Tale of the Kulet eclogite from the Kokchetav Massive, Kazakhstan

Transcription

J. metamorphic Geol., 2012, 30, 537–559
doi:10.1111/j.1525-1314.2012.00980.x
Tale of the Kulet eclogite from the Kokchetav Massive, Kazakhstan:
Initial tectonic setting and transition from amphibolite to eclogite
R. Y. ZHANG,1,2 J. G. LIOU,1 S. OMORI,3 N. V. SOBOLEV,4 V. S. SHATSKY,4 Y. IIZUKA,5 C.-H. LO2
AND Y. OGASAWARA6
1
Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305, USA
([email protected])
2
Department of Geosciences, National Taiwan University, Taipei, 106, Taiwan
3
Department of Earth and Planetary Sciences, Faculty of Sciences, Tokyo Institute of Technology, Meguro, Tokyo 152-8551,
Japan.
4
V. S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090,
Russia
5
Institute of Earth Sciences, Academia Sinica, Taipei, 11529, Taiwan
6
Department of Earth Sciences, Waseda University, Shinjuku-Ku, Tokyo 169-8050, Japan
ABSTRACT
The Kulet eclogite in the Kokchetav Massif, northern Kazakhstan, is identified as recording a prograde
transformation from the amphibolite facies through transitional coronal eclogite to fully recrystallized
eclogite (normal eclogite). In addition to minor bodies of normal eclogite with an assemblage of
Grt + Omp + Qz + Rt ± Ph and fine-grained granoblastic texture (type A), most are pale greyish
green bodies consisting of both coronal and normal eclogites (type B). The coronal eclogite is
characterized by coarse-grained amphibole and zoisite of amphibolite facies, and the growth of garnet
corona along phase boundaries between amphibole and other minerals as well as the presence of
eclogitic domains. The Kulet eclogites experienced a four-stage metamorphic evolution: (I) pre-eclogite
stage, (II) transition from amphibolite to eclogite, (III) a peak eclogite stage with prograde
transformation from coronal eclogite to UHP eclogite and (IV) retrograde metamorphism. Previous
studies made no mention of the presence of amphibole or zoisite in either the pre-eclogite stage or
coronal eclogite, and so did not identify the four-stage evolution recognized here. P–T estimates using
thermobarometry and Xprp and Xgrs isopleths of eclogitic garnet yield a clockwise P–T path and peak
conditions of 27–33 kbar and 610–720 C, and 27–35 kbar and 560–720 C, respectively. P–T
pseudosection calculations indicate that the coexistence of coronal and normal eclogites in a single
body is chiefly due to different bulk compositions of eclogite. All eclogites have tholeiitic composition,
and show flat or slightly LREE-enriched patterns [(La ⁄ Lu)N = 1.1–9.6] and negative Ba, Sr and Sc and
positive Th, U and Ti anomalies. However, normal eclogite has higher TiO2 (1.35–2.65 wt%) and FeO
(12.11–16.72 wt%) and REE contents than those of coronal eclogite (TiO2 < 0.9 wt% and
FeO < 12.11 wt%) with one exception. Most Kulet eclogites plot in the MORB and IAB fields in
the 2Nb–Zr ⁄ 4–Y and TiO2–FeO ⁄ MgO diagrams, although displacement from the MORB–OIB array
indicates some degree of crustal involvement. All available data suggest that the protoliths of the Kulet
eclogites were formed at a passive continent marginal basin setting. A schematic model involving
subduction to 180–200 km at 537–527 Ma, followed by slab breakoff at 526–507 Ma, exhumation and
recrystallization at crustal depths is applied to explain the four-stage evolution of the Kulet eclogite.
Key words: amphibolite; Kokchetav Massif; Kulet coronal eclogite; tectonic setting; transition.
INTRODUCTION
The Kokchetav Massif [a diamond-bearing ultrahighpressure (UHP) metamorphic terrane], Kazakhstan
has attracted much attention worldwide, because it
provides an excellent opportunity to investigate questions about: (i) deep subduction and exhumation processes of supracrustal materials; (ii) geochemical
recycling; and (iii) interactions of crustal and mantle
rocks. Most past studies focused on the western, diamond-bearing, part of the Kokchetav massif, and
2012 Blackwell Publishing Ltd
chiefly involved origin of diamond, P–T conditions,
ages and exhumation models of UHP metamorphic
rocks (Sobolev & Shatsky, 1990; Zhang et al., 1997;
Kaneko et al., 2000; Hermann et al., 2001; Katayama
et al., 2001; Dobretsov & Shatsky, 2004; Ogasawara,
2005; Korsakov & Hermann, 2006). The Kulet area in
the southeastern Kokchetav Massif is poorly studied in
comparison with the Kumdy-Kol area, although
numerous eclogite bodies (100 · 40 m–2000 · 940 m
in diameter) occur as lenses in various schists and
gneisses. Until 1997, this area was thought to be a part
537
538 R. Y. ZHANG ET AL.
of the Kokchetav UHP metamorphic belt based on
petrological study of whiteschist (Zhang et al., 1997),
but it was the discovery of coesite in garnet from a
pelitic schist (Shatsky et al., 1998; Masago et al., 2009)
and whiteschist (Parkinson, 2000) that confirmed UHP
metamorphism in the Kulet area (unit II).
Apart from a few dark-coloured eclogite bodies with
equigranular granoblastic texture, most Kulet eclogitic
bodies are pink to pale greyish green, and consist of
two types of eclogitic rock, namely equigranular
eclogite with an assemblage of Grt + Omp + Qz ±
Ph (normal eclogite) and inequigranular eclogitic rock.
The later one contains coarse-grained amphibole and
zoisite that are partially replaced by very fine-grained
garnet coronae and omphacite (coronal eclogite).
These petrological types are not found in other
Kokchetav eclogites, and raise questions about: (i) the
origin of such unusual eclogitic rocks; (ii) their bulk
compositions; and (iii) why coronal and normal
eclogites coexist in a single body? Petrographic study
indicates the coarse-grained amphibole and zoisite are
relict phases of pre-eclogite stage. Ota et al. (2000)
studied numerous Kulet eclogites and indicated that
these eclogites were metamorphosed at P–T conditions
of 650–750 C and 27–32 kbar, some bodies are in
coesite eclogite zone, and others are in quartz eclogite
zone (Fig. 1). However their study identified coarsegrained amphibole and zoisite either as part of the
eclogite assemblage or a retrograde phase, leading to a
misinterpretation of the metamorphic history of the
Kulet eclogite. Moreover, some coronal eclogites
occurring at the margins of eclogite bodies were
incorrectly named as retrograded amphibolite.
The prograde transition from amphibolite to eclogite in the Kulet eclogite has also been recorded in other
HP ⁄ UHP terranes (Liu & Ye, 2004; Young et al.,
2007). In the present study, five representative eclogite
bodies are selected for petrological and chemical
studies in order to (i) determine the metamorphic
evolution of the Kulet eclogites; (ii) characterize their
geochemistry and define the protolith rock types and
the tectonic setting in which these rocks formed; and
(iii) propose a tentative tectonic model to explain the
formation and exhumation of Kulet UHP metamorphic rocks.
GEOLOGICAL OUTLINE
The Kokchetav Massif in northern Kazakhstan is situated in the Central-Asiatic mountain belt, and is
considered to be a block of the Kokchetav-North Tien
Shan massif. The Central-Asiatic mountain belt was
69°E
70°E
Kokchetav
B
Astana
L
Kazakhstan
A
Almaty
C
VII
Aral Sea
500 km
B
I
Grt-Bt gneiss, orthogneiss
eclogite and marble
II
Orthogneiss, blastomylonite
mica schist and eclogite
III
High-alumina schist
IIa
Eclogite pods (scale exaggerated)
Leninsk
IV
V
a
Barchi kol
a
C
L
Other pre-ordovician rocks (V-VII)
Zerenda series (I-IV)
A
UHP-HP units
Study area
V
Riphean -Vendian cover rocks,
quartzite, black slate, marble dolomite, metavolcanic rocks
VI
Riphean to Vendian rocks with
Early Cambrian rocks. a- Island arc
volcanic, b- Metamafic rock with
barroisite
Pre-Vendian gneiss, basement and
protolith for Zerenda Series
VII
Carbonatite and alkaline ultramafic
rocks in fault zones
Daulet suite, low P/T rocks with
cordierite and andalusite
B
IIb
B
Kumdy Kol
L
b
IIb
Sulu - Tjube
IIc
B
L
IIb
IIa
IIa
IIb
B
L
IIa
B
Enbek - Berlyk
IIb
L
Kulet
Fig.2
IIb
53°
N
B
Post-metamorphic rock series
53°
N
IV
IIb
C
Silurian - Devonian and young
volcanic and sedimentary rocks
B
Ordovician island-arc complex
Ordovician bimodal
A
volcanic rocks
Palaeozoic granite and
mafic rocks
L
0
Lake
5
10 km
D
B
N
L
IIb
L
Fig. 1. Simplified geological map of the Kokchetav Massif, modified after Dobretsov et al. (1995) showing the Kulet study area of
Fig. 2.
