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Late WeichselianVegetationand
Ice-Front Oscillationsin the BergenDistrict,
WesternNorwav
JAN MANGERUD
Mangerud. J. 1970. Late Weichselian Vegetation and lce-Front Oscillation.
in the Bergen District, Western Norw,ay. Norsk geogr. Tidsskr.2l, 121-145.
Thc published pollen diagram spans the Late Weichsclian and Early'
Flandrian (Holocene) Age. Grass tundra formed the vegetation during the
Oldcr Dryas and Early Allcrijd. The vegctation of the Later Allercid can be
charactcriscd as park tundra, with tree birches and willow (Sa/u/ scrun.
The summer temperature of the Latc Aller6d is assumed to have been
2-2.5" C lorver than at the present day. During the climatic deterioration of
the Younger Dryas. birch (Betula) suffered a major setback. The ice-front
oscillation during thc Late Weichselian is clarified, mainly on the basis of
fossiliferous till and sediments bclow till. The ice-front retreatcd during the
mild interstadials, Bdlling and Allerijd, whilst there were marked advances
during the Older and Younger Dryas. The final scction deals with the general
principles underlying a stratigraphic subdivision of the Late Quaternary.
Jan Mangcrud,
Geologisk Ittstitutt, avd. B, Universitetet i Bargen, Beret'tr
CONTENTS
I ntroduction
INTRODUCTION
t2l
For some time now. deposits from the Bcilling
lnterstadial, buried beneath lodgement till (Fig.
Pollen diagram from a peatbog at Dale,
5), have been known from Blomvig (Fig. 1;.
Blomciy
I z)
Consequently, a glacial advance over Blomiiy
Thesediments.....
124
must have occnrred at some subsequent time.
Pollen and spores .
126
though the actual date of that event has reC l i m a t i c d e v e l o p m e n ta n d d a t i n g s . . . .
130
mained unknown. Bearing this in mind. I
therefore conducted a pollen-analytical investiIce-front oscillations
l3Z
Bergen area ..
132 gation, and obtained C14-datings for sediments
Correlations with southern Scandinavia 136 from a bog at Dale (Fig. l). which overlie
that till stratigraphically. By this method, I
Clr-<iatings
1 3 6 dated the glacial advance to the Older Dryas
Stadial (Fig. 7). The examination of this bog
Palaeogeographicalmap of southern Norproduced results additional to the desired
$,ay during the Younger Dryas Stadial l19
dating and these will be treated in a serrarate
section.
Principles for the stratigraphical subMarine sediments which have been overdivi5i6n of the Quaternary .
t42
ridden by ice have been noticed for a long time
Acknowledgements
1 4 5 in the Bergen area (Rekstad 1900, C. F. Kolc l e r u p 1 9 0 8 ,p p . 5 5 6 6 . U n d A s 1 9 4 2 ,1 9 6 3 .p . t 3 .
R eferences
1 4 6 H. Holtedahl 1964, Mangerud 1968. 1970).
i
NarsAgeogr. Tidsskr.
t:2
J. Marrycrud
c
F., //
5"E
Fig. l. Map o[ the Bergen area. with insct map s h o w i n gi t s p o s i t i o ni n s o u t h e r nN o r w a l . ( ( ) n t ( ) u r
intervals of 200 m for both land and sea. Only a few of the main dircctions of the glacial striac
:irc indicated.The end moraines from the later part of the Youngcr Dryas are shorvn as solid
hlack lines. stippled in places where the positiont r f t h e i c c - f r , t n its r r n c c r t a i n
I have started a systematic investigation of
these sedimentsand a more detailed description
o f t h e r e s u l t s , w i t h a f u l l e r d i s c u s s i o n .w i l l
be publishcd later. Here. I only intend tcr
s u m m a r i s et h o s e r c s u l t s w h i c h a r e o f i m p o r t a n c c i n c l a r i f y i n g t h e o s c i l l a t i o n so f t h e i c e front (Fig. 7).
T h c p r e s e n tp a p e r d e a l s r v i t h t h e s e d i m e n t s .
t h e i r f o s s i l s .c l i m a t i c r i e v e l o p m e n t .l a n d f o r m s ,
Cl l-ciatings etc. Sincc in the course of this
w o r k I e n c o u n t e r e dm a . j o r p r o b l e m s c o n n e c t e d
w i t h t h e s t r a t i g r a p h i cs u b d i v i s i o n a n d c o r r e l a t i o n o f v a r i o u s e v e n t s . I s h a l l C i s c u s si n t h c
final scction tlre general principlesr-rnderlving
a s t r a t i g r a p h i cs r - l b c i i v i s i oonf t h e L a t e Q u a t e r n ary.
Late Weichselian in the Berpen District
t23
Fig' 2. Vertical air-photo of Blomiiy. x - the peatbog at Dale to which the pollen diagram (pl. 1)
-6nty
refers. o - the graveyard at Blomvig (Fig. 5). Westwards, outside the photo, ih"r" ur"
a few
small skerries separating the island from the North sea. (photo by Noi-rtv e/s.)
POLLEN DTAGRAM FROM A PEATBOC
AT DALE, BLOMoY
Top<>graphy.
Blomciy is situated on the outermost part of the coast bordering the North
Sea.The island'shighestpoint is a mere 73 m
above sea-level.The dominant geologicalfeature is of surfaceoutcropsof naked crystalline
rocks, all around (Fig. 2). The principal soil
types are peat and weathering products. In
hollows, small pockets of glacial and marine
sedimentscan be found. The Late Weichselian
marine limit is approximately 30 m a.s.l.
(Und6s 1945).
Regarding thc interpretation of the pollen
Ciaglam,I shouldlikc to point out that because
of the higher sea-level at that time, Blomciy
rvas split up into a number of small islands, the
largest being only 1 X 1.5 km in extent. The
diagram presumably reflects only the local
vegetation on a couple of these islands.
The present-day vegetation is limited first
and foremost by the scarcity of soil. There are
no woods on Blomciy, but this is partly due
to human interference. Apart from the cultivated areas, the vegetation is mainly heather
moorland of western Norwegian type, strongly
influenced by sheep grazing.
The peatbog (Fig. 3) from which the pollen
profile was collected is quite small, ca. l0 X
30 m, with a catchment area of 0.03 sq. km.
t24
!. Mangerud
photo was
Fig. 3. The peatbog at Dale (Pl. 1). The person is standing beside the bore-hole. The
taken in a more or less due N direction.
It lies ca. 36 m a.s.l. I made trial borings in
several bogs lying above the marine limit, but
this bog proved to be the deepestand, in fact'
the only one containing sedimentswhich could
be considered likely to be older than the SubAtlantic zone.
The sediments
Grain-size analyses and mineral content.
First of all, organic matter was removed by
oxidation in 6 % HrO, solution. Thereafter
grain-size analysesof the mineral matter were
carried out by the sieving and pipette method.
pollen
The samplesvaried from 2-5 cm in thickness,
for
procedure.
The
samples
Sarnpling
and their position in the stratigraphy is shown
for
estiused
those
of
some
well
as
as
analysis,
mating the loss on ignition, were taken with in Pl. l. The grain-sizedistributionsare shown
a Hiller sampler. The samples for the other as histograms in Pl. l, and as cumulative
investigationswere taken with a piston sampler. curvesin Fig.4.
All the sampleswere composed of poorly
Borings were made on three separate occasions, correlations being made visually litho- sorted clay and silt; the sedimentsmust, thereThe
stratigraphically, sincethe depthsof the borings fore, have been transportedin suspension.
(A6
gray
gyttja
clay
upper
the
from
samples
beneaththe bog surface varied. The boundaries
the
limit
poorly
than
sorted
more
A7)
are
and
sharp,
apart
between the various depositswere
from that between the lower grey, gyttja clay given by Selmer-Olsen(195a, Fig. 2l) fot
lacustrine sediments,whilst the remaining sam'
and the brownish-grey clay gyttja. This diffiples just fall within the limit. The lake basin
correlating
in
uncertainty
some
culty has led to
from which the samples are derived measures
taken
the
samples
of
of
some
the stratigraphy
for loss on ignition, grain size analysis, and only ca. 10 X 30 m, however,so that a better
degreeof sorting was virtually impossible.The
C14-dating (T-625).
Late Weichseliart in tlta Berpen District
atterberg:
M]ELE
LEIR
CLAY
MO
5AND
SILI
GRUS
SAND
A5
a" 1A0
ISTEII
GRAVEL
A1
+
l"/
T
125
t
€0
//'-
l1
'r'//,/.
4,: _
I ; a-
:::1
rp
4.2
2P
ap
,lu
,iP
,lP
5e
t?
1q
0 )25mm 0.25mm 0 5mm
l,l
21
tt
rmm
0
2mm
'i?
4mm
8mm
l6mm
7 q
l{
-a.9
Fig. 4. Grain size analysis cumulativecurles. Thc stratigraphic position of the samplescan be found
from Pl. 1. A I is from the bluish-greyclay, ,{3 from the lower, gyttja clay, A 5 from the top of the
clay gyttja, and A 7 from the upper, gyttja clay. The curves for samplesA2. A4 and ,{6 fit between the curveswhich appear in the diagram.
catchment area for drainage .into the basin is
small, and there are no permanent streams
-lhe
flowing in.
conclusion would therefore
simply seem to be that the sedimentshave been
carried into the lake basin by sheet-wash and
by small temporary streams. Possibly, too,
some material was wind-blown. The source
material was mainly the small amount of till
present within the catchment area.
There appeared to be appreciable variations
in the mineral content of the sieved samples.
'l'hese
were therefore separated, using a bromoform solution (sp. wt. 2.8.); the results for the
content of heavier minerals are presented in
Pl. l. lt appears that there is in fact relatively
little variation. Under the microscope, all the
samples, except A l. were found to contain
aggregates of fine particles, which had obviously not been dispersed during the grainsize analyses and which. consequently, represent an appreciablesource of error in the heavy
mineral separation results. Some of the aggregates, mentioned above, were cemented together
with iron oxide. a fact which implies a fairlv
advanced degree of weathering in the catchment area.
Lo,cs on ignition. The sediments were dried
at 105-110"C, thereafter ignited in an oven
at 750' C. The loss on ignition has been calculated in relation to the dry weight of the sample.
64 samples were analysed.
The loss on ignition provides a relatively
good picture of the humus content, which is
in this case an important characteristic of the
sediments investigated. The layer bounciaries
coincide with marked changes in the course of
the curves for loss on ignition, so that the
colour and texture of the sediments are obviously to a high degree determined by the
humus content.
The basal, bluish-grey clay showed ignition
lossesof 2.5 and 3.8 %. Ekstrijm (1927, p. 133)
showed that an ignition loss of 1.5-3 nh for
sediments with a similar clay content to the
above is due to water so tightly bound that
it does not evaporate at ll0" C. The humus
content of the bluish-grey clay, therefore.
probably lies around 0-2 Ii.
