNETOSTRATIGRAPHY OF THE MILAN SUBSURFACE
SCARDIA G. 1, MUTTONI Giovanni 2
1 - CNR-IDPA, ALP
2 - Università di Milano, ALP
Key terms: Magnetostratigraphy; alluvial plain; Milan subsurface
Four cores have been taken from the surroundings of the city of Milan, in the
framework of the Milan CARG project. The northernmost drillings (Milano
Triulza RL10, Milano Parco Nord RL11) were drilled to 100-m depth; the
southernmost drillings (Peschiera Borromeo RL8, Gaggiano RL9) reached a
depth of 180 m and 150 m, respectively. A total of 530 m of sediments was
recovered.
The overall core lithostratigraphy is composed by three superimposed lithologic
sequences, consisting, from the bottom, of alternated silt and medium- to
fine-grained sand, arranged in fining-upward cycles, interpreted as meandering
alluvial plain; the central sequence develops with coarse-grained sand, pebbly
sand and subordinated gravel, interpreted as distal braidplain. Medium- to
coarse-grained, poorly sorted, massive sand and pebbly sand, and
clast-supported gravels with sandy matrix, interpreted as proximal braidplain,
characterize the upper sequence. As a whole, the central and the upper
sequence can be regarded as a prograding braidplain, composed by severall
small-scale fining-upward cycles.
Paleomagnetic properties were studied on a total of 79 samples collected from
cohesive fine-grained sediments with a common average sampling frequency in
the order of one sample every 3/4 core-meters. The intensity of the NRM
(measured at the Alpine Laboratory of Paleomagnetism) was in the order of 10
-3
-10 -4 A/m and orthogonal projections of demagnetization data typically
indicated the existence of a lower unblocking temperature component,
superimposed to a higher unblocking temperature component. The higher
temperature component was removed to the origin of the demagnetization
axes mainly in the magnetite and hematite temperature ranges between ~350
and ~680 °C and it is interpreted as the characteristic component. This
characteristic component bears either positive (down-pointing) or negative
(up-pointing) inclinations with overall mean values of 60° ± 15 and -54° ± 16,
respectively, and is regarded as acquired at or shortly after sediment
deposition (DRM or pDRM).
At least a magnetic polarity reversal has been recognized in each core, in the
depth range of 60-80 m, and it has been interpreted, by means of the available
SESSIONE T09
pollen biostratigraphy and the regional framework reported in Carcano & Piccin
(2002), Muttoni et al. (2003), Scardia et al. (2006), as the Brunhes/Matuyama
boundary; in cores RL 8 and RL9 also the Jaramillo Subchron was recognized.
The major lithologic change observed in each core, produced by a depositional
switch from distal meandering alluvial plain to a prograding braidplain, occurs
during a reverse polarity period, interpreted as Subchron Late Matuyama, and
it is well constrained between the Subchron Jaramillo and the
Brunhes/Matuyama boundary in cores RL8 and RL9; the same age constrain
can be inferred in cores RL10 and RL11. This episode, already observed by
Carcano & Piccin (2002), has been correlated by Muttoni et al. (2003) to an
important Pleistocene climatic event, related to the onset of the major
glaciations at the southern foothills of the Alps occurred at ~0.87 ka, during
the Subchron Late Matuyama.
REFERENCES
Carcano, C., Piccin, A., eds, 2002, Geologia degli Acquiferi Padani della Regione
Lombardia: Firenze, S.EL.CA, pp. 130.
Muttoni, G., Carcano, C., Garzanti, E., Ghielmi, M., Piccin, A., Pini, R., Rogledi,
S., Sciunnach, D., 2003, Onset of major Pleistocene glaciations in the Alps:
Geology, v. 31, pp. 989-992.
Scardia, G., Muttoni, G., Sciunnach, D., 2006. Subsurface magnetostratigraphy
of Pleistocene sediments from the Po Plain (Italy): Constraints on rates of
sedimentation and rock uplift. Geological Society of America Bulletin, 118, p.
1299-1312.
T09-5 Orale
Pavesi, Marta
STRATIGRAPHIC ARCHITECTURE OF QUATERNARY ALLUVIAL
DEPOSITS FROM SOUTHERN LOMBARDY: IMPLICATIONS FOR AQUIFER
MANAGEMENT
AMOROSI Alessandro 1, PAVESI Marta 1, RICCI LUCCHI Marianna 1, SARTI
Giovanni 2, PICCIN Andrea 3
1 - Università di Bologna
2 - Università di Pisa
3 - Regione Lombardia
Key terms: Stratigraphy; Aquifer; Quaternary; Po Plain; Lombardy
Understanding stratigraphic architecture and sediment-body geometries is of
fundamental importance for interpreting the distribution of internal aquifer
systems properties. In this work, we show how accurate subsurface
investigations in southern Lombardy, including detailed facies analysis from
cores, may provide the basis for the three-dimensional reconstruction of
sedimentary bodies, and thus for aquifer management.
Stratigraphic architecture within non-marine strata, reconstructed from
detailed facies analysis of a 114m-long core and stratigraphic correlations of
water wells, reveals distinctive cyclic changes in lithofacies and channel
stacking patterns. Each cycle includes basal, silt-clay overbank deposits and
lenticular fluvial-channel sands, with upward transition to increasingly
amalgamated fluvial-channel sand bodies. Lower cycle boundaries, generally
corresponding to the top of sheet-like fluvial complexes, are locally associated
to the presence of organic-rich, paludal clays.
The pollen record parallels facies architecture, showing a distinctive cyclic
pattern falling in the Milankovitch (100 ka) band. Floodplain deposits in the
lower parts of cycles are associated to pollen diagnostic of warm-temperate
climatic conditions. In contrast, fluvial-channel bodies in the upper parts of
cycles display a pollen signature that reflects transition to cold-climate
conditions.
The good match between sedimentologic and pollen data at the southern
margin of the Po Basin suggests that development of laterally extensive fluvial
sand bodies occurred primarily during glacial periods. On the other hand,
channel abandonment and return to floodplain conditions took place at the
onset of the interglacials.
Changes in sediment supply, induced by climatic fluctuations and variations in
vegetation cover, and expressed as changes in sediment flux and grain size,
appear as the major controlling factor of alluvial architecture in the study area.
Changes in accommodation space, resulting from sea-level variations under a
regionally high rate of subsidence, also played a fundamental role in
determining sediment stacking patterns.
On the basis of internal facies architecture and distinctive pollen attributes, the
cycles identified in the subsurface of southern Lombardy can be correlated with
the transgressive-regressive sequences recently recognized in the Po coastal
plain.
From a hydrogeological perspective, the study area is of strategic importance:
fluvial-channel, sand-rich bodies represent potential aquifers, whereas
mud-prone units are regarded as laterally persistent permeability barriers. In
this work, the detailed geometry of the uppermost two aquifers was
reconstructed through numerous cross sections. This allowed the construction
of subsurface contour (isobath) maps of top and bottom of aquifers, as well as
isopach maps, leading to delineation of the related three-dimensional
volumetric model. Geometric description and the estimate of the hydraulic
parameters of the study units, combined to the appraisal of recharge and
outflow conditions leads to the definition of the water budget in the study area,
allowing the characterization of reservoir finalized to rational management of
the water resource.
T09-6 Invitato
Fontana, Alessandro
LATE QUATERNARY ALLUVIAL ARCHITECTURE OF THE
VENETIAN-FRIULIAN PLAIN (NE ITALY)
FONTANA Alessandro 1, MOZZI Paolo 1, BONDESAN Aldino 1
1 - Università degli Studi di Padova, Dipartimento di Geografia
Key terms: alluvial geology; geomorphology; Venetian-Friulian plain;
Quaternary
The Venetian-Friulian plain represents the foreland basin of the South Eastern
Alps and has been formed by the depositional systems of the main Alpine
rivers, that built alluvial megafans during Late Quaternary. These features are
87
fan shaped and are characterized by large dimensions (length: 50-70 km,
width: 30-50 km; area: 1000-2500 kmq) and internal longitudinal
differentiation.