ORIGIN OF THE KULET ECLOGITE 539
created by the collision of the Siberian continent with
North China, Tarim, Tadzik, Karakorum and Kazakhstan-North Tien Shan continents (Zonenshain
et al., 1990). The Kokchetav Massif is composed of
several Precambrian metamorphic rock series, Cambrian–Ordovician island arc volcanic and sedimentary
rocks, Devonian volcanic molasses, CarboniferousTriassic shallow-water and lacustrine deposits. All
these rocks were intruded by post-collision granites
(Shatsky et al., 1999).
The metamorphic rocks exposed in the central part
of the Kokchetav Massif have been named the Zerenda
Series, and on lithological and metamorphic characteristics divided into four units (Dobretsov et al., 1995;
Fig. 1). Unit I exposed in the Kumdy-Kol and BaechiKol areas (‘‘Kol’’ means lake) was named the KumdyKol western domain (Theunissen et al., 2000a), and
consists of schist, gneiss, eclogite, quartzite, marble,
garnet pyroxenite and clinochumite-bearing ultramafic
rock. Diamond-bearing rocks including pelitic schist,
paragneiss and dolomitic marble crop out as thin lenticular or lens-like bodies within garnet biotite and
garnet two-mica gneisses. Diamond-bearing metasedimentary rocks and eclogites in western domain recrystallized at 40–60 kbar 780–1000 C (Sobolev &
Shatsky, 1990; Shatsky et al., 1995; Zhang et al., 1997;
Maruyama & Parkinson, 2000). U–Pb dating of zircon
from diamond-bearing rocks yielded UHP metamorphic ages of 530 ± 7 Ma (Claoue-Long et al., 1991),
537 ± 9 Ma (Katayama et al., 2001) and 527 ± 5 Ma
(Hermann et al., 2001); retrograde metamorphism of
amphibolite facies occurred at 526 ± 5 Ma (Hermann
et al., 2001) to 507 ± 8 Ma (Katayama et al., 2001).
The formation of some granitic gneiss and migmatite
was attributed to partial melting of diamond-bearing
rocks at 526 ± 2 Ma during exhumation of UHP
metamorphic rocks (Ragozin et al., 2009). The retrograde mica from diamond-bearing garnet–biotite
gneiss yielded a 40Ar ⁄ 39Ar age of 517 ± 5 Ma (Shatsky et al., 1999). Based on geochronological data of
different stages, Hermann et al. (2001) and Hacker
et al. (2003) suggested that the exhumation of the
diamond-bearing UHP rocks of the Kokchetav Massif
was ultrarapid.
Unit II occupies the Sulu–Tjube, Enbek–berlyk and
Kulet areas, east–southeast of unit I, and is mainly
composed of pelitic schist (Grt + Ms + Qz ±
Ky ± Pl ± Chl, mineral abbreviations after Whitney
& Evans, 2010) and paragneiss. Lenses or boudins of
orthogneiss, eclogite, whiteschist (Tlc + Grt + Ky ±
Ph + Rt ± Qz ± Amp) and quartzite are within or
closely associated with schist and gneiss. Coesite was
found as inclusions in garnet from mica quartz
schist (Shatsky et al., 1998; Masago et al., 2009) and
whiteschist (Parkinson, 2000). No age data are
available for the Kulet eclogite, but 40Ar ⁄ 39Ar mica
cooling ages of 519 ± 2 and 521 ± 4 Ma were,
respectively, obtained for a phengite separate from a
micaschist and a biotite separate from an interleaved
granitic gneiss from the Kulet area. These ages were
interpreted as the age of the early exhumation stage
(Theunissen et al., 2000a). The 40Ar ⁄ 39Ar data of
biotite from a whiteschist yielded a weighted mean age
of 504.7 ± 1.0 Ma (Hacker et al., 2003), but insufficient data do not allow us to evaluate the significance
of this age.
Unit III in the northeastern vicinity of Enbek–Berlyk is a coherent, fault-bounded slice consisting of
garnet–mica–schist and kyanite ⁄ sillimanite-bearing
aluminous gneisses. Gabbro–norite–diorite sills that
have been incompletely transformed to eclogite
assemblages intruded these Al-rich schists. No precise
age and P–T estimates are available for these rocks.
Unit IV (Daulet suite) underlying units I and II consists of low-P, high-T cordierite (±andalusite)-bearing
metapelite. The metamorphic conditions range from
500 to 600 C and <5–6 kbar (Maruyama & Parkinson, 2000).
The UHP–HP units are structurally overlain by
Riphean–Vendian platform strata and weakly metamorphosed rocks, and are underlain by the Daulet
Suite of low-pressure schists (Dobrzhinetskaya et al.,
1994; Dobretsov et al., 1995; Kaneko et al., 2000). The
major tectonic boundaries juxtaposing these units are
interpreted to be subhorizontal faults or shear planes
(Kaneko et al., 2000; Yamamoto et al., 2000a). The
boundaries are locally crosscut by post-orogenic highangle normal and strike-slip faults with NE–SW and
NW–SE trends (Dobretsov et al., 1995; Kaneko et al.,
2000).
SAMPLE DESCRIPTIONS
Numerous lensoidal bodies of eclogite of variable size
occur in metapelite (Grt–Ms–Qz schist) in the vicinity
of the Zealtau Lake in the Kulet area. The eclogite
lenses strike roughly NE–SW on the south–southeast
side of the lake, but change to NW–SE in the southwest side, concordant with the foliation of country
rocks (Fig. 2). Based on rock assemblage, texture and
colour, these eclogite bodies are divided into two types.
Type A (minor) is massive, dark green. It is only
composed of normal eclogite that has an equilibrium
assemblage of Grt + Omp + Qz + Rt ± Ph with
fine-grained granoblastic texture. Type B body
(abundant) is pale greyish green, and consists of both
normal and coronal eclogites. The coronal eclogite is
characterized by the presence of coarse-grained, relict
amphibole and zoisite of the pre-eclogite stage in the
eclogitic matrix and by coronal texture. Petrographic
characteristics of these rocks are described below.
Type A eclogite body (No. 1)
The No. 1 body is the largest in this area (Fig. 2), and
has a fine-grained granoblastic texture, with most
samples having a simple assemblage of Grt + Omp +
Qz + Rt; minor samples contain a small amount of
N
Lake
Zealtau
No. 5
02KL-5
d
c
02KL-4
No
.4
b
a
68
f
e
d
c
ab
40
82
40
f
e
i
gh
b
02
a
K
No. 3 02K L1 KL3-3
02 L2
KL
3
No. 2
j k
99KL-4
d
c
No. 1
a
b-d
e f
g h
99KL3-2
i j
25
Eclogite in unit 2
Daulet suite
White schist
Schist & gneiss
Foliation attitude
Coesite
zone
Fault
additional eclogitic phases of phengite and zoisite (or
clinozoisite, Fig. 3a). This type of eclogite is characterized by having no relict coarse-grained amphibole or
zoisite of pre-eclogite stage. Garnet (‡50 vol.%)
has euhedral or rounded shape with variable size of
0.05–1 mm, but most grains are 0.2–0.3 mm across,
and are equidimensional. Some relatively coarser garnet grains are formed by coalescence of several finegrained crystals, and contain abundant fine-grained
inclusions of omphacite and quartz (Fig. 3a); minor
inclusions of taramite, epidote and plagioclase only
occur in some garnet grains (Fig. 3b). Most omphacite
occurs as well recrystallized grains; only subordinate
omphacite occurs as poorly shaped patches consisting
of small omphacite laths. Minor fine-grained, secondary clinopyroxene with low jadeite component occurs
around coarser omphacite (Fig. 3c); retrograde biotite,
albite, epidote and chlorite after biotite are also present
in a few samples (Fig. 3d). Two occurrence modes of
amphibole were identified: fine-grained inclusions in
garnet (Fig. 3a,b) and retrograde phase in the matrix
(Fig. 3c, left bottom). In addition, there are rare epidote inclusions in garnet (Fig. 3b) and fine-grained
clinozoisite as possible eclogitic phase in the matrix
(Fig. 3a). Rutile is not altered in most samples, but
only in some samples it is partially replaced by ilmenite
and titanite.