126
t. Mangerud
s p e c t r u mt h e r e i s o n l y 3 ' i I I y . s t r i x ,c o m p a r e d
to 4O /6 Pediastrum.
It is surprising that I did not find more
Ilystrix and Di.scorhilrd.even in the lacustrine
s e d i m e n t si n t h i s b a s i n . w h i c h l i e s o n l y a f e w
hundred metres distant fronr the North Sea.
Nor is there any indication of a marine en.
vironment higher up in the sediment sequence.
After the disappearanceof the ice, the first
sediment to be laid down was almost free from
organic matter. the bluish-greyclay. T'he material was mainly eroded by rainwater, and transported by sheet-wash.Gradually, as vegetation
Sedintentution retc.t. The rate of sedimentaappeared.its remains became mixed in with the
tion may be estimated in various ways. Use of
minerogenic component, at the same time as
^t-672
the C1a-datings
and T-624 (Pl. 1) yields
the soil surface became stabilised by the vegea figure of 0.5 mm/year as an average value
tation cover. At the transition to the upper,
for the clay gyttja and the lower gyttja clay.
grey gyttja clay. a strong decrease in the
If we assume that the upper, grey gyttja clay
amount of minerogenic material occurs. which
was deposited during the Ycunger Dryas Stadiis quite obviously due to a thinning out of the
al, and that this lasted ca. 700 years, then the
vegetation cover. At the transition to the
rate of sedimentation in this instance was
Blomiiy Gyttja Member, a radical change takes
0.2 mmf year. Pollen analysis,however, indicates
place. since the minerogenic component almost
that there is possibly a hiatus between the
entirely disappears.I do not intend to discuss
grey gyttja clay and the overlying gyttja. Howfurther the conditions under which the brown
ever, it is hardly likely that this is the full
gyttja was laid down. but the sediment proexplanation. A real decreasein sedimentation
vides a useful basis for comparison and indir a t e a p p e a r sr e a s o n a b l es. i n c e o n e m u s t a s s u m e
cates that the vegetation cover must have been
that the thin cover of unconsolidated material
fairly sparseeven when the brownish-grey clay
on the bedrock surface would be wholly
gyttja was laid down.
washed away, thus diminishrng the area covered
by unconsolidated sediments.
This rate ot sedimentation is of the same
degree of magnitude as that found by Berg- Pttllcn und.spores
l u n d ( 1 9 6 6 , p . 7 8 ) i n B l e k i n g e .A n y m o r e
Lahoratrry lcchniquc.s, identilication.s and
detailed comparisons would be valueless,since
diagram.t.The samples were prepared by Erdtthe dimensions of the respective lake basins
man's acetolysismethod (Fregri & Iversen 1964.
and the supplies of unconsolidated material
p. 7 | ). Samples I - 12. with the exception of
are so completely different.
No. 8, were treated. in addition. with HF
On average, the organic material content of
(op. cit. pp. 69-70).
the Blomiiy Cilay Gyttja Member is l0 7 by
The pollen counts were done by myself. in
weight, which is equivalent to a little less than
close
collaboration with Prof. Ulf Hafsten.
l5'/, by volume. lts total thickness is 90 cm.
who
has
checked most of the difficult identiI n t h e a b s e n c eo f t h e m i n e r o g e n i cc o m p o n e n t
fications
important finds.
and
t h e t h i c k n e s sw o u l d o n l v h a v e b e e n l 3 c m .
Sample No. 8 has been analysed by Dr.
Bjrirn Berglund of Lund University, for the
Ctnclusion
purpose of making a Betult analysis. He has
-Ihe
sediments are purely lacustrine. The
found nearly 2'/r, sf Juniperu.r pollen in this
pollen diagram (Pl. l) showsthat in the lowest sample.As the pollen diagram shows,I have
The loss on ignition results shows that there
was little organic production in the lake basin
at the time when the Blomiiy Clay Gyttja
Member was laid down. and in particular, that
the supply of humus from the catchment area
w a s l o w i n r e l a t i o nt o t h e s u p p l y o f m i n e r o g e n i c
m a t e r i a l . T h i s w a s p r o b a b l y a c o n s e q u e n c eo f
t h e v e g e t a t i o nc o v e r b e i n g t o o s p a r s et o p r o t e c t
the soil surface against erosion by rainwater and
periglacial processes.Variations in the ignition
loss, therefore. reflect variations in the desree
of vegetation cover.
Lute lleichst:liurt itr tht' Rcrpctt l)istrict
not identified many pollen <>fJttnipt'rtt.,;.This
possiblv representsa systentaticsource of error.
During deposition of the oldest layers of
sedrment. there have obviously been only
scattered individual trees present. or open
woodland. The pollen diagram. therelore.has
b e e n c o n s t r u c t e da s a t o t a l d i a g r a m l F e g r i &
I v e r s e n 1 9 6 4 . p . l l 9 e t s e q . ) .A l l p o l l e n t y p e s .
with the sole exception of pollen of aquatic
plants.have been included in the pollen sum.
T h e r e i s p r o b a b l y v e r y l i t t l e s e c o n d a r yl r e b e d ded.) grollen present. since, as mentioned prev i o u s l r . . t h e a m o u n t o f u n c o n s o l i d a t e ds e d i
ments in tl-ris area was small. and these for
t h e m o s t p a r t c o n s i s t e do f t i l l . H a f s t e n ( 1 9 6 3 )
attempted to exclude pollen derived by longdistance wind transport, from other floristic
areas. I havc not done this. since I consider
a pollen diagram ought to represent he pollen
rain as such. and that any interpretations
should then follow logically.
ll-
from which sample No. 2 was taken, however.
shows that the vegetation must have al,
ready achieved by that time a fair distribution
well beyond the strand zone. It is unlikely.
that there were any trees, perhaps not even
bushes either, so the vegetation is best charact e r i s e da s a g r a s s s t e p p e .o r g r a s st u n d r a .
Ptillen ttnc B2: Betula-Salix-NA p-A.t,tL'ttt
hlugc zttnc. The zone is characterisedby high.
t h o u g h d e c r e a s i n gN
, A P v a l r - r e so,n a c c o u n t t t f
the rise in Betula and ^talix, which are the mosl
important'AP' components.
I have not distinguished between pollen oi
the different Bctulu species.mainly becausethe
sampleshave been treated with HF and pollen
size, therefore. cannot be used as a reliable
criterion. Sample No.8, however, has been
analysed by Dr. BjrJrn Berglund, who has
separatedBetulu nuna on the basis of his own
c r i t e r i a ( B e r g l u n d 1 9 6 6 .p . 3 7 ) . T h e r e s u l t w a s
14'i, of B. nana typa and 86,/c of R. puhe.s
PtilL.n :rtnc Bl: (jruntineuc Peuk 11tne.The c(ns agg. type. At that time, there was a
two deepest pollen spectra are characterised, real dominance of arboreal birch species,but
first and foremost, by Gramineae values of over
one should not conclude further from this
-10',i. nnd this has been used as the charac- that the same applies in the
lower part of the
teristicfor the pollen zone.
diagram.
Sample No. lcontains very little pollen
A speciesidentification was not carried our
l t h a s a h i g h e r c o n t e n t o f A P ( a r b o r e a lp o l l e n ) , for Salix either. A series of pollen types were
particularly of Betula and Pinus, than the overin fact encountered, some of which showed
lying samples. In its main features. however. it
marked morphological differences, and I am
has the same composition as No. 2. and in
in no doubt that there must have been bushconsequenceI assume that it really represents type Sa/h speciesin addition to the low-growthe local vegetation. The higher AP content
ing types such as S. herbuccu, S. pclari,s etc.
ls a consequenceof the small amount of pollen
Pirrr.r exhibits a small. but pronounced inproduced locally and the correspondingly increase between samples 6 and 7. This is cercreased importance of pollen derived from
tainly pollen derived from long-distancetransl o n g - d i s t a n c et r a n s p o r t . T h e c o n c l u s i o n d r a w n port. and the increasemay be due to augmenmust be that zone Bl reflects the pioner
tation of the supply of Pinus pollen, or to
vegerarion. and the cr +-dating (T-672) of
reduced production of local pollen of other
12,O7(t= | 80 BP thus dates the first immikinds. The first alternative would seem the
gration of plants.
most likely explanation in the upper part of
The Chenopodiaceaein Norway are especially zone 82, whilst the latter perhaps applies to
r e p r e s e n t e db y s e a s h o r ep l a n t s ( L i d 1 9 6 3 , p .
zone 83. Sample No. 8 was analysed by Berg2 7 1 ) . a n d t h e h i g h p e r c e n t a g eo f C h e n o p o d i - lund. as mentioned earlier, and the high pina.s
aceae rn sample No. I indicates.therefore, that
value is probably due to the use of another
seashoreplants were amongst those which first
method of counting damaged pollen grains.
-Ihe
became established thereabouts.
relatively
The low values for Ericales pollen is rather
high trrganic matter content of the sediments surprising; not until sample 9 does it reach
128
J. Mangerud
I 7; . This may be due to the presence of snowbeds, since Empetrum is chionophobous, or to
delayed immigration. Most probably, however.
it is due to the lack of leaching of the soil at
that time (Iversen 1954, p. 108), since Enpetrum is an acidophilousplant.The high values
for Pediastrum in zone B2 indicate eutrophic
conditions, and it is noticeable how, when
Empetrum heath becomes established in the
area in zone 84, Pedia.gtrum disappears from
the lake, whilst the acidophilous Isoetes increasesmarkedly.
Both the species frequency and the large
quantity of herb pollen indicate that heliophile
plants dominated during the whole zone of B,2.
In the lower part of the zone the vegetation
was still tundra, later on with admixture of
shrubby willows and tree birches, such that
the vegetation in the upper part of the zone
(Late Allercid) must be characterised as park
tundra (Berglund 1966,p. 139).
Apart from this general characteristic, it is
difficult to draw any safe conclusions about
the types of vegetation present. I should like
to mention a few interesting points. Plantagu
maritima indicates that the diagram throughout
is influenced by the seashorevegetation,which
was present only a few hundred metres away
from the lake basin. Fegri (1940, p. 34) and
Hafsten (1963, pp. 333-335),in their interpretation of similar diagrams, have both stressed
the importance of snow-beds. Snow-bed communities have indeed played some part on
Blomtiy too, but in the absence of a closer
identification of the species concerned, it is
difficult, in the pollen diagram, to separate
the snow-bed communities from the other
heliophile plant communities.