Geological and geomorphological surveys, boreholes, paleoenvironmental
analyses allowed to reconstruct the sedimentary evolution and architecture
characterizing the upper 50 m of the alluvial sequences. A data base of ca. 400
radiocarbon datings of alluvial and lagoon deposits provided a robust
chronological framework.
The alluvial megafans achieved their present shape and dimensions during the
LGM (Last Glacial Maximum, 24.0-14.5 ka BP, uncal.), when the glaciers
hosted in the Alpine valleys reached the plain, feeding the alluvial systems with
large water and solid discharge. Alluvial sedimentation took place in the whole
Venetian-Friulian plain, leading to the aggradation of 20-35 m of deposits.
In the apical sector of the megafans, LGM alluvial sequence consists only of
gravels, organized in 1-2 m thick, few to tens of metres wide channel bodies,
stacked in continuous sequences. This upper sector of the megafans, called
"high plain", was formed by braided palaeochannels which aggraded on the
plain and could transport gravels up to 20-30 km from the fanhead.
Downstream from this portion the loss of transport capacity along the
unconfined rivers allowed the sedimentation of sand or finer sediments; the
architecture of the distal sector generally consists of shallow lenses of sandy
channel deposits, scarcely interconnected, within overbank fines.
At the end of LGM, the glaciers melted out starting a phase of deep fluvial
incision of the apical sector of megafans; several incised valleys formed also in
the distal portions and large areas of the Venetian-Friulian plain were deprived
of sediments due to prevalent sedimentary by-pass between 14.5-8.0 ka BP
uncal. Due to canalization of the sedimentary flux, between Late Glacial and
early Holocene the gravels could move tens of kilometres downstream than
during LGM in the incised valleys, reaching the distal sectors. Only since middle
Holocene a new phase of sedimentation took place in the distal sector. Due to
marine transgressions, around ca 6.0 ka BP uncal. lagoon and delta formation
started and fluvial incisions silted up in the distal sector of the megafans,
where many meander belts developed. The different channel belts are
generally separated by portions of LGM plain and their evolution seems to be
driven by avulsive processes. Widespread aggradation started around 4-3 ka
BP uncal., with formation of fluvial ridges along the terminal tract of Alpine
rivers. The LGM deposits are separated from Holocene alluvial and coastal
deposits by an unconformity with regional extent, ranked as a 6th order
bounding surface. In the incisions the unconformity truncates the LGM series.
On the megafan surface, the unconformity was marked by the formation of
soils with hardened calcic horizons, known as "caranto"; after their
sedimentary burial they could be easily recognized in the stratigraphic record
also with drills or penetration tests.
Recent boreholes performed, down to 100 m of depth, evidenced that also
during MIS 6 an important aggradation phase took place, probably triggered by
the debouch of the glaciers in to the plain; geometric and sedimentary
characteristics of these middle Pleistocene deposits are similar to those of the
LGM. Thus the growth of the Venetian-Friulian plain seems to have been mainly
constrained by sedimentary supply feed by glacial advances, in spite of the low
stand position of the sea level. On the other hand, phases of sea level high
stand affected the alluvial systems only in the coastal portion and had minor
consequences in the whole surface of megafans.
T09-7 Orale
Bondesan, Aldino
THE GEOSINPAV PROJECT. A MAP OF THE MORPHO-SEDIMENTARY
SYSTEMS OF THE PROVINCE OF VENICE (ITALY)
BONDESAN Aldino 1, FONTANA Alessandro 1, MENEGHEL Mirco 1, MOZZI Paolo 1,
PRIMON Sandra 1, FURLANETTO Paola 2, VITTURI Andrea 3, ABBÀ Tiziano 3,
BASSAN Valentina 3, MAZZUCCATO Andrea 3, et al.
1 - University of Padova
2 - Akeo (Padova, Italy)
3 - Provincia di Venezia
Key terms: plain; cartography; geomorphology; Venice
The GEOSINPAV Project, whose name results from a previous project about a
landscape information system, has been started through a Memorandum of
Understatement between the Province of Venice and the University of Padova.
It aims at providing a geological model of the Venice provincial area taking
advantage of the stratigraphic data stored in Province Archives and by new
field surveys and corings.
Recently the Province of Venice financed the geomorphological and pedological
maps (scale 1:20.000) and other hydrogeological and environmental studies.
The new data collected in the above mentioned projects allowed differentiation
of Venetian plain in alluvial megafan systems correlated to main Alpine fluvial
depositional systems. Also differences between Pleistocene and Holocene fluvial
activity was considered, and in the last part of Oxygen isotopic stage 2 an
aggradational trend 10 times greater than during Postglacial was recognised.
The research intends to characterise the morpho-depositional units of the
alluvial plain belonging to the main fluvial systems and those related to other
depositional settings (littoral, delta and lagoonal units) identifying the
sedimentary bodies and the distribution of deposits, at variable deepness,
depending on the available datum. This will allow to define the
chrono-stratigraphic relationships and the 3D geometry of the geological
bodies, and to understand the dynamics and sequence of the processes that
built the plain itself.
For each area the most representative geological profile has been drawn,
chosen among a complex of available stratigraphic logs. These latter mostly
result from the analyses of reports and geological papers performed by the
Province itself in different other projects or through a data sharing with other
research institutions.
The production of a detailed geological map is one of the purposes of this
research, and will allow a sound basis for the evolutionary model: mapping will
integrate direct information from fieldwork (using the standard international
methods of Quaternary Geology for the study of fluvial-coastal plains and
lagoons), as well as other important data gained from remote sensing (aerial
pictures and satellite image), topographic microrelief, geophysical surveys,
historical cartography and archaeology. Large part of the proxy data used for
recognition of surfaces of different ages will belong to paleopedology,
sedimentology and geoarchaeology.
SESSIONE T09
88
Along with the wealth of data already available to the research group, field
activity will take advantage of temporary outcrops. In addition, a large number
of hand bore-hole will be drilled to depths of c. 10 m, allowing sampling of
sediments to be used for micropaleontological, pollen, sedimentological,
geochronological, geochemical and paleopedological analyses.
All the data will be uploaded and stored in a digital georeferenced database for
optimal processing and visualization.
Some key areas for the study of the erosion and aggradation phases which
have characterized the fluvial systems of the eastern Alps in the last 24.000
years will be illustrated in this presentation. In particular, the main
sedimentary phases from the MIS 5.5 to present time interval will be analysed
in their spatial development. It will be also possible to recognize locally-derived
evolutionary differences, related, for example, to the differential subsidence of
some sectors of the plain or to human intervention.
T09-8 Orale
Piovan, Silvia
STRATIGRAPHY AND GEOMORPHOLOGY OF AN ABANDONED
DISTRIBUTARY CHANNEL OF THE PO RIVER (ITALY)
PIOVAN Silvia 1, MOZZI Paolo 1, STEFANI Cristina 2, MIOLA Antonella 3
1 - Dipartimento di Geografia - Università di Padova
2 - Dipartimento di Geoscienze - Università di Padova
3 - Dipartimento di Biologia - Università di Padova
Key terms: Po; palaeochannel; alluvial ridge; palaeohydrography; stratigraphy
Some authors (Veggiani, 1972; Castiglioni, 1978, Peretto, 1986) have
evidenced the existence of a paleochannel of the Po river which crossed the
stretch of the present-day alluvial plain between Po and Adige rivers. The
northernmost branch of this paleochannel extended from Rovigo to the Venice
lagoon near Chioggia.
This multidisciplinary research provides some sedimentological data and
geomorphological evidence for the reconstruction of the stratigraphical
architecture of the alluvial ridge, the paleohydrographic evolution and, in
particular, the age of deactivation of this Po distributary channel. In this sense,
archeological and large scale paleoclimatic considerations (De Bon, 1939;
Bosio, 1967; Veggiani, 1972) alone have been not conclusive.