Type B eclogite body
All type B eclogite bodies (Nos 2–5) are pale greyish
green, and comprise both coronal (most) and normal
(minor) eclogites. Some eclogite bodies (e.g., Nos 3 &
4) are closely associated with whiteschist (Fig. 2).
Normal eclogites are similar to the eclogites from
body 1. They consist of Grt, Omp, Qz, Rt ± Ph,
and show equigranular granoblastic texture
1 km
Fig. 2. Schematic geological map of the
Kulet area, showing sample localities of
investigated eclogite bodies. The
boundaries of coesite- and quartz-eclogite
zone and some whiteschist locations are after
Ota et al. (2000) and Parkinson (2000),
respectively.
(Fig. 3e). Garnet and omphacite occur in variable
amounts. Quartz content ranges from 4 to 8 vol.%;
rutile is <3 vol.%. Both garnet and omphacite are
fine-grained ranging from 0.05 to 0.4 mm; quartz is
0.2–0.7 mm in size. Garnet contains abundant inclusions of Omp + Qz ± Brs ± Rt in sample 99KL-4h,
and is partially surrounded by retrograde amphibole ± plagioclase or by biotite (Fig. 3f). Rutile is
locally replaced by titanite. Most omphacite is little
altered, but some grains are rimmed by very thin
symplectite of amphibole ± plagioclase. Secondary
veins of amphibole, epidote and quartz or albite are
developed along microfractures in some eclogites.
Coronal eclogites are pale greyish green (Fig. 4a),
and preserve both pre-eclogite stage relict and eclogitic minerals. The relict phases (5–25 vol.%) include
coarse-grained (1 to >10 mm) amphibole, that is
colourless or pale yellow, zoisite and minor quartz.
Fine-grained garnet coronae are developed along the
margins of amphibole or at the interfaces between
zoisite and amphibole (Fig. 4b). The amphibole shape
is irregular, due to garnet corona replacement.
Moreover, neoblastic garnet has also grown in
amphibole, and fine-grained, clouded garnet and
omphacite laths occur as prograde products in zoisite;
their grain sizes increase from core (2–3 lm) to rim
(100 lm) of zoisite (Fig. 4c). Eclogitic domains consist of fine-grained garnet (5–200 lm), omphacite and
minor quartz, rutile ± phengite. Garnet exhibits a
discontinuous corona texture around aggregates of
fine-grained omphacite ± quartz indicating that primary plagioclase (?) has been totally replaced by
omphacite ± quartz (Fig. 4d). The margins of some
eclogite bodies contain secondary, coarse-grained
aggregates (up to 1 cm) of green amphibole that
contains many inclusions of garnet, omphacite and
titanite with relict rutile.
(a)
(b)
(c)
(d)
(e)
(f)
Fig. 3. Back-scattered electron images (BEI a–d) and plane light photomicrographs (e & f) showing normal eclogite and retrograde
alteration. (a) Garnet from normal eclogite showing granoblastic texture and numerous inclusions of quartz and omphacite and
coalescence of several fine-grained garnet crystals. (b) Inclusions of quartz, taramite, plagioclase, epidote and apatite in a coarser
euhedral garnet. (c) Normal eclogite (99KL3-2d) showing symplectites after omphacite and retrograde amphibole (left bottom). (d)
Retrograde biotite, albite and chlorite after biotite are also present in a few samples. (e) Normal eclogite from body 2 showing mineral
assemblage of Grt + Omp + Qz + Rt and equigranular granoblastic texture. (f) Retrograde amphibole and biotite surrounding
garnet in normal eclogite.
(a)
(b)
(c)
(d)
Fig. 4. Photograph (a), photomicrographs (b & d) and back-scattered electron image (c) showing the field view and transitional
textures from amphibolite to eclogite in type B eclogite body. (a) Pale grey transitional rock (coronal eclogite) fragment from type B
body. (b) Fine-grained garnet grown along interphase boundaries between zoisite and amphibole (sample 99KL-4e). Crossed polars. (c)
Neoblasts of garnet and omphacite in zoisite (sample 99KL-4k). (d) Fine-grained garnet surrounding an omphacite patch that consists
of many small omphacite laths. The omphacite patch may be after plagioclase(?) (sample 99KL-4e). Crossed polars.
Three modes of occurrences for amphibole were
found in type B body: (i) inclusions in garnet from
both coronal and normal eclogites (similar to Fig. 3b);
(ii) coarse-grained relicts of the pre-eclogite stage in
coronal eclogite (Fig. 4b); and (iii) retrograde phase in
both eclogites that can be clearly distinguished from
the pre-eclogite facies amphibole by its occurrence,
colour and replacing texture. The retrograde brown or
green amphibole is interstitial between garnet and
omphacite, and replaces fully recrystallized garnet
(Fig. 3f). In contrast, the light-coloured relict amphibole was replaced by fine-grained garnet coronae
(Fig. 4b).
Sample 02KL-4e shows a gradual change between
normal and coronal eclogite, with garnet and interstitial omphacite patches consisting of many tiny omphacite laths, but no individual coarser omphacite
grains. Only minor (<5 vol.%) amphibole relicts are
preserved, and they have much smaller grain size than
those in coronal eclogite.
GEOCHEMISTRY OF WHOLE ROCK AND
MINERAL
Analytical methods
Bulk composition
Major and trace elements of whole rocks were analysed
at the V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of Russian Academy of Sciences in Novosibirsk, Russia. Major elements were
determined by XRF spectrometry, with standard
deviations for Al, Si, Mg and Ca of 1.3, Fe, 0.9, Ti and
Mn of 0.3, and K of 0.4. Trace elements were determined by ICP MS. Analytical procedures have been
described by Shatsky et al. (2006).
Mineral compositions
Minerals from body 2 were analysed employing a
JEOL 8900 Superprobe with 15 kV accelerating
potential and 12 nA beam current at Waseda
University, Japan; other samples were analysed at the
Institute of Earth Sciences, Academia Sinica, Taiwan,
using a field emission electron probe micro analyzer
(FE-EPMA: JEOL JXA-8500F) equipped with five
wavelength-dispersive spectrometers. A 2 lm defocused beam was used for quantitative analysis at an
acceleration voltage of 12 kV with a beam current of
6 nA. The measured X-ray intensities were corrected
by ZAF method using the standard calibration of
synthetic chemical-known standard minerals with
various diffracting crystals: diopside for Si with TAP
crystal, rutile for Ti with PET crystal, corundum for
Al (TAP), chromium oxide for Cr (PET), fayalite or
hematite for Fe (LiF), tephroite for Mn (PET),
periclase for Mg (TAP), wollastonite for Ca (PET),
albite or jadeite for Na (TAP) and adularia for K
(PET). Peak counting for each element and
both upper and lower baselines are counted for 10
and 5 s, respectively. The analytical results of whole
rocks and minerals are described in the following
sections.
Major and trace elements of whole rock
Thirteen eclogite samples from three eclogite bodies
(3–5) were selected for bulk chemical study (Table 1).
All eclogites have basaltic composition with low SiO2
(45.59–52.21 wt%), Na2O (0.97–2.33 wt%) and K2O
(0.12–0.26 wt%, with three exceptions). Fe2O3, MgO
and CaO contents are 9.50–18.60, 7.25–10.11 and
9.74–12.44 wt%, respectively. Among them, body 3
eclogites have higher Na2O content (1.84–2.33 wt%)
than eclogites (0.97–1.60 wt%) from bodies 4 and 5.
Normal and coronal eclogites, however, show some
difference in some major and trace element contents.
Two normal eclogite samples in body 5 have higher
TiO2 (1.35–2.60 wt%), FeOtotal (12.11–16.72 wt%)
than those of coronal eclogite (TiO2 0.63–0.64 wt%
and FeOtotal 10.38–11.46 wt%) in the same body. the
Table 1. Major and trace elements of Kol let eclogitic rocks.