Of all the ecological factors, I would, however. lay particular stress on the edaphic. In
Late Weichselian times, when no weathering
soils had yet been formed, most of Blomciy
was completely naked rock. Soil was present
only in the cracks and crevices which seam
the bedrock in all directions,, and in which
there is a continuous variation in scale, from
narrow rifts a few cm wide, up to features
gouged out by glacial erosin, and being 10-30 m
deep relative to the intervening rock ribs. These
depressions contained both the deepest and
most extensive accumulations of soil, and, on
account of their topographic situation, this
was allied to humid conditions and a favourable local climate, wind-shelter in particular.
If the vegetational successionis viewed from
this standpoint, the marked fall in the curve
for Gramineae pollen after zone Bl is explained by the establishment of new plant
communities in these depressions.First of all
there was a damp meadow, dominated, on
account of the humid conditions. more by
Cyperaceae (pollen maxima in samples 3.4
and 5) than by Gramineae. 'fhis gave way in
its turn to shrubby vegetation wjth some trees.
Betula and Sa/jx. The trees (Betula puhescens
agg.), and perhaps the willow thickets as well.
remained, throughout zone F.2, restricted to
these habitats, with relatively deep soil and a
favourable local climate.
On the outskirts of this shrubby vegetation
with trees, and in all the minor depressions in
which this vegetation did not find a foothold.
there was probabty little change in the type
of vegetation from zone Bl, termed Artemisiagrass vegetation by Berglund (1966, p. 90).
Pollen z.oneBJ: Salix-Nl p A,ssemblage:une.
'l'his
zone is characterised by a marked decline
in the Betula curve, with a corresponding increasein NAP.
An interpretation of the Betula decrease is
strongly hampered by the lack of a species
determination analysis. It is quite obvious.
however, that the decline is due to a marked
retreat of Betula pubescens agg. Whether tree
birches disappeared entirely cannot be decided
on the basis of the present material, but I
consider it very likely.
The curves for several herbaceous plants
(Lycopodium, Rumex, Artemisia, Ranunculaceae) show a change from zone 82 to zone
83. The most obvious change, however, is the
strong increase in Cyperaceae. Following the
discussion on vegetational development in zone
82, the natural assumption is that the Cyperaceae, more than the other plants, occupied
the ecological niche vacated when the birch
woods disappeared.
Late Weichseliatt in the Bersen District
As I shall discuss later. under climatostratigraphy, it is clear that these changes in vegetation were due to a climatic deterioration.
I have not counted Pediastrum so carefully
as the pollen grains, but its decline in zone 83
ts significant and indicates a decline in the
authochthonous organic matter production of
the lake basin, which was probably conditioned
by the faf l in temperature. Pediastrum increasesagain slightly in zone 84, but disappears
completely thereafter, on account of the change
from eutrophic to oligotrophic conditions.
Pollen zone BJ: Betula-Ericales Assemblage
:one. This zone is represented by a single
spectrum (sample No. l3). in which Betula
'74'/c
comprises
of the AP and Ericales 62 %,
of the NAP.
The zone bears witness to a radical change
in the vegetation compared to zone 83. Sali-r
disappears almost entirely and Betula attains
complete dominance among the tree species.
There is a sudden and massiveincreasein heath
vegetation, with the result that other herbaceous plants almost entirely vanish. In this
zone the heath is an almost pure Empetrum
heath (80 c/, of the Ericales pollen), with some
Calluna, whilst later on C'alluna becomes the
dominant heath species.
The zone has a very limited extent, and this,
together with the marked changes in comparison
with zone 83, makes it but a small step to
draw the conclusion that a hiatus exists here,
'Ihere
are no other indications of this, however. so it is perhaps just as likely that it is
due to a low rate of sedimentation.
Vegetationally this zone may be correlated
with Jessen's zone IV, and indicates such a
marked climatic amelioration that there is no
doubt that it belongs in the Holocene"
Pollen :ttne 85: Corylus Range-zonc. The
rise in the Corylu.r takes place between samp l e s l 3 a n d 1 4 a n d t h e s u b s e q u e n tp e r i o d o f
time will not be discussedany further in this
paper. Therefore I have not bothered to zone
the diagram, to any finer degree. above this
noint.
129
Ephedra. Several finds have been made rn
Scandinavia of pollen of the steppe plants
Ephedra distochya and E. strobilacea. There
was discussion for a long time as to whether
Ephedra had in fact grown in Scandinavia, or
whether the pollen was derived from longdistance transport. Now, however, most people
seem to consider that it did in fact grow here.
both during the Late Weichselian and in the
Holocene (e.g. Iversen 1954, pp. 104-105,Hafsten 1956,pp. 5l-54, Berglund 1966,p. 148).
Ephedra has been found in Holocene sediments in eastern Norway (Hafsten 1956, pp.
-51-54)and in Late Weichselian sediments in
southern Norway (Hafsten 1963, p. 332). The
finds described in the present paper are the
first in western Norway. Pollen grains of both
E. strobilacea and E. distachya were found
(Pl. l). In addition, I have found a single
grain of E. distachya in samples from the
Corylus maximum in Lepsciyvann,Os (Fig. l),
C1a-dated to (T-580) 8380 i
180 Bp. This
sample indicated closed woodland, with only
8 % NAP.
According to Gams (cited in Iversen 1954.
p. 104), Ephedra has no particular temperature
demands, 'but it seemsto require both climatic
and edaphic dryness' (lversen, op. cit.). It is
therefore surprising to find Ephedra pollen in
western Norway, which has. at the present day,
a very humid climate. The generalisedpicture
of the vegetation (Plate l), in particular perhaps the large amount of Sulix, makes it
difficult to assume that the climate can have
been especiallydry hereabouts during the Late
Weichselian. This problem must remain for
the present unsolved.
After writing this section of the manuscript
I became aware of a detailed discussionof the
same problem by Danielsen (in press). Hc
refers to a series of accounts of long-distance
transport of Ephedra pollen from the present
day, and concludes that none of the species
of Ephedra have grown in .situ in Scandinavia
since the last Ice Age. Seen against the background of the material he presents, his conclusion appearsquite logical, and if one accepts
it, the problem regarding Ephedra in western
Norway js automatically solved.
130
J. Mangerud
Sa/ix. [n several spectra the Salix curve at.
tains 30 "/c of the total pollen sum. and in
pollen zones Bl, B2 and B3 it makes up no
less than 50-60'/" of all pollen derived from
trees and shrubs.
High percentages of Salix are often encountered in Late Weichselian sediments (e.g.
Krog 1954. Hafsten 1963, Chanda 1965, Berglund 1966, pollen diagrams II and V), and
this is discussedat length by Fegri (1936, pp.
l 7 - 1 8 , 1 9 4 0 , p . 3 5 . 1 9 5 3 ) .M o s t f r e q u e n t l y t h e
curve exhibits a maximum right at the base of
the diagram, thereafter declining rapidly upwards. Faegri(1936. p. 18) points out, however.
that the high Sa/ix pollen content must be
climatically conditioned, and does not merely
represent a pioneer vegetation. In the present
diagram the Salix curve rises steadily from the
base upward, practically to the top of pollen
z.one B2, and particularly during the period of
time represented by pollen zone 83, Sa/i.r
specieswere dominant in the vegetation.
Mainly on a basis of macrofossil analyses
made by Holmboe (cited in Feegri 1936, p. l8),
F:egri assumed (1936, pp. 18-19, 1940, p. 341
that it was principally Salix herbacea which
provided the lowermost Salix maxima in the
diagrams from Eigebakken and Brcindmyra,
He thereupon interpreted this as representing
an extreme. arctic, snow-bed vegetation. Later
on (Fegri 1953, pp. 70-71) he carried out species identification analyses of the Salix pollen
in these spectra, and then discovered that, in
addition, shrubby species of Salix had played
a certain role. He thereupon modified his interpretation, and states (op. cit., p. 7l) that the
vegetation 'was chionophilous, but hardly quite
as extreme as originally supposed'.
I have not made any detailed specific identifications f or Salix in the present diagram.
I have noted, however, that the genus is represented by a variety of pollen types, which are
so clearly differentiated morphologically that
on this basis alone I have no hesitation in
stating that, in addition, bush speciesof Salix
were represented. Taking into consideration
the high percentage of Sa/rx in relation to
Betula. as well. the above conclusion seems
to be the only reasonable one.
ln the Norwegian mountain areas. a dense
thicket of .lcll"t bushes is usually present.
especially on damp ground, both in the subalpine birch belt and in the low-alpine belt
above. Some of these species can tolerate a
heavy snow cover. but are not such extreme
chionophiles as S . herbaceaand S. polaris.Without wishing to lay too much stress on the
ecology of the various species, I would say
that the upper part of pollen zone 82 may
well represent the .lalix-rich areas in the upper
part of the subalpine birch belt in the Norwegain mountains at the present day, whilst
zone 83 is equivalent to the same area above
the tree-line for birch. As far as zones Bl and
the lower part of 92 are concerned, I would
prefer to let the question remain open, because, in this instance, I am uncertain whether
tree-birches or bush species of Szrlrx were
present.
Clirnatic development and datittgs
The main features in the climatostratigraphical classification are quite clear (Pl. l)
and are supported by the C1a-datings. I
propose, in the following section, to discuss
the major boundaries and certain special features of the climatic development.
Older DryaslAllerid. The ice withdrew from
Blomciy shortly before the bluish-grey clay was
laid down. This, the first indication of climatic
amelioration, can thereby be dated to a little
before (T-672\ 12,070 i 180 B. P.
The question which then arises is whether
it was a rapid improvement in the climate,
such that the vegetational development evi.
denced in pollen zones Bl and 82 merely
reflects an immigration succession and adjustment to that climate. or, whether the vegetational development indicates a more gradual
climatic amelioration over a longer period of
time.
Betuld can migrate rapidly, and in the Preboreal it achieved, throughout Scandinavia,
an extensive and rapid expansion as soon as it
had immigrated. I therefore consider that the
steady and tardy increase of Salix and Betula
[,at<t ll'eichselian in tha Bercen I)istrict
l3l
: i t t h e e x p e n s eo f N A P i n z o n e 8 2 i s c o n d r - reasoning that the climate was more or less
tioned by a gradual amelioration of the climate
as oceanic then as now. since the tritherm for
over the course of several centuries. even t h e b i r c h t i m b e r - l i n e f a l l s f r o m 1 0 " - l l ' C l i n
though this interpretation is somewhat tentative the coastal regions to ca. 8" C in the conon account of the lack of speciesdeterminations tinental regions of Norway (Aas 1964).On thrs
f or Bctula. The boundary Older Dryas Stadial/ assumption, the first method of estimation is
Allerrid Interstadial must therefore be placed the more logical, since all four of the localities
a t s o m e p o i n t w i t h i n t h i s p e r i o d o f c l i m a t i c used in the second method lie much further
improvement.
inland than Blomdy.