Remote sensing from Landsat TM and Aster images allowed to analyze major
landforms while the interpretation of oblique and vertical panchromatic aerial
photos gave a finer detection of the landforms. Microrelief based on a manual
interpolation of contour lines with spacing of 0.5 m from the "Carta Tecnica
Regionale del Veneto" at scale 1:5000 has been useful to develop a digital
elevation model. Cross sections down to the depth of 5-8.5 m have been
carried out with the Edelman hand auger in order to define the stratigraphy of
the paleochannel deposits.
Characterization of the sediments sampled in the boreholes benefited of several
methods. Loss on ignition (LOI) gave organic versus carbonate mineral content
ratio, palaeobotanical analyses established the vegetation assemblage of the
swamp environment, radiocarbon dating dated the peat layers and
petrographical analysis determined the composition of the sands in order to
relate with the appropriate fluvial basin, either Adige or Po.
The cross sections are very close to archeological sites such as Sarzano
(Rovigo), Saline and Chiaroni (San Martino di Venezze, Rovigo), Ca' Motte
(Villadose, Rovigo) and Conetta (Cona, Venezia).
Exemplary is the case of Saline and Chiaroni: the first site is directly related to
the paleochannel and cross-sections show that the archeological site lies on the
western side of the main sand body of the alluvial ridge, contrary to the remote
sensing indications. The transect in the second site area suggests the presence
of a bifurcation of the paleochannel, just upstream of where it is covered by the
modern Adige alluvial ridge, in agreement with the digital elevation model.
Furthermore the transect across a major crevasse splay deposit, as recognized
by remote sensing on the right side of the paleochannel and located between
Rovigo and modern Adige river, allowed to reconstruct the geometry of the
deposits and to clarify the relationship between its sands and the northernmost
Po distributary channel activity.
T09-9 Orale
Forno, M. Gabriella
STRATIGRAPHIC RECONSTRUCTION OF THE LANZO FAN RIGHT SECTOR
APPLIED TO THE GROUNDWATER RESEARCH
DE LUCA Domenico Antonio 1, FORNO M. Gabriella 1, GREGORIO Luca 1,
VATTERONI Roberto 1
1 - Dipartimento di Scienze della Terra, Università di Torino, Via Valperga
Caluso 35
Key terms: stratigrafia; ricerche idriche sotterranee; Conoide di Lanzo
The Lanzo Fan, developed in the western Piemonte Plain and extended about
300 km2, is formed by a very thick villafranchian transitional succession with a
thin terraced fluvial quaternary cover. In this alluvial fan a very important
water well fields is placed; it is the main City of Turin drinking water provision
source. In detail the prevailing water drawings of the SMAT (Society
Metropolitan Aqueduct Turin) is in the Venaria well field, placed in the fan distal
sector: in this sector the groundwater sources are potentially compromised by
road construction project. As possible alternative, the La Mandria regional Park
is selected for the realization of new boreholes. In this area a detailed geologic
survey is made and two core drillings are executed: these researches show
new data on the stratigraphic succession, now summarized.
An important erosional discontinuity is recognized in the Villafranchian
succession, in which the main groundwater extraction of the area is
concentred; this discontinuity, non reported in the previous geologic works,
allows us to distinguish two sedimentary complexes. The Lower Complex
(middle Pliocene) is formed by strongly consolidated, deformed and fossil
bearing silt, with subordinate gravel bodies. The Upper Complex (lower
Pleistocene?) consists of prevalently small coarse gravel, with subordinate
sand-silty bodies, both non containing fossil.
At the top, the fluvial sediments are also distinct in five allostratigraphic units
(middle-upper Pleistocene), forming five terraced surfaces: on these
sediments a loess aeolian cover is developed (upper Pleistocene), that gathers
the infiltration water subsequently carried to the surficial aquifer.
This reconstruction suggests that the fluvial cover forms a surficial little
productive aquifer: this is developed in little permeable gravel and silty
sediments, with a high clay tenor and a strong Fe oxides cementation
connected with the considerable weathering. The pollution vulnerability of this
aquifer is not sufficient to assure the water quality for drinking use.
The villafranchian Upper Complex constitutes also a surficial little productive
aquifer: in fact although it corresponds prevalently to permeable gravel
sediments, the aquifer is suspended on water courses.
Instead, the villafranchian Lower Complex is very interesting for the
groundwater research. In detail the gravel bodies are a deep confined aquifer:
good quality water in these sediments is protected by possible pollution.
The reconstruction permits also to recognize, at the bottom of the entire
continental succession, permeable sandy marine bodies: the next drinking
groundwater research in this sector is directed to these sediments, now only
locally utilized by deep wells.
T09-10 Orale
Pascucci, Vincenzo
COASTAL APRON-FAN SYSTEM OF ARGENTIERA (NORTHWEST
SARDINIA)
PASCUCCI Vincenzo 1, ANDREUCCI Stefano 1, MARTINI I. Peter 2
1 - 1 Istituto di Geologia e Mineralogia, University of Sassari
2 - Land Resources Sciences Department, University of Guelph
Key terms: Quaternary; Fan; Climate; OSL; Tyrrhenian
The coastal apron-fan system of Argentiera has been studied to analyze its
sedimentary evolution trough space and time during the Late Pleistocene.
Argentiera is located in a hilly area of northwest Sardinia and is characterized
by small coves bounded by cliffs alternating with wider flatter areas. The Upper
Pleistocene succession rests disconformably on Palaeozoic schists/phyllites.
The formation and characteristics of the apron-fan system are strongly
influenced by the morphology of the bedrock and by the availability of various
types of sediment. It can be subdivided into three major areas dominated,
from north to south, by debris-flow deposits that fill three small coves,
water-flow dominated alluvial fans in the central wider flat area, and coastal
dunes climbing over slightly steeper open rocky coasts. Sand and gravel beach
deposits underlay these deposits discontinuosly.
Two major sediment sources have been fed these deposits. The debris-flow
deposits derive almost exclusively from the weathering of the schists/phyllites
of the nearby hills and consist of angular metamorphic fragments and abundant
soil-derived reddish matrix. The sandy deposits of the other two areas derive
primarily from the marine shelf and consist mostly of fragmented shells and
algal material. The southmost dunes are almost exclusively composed of such
organogenic fragments. In the central area, overland water flows have
reworked the previously wind blown oranogenic sediments adding and mixing
some metamorphic fragments.
The presence of two major unconformities indicates that the variation in mode
of sedimentation and activation of different sediment sources are not just tied
to a lateral geographic setting but also to changing morphological and climatic
conditions of the area through time.
The sandy and gravely beach at the base dated (OSL dating) to about 100 ky
indicates its development during a high marine stand: the Neo-Tyrrhenian high
stand (OIS 5c) commonly recorded throughout the Mediterranean area. At that
time intense weathering occurred inland. This provided the material for the
debris-flows dominated colluvial/alluvial fans that filled the northern. The
organogenic sands of the central and southern part of the apron-fan systems
record a sea level drop that opened the marine deposits to erosion and inland
transport by the predominant northwestwind of the area (Maestrale). The wind
blown sand was reworked in the slightly lower central area were intense
rainstorm-fed water flows could be channelled, and remained as almost intact
dunes in the slightly higher area to the south.
All this can be tied to the major worldwide climatic changes and related
sea-level variations of the second last interglacial (Emian; Tyrrhenian) and the
last glacial period (Wurmian). Local variation in climate have also influenced
the sedimentation by an alternation of wet and dry conditions and related
development of luxuriant vegetation capable of retaining soil in the upland
slopes and disruption of the vegetation and intense erosion.
T09-11 Invitato
Severi, Paolo
STRATIGRAPHY OF THE MARECCHIA RIVER ALLUVIAL FAN (RIMINI ITALY) AND ITS HYDROGEOLOGICAL APPLICATION.