Sample
02KL-1
50.17
SiO2
0.76
TiO2
14.63
Al2O3
13.47
Fe2O3
MnO
0.26
MgO
8.20
CaO
9.74
2.09
Na2O
0.92
K2 O
0.04
P2O5
loss
0.26
Total
100.56
Trace elements (ppm)
Sc
16
V
124
Cr
135
Rb
21.0
Sr
30.6
Y
8.6
Zr
19.8
Nb
2.4
Ba
81.6
La
5.21
Ce
9.93
Pr
1.28
Nd
4.91
Sm
1.09
Eu
0.29
Gd
1.49
Tb
0.26
Dy
1.53
Ho
0.31
Er
1.09
Yb
0.93
Lu
0.13
Hf
0.55
Ta
0.11
Th
1.28
U
0.17
02KL-2
02KL-3
02KL-4a
02KL-4b
02KL-4c
02KL-4d
02KL-4e*
02KL-4f*
02KL-5a*
02KL-5b
02KL-5d
02KL-5d*
51.11
0.67
15.42
9.69
0.19
8.75
9.99
1.84
1.01
0.09
1.06
99.84
50.96
0.64
15.19
10.36
0.24
8.89
11.13
2.33
0.24
0.09
0.22
100.28
51.82
0.59
13.64
9.50
0.20
9.44
11.20
0.97
1.79
0.06
0.96
100.16
47.75
0.88
16.60
11.87
0.20
8.28
12.44
1.53
0.15
0.06
0.24
100.01
47.70
0.64
15.67
11.78
0.21
10.02
12.17
1.38
0.25
0.05
0.24
100.10
48.66
0.98
13.85
12.15
0.21
9.72
12.36
1.53
0.19
0.07
0.28
100.02
44.87
2.56
13.24
18.25
0.28
7.30
10.76
1.60
0.21
0.19
0.26
99.54
52.21
0.55
14.13
9.76
0.22
8.88
11.19
1.85
0.20
0.14
0.44
99.57
45.59
2.60
13.55
18.60
0.29
7.25
10.56
1.94
0.12
0.17
0.02
100.71
47.84
0.63
15.85
11.55
0.20
10.11
11.90
1.38
0.17
0.04
0.22
99.89
48.73
0.64
15.13
11.64
0.20
9.94
11.55
1.53
0.26
0.05
0.44
100.11
46.79
1.35
14.53
13.47
0.21
9.37
12.32
1.40
0.16
0.10
0.13
99.82
10
72
109
19.0
60.1
4.5
16.2
1.5
79.6
5.31
10.65
1.34
5.16
1.17
0.27
0.96
0.14
0.88
0.17
0.54
0.43
0.06
0.37
0.05
0.92
0.23
32
219
434
6.2
213.8
15.0
54.5
3.6
56.8
13.13
25.98
3.57
12.74
2.54
0.79
2.73
0.41
2.49
0.54
1.86
1.38
0.21
1.50
0.27
3.00
0.58
20
123
125
32.5
34.8
11.6
61.8
2.7
31.1
3.77
9.18
1.30
5.24
1.45
0.39
1.55
0.29
1.92
0.43
1.60
1.18
0.21
1.55
0.22
0.60
0.33
24
187
143
0.9
59.8
13.6
24.8
1.4
4.1
2.51
5.44
0.90
4.24
1.28
0.48
1.84
0.32
2.18
0.45
1.71
1.37
0.22
0.57
0.07
0.39
0.13
37
232
249
4.7
84.9
18.3
35.8
1.9
19.0
3.58
7.88
1.12
4.96
1.53
0.55
2.21
0.47
2.86
0.64
2.48
2.11
0.31
1.01
0.14
1.11
0.33
22
145
178
2.0
64.7
7.0
23.5
1.9
15.3
3.32
6.91
0.99
4.23
1.20
0.36
1.34
0.24
1.37
0.28
1.01
0.70
0.10
0.57
0.13
0.41
0.15
23
319
29
<
22.0
19.7
58.1
3.1
2.6
3.19
8.00
1.37
6.01
2.19
0.67
3.04
0.54
3.37
0.71
2.72
2.01
0.29
1.48
0.16
0.39
0.15
36
494
50
4.5
85.0
36.5
102.9
5.8
27.1
6.40
15.49
2.76
12.56
4.10
1.33
5.51
0.98
6.47
1.36
4.85
3.37
0.56
2.18
0.28
0.86
0.22
29
415
37
<
50.8
26.0
74.1
4.3
10.4
4.77
12.03
2.06
9.92
3.21
1.10
4.24
0.74
4.45
0.92
3.25
2.47
0.39
1.91
0.19
0.62
0.22
27
174
184
2.0
50.1
14.1
28.9
1.5
23.4
2.58
5.53
0.82
3.64
1.04
0.37
1.54
0.32
2.16
0.52
1.91
1.40
0.22
0.67
0.10
0.95
0.30
18
113
129
3.0
50.6
9.2
18.6
1.1
14.2
2.12
4.46
0.68
2.85
0.87
0.27
1.20
0.22
1.51
0.30
1.22
1.06
0.15
0.43
0.06
0.73
0.23
22
193
165
0.9
68.8
11.9
32.6
1.6
8.5
2.41
5.61
1.02
5.04
1.70
0.56
2.00
0.36
2.21
0.50
1.57
1.25
0.18
0.72
0.08
0.25
0.07
*Normal eclogite; others are coronal eclogite.
100
100
N-MORB
E-MORB
Arc tholeiite
(Aoba)
N-MORB
Arc tholeiite
Rock/primitive mantle
Rock/Chondrite
E-MORB
(Aoba)
10
02KL-1
02KL-2
02KL-3
Body 3
1
10
Arc
1
Body 3
100
02KL-1
02KL-2
02KL-3
10
02KL-4a
02KL-4b
02KL-4c Body 4
02KL-4d
02KL-4e
02KL-4f
1
Rock/Chondrite
100
10
1
Body 4
0.1
02KL-4a
02KL-4b
02KL-4c
02KL-4d
02KL-4e
20KL-4f
100
10
02KL-5a
02KL-5b
02KL-5c
02KL-5d
1
La Ce Pr
Nd
Body 5
Sm Eu Gd
Tb Dy Ho
Er
Yb
Lu
Fig. 5. REE patterns for both normal and coronal eclogites
from bodies 3, 4 and 5. All abundances are normalized to the
chondrite composition of Sun & McDonough (1989). Data of
N-MORB and E-MORB are from Sun & McDonough (1989),
and composition of Arc tholeiite (from the Aoba island) is after
Peate et al. (1997).
normal eclogite (02KL-04f) in body 4, however, has
the highest SiO2 (52.21 wt%) and very low TiO2
(0.55 wt%) and FeOtotal (10.06 wt%) contents. The
transitional eclogite (02KL-2e) has high TiO2
(2.56 wt%) and FeOtotal (16.41 wt%) contents.
Chondrite-normalized REE distribution patterns for
nine samples (except for three samples from body 3
and two from body 4) all show a flat REE pattern with
(La ⁄ Lu)N ratio of 1.2–1.5 and a negative Eu anomaly
(Fig. 5). The five samples (02KL-1, -2 & -3 and 02KL4a & -4d) show slightly LREE-enriched patterns with
(La ⁄ Lu)N of 1.9–9.6, but MREE and HREE of sample
02KL-1 and 02KL-4a are relatively flat. The normal
eclogite has higher concentrations of MREE, HREE
and V, Y, Zr, Hf trace elements than those of coronal
eclogite, but has low Cr content. Primitive mantlenormalized spider diagrams of whole rocks have negative Ba, Sr and Sc and positive Th, U and Ti anomalies (Fig. 6).
Rock/Chondrite
0.1
100
10
1
Body 5
0.1
02kL-5a
02KL-5b
02KL-5c
02KL-5d
Rb Th Nb La Sr
Zr Pr Eu Gd Ho
Y Lu
V
Ba U
Ta Ce Nd Hf Sm Ti
Dy Er Yb Sc
Fig. 6. Primitive mantle normalized trace-element patterns of
both normal and coronal eclogites from bodies 3, 4 and 5. The
compositions of primitive mantle, N-MORB and E-MORB are
after Sun & McDonough (1989). Arc tholeiite composition is
after Peate et al. (1997).