As mentioned previously. the vegetation of
I draw the conclusion, therefore, that the
the uppermost part of pollen zone B2, repre- summer temperature during the Allercid Intersenting the end of the Allercid, consisted for
stadial was only 2-2.5'C lower than today.
a large part of tree birches (Betula pube.rcens 1'his may seem a small amount, but it agrees
aBB.).This provides us with a minimum value
well with Iversen's results ( I 954. pp. 97-98)
for tmean) summer temperature. Aas (1964) from Denmark.
has investigatedthe present-daytimber-line for
Rctulu in Norway. I'his tree-limit decreases
Ytunger DryrLr.The boundary Allerrid Interstronglv in altitude westward towards the coast stadial/Younger Dryas Stadial is very sharp and
of \ /estern Norway, and if we project the limit
I set this boundary to coincide with the lithowestward from his 500 m a.s.l. isohypse, stratigraphic boundary
brownish-grey clay
the theoretical limit for Blomciy lies at about
gyttja/upper. grey clay gyttja. Pollen sample
300 m a.s.l.. maximum 400 m. This implies No. 9 is taken at this boundary, but has to
that the timber-line for Betula at the end of
be assigned to pollen zone BZ. The zonal
the Alleriid Interstadial probably lay ca. 300 m
boundary B2lB3, which also bears evidence
(maximum 400 m) lower than today. Aas (1964) of a marked climatic deterioration.
must therefound that the best climatic correlation with
fore lie a few cm above the lithostratigraphic
the timber-line was with the mean temperature boundary. The Cta-datings for the upper part
for the three warmest months (a tritherm), bur
of the Allerdd, (T-624) 10. 940 { 180, agree
that the correlations with the warmest, or the
well with Danish datings.
two warmest. months were also good. The
Both the sediments and the vegetation indivertical gradient for atmospheric temperature cate a very marked climatic deterioration
at
change along the Norwegian coast is 0.6-0.7" C/
the boundary Allercid/Younger Dryas, leading
1 0 0 m ( A n d e r s e n 1 9 6 8 .p . 1 3 1 ) .A 3 0 0 m ( m a x i - to a return of a tundra vegetation.The present
mum 400 m) Iower timber-line f or Batula
material does not, however, provide a basis
would thus indicate that rhe tritherm (or, infor 4 m61s detailed, quantitative evaluation of
stead. the temperature for the warmest month)
the climate during the Younger Dryas.
was 1.8-2.8"C lower at the end of the Allercid
than today. This can also be calculated in
Holocene . The most recent climatostratianother manner. Ily using the four localities graphic boundary that I shall discuss here is
lying closest to Blom6y (Aas 1964), we obtain
the climatic amelioration following the younger
an average temperature value for the birch
Dryas, which is usually employed as the
t i m b e r - l i n eo f l l . 7 ' C f o r t h e w a r m e s t m o n t h .
boundary between the Pleistocene and the
and 10.3"C for the tritherm. At Hellisciy Holocene.
lighthouse. ca. 25 km north of Blomciy, but on
This. too, is a sharp boundary, resulting
about. the same isotherm, the corresponding
probably from a very rapid improvement in
temperatures are 14.1' and 13.4" C (Bruun
cfimate. I'he closed woodlands of Betula (and
I 962). The differences, therefore, are 2.4" C for
later of Corylus), which rapidly became estabt h e u , a r m e s tm o n t h , a n d 3 . 1 ' C f o r t h e t r i t h e r m . lished, indicate that the climate, figuratively
The assrrmption is made for both modes of
speaking almost overnight. became better than
132
I. Mangerud
Litho-
Clihato
strat i graphy
-
sttat
T
Littorat
sand and
gravel
iI
I
fiard till,
richin
bould.rs
1 , 5m
Litto.aI
sedamehts
wath
tossils
ca 1,5m
lwood, bones
ot reinde€r,
birds and
whale,
molluscs)
Tilt
I
1
t2200! 350aE
{wood)
T- 139
t 2 7 0 0 :3 5 0R P
lMytilusedulis)
Ro c k
DRYAS
S]ADIAL
Fig. 5. The stratigraphyat the graveyardat Blomvig, ca. 20 m above sea level. The lithostratigraphy and fossils are essentiallyafter Und6s
(1942).F.orCla-datingsseeTable I.
that of the Alleriid, and quite soon more or
lessas today.
The C1a-dating(T-623) 9340 ! 160 B. p. is
from a sample some 5 cm in thickness.which
according to the pollen analyses represents a
time interval of several centuries, yielding,
therefore, a date which must be assumed tcr
be appreciably younger than the boundary.
ICE-FRONT OSCILLATIONS
Bergen area
Bdlling-Older Dryas.ln 1941,during excavations for a graveyard in Blomvig, littoral
sediments were discovered beneath lodgement
till (Undis 19aD (.Fie.5).
Und6s (1942, p. 106) assumedthese sedi
ments to be interglacial in age. C1a-datingl
(Nydal 1960, p. 88), however, gave dates ol
(T-138) 12,200L 350 B. P. and (T-139) 12,700
i 350 B. P. The glacier front, consequentlyi
must have retreated landward past Blomvig at
some time prior to 12,700 L 350, and then ad.
vanced over Blomveg and out into the North
Sea once again after 12,200 t 350. As men.
tioned during discussionof the pollen diagram,
this glacier advancemust be older than (T-672)
12,070 r 180, and must, therefore, have taken
place during the Older Dryas Interstadial.
At Sandviken in Bergen, during excavations
on a building site in 1968, I came across the
stratigraphy shown in Fig. 6. The Cla-dating
CI-750; 12,470 ! 150 B. P.) suggeststhat the
fossiliferous clay is from the Bcilling Interstadial.Above the clay are two till beds,separated by a 15 cm thick silt layer, containing
lenses and gently undulating lamina. The tills
can be interpreted as lodgement till from the
Older and Younger Dryas Stadials respectively,
whilst the silt layer may be from the Allerijd
Interstadial. I should perhaps emphasisethat
no fossils have been found in the silt layer,
and that this may possibly be subglacial in
origin. The interpretation that the clay dates
from the Biilling Interstadial cannot therefore
be proved from the stratigraphy, but is supported solely by the Cra-dating.
The sedimentsfrom Blomvig and Sandviken
are the only ones from the Bdlling Interstadial
that are known to exist in the Bergen area.
They indicate that extensiveparts of the area
were ice-free at that time, but it is not possible,
for the present, to decide whether or not the
ice-front had retreated still further inland
(Fig. 7).
Allerdd-Younger Dryas. Blomiiy finally became free of ice just before 12,070 * lg0 B. p.
(T-672), and was not subsequentlycovered by
ice. Whether this ice-melt started in the Older
Dryas Stadial, or whether it should be wholly
referred to the Alleriid Interstadial, is really
a question of definitions alone. At all events
the ice continued its retreat. There is a Cradating of shells from a till in Bergen (H.
Holtedahl 1964,p. 320), which gave fI-228A)
133
Late Weichselian in the Bergen District
LITHOSTRATIGRAPHY
Fig. 6. The stratigraPhY from an
excavation at Sandviken, Bergen'
ca. 8-10 m above sea level.
c l 4 -Y E A R S
BP
B.C.
Correlotion
with
C l i m o t o;trqtigrop h )
OSCILLAT]ONS
BLO!'o\'
!
u
NORT"
sEA r
!
OF
THE
os
POSITION OF
,^
to
THE GLACIER
7n
29
CORRELATIONWIIH
C t I M A T O- S I R A T IG R A P H Y
FRONT
vlg
3okm
:6rlo: rod'
HOLOCENE
8C0i
i'
10
!l
.;li
YOUNGER
ORYAS
STAOIAL
s9c0
i
i
ii no*oiir----=\= =..-------\
lorso.:ooj
Il
-=----------\
Ei
i [rozso'rrol
ql
,iltosao
' teo'
il 000
o
A L L E R OD
I N T E R_
STADIAL
' 190;
lllO7o
a"
E l
I
t80km)
[taoor tto]
Itsoo! 3oo]
[rrmo, no]
[r?oo' !so]
:
-
[]t930i1401:
1C
l
l
OLDER
DRYAS
STADIAL
BOLLING
INTER.
STADIAL
I
, r r - ] 13000
DRYAS
ST,AOIAL
weichselian in the Bergen
Fig. 7. oscillations of the position of the glacier front during the Late
C1a-datingswhich form
The
times.
various
at
ice-front
position
i-he
of
tie
indicates
curve
area. The
The profile runs in the
diagram.
to
the
added
been
have
of
events
the basis for this reconstructi6n
- a little to the N of Bergen' Os lies S of Be-rgen
direction of movement of the ice, Blomdy-Herdia
moraines frorn
(Fig. 1), but the datings from Os have been markecl in at HerCla because the end
and
Herdla'
thJYoong"t Dryas Stadial pass through both Os
t34
J. Mangcrud
VARIAT1ONO
S F T H E P O S I T I O NO F T H E G T A C I E R F R O N ]
0
l
o
2
0
r
0
Fig. tt A schematic correlation between the changes in the position of the ice-front in thc Bergen
area and in Vristergiitland in Sweden, during the Late Weichselian. The curve for the Bergen area
is that shown in Fig. 7. The curve for Vristergiitland has been constructed from data jn \liirncr
( 1 9 6 9 .P l . 2 ) a n d E . N i l s s o n( 1 9 6 8 .P l . l ) .
| 1 . 7 0 0I 1 5 0 B . P . ( N y d a l e t . a l . 1 9 6 4 ,p p . 2 8 3 2tt4). In addition, I have obtained a dating of
shell from a clay from Bergen, for which consolidometer investigations show that the clay
must have been pre-consolidated by ice. The
d a t i n g ( T - 7 5 1 )g a v e 1 1 . 4 0 0i I l 0 B . P . T h e i c e .
therefore, must have retreated inland beyond
Bergen early in the Allercid Interstadial (Fig. 7).
Quite recently. I have also obtained a Clldating of shells from a till at Eikangervig tFig.
l ) . w h i c h g a v e ( T - t t 4 6 ) 1 1 . 9 3 0. f 1 4 0 B . P . . t h u s
indicating a rapid retreat of the ice during the
Allercid.