SEVERI Paolo 1, CIBIN Ubaldo 1
1 - Servizio Geologico, Sismico e dei Suoli - Regione Emilia-Romagna
Key terms: subsurface stratigraphy; trasgressive-regressive cyclicity;
management of groundwater resources
The Marecchia River is about 500 kilometers long, and comes from the
northern Apennines toward the Adriatic Sea. Its alluvial fan is located at the
extreme south eastern part of the Po Plain near the town of Rimini.
This alluvial fan was studied during the Italian project of geological mapping at
1:50,000 scale (CARG project, sheet 256 "Rimini"). The geological survey was
based on the integration between surface and subsurface stratigraphy and
permitted to identify and map all the stratigraphical units detected in the
alluvial deposits in the Emilia-Romagna Apennines and alluvial plain.
According to the national stratigraphic guide, unconformity bounded
stratigraphic units (UBSU) were used to map the overall alluvial deposits
following their downcurrent facies evolution and geometry, starting from the
Apennines hills up to the Adriatic Sea. From the bottom, two main UBSU were
detected in the alluvial fan: the "Sintema Emiliano-Romagnolo inferiore"
(present only in the subsurface), and the "Sintema Emiliano-Romagnolo
superiore". In the last one, five depositional trasgressive-regressive cycles
have been detected. They are 10s to 100s m thick, covering a time-interval of
about 100 ky each one and bounded by regional-wide UBSU. The youngest
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three cycles crop out as fluvial terraces in Marecchia valley and thus have been
formalized as 3 sub-synthems, named AES6, AES7, and AES8. The last one
(Ravenna Sub-synthem) correspond to the well-known late
Pleistocene-Holocene transgressive-regressive cycle of the Po Plain).
In the subsurface, each cycle/sub-synthem is composed by 1) a basal
trangressive portion characterized, at the present-day cost line, by marine
sands deposits and 2) a regressive portion, ending with wide fluvial gravel
bodies. These bodies represent the alluvial fan stage of each cycle. AES8 is
mostly composed by the basal trangressive part of the cycle. The vertical
repetition of different sub-synthems produced the typical cycling architecture of
the whole Marecchia River alluvial fan.
Thanks to the data number and quality for subsurface analysis, some
geological reconstruction was realized in order to correlate the geometry of
stratigraphic units from the outcrop part, toward the buried part of the alluvial
fan. This stratigraphic reconstruction was crucial for the development of a
hydrogeological model realized by some Institutions applied in management of
water resources (Regione Emilia-Romagna, Provincia di Rimini, Autorità di
Bacino Mareccia-Conca, HERA SpA, Romagna Acque SpA).
The geological model permitted:
1) the definition of the hydristratigraphic architecture of Marecchia alluvial fan
and the recontrustion of detailed maps of each different aquifers
(corresponding to the upper part of the sub-synthems) and aquitards
(corresponding to the lower part of the sub-synthems);
2) the optimization of a groundwater monitoring network appositely realized by
the Provincia di Rimini (about 70 wells divided in different aquifers);
3) the individuation of the recharge areas.
Merging all the geological and hydrogeological (quantitative and qualitative)
data, the conceptual model of the groundwater flow in the whole aquifer was
understood.
Finally a groundwater mathematical model (flow and nitrate transport) was
implemented by ARPA Emilia-Romagna, in order to find the best management
of groundwater resources.
hydrogeological parameterizations were calculated by assigning hydraulic
conductivity and porosity values to the aquifer materials, aiming to honor its
heterogeneity. Analyses of the hydrogeological unit geometries and their
developments in depth were carried out within the considered volume. Plain
views and cross sections along both longitude and latitude are featured by
GOCAD; it was possible to compare cross sections found in literature and
results obtained by the described methodology. The Alessandria Province's
plain portion was chosen to perform detailed comparisons in term of
geometries and texture percentages, underlining a reasonable level of
accordance (Del Rosso, 2005). Hydraulic conductivity and porosity values
distributions were also compared with maps on a regional scale (Bove et al.,
2004), for increasing depths. In addition, the large number of available
hydrogeological studies of the area played a fundamental role during both the
definition of the model and its validation. This obtained model integrates
hydrogeological knowledge from traditional methods and innovative
information technologies. It provides a common framework for different
hydrogeological applications and constitutes a powerful tool to carry out
quantitative and qualitative analyses for water resources management. As an
example, the application of a groundwater flow simulation code to the study
area is described hereunder. The water table elevations were obtained in
steady state conditions for the year 2003. Simulated and measured head
values were compared in correspondence with piezometers of the regional
monitoring net. Although on a regional scale the model is calibrated,
improvements are needed on a local scale. Once better calibrated, the
groundwater flow model could be easily applied to simulate different scenarios,
as severe draught or intense rainfalls. Models on a local scale, designed on the
basis of the regional one, can be utilized to assess correct use and
management of water resources. Furthermore the achieved refined
discretizations is shown to improve contaminant plume simulation when
transport codes are applied.
T09-12 Orale
DIRECTIVES 2000/60/CE AND 2006/118/CE: IDENTIFICATION OF THE
GROUNDWATER BODIES
AURIGHI Marina 1, ASTORI A. 1
1 - Regione Veneto - Direzione Ambiente - Servizio Tutela Acque
Key terms: Water Framework Directive; groundwater bodies identification;
European laws
The Water Framework Directive establishes that the typological
characterization of the superficial water bodies should be carried out and for
such activity the directive supplies specific procedural indications. As far as the
groundwater bodies, even if the same type of typological analysis is not
provided, the directive 2000/60/CE and in the so-called "directive daughter" on
groundwater bodies 2006/118/CE recognize the typological characterization of
the groundwaters bodies as a tool of great importance in water resource
management.
The European laws establish that an initial characterization of all the
groundwater bodies should be carried out in order to asses their uses and the
degree to which they are at risk of failing to meet the objectives for each
groundwater body. Further characterization should be carried out for the
groundwater bodies, which have been identified as being at risk in order to
establish a more precise assessment of the significance of such risk and
identification of any measures to be required.
A working group constituted from Regions and regional Agencies, Ministry,
Apat, CNR, Authorities of River Basin and other agencies, has worked to
identify a methodological procedure for the identification of the groundwater
bodies. In this communication some starting points for discussion are given.
Farina, Marco
HYDROGEOLOGICAL AND STRATIGRAPHIC ANALYSIS OF AQUIFERS OF
THE RENO AND SAVENA ALLUVIAL FAN : RELATIONSHIPS WITH
ANTROPIC ATCIVITIES
FARINA Marco 1
1 - Comune di Bologna
Key terms: alluvial fan; geological analysis; groundwater use; contamination
The presence of superposed aquifers in Emilia Romagna territory is due to the
alternation on the vertical one of porous alluvial bodies and fine sediments, in a
hierarchical frame. In the Reno and Savena alluvial fans(Bologna), geological
documentation is implemented with piezometric and hydrochemical analysis.
Concerning to relationship with the human activities, in the alluvial fans take
place:
a remarkable water catchment to civil use, particularly between 100 -350 m of
depth, for volumes over 30 million mc/y;
a meaningful contamination from chlorinated compounds, that is distributed up
to around 150 ms of depth.
In the coarse bodies, aquifers are characterized according to depth, lithology,
position in comparison to the aquitards: the recharge (from ground, from
river), the level excursion, the relationship with the pumping dynamics, the
contamination degree, the functions of transport, constitute elements of
characterization of the different strata.
The anthropical contamination also reaches deep aquifers bypassing aquitards
of remarkable dimensions (Delta Aquitard, over 20 m of thickness), through
artificial preferential paths, or smaller aquitards where continuity is lacking: it
is hypothesized that contamination passes. The natural contamination occurs
as soon as the depth is increasing, in the bottom of the strata: water is loaded
of Fe and Mn, owing to a progressive reduction of the water circulation.