Mineral compositions
Compositions of representative minerals from normal
and coronal eclogites are listed in Tables 2–5, respectively; additional data are shown in the Tables S1–S3.
Garnet and omphacite formulae have all Fe expressed
as Fe2+. In the end-member calculation of clinopyroxene, Fe3+ = Na–Al if Na > Al (Cr can be ignored
for Cpx of the Kulet eclogites), and all Fe expressed as
Fe2+ if Na £ Al, based on six oxygen ions. The
amounts of ferric and ferrous iron for amphibole
formula were calculated using the procedure described
by Schumacher (1991). Iron is expressed as Fe3+ in
zoisite ⁄ clinozoisite formula.
39.24
0.03
0.12
22.12
21.85
0.49
6.11
9.06
0.00
0.08
99.09
39.02
0.28
0.00
21.42
22.70
0.60
4.90
10.62
0.01
0.00
99.54
3.03
0.02
0.00
1.96
0.00
1.47
0.04
0.57
0.88
0.00
0.00
7.97
SiO2
TiO2
Cr2O3
Al2O3
FeO
MnO
MgO
CaO
Na2O
K2O
Total
Si
Ti
Cr
Al
Fe3+
Fe
Mn
Mg
Ca
Na
K
Total
2.00
0.00
0.00
0.45
0.00
0.11
0.00
0.46
0.52
0.43
0.01
3.99
55.58
0.15
0.10
10.63
3.77
0.00
8.68
13.53
6.21
0.18
98.82
3.44
0.02
0.00
2.10
0.00
0.08
0.00
0.37
0.01
0.08
0.86
6.96
50.84
0.33
0.00
26.29
1.47
0.04
3.69
0.13
0.62
9.97
93.38
Phn*
f39-40
av2
99KL3-2c
Omp*
1b-F41
6.59
0.06
0.00
2.66
0.03
1.15
0.01
2.49
1.39
1.05
0.12
15.55
45.46
0.55
0.01
15.59
10.00
0.05
11.54
8.98
3.73
0.65
96.57
Ktp
2b-55
ret
6.10
0.04
0.01
5.46
0.52
0.00
0.01
0.05
3.68
0.00
0.00
15.87
39.26
0.34
0.04
29.81
4.04
0.05
0.23
22.11
0.00
0.00
95.89
Czo
1b-21
3.03
0.02
0.00
1.92
0.00
1.80
0.04
0.35
0.81
0.02
0.00
7.99
38.55
0.40
0.00
20.70
27.35
0.62
2.99
9.58
0.11
0.00
100.30
Grt
1c-70
host.c
3.05
0.00
0.00
1.96
0.00
1.91
0.04
0.42
0.57
0.01
0.00
7.97
39.06
0.01
0.03
21.34
29.20
0.61
3.58
6.87
0.07
0.02
100.79
Grt
1d-35
r
2.02
0.00
0.00
0.35
0.00
0.28
0.00
0.39
0.53
0.43
0.00
4.02
54.58
0.13
0.00
8.13
9.10
0.07
7.16
13.44
6.01
0.01
98.64
Omp
1d-19
r
2.00
0.00
0.00
0.21
0.00
0.33
0.00
0.51
0.69
0.28
0.00
4.03
53.75
0.16
0.00
4.83
10.58
0.00
9.21
17.21
3.85
0.00
99.59
6.57
0.09
0.00
1.97
0.18
2.09
0.02
1.98
1.63
0.70
0.20
15.45
43.25
0.80
0.00
11.02
19.42
0.18
8.76
10.03
2.39
1.03
96.88
Mg-Hbl
1d-38
ret
99KL3-2d
Omp
1b-9
sym
2.85
0.23
0.00
1.23
0.00
1.19
0.00
1.33
0.01
0.02
0.90
7.76
37.60
4.00
0.00
13.76
18.77
0.07
11.71
0.10
0.12
9.25
95.38
Bt
1d-av4
ret
6.06
0.01
0.01
4.28
0.00
4.27
0.01
5.11
0.02
0.00
0.02
19.79
28.62
0.07
0.05
17.15
24.08
0.06
16.17
0.07
0.00
0.06
86.32
Chl
1d-33
ret
2.95
0.00
0.00
1.04
0.00
0.01
0.00
0.00
0.07
0.92
0.01
4.99
67.81
0.03
0.00
20.28
0.20
0.00
0.03
1.41
10.89
0.21
100.85
Ab
1d-63
ret
3.00
0.01
0.00
2.00
0.00
1.59
0.03
0.59
0.77
0.00
0.00
7.99
38.67
0.13
0.01
21.89
24.47
0.50
5.13
9.24
0.00
0.00
100.05
Grt*
1b-av2
c
1.98
0.00
0.00
0.41
0.00
0.14
0.00
0.50
0.58
0.41
0.00
4.02
55.01
0.07
0.04
9.59
4.69
0.00
9.42
15.16
5.82
0.00
99.79
Omp*
1b.28
c
3.39
0.04
0.00
2.12
0.00
0.11
0.00
0.36
0.00
0.08
0.87
6.98
49.75
0.84
0.00
26.43
2.01
0.00
3.59
0.02
0.57
10.03
93.25
Ph*
1b.23
2.98
0.00
0.00
2.01
0.00
1.59
0.02
0.65
0.75
0.00
0.00
8.01
101.55
39.05
0.08
0.00
22.28
24.92
0.38
5.68
9.16
Grt*
2G.20
m
1.98
0.00
0.00
0.38
0.00
0.16
0.00
0.51
0.61
0.38
0.00
4.02
54.46
0.03
0.00
8.90
5.34
0.01
9.40
15.62
5.34
0.00
99.10
Omp*
2G.58
3.40
0.05
0.00
2.07
0.00
0.13
0.00
0.37
0.00
0.05
0.92
6.99
49.68
0.94
0.09
25.69
2.18
0.00
3.59
0.02
0.37
10.50
93.07
Ph*
2s44
99KL3-2g
*The data are used to estimate P–T conditions (other Tables same). c, core, m, mantle, r, rim; i ⁄ g, i ⁄ omp, inclusions in Grt and Omp, respectively. ret, retrograde mineral; sym, symplectite; ave, average.
3.03
0.00
0.01
2.01
0.00
1.41
0.03
0.70
0.75
0.00
0.01
7.96
Grt*
1b-2
r
Grt*
1b-4
c
Mineral
No.
Note
Sample
Table 2. Representative mineral compositions of normal eclogite from body 1.