I h a v e n o c o n c r e t e e v i d e n c ea s t o h o w f a r
inland the ice had melted in the Alleriid. Skreden 11967),however, describes from the Voss
a r e a l a y e r s o f w e l l - s o r t e ds i l t a n d c l a y l y i n g
between two beds of till. and he considers that
the former sediments were deposited in an icedammed lake. Skreden (op. cit. pp.79-80)
statesthat it is possiblethat this ice-free period
was the Allertid-Younger Dryas. but since no
fossils were found it is not possible to say
a n y t h i n g d e f i n i t e o n t h i s q u e s t i o n .F u r t h e r i n v e s t i g a t i o n sa r e n o w i n h a n d . I f i n d i t q u i t e
l i k e l y . n e v e r t h e l e s st.h a t t h e i c e - f r o n t h a d r e t r c : r t e di n l a n da s f e r a s V o s sd u r i n g t h e A l l e r o d .
lf rve accept that Bergen was free from icc in
1 1 . 7 0 0a 1 5 0 B . P . . a n d E . i k a n g e r v i ign l l . 9 - 3 0
r 140 B. P.. then there were after all 7-800
y e a r ss t i l l h e f o r e t h e o n s e to f t h e c l i m a t i c d e t e r -
ioration of the Younger Dryas Stadial. The
datings from Os (see below) point to the same
conclusion.
-['he
end-moraine. which I correlate with the
Ra-moraine in eastern and southern Norway.
r u n s t h r o u g h O s , s o u t h o f B e r g e n( F i g . l ) . O n
the diagram illustrating the oscillations of the
ice-front tFig. 7), therefore. the datings from
Os are entered together with Herdla. which is
a s s u m e dt o b e l o n g t o t h e s a m e s y s t e m o f e n d moratnes.
-l
h e r e a r e - 5( t - l - d a 1 i n g s f r o m O s t l . a b l e l ) .
of fossils which have subsequently been overr i d d e n b y i c e . T h e o l d e s t ( T - 3 0 5 )g a v e I 1 . 7 0 0 I
210 ts. P. and since these fossils demand relatively clear water as a habitat 1H. Holtedahl
1 9 6 4 , p . 3 2 1 , 1 t. h e i c e m u s t a l r e a d y h a v e r e treated quite some way beyond Os.The youngest
'I-304)
gave 10.150: 300
datings(T-229 and
a n d 1 0 , 0 5 0 i 2 5 0 r e s p e c t i v e l y( H . H o l t e d a h l
y d i c a t et h a t t h e g l a c i e r
1 9 6 4 .p p . 3 2 0 - 3 2 1 ) . ' l - h ei n
d i d n o t r e a c h t h e o u t e r m o s t i c e - m a r g i no f t h e
Younger Dryas before the very end of this
stadial.
Itttltx'ena.During the Holocene the ice obviously melted quickly away from the fjords.
'Ihere
is a Cl+_datingof gyttja (Klovning
& H a f s t e n 1 9 6 5 ,p . 3 3 7 ) f r o m F l i m . i n n c r m o s t
i n t h e S o g n e f j o r d 1 F i g . 9 ; . o f 1 - I ' - . 1 1 29), 1 0 0i
. 1 0 ( )B . P . . a n d a n o t h e r , o f g y t t j a f r o m B u s n e s ,
i n n e r n r o s ti n t h e H a r d a n g e r f j o r d { F i g . t ) ) o f
Latc Wcichselian irt thc Berqen Districl
135
I-413
l 5 l 0 : 36 0
.;
\-
,,''---q
\
130?
l
E 2 9 0 : 1 2 0\
1846[r930:ra0)
I-ig. 9. A cartographic comparison of the (lr1-datings which are assumed to provide infornlation on
the cpursc 6f the deglaciation in Norway. Datings shown in parentheses have bccn madc on fossils
ovcr which the icc-front has subscquently passed. These therel'orc prclvide a minimum agc for the
last time thc locality was covered by ice. Datings not in parenthcscs. on thc othcr l.rand. provide a
minimum age for wl.ren the area becamc frec of ice. Datings which are underlincd refer to marlnc
shells. thc rcst t() lacustrinc gf-ttja. wooC or charcoal samples. The Ra cnd-morainc is shorvrr as in
F i g l { ) . F o r r e f e r s n c e s .s e c A p p e n d i r . p . 1 4 5 .
136
l. Martgerud
In western Norway. in the Late Weichselian.
9720 ! 330 B. P. (T'-585)lAnundsen & Simonwere but short distances between the
there
y
o
u
n
g
e
r
e
n
d
m
o
r
a
i
n
e
s
s e n 1 9 6 7 . p . : 1 5 ) .E v e n
of
accumulation and the ice-front. Outareas
but
these
mountains,
the
can be found up in
the relatively vast mountainous
flow
from
future.
the
in
closely
more
will be investigated
areas took place through narrow valleys and
fjords. a state of affairs which led to a rapid
and extensiveadvance of the ice-front following
C ttrrt'lttliotts with sttuthtrn Scunditruvia
climatic deterioration. Deep fjords gave rise to
-T-he
glaciers on a large-scale, and
main features of the course of de- calving of the
thereby, to a rapid retreat of the ice-front
glaciation in Denmark (S. Hansen 1965; and
following climatic improvement.
Sweden (S. Lundqvist 1965) are known. There
is no unanimity. however. on all datings and
correlations of the position of the ice-front.
In Fig. 8 I have drawn up a schematic comparison betwecn the oscillations of the icefront in the Bergen area and in Vastergcitland
in Swcden. The curve for the latter area, relating to the Younger Dryas and Allercid, has
been constructed from E' Nilsson's data (1968'
Pl. l), and the section relating to earlier periods
from Mcirner ( 1969. Pl. 2)' There are very
great moments of uncertainty applying to the
time correlations between the two areas. and
detailed comparisons have little or no value.
The main features are neverthelessclear; in
western Norway there were large oscillations
in thc positions of the ice-front' whilst in
Sweden there was a rapid retreat from icemelting during the mild interstadials (Btilling'
C1]-DATINGS
A seriesof Cl+-datings from Late Weichselian
sedimentsexists from the Bergen area. All the
datings were carried out by the Radiologicat
Dating Laboratory at Trondheim. They are
-l-able
presented in
I. All dates are based on
t h e L i b b y v a l u e . f o r t h e h a l f - l i f e .o f 5 5 7 0 I 3 0
years, and this has been used throughout in
the values quoted in the text. All datings are
given in C1-l-yearsbefore the present day (8.P.).
using 1950 as the reference year.
The datings have been made on pieces of
wood, lacustrine gyttjas and marine fossils. In
the following sections.I shall discussthe prob-
lem of dating marine fossils. since these are
dealt with in a great variety of ways in tabu'
geological literature.
A l l e r c i d ) a n d a s l o w e d r e t r e a t o r s t a g n a t i o n lations of dates and in the
particular
are very important.
in
Two
factors
during the cold stadials (Older Dryas, Younger
and the apparent
isotopic
fractionation
namely
Dryas). However, in Sweden too, a few minor
basins.
the
ocean
seawater
.in
age
of
(E.
rdvances of the ice have been reported
Isotttpic fractionatitm. In the course of many
Nilsson 1968, p. l4 and pp. l6-17' Mcirner
reactionsin nature (e.g.photosynthesis)
chemical
pp.
252-255).
1969,p. 128, Hillefors 1969,
occurs between the three cara
fractionation
movements
the
in
These major differences
C13 and Cl'1. Both theoretical
bon
C12,
isotopes
Sweand
Norway
rvestern
in
of the ice-front
results (Craig 1954, pp. 133experimental
and
in
differences
part,
to
be
due
in
den may,
134 and 147) indicate that a close relationthe development of the climate' I would ass h i p e x i s t sb e t w e e nf l r i 3 n d C l l , a n d t h a t t h e
sume. however. that the difference was first
process
anc! forcmost conditioned by the large glacio- enrichment factor in the fractionation
I
giverr
in
a
of
Cll
enrichment
Thus
the
is
2.
logical differences between the two areas.
particThis
is
of
Ctlt.
twice
that
is
compound
I n t h e c a s t e r np a r t s o f t h e S c a n d i n a v i a ni c e ularly important because C1+ is radioactive
sheet. there were long distances between the
a c : u m u l a t i o n : ' L i e a sa n d t h e a c t u a l i c e - f r o n t ' a n d t h e c o n t e n t o f t h i s i s o t o p e , c o n s e q u e n t l y .
is
and throughout this region there were divergeni starts to decrease as soon as the carbon
with
atmospheric
equilibrium
removcd
from
excess
of
any
directions of ice-flow, such that
accun.lulationin the central areasbecame spread c a r b o n . B y m e a s u r i n gt h e r e l a t i o n s h i pC l : r / C l 2
in a carbon conrpound. it is possiblc. horvever.
( ) r - rot v c r a n c x t e n s i v ci c e - l r o n t .
Late lleichselian
in tlte Berpen Districl
137
Table I. Ct{-dated samples of Late Weichselian age from the Bergen area. Datings for which no reference to a
dating list is given have been supplied by Dr. Reidar Nydal (personal comm.). Samples for which the laboratory
numbers are italicized were submitted by the author. Sample T-594 was collected by C. F. Kolderup. All the
rest of the italicized samples were collected by r.nepersonally. All the localities can be found in Fig. l.
Radiocarbon age
Years B.P. (1950)
1 2 7 0 0 , i3: 5 0
Laboratory numbers
and dating lists
T-139
N y d a l 1 9 6 0 p, . 8 8
Locality
BIomvAg
Blomdy
Dated material
Comments. Refcrences
Marine mollurcs From fossil-bearing gravel
Mytilus edulis
below layers of mud and till.
l2 m above sea level (Fig. 5).
T h e d a t i n g i s d i s c u s s e db y
O. Holtedahl (1960,p. 4l l),
H. Holtedahl (1964, p.322)
a n d M a n g e r u d ( 1 9 6 8 ,p . 4 6 5 ) .
T-750
Sandviken
Bergen
Marine molluscs
Chlamys
islandicus
From clay below two beds of
till (Fig. 6). The date obtained
would suggest that the clay
belongsto the Bolling Interstadial.
r2200 350
T-138
Nydal. 1960.p. 88
Blomvag
Blomoy
Wood
From the same bed as T-139.
above. The wood was preserved
in alcohol for 18 years, and
might consequently have been
contaminated by younger carbon. Note that the dating
1 2 1 0 0 : l 3 0 0 ,u s e db y O . H o l t e d a h l ( , l 9 6 0 ,p . 4 l l ) a n d M a n g e r u d ( 1 9 6 8 ,p . 4 6 5 ) , i s i n c o r r e c t .
r2070 r 180
T-672
Dale,
Nydal et. al. 1970. B I o m o y
pp.210-21
I
Gyttja clay
S e eP l . l . T h e d a t i n g i n d i c a t e s
a minimum age for the deglaciation of Blomoy (Mangerud
12470
t50
1 9 6 8p, . 4 6 s ) .
ul930 ,, 140
T-u46
Eikangervag
Marine molluscs Fossils present in till.