T09-13 Orale
Bonomi, Tullia
3D RECONSTRUCTIONS OF SHALLOW AQUIFER HETEROGENEITIES ON
A REGIONAL SCALE
BELLINI Roberta 1, BONOMI Tullia 1
1 - Università degli Studi di Milano - Bicocca
Key terms: database; 3d reconstructions; aquifer heterogeneities; stratigraphic
data
A computer-based 3D hydrogeological model of the Piedmont Region shallow
aquifer was developed from detailed stratigraphic reconstructions, utilizing a
database and geomodeling software. The methodological approach is based on
advanced information technologies and allowing a spatially and vertically
refined volumetric discretization of the textural characteristics of the aquifer on
a regional scale. The study area extends over more than 7000 km2, focusing
on the shallow unconfined aquifer which lies in highly heterogeneous alluvial
deposits. Stratigraphic information of 2717 wells located within the area
represented a numerically consistent data set in order to support the desired
level of detailed elaboration. Firstly, the information was stored in a
hydrogeological database by means of translation into alphanumeric code of
each stratigraphic layer. Secondly, gravel, sand and clay percentages were
extracted in three different data sets for further elaborations. Finally, 3D
textural reconstructions were carried out within a stratigraphic grid (306 rows,
272 columns and 28 layers, 500 m cell spacing) used to represent the aquifer
volume set by GOCAD (Geological Object Computer Aided Design). The upper
and lower grid boundaries are the Digital Terrain Model and the aquifer bottom
elevation surface, respectively. This surface was obtained as a result of a
previous study (De Luca et al., 2002). Different hypotheses of volumetric
textural distributions were obtained with the Kriging interpolative method,
utilizing variogram models calculated either on a regional scale or on a local
scale. In particular, three different depositional basins were identified and
taken into account. Accordingly to the same approach, hypotheses of
T09-14 Orale
T09-15 Poster
Aurighi, Marina
Bersezio, Riccardo
QUATERNARY HYDROSTRATIGRAPHY OF THE PO PLAIN FOREDEEP IN
LOMBARDY: CONTROLS ON AQUIFER ARCHITECTURE IN THE SAN
COLOMBANO AL LAMBRO THRUST-FOLD AREA.
BERSEZIO Riccardo 1, CAVALLI Emmanuele 1, BAIO Mariangelo 2, TURRI Stefano 1
1 - Dipartimento Scienze della Terra - Università di Milano, via Mangiagalli 34,
20133 I-Milano
2 - CEPAV 1 - Via Emilia, San Giuliano Milanese (MI)
Key terms: Alluvial Sediments; Aquifers; Hydrostratigraphy; Po Plain;
Quaternary
The ongoing hydrologic crisis in Northern Italy highlights the need to
ameliorate the knowledge of aquifer architecture in the Po foredeep, with
multiple scale studies of increasing detail. The present work is developed in the
frame of the Project "Integrating geophysical and geological data for modeling
flow in some aquifer systems of alpine and apenninic origin between Milano and
Bologna" (PRIN 05-07), which has the general purpose of modeling the
sedimentary architecture and water flow in the aquifer systems of the Po plain
at different scales.
In Lombardy, our study area encompasses the region between the Lecco glacial
amphitheatre (to the North) and the present-day Po river (to the South). In
this area, the Quaternary hydrostratigraphy and basin evolution are controlled
by i) the tectonic evolution of the Apennines, ii) the structural grain and
subsidence of the south-dipping Pliocene homocline of Southern Alps, iii) the
climate/hydrologic cycles and the glacial evolution on the alpine side. Here we
focus on how tectonic and subsidence controlled the aquifer origin and
architecture in the region of the very low Quaternary relieves of San
Colombano al Lambro, Casalpusterlengo and Zorlesco, at the southern end of
the study area. These isolated highs represent the remnant surface
morphology of the buried thrust-related anticlines that form the Emilian Arc. A
few km to the north a northernmost and most external Apenninic front
(Corneliano-Soresina) intersects the South-verging frontal thrust of Southern
Alps (Ripalta-Bordolano structure).
Our research is based on geological and geomorphological mapping at
1:10.000, integrated with the stratigraphic reconstruction of the subsurface
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and radiocarbon age determinations on some wood and peat samples. The
traditional methodology for hydrostratigraphic reconstruction is facilitated by
the notable abundance of borehole/well data that have been collected in
Lombardy, at the southern margin of the Alps. Nevertheless, the subsurface
data are stored in a variety of private and public data-bases, which are totally
inhomogeneous, making the access to this wealth extremely difficult.
Therefore, we dedicated a relevant part of the work to implement a new
relational Geo-database (SILLARO.dati) that permitted to store and organize
the new and pre-existing surface and subsurface data collected from different
sources. SILLARO provides the dynamic platform to create thematic maps and
to support numerical analysis of lithologic, stratigraphic and hydrogeologic
data. Before their storage, the spatial attributes of the data points are checked
by a control system, in order to avoid duplications.
The first result of the progressing project is the hydrostratigraphic
reconstruction. It includes three Aquifer Groups of Pleistocene age, resting
above a tilted and folded basal aquiclude. The latter consists of the buried
equivalent of the fine-grained, shallow marine, San Colombano Fm., Late
Pliocene-Early Pleistocene in age. The major erosion surfaces that truncate the
Aquifer Groups have been mapped by ordinary kriging. The maps show a
complex pattern of nested valley fills separated by buried highs that consist
either of uplifted marine sediments (Plio-Pleistocene) or of Middle Pleistocene
transitional to fluvial deposits, with remnants of a thick fersiallitic soil profile at
the top. This structure is due to the en-echelon pattern of the San Colombano
and Casalpusterlengo thrust-related anticlines that originated: i) uplift and
truncation of the littoral to alluvial regressive cycles forming the Middle
Pleistocene Aquifer Group and its plunge beneath the mentioned Upper
Pleistocene hydrostratigraphic units; ii) the complex subsidence and
accommodation pattern and the subsurface divide between the Upper
Pleistocene Po-related aquifers to the South, and the aquifers formed by its
northern tributaries to the North (Lambro, palaeo-Sillaro, Adda).
T09-16 Poster
Dell'Arciprete, Diana
GEOLOGICAL AND STATISTICAL CHARACTERIZATION OF A FLUVIAL
POINT BAR-CHANNEL AQUIFER ANALOGUE
BERSEZIO Riccardo 1, DELL'ARCIPRETE Diana 1, FELLETTI Fabrizio 1
1 - Dipartimento Scienze della Terra - Università di Milano
Key terms: Aquifer Sedimentology; Fluvial Sediments; Quaternary; Po Plain;
Transition Probability Statistics
Geological and sedimentological models of alluvial aquifers are used to assist
the hydrogeological studies for remediation of contaminated sites at the
(hydro)facies scale. The knowledge of size, geometry, stacking patterns and
internal constitution of the elementary depositional units of exposed analogues
is relevant to obtain the parameters to condition aquifer simulations with
different geostatistical models.
At this purpose we are studying some quarry exposures of point bar-channel
depositional elements that belong to the historical sediments of the terraced
meandering valley of the Lambro River, an alpine tributary of the Po River
running from the foothills of the Southern Alps in the region between the Ticino
and Adda rivers. These exposures provide good analogues of meandering river
fluvial aquifers, that are typical of the southern fringe of the Quaternary alluvial
aquifer complexes of the Po plain, on the alpine side. The present study
belongs to the Project "Integrating geophysical and geological data for
modeling flow in some aquifer systems of alpine and apenninic origin between
Milano and Bologna" (PRIN 05-07) that aims to model the sedimentary
architecture and the groundwater flow at different scales.