6.31
0.04
0.00
2.91
0.06
1.38
0.01
2.25
1.49
1.07
0.13
15.66
42.84
0.39
0.04
16.78
12.27
0.04
10.26
9.43
3.75
0.70
96.52
Trm
61-2
i⁄g
6.01
0.01
0.00
4.51
1.46
0.00
0.01
0.01
3.99
0.00
0.00
16.00
37.85
0.06
0.03
24.09
10.99
0.07
0.04
23.43
0.00
0.01
96.55
Ep
63-4
i⁄g
2.85
0.00
0.00
1.12
0.00
0.03
0.00
0.01
0.14
0.88
0.01
5.03
64.27
0.00
0.00
21.36
0.87
0.00
0.09
2.86
10.19
0.10
99.74
Pl
65
i⁄g
2.73
0.00
0.00
1.24
0.00
0.02
0.00
0.00
0.28
0.73
0.00
5.01
61.12
0.01
0.00
23.53
0.64
0.01
0.06
5.80
8.41
0.01
99.58
Pl
66
i⁄g
6.86
0.06
0.01
1.99
0.06
1.08
0.00
2.91
1.43
0.97
0.15
15.52
47.00
0.52
0.07
11.54
9.90
0.02
13.39
9.12
3.43
0.78
95.78
Ktp
1b.11-4
av4
55.02
0.09
0.01
7.98
5.74
0.01
9.64
16.03
5.00
0.00
99.52
39.00
0.02
0.00
21.77
27.07
0.53
4.02
8.69
0.02
0.00
101.12
3.02
0.00
0.00
1.99
0.00
1.75
0.03
0.46
0.72
0.00
0.00
7.99
SiO2
TiO2
Cr2O3
Al2O3
FeO
MnO
MgO
CaO
Na2O
K2O
Total
Si
Ti
Cr
AL
Fe3+
Fe2+
Mn
Mg
Ca
Na
K
Total
6.80
0.07
0.00
2.03
0.21
1.19
0.00
2.76
1.45
0.96
0.05
15.52
46.81
0.61
0.00
11.85
11.53
0.01
12.73
9.29
3.40
0.30
96.52
Ktp
690-1
ret
3.01
0.03
0.00
1.92
0.00
1.69
0.04
0.37
0.93
0.02
0.00
8.01
38.20
0.53
0.02
20.75
25.73
0.54
3.17
11.00
0.10
0.00
100.06
Grt
731
1.98
0.00
0.00
0.35
0.00
0.28
0.00
0.46
0.58
0.36
0.00
4.02
54.67
0.12
0.02
8.14
9.16
0.06
8.52
14.85
5.14
0.00
100.69
Omp
732
6.42
0.08
0.00
2.53
0.22
1.70
0.00
2.11
1.48
0.95
0.22
15.71
43.03
0.72
0.00
14.39
15.39
0.00
9.51
9.28
3.28
1.14
96.73
Ktp
734
ret
99KL-4h normal eclogite
3.00
0.00
0.00
2.01
0.00
1.30
0.03
0.79
0.86
0.00
0.00
7.99
39.44
0.07
0.04
22.39
20.38
0.47
6.99
10.49
0.03
0.00
100.31
Grt*
855-6
av2
1.98
0.00
0.00
0.31
0.00
0.09
0.00
0.64
0.70
0.29
0.00
4.01
55.46
0.04
0.08
7.40
2.96
0.00
12.08
18.31
4.24
0.00
100.58
Omp*
858
3.56
0.01
0.00
1.89
0.00
0.06
0.00
0.48
0.00
0.04
0.93
6.97
53.81
0.19
0.02
24.29
1.10
0.02
4.92
0.00
0.30
11.03
95.07
*Ph
850
7.14
0.03
0.00
1.53
0.20
0.64
0.01
3.51
1.58
0.57
0.09
15.30
50.75
0.28
0.00
9.21
7.11
0.07
16.74
10.47
2.09
0.52
97.24
Mg-Hbl
859-60
relict
99KL-4e coronal eclogite
7.64
0.01
0.00
0.67
0.21
0.46
0.00
4.08
1.69
0.30
0.04
15.08
55.28
0.08
0.00
4.11
5.75
0.01
19.79
11.41
1.11
0.21
97.77
Act
866
r.ret.
3.02
0.00
0.00
2.03
1.36
0.03
0.86
0.67
0.00
0.00
7.97
1.36
0.03
0.75
0.90
0.00
0.00
8.02
39.35
0.03
0.00
22.41
21.18
0.51
7.56
8.14
0.02
0.00
99.20
Grt
615
r
3.00
0.00
0.00
1.97
38.70
0.03
0.05
21.62
20.94
0.49
6.53
10.86
0.03
0.00
99.25
Grt
617
c
0.09
0.00
0.57
0.64
0.34
0.00
4.00
1.97
0.00
0.00
0.39
54.25
0.11
0.03
9.07
2.96
0.02
10.56
16.58
4.78
0.00
98.35
Omp
605-9
av4
6.00
0.00
0.01
5.83
0.13
0.00
0.00
0.01
4.03
0.00
0.00
16.01
38.79
0.02
0.05
31.99
0.99
0.01
0.05
24.29
0.00
0.00
96.19
Zo
653
relict
1.43
0.04
0.87
0.67
0.00
0.00
8.00
3.00
0.01
0.00
1.99
38.67
0.11
0.00
21.78
22.09
0.54
7.52
8.01
0.03
0.00
98.75
Grt
672
ecl-dm
99KL-4f coronal eclogite
0.08
0.00
0.57
0.64
0.35
0.00
4.00
1.99
0.00
0.00
0.38
54.98
0.08
0.03
8.90
2.55
0.00
10.51
16.45
5.01
0.00
98.51
Omp
667
ecl-dm
1.56
0.05
0.58
0.76
0.00
0.00
7.98
3.02
0.00
0.00
2.00
38.64
0.02
0.00
21.76
23.91
0.72
5.00
9.02
0.00
0.00
99.07
Grt
746-m
c-m
ecl-dm, eclogite domain; in ⁄ zo, in ⁄ amp, neoblasts in zo and amp. Relict phase of pre-eclogite stage; sym, symplectite. Other explanations are same as Table 2.
1.99
0.00
0.00
0.34
0.00
0.17
0.00
0.52
0.62
0.35
0.00
4.01
Omp
699-70
Grt
706
m
99KL-4c normal eclogite
Mineral
No.
Note
Sample
Table 3. Representative mineral compositions of eclogite from body 2.
1.44
0.03
0.61
0.86
0.01
0.00
7.98
3.01
0.00
0.00
2.01
38.46
0.03
0.02
21.76
22.05
0.46
5.20
10.30
0.07
0.00
98.35
Grt
745-r
r
0.12
0.00
0.56
0.64
0.36
0.00
4.02
1.98
0.00
0.00
0.36
54.59
0.12
0.08
8.38
4.00
0.02
10.37
16.46
5.12
0.00
99.14
Omp
756-7
av2
1.63
0.04
0.59
0.68
0.00
0.00
7.97
3.05
0.00
0.01
1.96
38.49
0.06
0.08
21.06
24.63
0.65
5.00
8.04
0.01
0.00
98.02
Grt
782
in ⁄ zo
1.61
0.04
0.57
0.81
0.00
0.00
8.01
3.01
0.00
0.00
1.96
38.83
0.01
0.00
21.46
24.84
0.67
4.89
9.71
0.01
0.00
100.42
Grt
790
in ⁄ zo
1.46
0.04
0.60
0.94
0.00
0.00
8.02
2.96
0.01
0.00
2.02
37.71
0.09
0.00
21.79
22.17
0.55
5.12
11.17
0.00
0.00
98.60
Grt
791
in ⁄ zo
0.12
0.00
0.56
0.66
0.33
0.00
4.01
1.99
0.00
0.00
0.34
54.40
0.00
0.04
8.00
3.99
0.01
10.25
16.83
4.72
0.02
98.26
Omp
786
in ⁄ zo.m
99KL-4k coronal eclogite
6.00
0.01
0.01
5.77
0.23
0.00
0.00
0.01
3.98
0.01
0.00
16.00
38.81
0.06
0.05
31.65
1.76
0.00
0.03
24.04
0.03
0.00
96.43
Zo
784-4
relict
6.83
0.05
0.00
2.05
0.12
1.34
0.01
2.63
1.54
0.81
0.11
15.49
46.41
0.49
0.02
11.80
11.87
0.06
12.00
9.75
2.85
0.57
95.82
Hbl
804-5
ret
6.52
0.08
0.00
2.47
0.04
1.42
0.00
2.48
1.63
0.91
0.11
15.66
44.02
0.69
0.03
14.12
11.76
0.01
11.25
10.24
3.17
0.58
95.87
Ed
797-8
ret
6.44
0.07
0.01
2.51
0.18
1.40
0.01
2.44
1.57
0.93
0.12
15.67
43.57
0.60
0.09
14.38
12.76
0.08
11.08
9.92
3.23
0.63
96.34
Prg
801
ret
56.32
0.12
0.01
9.87
2.02
0.03
10.59
15.56
5.28
0.03
99.83
40.29
0.22
0.09
22.54
20.29
0.56
8.18
9.47
0.02
0.00
101.67
3.01
0.01
0.01
1.98
0.00
1.27
0.04
0.91
0.76
0.00
0.00
7.99
SiO2
TiO2
Cr2O3
Al2O3
FeO
MnO
MgO
CaO
Na2O
K2O
Total
Si
Ti
Cr
Al
Fe3+
Fe
Mn
Mg
Ca
Na
K
Total
3.59
0.01
0.00
1.88
0.00
0.05
0.00
0.48
0.00
0.03
0.85
6.90
53.85
0.23
0.00
23.91
0.90
0.04
4.82
0.02
0.24
10.03
94.04
Ph*
1a3-4
ecl-dm
6.11
0.02
0.01
5.82
0.07
0.00
0.01
0.03
3.86
0.00
0.00
15.92
39.89
0.14
0.12
32.21
0.57
0.05
0.12
23.49
0.00
0.00
96.59
Zo
2b-77
relict
ecl-dm, eclogite domain; in ⁄ zo, neoblast in zoisite.
1.99
0.00
0.00
0.41
0.00
0.06
0.00
0.56
0.59
0.36
0.00
3.98
Omp*
1a-5
ecl-dm
Grt*
1a-10
ecl-dm
02KL-2 coroal eclogite
Mineral
No.