Chlamys islandicus,
Saxicava sp.
lr1700 , 150
T-228A
Nydafet. al.1964
p p . 2 8 32 8 4
Florida
Bergen
Marine molluscs Fossils present in till
Chlamys islandicus (H. Holtedahl 1964, p. 320)
Mva truncata
I I 700
230
T-105
Lundetre.
Nydal 1962.p. 172 O s
Bryozoan
limestone
Limestone containing Bryozoa
deposited on a rockface and
subsequently covered by clay
and till (H. Holtedahl 1964).
r | 500
100
T.T42
Nydal 1960,p. 89
Ulvenvann
Os
Marine molluscs
M).a truncTto
Fossilspresent in till
(H. Holtedahl 1964, p. 32O,
U n d h s 1 9 6 3 ,p . 1 3 , O . H o l t e d a h l 1 9 6 0 ,p . 4 0 9 ) .
T-7-tl
Grieghallen,
Bergen
Marine molluscs Occurring in a clay which had
Chlamys islandicus been preconsolidated by the
p r e s s u r eo f a n o v e r r i d i n g g l a cier. Stratigraphy not clear.
il400 , ltO
/Conttl.
Nors/t tteoqt
Titl.s.skr.
ne.yl paqe.l
r38
I. Murtgcrud
Table I contd.)
Radiocarbon age
Years B.P. (1950;
Laboratory numbers
and dating lists
Locality
Dated material
Comments. References
1 1 0 7 0, 1 9 0
T-625
Nydal et. al. 1970
pp.2l0-211
Dale
Blom<iy
Clai gl'ttja
See Pl. l. Clay gyttja deposited
during the Allerod Interstadial.
10970 180
T-594
Nydal et. al. 1970
p.2ll
Vinnes
Fusa
Marine nrolluscs
.Lh'a trutlcota
No signs were described of a
subsequent ice-advance over
the clay in which the fossils
occur (C. F. Kolderup 1908.
pp. 85 ff.). This problem will
now be more closell inrestigatcd.
1 0 9 4 0 . t1 8 0
T-624
Nydal et. a1.1970
pp.2l0-211.
Dale
Blomiiy
Clal gyttja
S e e P l . l . T h e s a n r p l ed a t e s t h c
uppermost part of the .\llerod
lnterstadial.
T-752
Marine nrolluscs ln clayey till. a few cnt abore
Osoyri
the bedrock surface. Fabric
sentrum,Os. Mya truncatt
t0790
I l0
Saxicava pholas.
analysisshows that the long
axes of pebbles are parallel lo
lhe youngest glacial striae ol.t
that rock surface.
1 0 1 5 0, 3 0 0
T-229
N y d a l 1 9 6 2p, . l 7 l .
Osiryrt
Os
Marine r-nolluscs
Mlo tltttl(ota
F o s s i l s p r e s e r r ti n t i l l
(H. Hohedahl 1964.p. -tla-).
10050 250
T-304
N y d a l 1 9 6 2p, . l 7 l .
Lundetre
Os
Marine fossils
Balanus porcalus
Sa.ri<eya arctica
Fossilsin clay subsequcntll
overridden by ice (H. Hoitedahl 1964).
ro find out whether or not isotopic fraction'
ation has taken place. and, under the above'
mentioned presupposition. to calculate the
m a g n i t u d e o f t h i s p r o c e s sf o r C 1 a .
In practice, ths Ql 3 content of a sample is
expressedas the deviation (dC13) from a stand a r d v a l u e . e x p r e s s e dp e r m i l l e ( C r a i g 1 9 5 4 ,
p . 1l 6 ) :
r) Cr3
-.
Cr:'Crr sample
C n , / C r 2s t a n d a r d
| 000
c 1 3 , c r 2s t a n d a r d
Craig gives as average values {Craig 1953
,l954)
relative to the Chicago PDB stanand
c l a r d { C r a i g l 9 - s 7 .p . 1 3 5 ) :
,)Cr3
-]
72)
t t l o of o r a t m o s p h e r i cC O " ( 1 9 - 5 3p..
*
-25,4
Oloo for ordinary terrestrial
p l a n t s ( 1 9 5 3 .p . 6 9 )
0 . 2 , tI o o f o r m a r i n e l i m e s t o n e s{ I 9 5 3 .
p . 6 l ) a n d f o r m a r i n es h e l l st 1 9 5 4 .p '
| 36)
-13.4 o/()0 for marine plants {calculated from his Table 4; 1953. p. 63)
, - 2 . 2 , i / 1 ; 1 1f o r o c e a n w a t e r ( c a l c u l a t e d
f r o m h i s T a b l e 2 ; l 9 - 5 4 .p . l 3 6 t
M a r i n e s h e l l sa r e e n r i c h e d w i t h c a . l 5 " / . i r
( t r bv isotopic fractionation. in comparison
w i t h t e r r e s t r i a lp l a n t s ,t o w h i c h t h e C l + - a c t i v i t y
i n t h e s t a n d a r d ( 9 5 ' / , o f t h e a c t i v i t - vi n t h e
NBS oxalic acid; is correlated. Enrichment
w i t h C t + i s t w i c e a s m u c h . i . e .c a . 5 ' i . e q u i v alent to ca.400 Cll-years.
As indicatedin the table above. little or no
i s o t o p i c f r a c t i o n a t i o nt a k e s p l a c e b e t w e e ns e a v i a t e r a n d s h e l l s .B r o e c k e r & O l s o n t 1 9 5 1 . p .
L u e W c i c l t . s e l i u ni r t t l t e B c r c c t t I ) i s t r i c t
178) have also found that the Ct+-activity in
'coastal shells' is more or less
the same as in
the 'adjacent surface ocean'.
'l'he
upparent oge ()f s(.awalcr. Exchange of
carbon between the ocean and the atmosphere,
naturally enough, only occurs at the surface
contact. Since radioactive decay of Cl-l takes
place at all depths, the seawater assumes an
apparent Cl+-age dependent upon the length
of time it has remained in the ocean depths
(lJroecker et al. 1960, pp. 2903-4). In the
Atlantic Ocean this apparent age varies, acc o r d i n g t o B r o e c k e r e t . a l . 1 1 9 6 0 ,p . 2 9 2 1 ) , b e tween 300 and 900 years, the greatest age discovered for oceanic deep water. In oceanic
regions in which old deep water reappears at
the surface. the seawater will show a particularly low Cl1-activity; e.g. a dating of a
freshly killed seal jn the Antarctic had an
apparent age of 1300 years (Broecker & Olson
1 9 6 1 .p p . 1 7 9 a n d 2 0 0 ) .
L'orrcction:;.The two factors mentioned above
itre both operative. but in opposing directions.
In comparison with terrestrial plants. isotopic
f r a c t i o n a t i o n l e a d s t o a n i n c r e a s ei n t h e C t r activity of marine shells. whilst the apparent
age of seawater leads to decrease.
In many areas, e.g. the North-Atlantic. it
appears that these two factors in surface water
cancel each other out. more or less.so that
surface water possessesthe same C-'ll-activity
-I'his
as recent terrestrial plants.
is why many
l a b o r a t o r i e s( R a d i o c a r b o nM e a s u r e m e n t sC: o m p r e h e n s i v eI n d e x . 1 9 5 0 - 1 9 6 5p. . 2 ) c a l c u l a t et h e
age of marine shells on a basis of the uncorrected Cll l-activity, or else corrected for
the deviation in r)Ct;t in relation to the normaI value for marine shells.Nydal (personal
conrm.) found that shells collected in the
Trondheimsfjord in 1957 had practically the
same activity as the NBS standard, and all
d a t i n g s f r o m t h e T r o n d h e i m l a b o r a t o r y .t h e r e f o r e . a r e c a l c u l a t e di n t h a t m a n n e r . i n c l u d i n g
of course ell the datings in Table I. Among
t h e s n m p l e si n c l u d e d i n l ' a b l e l . r ) C r 3 h a s o n l y
'I'-304
been measured for
and T-105. Shell
d a t i n g s w h i c h a r e c a l c u l a t e di n t h i s w a y t h u s
h a v c a n ' i n b u i l t c o r r e c t i o nf a c t o r ' f o r t h e
x p p a r e n ta g e o f s e a r v a t eo
r f,100 years.
139
Many other laboratories (e.g. Hikansson
1 9 6 9 ,p p . 4 4 0 - 4 4 1I,. O l s s o n e t a l . 1 9 6 9 ,p p . 5 1 5
and 530), however, also correct shell datings
for the deviation in r)Cl rl in relation to terrestrial plants (dCtlt : -25 oloo in PDB scale).
These datings thereby give the apparent age
for the seawater from which the shells had
taken up their carbon. In order to obtain the
age of the shells.themselves,these datings need
to be corrected for the apparent age of the
seawater.
As far as the datings in Table I are com.
cerned, the 'inbuilt correction' is probably ol
the right order of magnitude, so that the ages
cited for these samples are directly comparable
with terrestrial samples.However, no datings of
recent shells from western Norway have been
made. and possibly local variations may occur
between the coast and sites further inland up
the fjords. This will now be investigated more.
closely.Another problem is whether the oceanic
circulation may have been different during the
Late Weichselian from that of today. Regarding
shells which have lived close to the ice-front.
it is also problematic whether the seawater in
this region can have been enriched with older
carbon from CO, in the ice melt-water.
PALAEOGEOGRAPHICAL MAP OF
SOTJTHERN NORWAY DT]RING THE
YOUNGER DRYAS STADIAL
1'o put conditions in the Bergen area into
some sort of perspective. I have drawn up .r
palaeogeographicalreconstruction of southern
Norway during a late stage of the Younger
D r y a s S t a d i a l l F i g . l 0 ) . A s l . r o r td i s c u s s i o no f
this map will now be given.
Tha ice-lrtntl. On the map, the ice-front
from the Swedish border to Jdsenfjord has
been drawn according to its position in the
'Glacial
Map of Norway' (O. Holtedahl &
B. G. Andersen, in O. Holtedahl 1960). In
western Norway it is based on Undis (1963).
I-1. Hoftedahl (1967). Anundsen (1968). and
m y o w n i n v e s t i g a t i o n s .A s i n d i c a t e d o n t h e
map, the detailedcourse of the ice-front has
not been plotted yet, but the main features
c a n b e c o n s i d e r e dr e : r s o n a b l vc e r t a i n .
140
I. Mangerud
Dryas Stadial
Fig. 10. Palaeogeographic map of southern Norway during the later part of the Younger
Foi references to the literature used see in the text.