The aquifer analogue presented here (volume about 10000 cubic meters)
consists of two superimposed bar-channel units of sand and subordinate
gravel, that formed in two different meander loops of the Roman-Medieval
Lambro river. We developed a hierarchical model based on the data obtained
from direct inspection of 5 quarry faces, that have been mapped and logged
during excavation. The maps of these faces show the shape of the two
superimposed depositional elements, of their component unit bars and channel
fills and the distribution of the individual (hydro)facies. By these maps the
geomorphic parameters of the architectural elements (height/width of the unit
bars, main channels and possible eddy scour accretions, chute channels) were
obtained. These data show the transition from the lower sand-rich, aggrading,
bar-channel complex to the gravel-rich, accretion-dominated Medieval unit,
possibly linked with a stage of increased discharge.
The low lateral and vertical persistence of the laterally accreted unit bars
(meters), their irregularly curved and oblique shape, their recurrent
truncations, the location of chute channels, and the bar/channel transitions,
control the position, volume and connectivity of the most and least permeable
hydrofacies units. Transition Probability statistics (T-Progs; Carle and Fogg,
1996) was computed between the 5 most represented hydrofacies (Open
Framework Gravels, Gravelly Sands + Sandy Gravels, clean Sands, very fine
Sands, silt + clay), yielding estimates of connectivity and correlation trends
between the facies. The analysis of vertical and horizontal transitions quantifies
the dimensional ranges of the elements of the sedimentary hierarchy, such as:
i) fining upwards sequences of the point bar-channel sequences of the two
major units, ii) periodicity of OFG repetitions within unit bars, iii) distribution of
clay drapes and balls, iv) occurrence of the bar-channel transition (that is
represented by the OFG-GS-SG to S facies transition).
The final model provides 1) the spatial description of aquifer heterogeneity, 2)
the quantification of volume, continuity and connectivity of the most and least
permeable units, 3) the conditioning elements for 3-D geostatistical simulation
of the aquifer and for numerical modelling of flow and, 4) some tools for the
prevision of the fluvial architecture of this kind of aquifers that formed within
the entrenched and terraced meandering river valleys in the northern side of
the Po plain.
Carle, S.F., and Fogg, G.E. (1996) - Transition probability-based indicator
geostatistics. Math. Geology, 28(4), 453-477.
T09-17 Poster
Turri, Stefano
GEOLOGICAL SETTING OF A PLEISTOCENIC GLACIER MARGINAL AREA:
AN EXAMPLE FROM THE NORTHERN PO PLAIN (LOMBARDIA)
STRINI Andrea 1, BINI Alfredo 1, TURRI Stefano 1
1 - Università degli Studi di Milano, Dipartimento Scienze della Terra
Key terms: Quaternary deposits; Pleistocenic glaciers; Po Plain; Lombardy
During Pleistocene the dynamic of glaciers largely dominated the evolution of
the lombardian northern Po Plain where glacial morphologies (e.g. morains and
fluvioglacial terraces) and typical glacial and fluvioglacial sediments are often
very well preserved. This particular landscape is geographically identified as
"High Plain"..
In order to understand the architecture of these deposits, their relationship
with the southward "Low Plain" and the landscape evolution, a detailed
geological survey was carried out in the area between Adda and Lambro rivers,
NE of Milan.
This area is characterized by a well preserved terminal morain system
(amphitheatre) along the Lambro river and a less preserved morain system in
the Adda area where a deep canyon cuts the Quaternary succession. On the
outside of the morain systems, several orders of terraces represent the
remains of the ancient fluvioglacial plains..
Morphological, sedimentary and weathering criteria have been adopted for
distinguishing different units. Moreover, more than 200 stratigraphic records
allowed the reconstruction of subsurface geology.
The present work is part of the Project "Integrating geophysical and geological
data for modeling flow in some aquifer systems of alpine and apenninic origin
between Milano and Bologna" (PRIN 05-07). All the surface and subsurface
geological, geomorphological and stratigraphic data are organized in the
Geo-database "Sillaro Dati".
Different early pleistocenic conglomerates (Ceppo) have been recognized on
the basis of their petrographic content, varing from a very local petrography
(Ceppo del Naviglio di Paderno) to a wider petrographic composition (Ceppo
dell'Adda). Conglomerates and their weathering products are common on
slopes in particular in the Adda Canyon; moreover the wheatered Ceppo
dell'Adda covers a wide area West of Trezzo sull'Adda.
Glacial and fluvioglacial deposits have been grouped into five main
Allostatigraphic units: from the youngest (last glacial episode) to the oldest one
they are: Cantù Alloformation, Besnate Allogroup, Binago Alloformation,
Specola Alloformation and Bozzente Allogroup. Sedimentary characteristics and
petrographycal content of these units are very homogeneous, but they can be
distinguished thanks to intensity and depth of weathering. The weathering
profile thickness varies from several meters in the oldest units to only one
meter in the Cantù Alloformation; weathering involves all the lithologies in the
oldest units, whereas only carbonates in the most recent one..
Furthermore, on the most ancient terraces thick loess sequences are present,
often intencely weathered with the development of particular pedogenetic
features.
The old terraces are cut by narrow valleys in which there are Besnate and
Cantù sediments. Only south of Arcore and Trezzo sull'Adda these younger
sediments are widely spread over the plain.
The studied area is an example of the transition zone between the external part
of the terminal morain system and the fluvioglacial plain and it clearly shows
how the sediment deposition is driven by glaciation-deglaciation cycles. Finally
the present sedimentary architecture and morphology are the result of a long
geological history and not only of the more recent events.
T09-18 Poster
Piacentini, Daniela
HYDROSTRATIGRAPHY OF THE SECCHIA AND PANARO ALLUVIAL FAN
AQUIFERS: IMPLICATIONS ON GROUNDWATER NUMERICAL MODELING
AND WATER RESOURCE MANAGEMENT
MARCHESINI Lorenzo 1, DEL MASCHIO Lorenzo 1, PERONI Elisabetta 1,
PIACENTINI Daniela 2
1 - Agenzia d'Ambito per i Servizi Pubblici di Modena ATO 4
2 - Dipartimento di Scienze della Terra - Università degli Studi di Modena e
Reggio Emilia
Key terms: Groundwater; aquifer; stratigraphy; modelling; hydrofacies
Understanding of groundwater systems in terms of both stratigraphical
arrangement of the reservoir units and aquifer modelling has become of great
importance in water resource management in order to provide a fundamental
basis to define not only the sustainability levels of water exploitation, but also
the best protection strategy of the resource.
These issues are part of the mission of the ATO Authorities which are district
councils assigned to the reorganization of public utility water services (potable
water distribution and wastewater collection and treatment) by means of
specific technical and economical standards. In particular, the ATO Authority of
the Modena province, since its establishment, has played a key role on the
groundwater protection and management on its dependency. This commitment
has led the Authority to develop a groundwater numerical flow and transport
model of the Secchia and Panaro alluvial fan aquifers.
The Secchia and Panaro alluvial fan aquifers are part of the middle to late
quaternary filling of the Po Plain sedimentary basin, made up of sandy gravel
alluvial beds widely interbedded with mud and clay lenses on the subsurface of
the alluvial plain.
The overall hydrostratigraphic setting has been defined at a basin-wide scale
by ENI-AGIP and Regione Emilia-Romagna (1999) on a generally acknowledged
model consisting of hierarchically organized hydrostratigraphic units separated
by continuous permeability barriers (A, B and C Aquifer Groups) made up of
genetically related facies assemblages (Aquifer complexes). Interest for this
work is predominantly for the late Pleistocene-olocene deposits of the "A"
Aquifer Group which is the only one actually exploited.
However, the detail of this stratigraphic framework is not appropriate for the
purposes of a fine-tuned model as it does not take into account lower rank
permeability barriers, which possibly isolate multiple semi confined and
confined aquifer, and whose lateral continuity is still debated.
Thus, an effort is being made to define a high-resolution 3D hydrostratigraphy
of the aquifers which will be used as a basis for the flow and transport
numerical model.