Note
Sample
6.95
0.03
0.00
2.06
0.15
0.44
0.01
3.32
1.32
0.81
0.08
15.16
49.89
0.24
0.01
12.53
6.27
0.04
15.99
8.88
3.01
0.46
97.31
Brs
2a-58
relict
3.00
0.00
0.00
1.99
0.00
1.35
0.03
0.81
0.83
0.00
0.00
8.00
39.39
0.02
0.06
22.17
21.13
0.46
7.12
10.12
n.d
n.d
100.5
Grt
1g36
1.99
0.00
0.00
0.35
0.00
0.09
0.00
0.58
0.67
0.31
0.00
3.99
55.90
0.00
0.01
8.39
2.96
0.01
11.00
17.44
4.49
0.00
100.22
Omp
1S46
6.21
0.01
0.01
5.57
0.09
0.00
0.00
0.01
4.05
0.00
0.00
15.94
40.29
0.11
0.04
30.67
0.69
0.00
0.03
24.49
0.00
0.01
96.32
Zo
1S43
7.22
0.03
0.00
1.42
0.05
0.64
0.00
3.61
1.64
0.59
0.05
15.26
51.34
0.24
0.01
8.56
6.36
0.03
17.20
10.85
2.18
0.29
97.07
Hbl
av3
relict
02KL-4b coronal eclogite
Table 4. Representative mineral compositions of eclogites from bodies 3 and 4.
7.59
0.01
0.00
0.77
0.08
0.48
0.00
3.98
1.61
0.43
0.04
14.99
54.42
0.12
0.01
4.69
5.59
0.00
19.13
10.76
1.60
0.21
96.53
Act
1S49
relict
3.00
0.02
0.00
1.99
0.00
1.74
0.02
0.59
0.61
0.00
0.00
7.98
38.61
0.39
0.00
21.81
26.85
0.38
5.09
7.38
n.d
n.d
100.50
Grt
45-6
av2
2.00
0.00
0.00
0.33
0.00
0.12
0.00
0.57
0.66
0.33
0.00
4.01
55.42
0.05
0.04
7.70
4.14
0.00
10.54
16.98
4.79
0.00
99.66
Omp
2s-29
7.11
0.04
0.01
1.55
0.13
1.00
0.00
3.11
1.44
0.87
0.00
15.26
49.50
0.36
0.08
9.14
10.28
0.04
14.53
9.33
3.13
0.02
96.51
av4
Brs
02KL-4e coronal eclogite
3.01
0.01
0.00
1.95
0.00
1.76
0.03
0.54
0.71
0.00
0.00
8.01
38.21
0.11
0.00
21.02
26.73
0.50
4.64
8.42
n.d
n.d
99.63
Grt*
4F-16
2.00
0.00
0.00
0.32
0.00
0.22
0.00
0.50
0.62
0.36
0.00
4.02
54.35
0.00
0.00
7.39
7.22
0.13
9.22
15.68
5.05
0.02
99.05
Omp*
4F-22
3.50
0.02
0.00
1.95
0.00
0.12
0.00
0.45
0.00
0.03
0.91
6.98
52.35
0.36
0.00
24.77
2.20
0.00
4.52
0.05
0.20
10.69
95.14
Ph*
4F-30
6.90
0.04
0.00
1.80
0.12
1.24
0.01
2.84
1.43
0.94
0.16
15.48
47.42
0.36
0.02
10.47
12.14
0.08
13.11
9.16
3.35
0.85
96.96
Brs
av5
relict
3.01
0.01
0.00
1.95
0.00
1.76
0.03
0.54
0.71
0.00
0.00
8.01
38.21
0.11
0.00
21.02
26.73
0.50
4.64
8.42
n.d
n.d
99.63
Grt*
4F-16
02KL-4f normal eclogite
2.00
0.00
0.00
0.32
0.00
0.22
0.00
0.50
0.62
0.36
0.00
4.02
54.35
0.00
0.00
7.39
7.22
0.13
9.22
15.68
5.05
0.02
99.05
Omp*
4F-22
3.50
0.02
0.00
1.95
0.00
0.12
0.00
0.45
0.00
0.03
0.91
6.98
52.35
0.36
0.00
24.77
2.20
0.00
4.52
0.05
0.20
10.69
95.14
Ph*
4F-30
6.90
0.04
0.00
1.80
0.12
1.24
0.01
2.84
1.43
0.94
0.16
15.48
47.42
0.36
0.02
10.47
12.14
0.08
13.11
9.16
3.35
0.85
96.96
Brs
av5
relict
Table 5. Representative mineral compositions of eclogite from body 5.
Sample
02KL-5a eclogite
02KL-5b coronal eclogite
Mineral
No.
Note
Grt*
2a-30
host-c
Omp*
2a-27
i⁄g
Grt*
2a-60
Omp*
2a-59
Grt
2b-41
hst
Omp
33-5
i ⁄ g.r
Brs
2b-36
i ⁄ g.m
Brs
75-7
relict
Grt
5b-103
c
Grt
5b-101
r
Grt
2b-46
in ⁄ zo
Grt
2b-47
in ⁄ zo
Grt
2b-48
in.zo
Zo
av7
relict
Brs
5b-99
relict
SiO2
TiO2
Cr2O3
Al2O3
FeO
MnO
MgO
CaO
Na2O
K2O
Total
38.61
0.04
0.14
21.23
27.04
0.55
4.49
7.94
0.05
0.00
100.09
54.60
0.05
0.00
8.25
8.14
0.06
8.71
13.58
5.80
0.00
99.20
38.68
0.01
0.01
21.38
26.95
0.51
4.31
8.14
0.05
0.01
100.06
54.74
0.12
0.01
8.43
7.55
0.07
8.22
13.70
6.09
0.03
98.96
39.20
0.04
0.00
22.33
27.77
0.63
4.82
6.30
0.05
0.02
101.17
54.15
0.14
0.07
8.45
8.23
0.09
8.43
13.91
5.71
0.02
99.19
43.372
0.39
0.02
15.44
13.27
0.03
10.71
8.74
4.06
0.09
96.11
46.14
0.50
0.01
12.15
13.56
0.04
11.20
8.34
3.76
0.55
96.26
40.54
0.04
0.00
22.77
20.92
0.44
9.72
6.61
0.04
0.00
101.08
40.08
0.04
0.00
22.59
17.71
0.33
9.90
8.42
0.00
0.00
99.07
40.22
0.12
0.00
22.46
20.43
0.39
8.23
8.11
0.07
0.02
100.05
39.81
0.02
0.00
22.02
18.80
0.44
7.46
10.19
0.01
0.02
98.77
39.90
0.00
0.00
22.12
17.78
0.27
6.54
12.02
0.04
0.00
98.66
39.84
0.04
0.11
32.17
0.70
0.04
0.12
23.31
0.03
0.01
96.36
47.13
0.46
0.11
14.15
6.86
0.00
14.68
9.36
3.29
0.43
96.47
3.02
0.00
0.01
1.96
0.00
1.77
0.04
0.52
0.67
0.01
0.00
8.00
2.00
0.00
0.00
0.36
0.00
0.25
0.00
0.48
0.53
0.41
0.00
4.03
3.03
0.00
0.00
1.97
0.00
1.76
0.03
0.50
0.68
0.01
0.00
7.99
2.00
0.00
0.00
0.36
0.00
0.23
0.00
0.45
0.54
0.43
0.00
4.03
3.02
0.00
0.00
2.03
0.00
1.79
0.04
0.55
0.52
0.01
0.00
7.97
1.99
0.00
0.00
0.37
0.00
0.25
0.00
0.46
0.55
0.41
0.00
4.03
6.38
0.04
0.00
2.68
0.17
1.30
0.00
2.35
1.38
1.16
0.02
15.48
6.78
0.05
0.00
2.11
0.13
1.41
0.00
2.45
1.31
1.07
0.10
15.43
3.02
0.00
0.00
2.00
0.00
1.31
0.03
1.08
0.53
0.01
0.00
7.98
3.02
0.00
0.00
2.01
0.00
1.12
0.02
1.11
0.68
0.00
0.00
7.97
3.04
0.01
0.00
2.00
0.00
1.29
0.03
0.93
0.66
0.01
0.00
7.96
3.05
0.00
0.00
1.99
0.00
1.20
0.03
0.85
0.84
0.00
0.00
7.96
3.06
0.00
0.00
2.00
0.00
1.14
0.02
0.75
0.99
0.01
0.00
7.95
6.12
0.00
0.01
5.82
0.09
0.00
0.00
0.03
3.83
0.01
0.00
15.92
6.70
0.05
0.01
2.37
0.09
0.63
0.00
3.11
1.42
0.91
0.08
15.37
Si
Ti
Cr
Al
Fe3+
Fe
Mn
Mg
Ca
Na
K
Total
The explanations are same as Tables 2–4.