The end-moraines(Ra'moraines)'The endmoraines (Ra-moraines), which I have used
in the reconstruction (Fig. l0), have without
doubt been laid down during the Younger
Dryas Stadial, but it is scarcely likely that
moraine formation was strictly synchronous
along the whole of the ice-front. I do not intend
to discussthis any further in the presentpaper'
however,
Sea level. The extent of marine deposits in
Fig. l0 is based, essentially, on that given in
the'Glacial Map of Norway' (O. Holtedahl &
B. G. Andersen,in O. Holtedahl 1960).In the
region of the Oslofjord, the sea covered the
whole of the land surface up to the ice-front;
only in the extreme south-east was any dryland present, and the sea-level (marine limit)
hereabouts was 176 rn higher than today
Late Weichseliart in the Bercert I)istrict
(.Holmsen 1951. map). At Lista, the southernmost point of Norway, sea-level during the
Younger Dryas was a maximum of 6 m above
present-day sea-level (Hafsten 1963, p. l2'l),
possibly even somewhat lower than today (B.
G. Andersen 1960, Pl. 8), though increasing
rapidly inland towards the north-east.
ln western Norway (Figs. 1 and l0), too.
the shoreline for the Younger Dryas rises
steeply from the coast inland. In western Norway the landscape has a high relief, so that
at the time of high sea-level in the Younger
Dryas, the sea penetrated into many valleys
and covered small areas of low-lying ground.
whilst the higher ground in between remained
dry-land. [t is impossible to show such details
on a map of this scale - the map therefore
provides only a schematic picture of the scale
of magnitude of the areas covered by the
sea, and not the precise boundaries of land
and sea.
Marina scdiments and lossils. In the Oslofjord area. the glacier calved directly into the
sea, so that the Ra-moraine here was submarine. On the seaward tdistal) side of the
Ra-moraine, extensive and thick deposits of
glaciomarine clay (the Yoldia clay) were laid
down (Brcigger1901.p.76). Twenty-four species
of molluscs have been found in this clay (op.
cit., p. 32); some of the commonest of them are
depicted in Fig. 10. Feyling-Hanssen (1964)
has investigated the foraminifera in the clays
and he presumes (op. cit.. p. 175). that his
foraminiferan-zone A,,, is contemporaneous
with the formation of the Ra-moraine. The two
samples shown in Fig. l0 are typical of that
zone.
The molluscan fauna is arctic, Portlandia
urc!icu being found nowadays only in higharctic marine areas. The foraminiferan fauna.
too, is arctic (Feyling-Hanssen 1964, pp. 148l5l), and bears a particularly strong resemblance to the present-day fauna close to the
glaciers in a couple of fjords in Spitsbergen.
The whole of the Oslofjord was greatly influenced by the calving glacier and the cold
me'lt-water, and must be characterised as a
high-arctic, muddy fjord.
An extensiveinvestigationof the fossil marine
t4l
shell fauna in the Bergen area has also been
carried out (C. F. Kolderup 1908). Here, however. the shell finds are somewhat scattered on
the whole and this makes the stratigraphic
relationship exceedingly complicated. On the
map (Fig. l0) the most important speciesfrom
C1+-dated sediments at Os and Vinnes are
shown.
The shellsfrom Vinnes are Cla-dated (T-5941
to 10,970 I 180 B. P., which indicates that the
Vinnes clay is from the Allercid or Younger
Dryas. Vinnes is the only site in the Bergen
area at which Porllandia arctica has been found.
Cl. F. Kolderup (1908, pp. 88-89) points out
that here the fauna is, nevertheless,more boreoarctic in character than the purely arctic fauna
in the Yoldia clay in the Oslofjord. This is
also the general impression gained from the
molluscan faunas of other deposits which are
considered to belong to the Younger Dryas.
likewise for a foraminiferan sample from Os
(Feyling-Hanssen 1964, p. 155). The state of
the matter, as with so many unsolved problems.
is at present such that I would draw only the
most tentative conclusions. All the same. it
seems as though the ecological conditions in
Western Norway were much more highly differentiated compared to the Oslofjord.
Vegelation. For Norway, pollen diagrams,
which cover part of the Late Weichselian.
exist from Lista (Hafsten 1963), Jaren (Faegri
1936, 1940, Chanda 1965), Bdmlo (Fregri 1944)
and the present one from Blomciy (Pl. l),
which is at present the northernmost of all. A
survey covering the rest of Scandinavia can be
found in Berglund (1966, p. l2$.
For the map (Fig. 10) I have used the diagrams from Hafsten, Chanda and my own work.
since these all treat the material in more or less
the same fashion.
There is general agreement that the Pinas
pollen which is encountered has been derived
from long-distancetransport. Betula pollen size
analyseshave only been made by Fagri (1940.
p. 82), who found that during the Younger
Dryas (his pollen zone lY) Betula nana was
completely dominant, although he did not
entirely rule out the possibility that some treebirches may also have been present. Hafsten
142
J. Martgerud
( 1 9 6 3 , p . 3 3 6 ) s t a t e st h a t t h e r a p i d s p r e a d o f
'seems to indibirch after the Younger Dryas:
nevertheless.
were,
cate that arboreal birches
Fini-glacial
the
present on Lista at the time
place"
took
improvement of climate
In western Norway during the Younger
Dryas Stadial there lras a tundra vegetation
of grasses, sedges and other herbs. and on
Jeren some heath speciesas well. There were
scatteredoccurrencesof shrubby willows (Sa1ix)
and dwarf birch (Betula nana). Possibly. in
addition, there were a few clumps of tree
birches in particularly favourable situations'
"Ihis
tundra vegetation was also found in
northen Denmark and over the greater part of
central and southern Sweden (Berglund 1966.
p.123).
ample, the Late Weichselian sediments from
Dale, Blomciy, described in this paper, which
were laid down in, and in consequence restricted to. a basin measuring only 10 X 30 m'
Another problem posed is the brevity of the
time intervals involved, which are often (as in
the present paper) only a few centuries. The
stratigraphic units must therefore be much
smaller. and the boundaries. particularly in
biostratigraphic classifications' defined on criteria other than those employed in pre-Quaternary stratigraphy. Very high standards of
accuracy are called for, too, when correlations
are made.
An important principle in the above-mentioned proposals (Hedberg 1961. 1967)' is that
a clear separationshould be made betweenlitho-
stratigraphicb
. i o s t r a t i g r a p h i ca n d c h r o n o s t r a t i graphic subdivisions.This terminology has been
PRINCIPLES OF THE STRATJproposed also for Quaternary stratigraphy
GRAPHICAL SUBDIVISION OF THE
(Flint 1965. Liittig 1968)' but in this case at
LATE QUATERNARY
least three additional subdivisions are called
(Am. Com. Strat.
In the literature on Quaternary stratigraphy for. namely soil-stratigraphic
(Am' Com.
there are an infinite number of subdivisional 1 9 6 1 . p . 6 5 4 ) , c l i m a t o s t r a t i g r a p h i c
morphoand
1965)
p.
Li.ittig
660.
Strat. 1961.
schemes.and the classificatory principles and
1962;.
Willman
(Frye
&
stratigraphic
terminologies employed are very varied' One
In the following section I intend to dwell
of the reasons for this state of affairs is
on each of the main points of this
briefly
that developments during the Late Quaternary
and thereby hope to stimulate
terminology.
are so very important for an understanding of
problems of principle. In my
these
on
debate
conditions at the presentday ' that investigations
step forward will have been
major
a
opinion,
a
from
have been carried out by scientists
principles
were to be adopted.
these
if
taken
geography.
(geology'
variety of disciplines
more precise dismuch
that
result
with
the
forown
with
its
botany, zoology etc.), each
could
correlations
and
boundaries
of
cussion
differing
with
problems
and
mulation of the
place.
take
backgrounds.
Bi ostr ut igr aphy. Biostratigraphic units should
One hopes that international cooperation
be defined without exception on a basis of
can lead to the adoption of more uniform
fossil content (Hedberg 1961. p. 22)' without
rules for stratigraphical subdivision, so that it
climate or time.
becomes easier to form general .impressions any reference to environment,
system ls
po'llen
zonation
Nowadays. Jessen
out of the ever-increasingvolume of literature'
whole
the
over
extent
an
increasing
in use to
Agreements on stratigraphic terminology (Hed"
alhave
authors
many
As
Europe.
of
northern
berg 1961, 1967) should also form the basis for
development.
vegetational
pointed
out.
ready
Quaternary stratigraphy, but several modificae.g. in Norway (Hafsten 1969' p. l), has been
tions are necessary in addition. because of the
so different from that occurring in Denmark'
difspecial problems posed. The most'obvious
that many of the criteria for Jessen's zone
the
is
that
ference relative to older sediments
boundaries cannot be used elsewhere. The
in'
sediments
greater part of the Quaternary
boundaries. therefore. are drawn on a basis ol'
have
only
and
vestigated are intercontinental
climatic or temnoral correlations (e.g. the zone
exFor
distribution.
regional
a very limited
[,atc lleichseliart itr tlta Bcrcctr I)istrict
L r 0 D 0i i
10000
t
[500
YO!NG€R9R!A:;IAJI
r L:,4 19!9 .
ALIERgOINIERSIAOIAL
' . ' r
' ' r
t2000
OOEf
t + !
ORYA5 5]Af,
t25ll
B'LL
!G
llol
tsr
\I:ASiAOIA
209
F R E h ' a € ,r ! 6 4 ' 9 i p r 0 3
a'rlti5a\
vaF\:!
E 6 1 9 6 3 , ! p ? 67 ?
(f!
.r rlr
t?8
;
Fig. ll. A comparison of various authors' viows on the age of the boundaries in thc climatostratigraphic subdivision of theLateWeichselian.All,with
the cxception of tserglund. use the half-life value
for (tl of 5570 years, thc Libby value. tserglund (1966, p.46) usesa half-life of 5730 years. I havc
also addcd his subdivision corrected for the standard half-life. but becausc his boundaries are partly
based on rhe Swedish clay-varve chronology. even this corrected subdivision is not wholly comparablc
with rhe rest. Several authors indicate a span of time within which the boundary should lie. For
thc sake t'f clarity this has bcen omitted from the Figure and only the most likely age indicated. Notc
that I have uscd the climatic changes to define the boundarjes and that. in c()nsequcnce. the agcs
g i v c r ra r e ( ) n l \ a p p r ( ) \ i m a t c .
boundarr Vlll/lX). In my opinion this practice
should be abandoned. However. unambiguously
defined boundaries, e.g. the rational limit for
( ' t t r y l u s .c a n b e ( a n d i n d e e d o u g h t t o b e ) u s e d
as zonal boundaries within the whole region
in u,hrch the phenomena occur. This poUen
forms the most important basis of the stratigraphic subdivision.