Available data consists mainly of row vertical logs showing coarse versus fine
grained horizons recorded during the drilling of water wells and the distribution
SESSIONE T09
of water chemistry data throughout the aquifer.
Aquifer stratigraphical style varies with distance from the fan apex to the distal
portions of the depositional systems from the stacking of gravel and sandy
gravel beds to the alternance of sandy gravel and muddy clay beds and lenses.
This sedimentary mark reflects changes in the transport energy and bedload
from the foothills to the plain, but also the interplay of climate variations and
neotectonic activity.
A critical step for the definition of hydrofacies distribution is given by the
identification of stratigraphical correlations between fine grained intervals and
lateral extent of aquitards. Major hindrances for aquifer modeling are the lack
of high-quality cores and detailed facies analysis coupled with a very high
depositional heterogeneity.
These conditions necessarily require the evaluation of alternative
methodologies of aquifer modelling as the application of appropriate facies
models at the data framework in order to attain a high-detail hydrofacies
distribution.
Further work will also be addressed on the use of a geostatistical approach and
on the use of hydrogeological data (hydraulic head and water chemistry spatial
distribution) to support the assessment of hydrofacies distribution.
T09-19 Poster
Stefani, Marco
LATE QUATERNARY FLUVIAL DYNAMICS CHANGE,
HYDRO-STRATIGRAPHIC ARCHITECTURE AND WATER SOURCE
POTENTIAL IN THE FERRARA PROVINCE
BORASIO Emanuele 1, COLOMBANI Nicolò 2, GARGINI Alessandro 2,
MASTROCICCO Micòl 2, MESSINA Andrea 2, STEFANI Marco 2, PUPPÌN Marco 2
1 - GEOTEMA, spin-off Università di Ferrara
Key terms: Sedimentology; Stratigraphy; Hydrogeology; Po Basin; Climate
Change
The increasing water consumption combines with the climatic trend toward
higher temperatures (2-3 C over the last 25 yr) and with the reduction of the
summertime Po River water flux to make the Ferrara Province water
management increasingly difficult. The water deficit is prompting a greater
attention to the subsurface water exploitation potential, influenced by the
depositional evolution of the basin. The outcropping sediments of the Province
largely consists of lower alluvial plain and delta top deposits of the Po River
system, accumulated during Holocene highstand times. In the shallow
subsurface (- 5 to - 40 m), is often preserved a large body of highly permeable
coarse sands, deposited into middle alluvial plain during the last synglacial
lowstand The fluvial sands form laterally extensive, flat laying, metric thick
bodies, characterised by a high hydraulic transmissivity. The sand body is
disconformably capped by Holocene lower alluvial plain and deltaic deposits,
characterised by organic-rich clay aquicludes and is therefore considered as the
first confined aquifer (A1-1). The body is developed in a broad central Po plain
band and outcrops at the Adriatic sea bottom. It is therefore highly vulnerable
to marine water penetration, when depressurised and not properly recharged.
The deeper subsurface sequences are formed by thick successions grading
from marine to deltaic and alluvial plain sediments, recording the Quaternary
climatic and eustatic fluctuations. Recent research performed by different
Authors demonstrates the reduced potential of the subsurface aquifer bodies,
because of the widespread man-induced salinization and the common
occurrence of reducing condition associated with high Fe, Mn, and ammonium
ions concentration. Water residence time in deeper, unexploited fresh water
reservoirs is often long, often in the 10.000 yr magnitude order. Subsidence is
also a major concern topic in this coastal region, already largely placed beneath
sea level, suggesting the need to stop the depressurisation of aquifers. The
whole of these factors strongly limits the sustainable water extraction potential,
which is confined to some shallow-subsurface alluvial sand aquifers, enjoying a
direct Po River recharging. Several of these bodies are already exploited, some
further potential is provided by the north-western portion of the province
(Bondeno-Settepolesini), which stands out in the regional frameworks for being
the only area showing a well developed fluvial meander pattern. Because of the
comparatively reduced subsidence influencing the stratigraphic evolution, the
permeable late synglacial middle alluvial plain sands are here preserved at
shallow depths and were therefore reworked by the meander river system,
during pre-Roman and Roman times. Different meanders are juxtaposed to
produce a continuous fluvial sand body, punctuated by minor abandonment
clay infilling. During early medieval times, the meander migration gave way to
the development of more rectilinear channels, during a phase of climatic
change and fluvial drainage pattern reorganization. Since the XVI century, the
area is affected only by the Panaro River flow, producing minor meander
structures. The meander sand body stays in direct erosive contact and in
hydraulic continuity with both the present day Po River bed sands and the
glacial deposits, thus providing a hydrological pathway for recharging the latter
buried aquifer. Hydrological modelling and continuous monitoring of the aquifer
unable an estimation of the area potential for potable water extraction to be
proposed, suggesting a possible use, particularly as a tampon system for the
severe summer shortage. The prevent a severe phreatic level lowering, the
extraction will have to fit the recharging potential of the Po waters. The
understanding of the area demonstrates that the integration of stratigraphic
and hydrogeology methods is a actual way for improved water management.
T09-20 Poster
Stefani, Marco
LATE QUATERNARY DEPOSITIONAL EVOLUTION , CLIMATIC CHANGE
AND THREE DIMENTION FLUIDO-STRATIGRAPHIC ARCHITECTURE IN
THE PO DELTA AREA
STEFANI Marco 1
Key terms: Stratigraphy; Sedimentology; Geological mapping; Delta; Italy
Interdisciplinary research on the late Quaternary sequences of the Po Delta
area was performed within the collaboration framework of the Regione Emilia
91
Romagna and the Ferrara University. The new understanding of the subsurface
depositional architecture is founding a hydrostratigraphic modelling attempt of
the area. Aquifers are here characterized by an elevated ionic concentration
and often by reducing chemical conditions, reducing their water extraction
potential. A fluidostratigraphic and geotechnical modelling of the subsurface is
however crucial also for the subsidence forecast of a topography already
largely beneath sea level. The first confined acquifer consists of permeable
sands, deposited into middle alluvial-plain environments, at about 300 Km from
the ancient coastline, during the last glaciation lowstand, under a cold and
mainly arid climate. During the latest Pleistocene, a stratigraphic gap surface
developed, associated with a gentle subaerial erosion supported by the
development of sediment trapping Pre-Alpine lakes and by a moister climates.
At about 10,000 yr B.P., a last eustatic rise triggered the starting of the coastal
plain sedimentation in the study area, associated with the accumulation of
organic-rich aquicludes horizons. The sedimentary accumulation was then
unable to counterbalance the relative sea-level rise and fast transgression took
place, triggering the development of a back-stepping deltaic-estuarine sand
systems. The vertical permeability of these bodies is probably comparatively
reduced, because of the interbedded muddy aquitards occurrence. The
maximum transgression was reached at about 5,500 yr B.P, while a condensed
level was slowing forming off-shore. During the early highstand, large coastal
bays were progressively enclosed by the lateral growth of sand barrier islands.
Several generations of prograding delta system then developed. The present
day phreatic surface is largely developed within delta top sediments,
accumulated over the last 3000 years. At about 3,000 yr B.P., a windy and arid
climatic phase is recorded by large fossil dune fields and exceptionally coarse
long-shore drift sediments, sourced by the Apennine area. This well sorted,
matrix deprived aeolian sand are characterized by high porosity and
permeability values, but they are poorly developed in the subsurface. During
Roman times, a large delta lobe prograded at the south of Comacchio, under
warm climatic conditions. A moister phase followed, during early Medieval
times, associated with a widespread reorganization of the drainage network.
The present day delta was started at the beginning of the XVII Century by an
artificial delta mouth cut, aimed at avoiding the silting up of the Venice Lagoon.
This artificial forcing triggered a very fast delta progradation, of about 20 Km
over less than 300 years, into marine water even 20 m deep. This progradation
was supported by a cool and moist climatic pulse, characterising the XVII-XVIII
centuries. During the early growth phase of the delta, progradation outspeeded
the fluid expulsion potential from the delta front muds, thus delaying the
compaction subsidence starting. Consolidation subsidence then became
important, reducing the progradation speed, but fluid expulsion and
compaction are still active in the delta front mud bodies, rich in biogenic
methane, increasing the subsidence. During the last century, strong subsidence
associated with water and methane pumping from the shallow subsurface and
a massive artificial reduction of the river sediment load stopped the delta from
prograding and forced widespread coastal erosion. An application of the
improved subsurface stratigraphic understanding to the fluid circulation and
subsidence could certainly improve the difficult environmental management of
this fascinating but fragile coastal area.
T09-21 Poster
Sarti, Giovanni
CHARACTERIZATION OF AQUIFER SYSTEMS FROM HIGH-RESOLUTION
SUBSURFACE STRATIGRAPHY: THE CASE OF THE EASTERN VALDARNO
BASIN (TUSCANY, ITALY)
SARTI Giovanni 1, AGUZZI Margherita 2, AMOROSI Alessandro 2
1 - Dipartimento di Scienze della Terra Università degli Studi di Pisa
Bologna
Key terms: Stratigraphy; Aquifer; Valdarno Basin; Tuscany; Plio-Quaternary
Realistic models of ground water circulation and transport in modern alluvial
and coastal plains demand an accurate reconstruction of subsurface
sedimentary architecture. In this study, we propose the characterization of a
multilayered aquifer from the subsiding eastern Valdarno Basin, a strategic
area for both water research and pollution issues, between the city of
Pontedera and S. Croce.
An integrated sedimentological, stratigraphic and micropaleontological study of
six continuously cored boreholes allows the detailed reconstruction of Pliocene
to Quaternary stratigraphy in the uppermost 100 m, and shows how a
multidisciplinary approach may represent a successful tool to define
three-dimensional facies relationships within sedimentary bodies, and thus
aquifer geometries. Moreover, AMS 14C dates associated to Sr isotope data
prompt to place the identified stratigraphic units in a worthy
chronostratigraphic framework, with a coherent depositional evolution in terms
of space and time.
The study area, oriented SW-NE along the Arno River course, is rimmed to the
south and to the north by the Pisa and the Cerbaie Hills, respectively, both
formed by Plio-Quaternary marine and continental deposits. A fault, located
along the southern margin of the Cerbaie Hills, causes the NNW-dipping, below
the Arno-plain, of the Plio-Quaternary deposits cropping out on the Pisa Hills.
Stratigraphic architecture in the study area is varied. Except for the Holocene
succession, consisting mainly of fine-grained alluvial-plain deposits lying onto
transgressive swamp deposits and showing a homogenous spatial distribution,
the pre-Holocene deposits exhibit noticeable distinct features west and east of
Pontedera, respectively, due to the activity of a normal fault with an Apenninic
orientation, causing the lowering of the west side of the study area. A thick
Pleistocene alluvial succession, made up by a cyclic alternation of
coarse-grained fluvial channel and fine-grained floodplain deposits, is recorded
beneath Pontedera, whereas eastwards the stratigraphic sequence is
characterized by Early-Middle Pliocene deposits, related to coastal-shallow
marine sands with very subordinate alluvial facies.
Given this structural setting, the reconstruction of stratigraphic architecture
leads to the identification, in the uppermost 100 m, of a multilayered confined
aquifer consisting of five aquifer systems (A-E) ranging in age between the
Holocene and the Early-Middle Pliocene.
Aquifer system A developed during the Holocene and exhibits a markedly
lenticular geometry recording the recent dynamics of the Arno River. The
underlying aquifer system (B), Lower-Middle Pleistocene-Holocene in age,
consists of sands and gravels of fluvial origin and is recorded only in the
SESSIONE T09
92
western sector of the examined area. The lower three aquifer systems (C-D-E),
characterizing the eastern sector of the study area, mainly consist of sandy
shallow-marine deposits, Early to Middle Pliocene in age, showing a cyclic
arrangement.
The Quaternary aquifer systems (A-B) exhibit a strongly lenticular shape,
reflecting their fluvial origin, while the Early-Middle Pliocene aquifer systems
(C-D-E) display a higher lateral continuity, as expected from sedimentary
bodies deposited in coastal-littoral setting.
The geological framework and the structural setting suggest the identification
of water recharge areas in the Middle Pliocene sandy deposits cropping out on
the Pisa Hills, taking into account their NNW dipping toward the Arno Plain.
T09-22 Poster
Ruberti, Daniela
ALLUVIAL PLAIN STRATIGRAPHY AND THE VOLTURNO RIVER PRESENT
AND RECENT DYNAMICS NEAR CAPUA (CASERTA)
COMPAGNONE Antonio 1, DE FALCO Maria 2, DE GENNARO Luca 3, RUBERTI
Daniela 4, VIGLIOTTI Marco 4
1 - Libero professionista; Via Mezza Appia, 95 bis - 81043 Capua
2 - CRdC INNOVA, Via Campi Flegrei, 34 - 80078 Pozzuoli (NA)
3 - Via Riviera Casilina, 79 - 81043 Capua
4 - Dipartimento di Scienze Ambientali, Seconda Università degli Studi di
Napoli, Via Vivaldi, 43 - 81100 Caserta
Key terms: alluvial plain stratigraphy; Volturno river dynamics; Campania
Plain; GIS; Southern Italy
On the basis of detailed analyses of numerous lithostratigraphic logs from
boreholes, field surveys and cartographic informations, it has been defined a
more precise geologic architecture of the northeastern region of the Campania
Plain. Mainly alluvial and volcanic lithofacies associations have been recognized,
related to the Volturno River and Phlegrean Field activities respectively.
The stratigraphic homogenization, the facies analysis and the reconstruction of
the geometric relationships allowed the recognition of a set of lithologies with a
specific stratigraphic meaning to which codes were assigned and stored in a MS
Access geodatabase.
The data have been managed into a GIS project, based on a numerical
cartography. A three-dimensional digital terrain model (DTM) was constructed
so as to allow detailed morphological analyses of the plain.
In order to better evidence the morphological surface on which recent alluvial
deposits accumulated, and in the attempt to correlate such a surface with the
present morphological setting, it has been realized a Digital Surface Model
(DSM): a three-dimensional geological model of the subsoil was produced by
fitting the depth values of each geologic unit from the database, using a
multilayer grid that integrates the surfaces (top and bottom) of the various
geological formations (DSM). Managing these databases also permits the
production of maps describing lithologies and deposits both on the surface and
at depth and their geometries; it also permits the recognition of the
paleosurfaces that conditioned the wandering of the Volturno River.
The depth of the lithofacies deposited above the Campania Grey Tuff (CGT)
have been recognized through queries in the GIS project. These depths have
been interpolated with the kriging method. The resulted surface represents the
paleomorphology on which, after the CGT deposition, deposits from minor
eruptions and alluvial sediments deposited, controlling the present day
morphology. It has been highlighted that:
- the CGT lithofacies strongly design a depressed morphology round the
Volturno River, while they crop out in the piedmont area.
- the contour map of the depth of the deposits younger than the CGT, outlines
a deep NE-SW depression extending from the Triflisco area. On the north to
this depression there is another one, less deep, with an almost parallel course.
Finally, the contour map also suggests the presence of a NW-SE step, that
lowers the surface towards SW.
The study has been integrated with geomorphologic analyses, conducted on
historical documents, using GIS technologies. All the acquired information,
elaborated with a three- dimensional graphic, have been compared with
morphologic characteristics of the area, past and present, obtained from
cartographic multitemporal relieves, that allow a precise reconstruction of the
main river course from 1830 to the present. These informations find a direct
correspondence with the areal distribution of the alluvial facies in the subsoil.
In particular, by comparison with the DTM, we noted that:
- A morphologically lowered area still exists in correspondence of main
depression recognized on the basis of facies analysis. Th

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