Morphostratigrophy. Frye & Willman ( 1962)
point out that the landforms are one of the
most important characteristics of Pleistocene
sediments. and that a subdivision on a basis
of forms will not always parallel the lithozone troundary would then, in the chronostratigraphic or other subdivisions. In practice
straphic subdivision scheme, be found at a
progressrvelyhigher level the further north one
landforms have for a long time been used, in
Norway as well, for stratigraphic subdivision.
went. as a consequenceof a delay in the imespecially for sediments deriving from the
migration of Corylus.
d e g l a c i a t i o n .l t i s i m p o r t a n t , c o n c e r n i n gc o r r e I have chosen to zone the pollen diagram
lations, to point out that morphostratigraphic
after the fossil content of the profile itself. and
t o i n c l u d e i n d i c a t i o n o f t h e z o n a l t y p e ( a s s e m - units. too. may be transgressional in time.
(This applies to e.g. the end-moraines, Raetblage-. range-. peak zone) in the name. The
Middle Swedish Endmoraines-Salpausselkd).
correlation with southern Norway and Den('limutostratigraphy. A pronounced characmark has been made on the basis of a climatic
interpretation of the diagram, and I have there- teristic of the Quaternary is the magnitude of
fore not included Jessen'szones at all.
the climatic fluctuations. As a result. they
I ith('strutigruphy- The lithostratigraphic sub- have come to form the most important basis
divisions are based on the lithological (physical.l for the stratigraphic subdivision of sediments
features of the sediments. Where the glacial. from the Quaternary Period. lnterpretation of
and to some extent also marine. sedimentsdealt the climatic development is often a synthesis
with in lhe present paper are concerned. this
built up from quite heterogeneousphenomena.
J. Mangarud
t44
H- 105/87
aM-19
R 61
G r N- 4 5 4
K l0l
u 2 C
L!
u
l
75
w 8 2
sl lg
'
r
rooo
"l""f-
,o'*o
t5oo
tosoo
--
ilooo
tlooo
rrsco B c
li5oo B P
ffom a sediment from thc
Fig. 12. Different Crl-datings of samplesof the same piece of wood,
The samplesu'eredistribRlierOd/younger Dryas bouidary, from the site at Ru<lsVedby in Denmark.
was
originally dated bv thc
p.
6).
K-101
(1960,
Tauber
H.
by
uted to rhe various laboratories
cor, has been used
using
determination.
solid-carbon method, but in the Figuie only a more recent
solid-carbonmethod'
the
by
made
was
only
St-18
datings.
other
th!
p.216).
Among
(Tauber 1964,
.ih.
deviation.
standard
one
lin" in<licalesthe dating resultsrvith
With regard to a definition of climatostratigraphical units, the proposal put forward by
the American Committee on Stratigraphical
Nomenclature (1961, p. 660) seems to be the
'A
most apposite. It commences as follows:
geologic-climate unit is defined from its record,
wbich are bodies of rock. soil and organic
material'. Later on in the definition they point
out that the boundaries between climatostratigraphic units are probably not contemporaneous for differing degrees of geographical
latitude.
In the present connection, we are interested
in the climatic fluctuations during the Late
Weichselian, in particular. For northern Europe
during this time a subdivision has been established (Fig. ll), which was originally defined
in Denmark (see Iversen 1953, p. 9; 1954'
p. 88). The terms are to some extent used
synomymously for Jessen'szones, but are now
so generally accepted as climatic stadials and
interstadials that I employ them in the latter
sense.
The comparative diagram (Fig. ll) shows
that these climatic fluctuations were essentially
contemporaneous within Europe. It is not clear,
however. whether the boundaries are strictly
synchronous; this is, in reality, highly unlikely.
Firstly, the climatic changes may have been
troth delayed and different in kind from one
area to another. Secondly.we are not measuring
absolute climatic parameters; instead we are
studying the effect of climatic change on the
vegetation. fauna. glaciers. sediments etc. It is
obvious that all of these various elenlents do
not react with the same speed to climatic
fluctuations, and that they do not all react in
like manner to changes in different factors
( s u m m e r t e m p e r a t u r e .w i n t e r t e m p e r a t u r e r. a i n fall etc.). Therefore, no single Cl'l-age can be
determined for the boundaries between the
climatostratigraphicunits, only an approximate
age can be assignedto them.
This climatostratigraphic subdivision has
proved to be very fruitful, so I intend to use it
here. In the Holocene (Flandrian) the climatic
fluctuations are less marked, though possibly
the tripartite subdivision proposed by Hafsten
(1969, p. 10) can be utilised.
As has been made clear above, I consider
that climatostratigraphic boundaries are not
contemporaneous; they ought not to be used.
therefore. as a matter of principle, in a chronostratigraphic subdivision scheme. In practice
this is particularly relevant for the Late Weichselian and Holocene, in which short periods of
time are involved and the demands for contemporaneity therefore high. The primary subdivision of the Quaternary into glacial and
interglacial periods is used' however, as a
chronostratigraphic subdivision as well. but
even for these units it will probably prove
necessary,in the future, to define the individual
boundaries more PreciselY.
Chronosrratigraphy and geologic-tinrc tttrits'
A chronostratigraphic unit is defined as: " . . a
body of rock strata which is unified by representing the rocks formed during a specific inter-
Late Weichselian irt tlrc Bercerr Dislrict
val of geologic time' (Hedberg 1961, p. 23).
Geologic-time units are a subdivision ol thc
rime-scale into units which correspond with the
chronostratigraphic units used to subdivide
rock strata.
For the Late Weichselian the radiocarbon
(C11) method is one of the most important
dating methods available. This method, however, contains quite appreciable sources of
error. Fig. 12 shows a series of datings of a
piece of wood from the Allercid/Younger
Dryas boundary from the site at Ruds Vedby
in Denmark. The sample was cut up and pieces
sent to various laboratories by H. Tauber
(1960, p. 6. 1964, p. 216) and the datings
themselves are here taken from Hikansson
(1968, p. 38). though they have been corrected
according to Radiocarbon Measurements:Comprehensive Index, 1950-1965.These cross-datings were made at an early stage when new
laboratories were in the process of being established, so that the degree of spread is greater
than would be the case were a fresh series of
datings made today. Other series of crosschecked datings, however. indicate that different dates will be obtained when different
laboratories date one and the same sample.
In addition to these sourcesof error, which are
purely due to measurement difficulties, there
are the 'geological errors', e.g. isotopic fractionation and the apparent age of seawater.
which have alreadybeen discussed,oradmixture
of younger or older carbon. A critical interpretation of C1{-datings is therefore called
for, and most often several datings should
made before the age of a sediment can be
considered certain. Some sediments cannot be
dated by this method at all, either because
they do not contain any carbon, becauselimestone deposits underlie the sediments to be
dated, or because the sediments have been
redeposited.
It would undoubtedly be highly desirable to
establish a chronostratigraphic subdivision of
the I-ate Weichselian and Holocene that'was as
widely applicable as possible. Despite all the
weaknessesattached to the method, as mentioned, C1a-datings form the most important
method we have totay for making time-corre-
145
lations over greater distances in space and as
between different types of sediments. It seems.
therefore, as though definitions of boundaries
directly in terms of C1 '1-yearsare tobepreferred
to type sections, which is otherwise the normal
practice. In this paper I have not used any
chronostratigraphic subdivision of the Late
Weichselian. since such a subdivision ought
first of all to have been accorded seneral
acceptance.
ACKNOWLEDGEMENTS
Professor LIlf Hafsten has been my inspiring
mentor in pollen analysis. Professor Hans Holtedahl kindly read through the manuscript
critically. Problems arising from the C1+-dating
method were discussedwith Dr. Reidar Nydal,
and a number of other. problems with colleaguesand studentsat the University of Bergen.
I am especially grateful to Mr. Dagfinn Moe.
Mr. Peter Emil Kaland, Mr. Bjrirn Bergstrcim
and Mr. Inge Aarseth. The illustrations were
prepared by Miss Ellen Irgens and Miss Gyri
Tveitt. The English translation was by Philip
Tallantire, B. Sc. Financial help has been
provided by 'Norges geologiske undersokelse'
a n d ' V e s t l a n d s b a n k e n sJ u b i l e u m s s a v e ' .
APPENDIX: REFERENCES TO FIC. 9
For all the datings in the vicinity of Bergen. from
T-594 in the south to T-846 in the north, and all
lying west of these, reference should be made
to Table I.
T-117: Nydal 1960.p. 87, O. Holtedahl 1960,p.
375,Feyling-Hanssen
1964,p. 172.
T - 1 1 8b i s : N y d a l 1 9 6 2 p. . 1 6 1 .
T-119 A & C: Nydal 1960, pp. ti6-t17.O. Holtedahl 1960.p. 377.
T-149 A: Nydal 11X0,p. 90, Chanda 1965.p. ll.
T-149 B; Nydal 1960,p. 90.
T-168: Nydal 1960,p. 91. B. G. Andersen 1960,
p. '71.
T-178bis: Nydal 1962.p. 168.
T-179: Nydal 1962, p. 168, O. Holtedahl 1960,
p. 376.
T . - 1 8 0b i s : N y d a l 1 9 6 2 p
, . 1 6 2a n d p . 1 6 8 .
T-215:Nydal et. al. 1964,p.289.
T-223: Nydal 1962,p. 168, Feyling-Hanssen1964,
p. I'73.
'l-249
B:; Nydal 1962,p. 172.Hafsten 1963.p. 32ti.
146
!. Matryerud
1964'
T-261: Nydal 1962,p' 170, Feyling-Hanssen
p.173.
T-286 & 2tt7: NYdal 1962,P. 169'
1964'
T-315: Nvdal 1962,p. 170, Feyling-Hanssen
p. r72.
r-ioo' Nyaut et al. 1970, p. 2l'1, ostrem 1965'
pp.16-21.
'f-+tZ,
Nya^t et al. l9?0. p. 215' Klovning &
, .337.
H a f s t c n1 9 6 5 P
, .278'
T - 4 1 3 :R c i t e 1 9 6 8 P
-t-424,
425 & 426 Nvdal et al. 197()' p 2l0'
B. G. Andcrsen1968,P. 75
T-449: Nydal et al. 1970. pp. 214-215'Hafsten
1965b, pp. 25-26.
'f-585: Anundsen& Simonsen1967,p. 35'
T-616: Nydal ct al. 1910,P.212.
T-617& 618: H. Holtedahl 1961. p. 194'
T-645: Nydal et aI.1970,pp.2ll-212.
T-664:Nydal et al. 1970,P' 228.
The dating t1400I 200 is from Sandmo (1960' p'
u ' a y . 1 9 3 1 ' 1 9 6 0 .D e t N o r s k e M e t e o r o l o g i s k e I n s t "
Oslo.
Chanda, S. 1965. The history of vegetation of
and Early PostA Late-Glacial
Brbndmyra.
Glacial dcposit in Jaren' South Norway' Uttiv'
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l'l pp.
Craig. U. 1953. The geochemistry of the stable
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3, 53-92.
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Danielsen, A. (in press). Pollen-analytic L1t:
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