S1). Minor garnet grains exhibit compositional zoning:
almandine and pyrope increase with decreasing grossular from core to rim (Fig. 7). In contrast, garnet
from coronal eclogite (Grt1) shows large variation in
composition (grs18–34 and prp12–38) even within a single
body (e.g., body 2) and three types of compositional
zoning. Type 1 is same as the zoning described above.
Type 2 involves decreasing alm with slightly increasing
Garnet
Garnet is present in stages II (Grt1) and III (Grt2), and
most are almandine-rich, ranging from 38 to 63 mol.%
(most >50 mol.%, Fig. 7). The garnet of normal
eclogite
(Grt2)
contains
higher
almandine
(>50 mol.%) than that from coronal eclogite, and is
relatively homogeneous in composition (see Tables 2 &
Alm
Alm
(c)
90
Zo
(a)
Normal
Eclogite 80
02KL-5B
*45
Omp
(Grt2)
*46 *47
*
48
70
r
r
4H
c
c
4C
*
c
c
50
Coronal
Eclogite
c
r
r
c
4E
4K
r
r r
m
r
4F
99KL3-2c
99KL3-2d
99KL3-2g
02KL-2
02KL-4b
02KL-4e,f
02KL-5a
02KL-5b
60
c
50
*
r
40
(a)
Grs
Body 1 & 3-5
Body 2 (99KL-4)
20
Al
30
40
50
60
10
20
46
r
45
* ***c
40
10
Coronal
Eclogie
(Grt1)
(b)
80
70
60
90
Qt
48
30
47
40
50
60
Prp
Fig. 7. Plots of garnet composition from five eclogite bodies in Alm–Grs–Prp space: (a) garnet from body 2, (b) garnet from other four
bodies and (c) BEI showing compositional change of the garnet corona from interphase boundaries to inside of zoisite. c, core; r, rim.
The composition ranges of garnet from body 2 are also shown in (b).
grossular and pyrope from core (alm53–55prp19–20grs23–
26sps1–2) to rim (alm47–48prp20–25grs28–31sps1) in sample
99KL-4k (Fig. 7a). In type 3 grossular increases and
pyrope decreases from core to rim with constant
almandine (sample 02KL-5b, Fig. 7b). Furthermore,
fine-grained garnet coronas replace zoisite from the
margins to interior of zoisite with increasing grossular
and decreasing pyrope and almandine (Fig. 7b,c).
Si pfu (3.59) in phengite was found in a coronal
eclogite (02KL-2) from body 3.
Zoisite and amphibole
The coarse-grained zoisite of the pre-eclogite stage has
variable Fe2O3 content ranging from 0.58 to 1.96 wt%
in coronal eclogite, but varies from body to body. The
zoisite from body 2 contains higher Fe2O3 (1.10–
1.96 wt%) than those from other bodies (0.58–
0.78 wt%). The possible eclogitic clinozoisite (stage
III) contains high Fe2O3 of 4.49 wt%.
Pre-eclogite stage amphibole includes inclusions in
garnet and coarse-grained, relict amphibole in the
matrix. Amphibole inclusions are barroisite (Brs) or
taramite with 3.76–4.06 wt% Na2O and 0.09–
0.30 wt% K2O. The relict amphibole varies from calcic
magnesiohornblende (Mg–Hbl) in sample 99KL-4e to
sodic–calcic Brs in sample 99KL-4f, 02KL-2, 02KL-4e
and 02KL-5b. The Mg–Hbl contains 2.09–2.49 wt%
Na2O and 0.52–0.73 K2O wt%, and has low NaA of
0.21–0.29. Actinolite is present at the margins of Mg–
Hbl grains. Both Mg–Hbl and actinolite have high Mg
number [Mg ⁄ (Mg + Fe2+) = 0.83–0.89]. Brs contains 2.92–3.39 wt% Na2O and 0.5 wt% K2O, and
NaB > 0.5. The Mg number of Brs ranges from 0.81
to 0.88. All retrograde amphibole of stage IV in
eclogite is calcic–sodic, including the varieties of
magnesiokatophorite, Mg–taramite and Brs and contains 2.70–3.81 wt% Na2O (most >3 wt%). It is distinguished from the pre-eclogite facies amphibole by its
low Mg ⁄ (Mg + Fe) ratio (0.53–0.77).
Omphacite
As with garnet, omphacite is present in stages II
(Omp1) and III (Omp2), and in both types of eclogite it
exhibits variable composition. In normal eclogite from
type A body (No. 1), jadeite content of omphacite
(Omp2) ranges from 38 to 45 mol.% (jd38–45aug52–
59aeg0–8). However, omphacite from a single sample
has a little variation in jadeite content (41–45, 44 & 38–
41 mol.%, respectively, for samples 99KL3-2c, 99KL32d & 99KL 3-2g). Omphacite inclusions in garnet have
a similar range in jadeite (jd36–46) component as in the
matrix omphacite. Retrograded clinopyroxene contains lower jadeite (jd24–34) than that of the primary
omphacite. In type B eclogite bodies, omphacite
(Omp2) is jd33–40aug53–64aeg2–8 for normal eclogite,
and jadeite of 36–37 for sample 99KL-4c, 39–40 for
99KL-4h, 37 for 02KL-4f and 38 for 02KL-5a.
Omphacite (Omp1) of coronal eclogite shows a large
variation in composition (jd27–44aug56–73), and has no
aegirine component with a few exceptions (Fig. 8).
Some omphacite grains in coronal eclogite preserve
weak zonation (e.g., 99KL-4k); rims contain higher Fe
and Ca and lower Na and Mg than cores. Jadeite decreases from core (35 mol.%) to rim (29 mol.%)
suggesting retrogression (Fig. 8). Symplectitic clinopyroxene has the lowest jd (jd04) in sample 99KL-4f.
P–T CONDITIONS
The observed mineral parageneses define four-stage
metamorphic events: (I) pre-eclogite stage (an amphibolite facies metamorphism), (II) transition from
amphibolite to eclogite, (III) a peak eclogite stage representative of the prograde transformation from coronal
to UHP eclogite and (IV) retrograde metamorphism.
The four-stage metamorphic evolution was not recognized by previous studies (e.g., Ota et al., 2000).
Phengite
Phengite occurs only in a small number of normal and
coronal eclogites as a minor phase (such as 99KL3-2c,
99KL-4e & 02KL-2). The Si value ranges from 3.38 to
3.59 pfu and varies from sample to sample; the highest
Omphacite in
80
Wo, En, Fs
80
Omp 50
20
Jd
Jd
ret
Aeg-Aug
Aeg
*
Aeg
ret
i
Fig. 8. Omphacite plot in (Ca–Mg–Fe)–Na–
Fe3+ diagram; the compositional zoning of
omphacite from 99KL-4k coronal eclogite is
also shown. Ret: retrograde.
*
**
Normal ecl (Omp2) Coronal ecl. (Omp1)
99KL-4e,f,k
99KL3-2c
02KL-2
99KL3-2d
02KL-4b
99KL3-2g
02KL-4e,f
99KL-4c,h
02KL-5b
02KL-5a
70
Omp
Aug
60
40
30
20
50
99KL-4k
Jd
Core
0.115 mm Rim
P–T conditions were estimated using both thermobarometry (Table 6) and isochemical phase diagrams (pseudosections). The P–T pseudosections were
calculated using Perple_X (Connolly, 2005; update in
April 2010) and the internally consistent thermodynamic data set (Holland & Powell, 1998; and their updates). The Kulet eclogites contain minor TiO2 (most
<1 wt%) and rutile is a minor phase in the mineral
assemblage. For simplicity, the model system Na2O–
CaO–K2O–FeO–MgO–Al2O3–SiO2–H2O was assumed, and the following solution models are used:
phengite, garnet, olivine and orthopyroxene after Holland & Powell (1998), omphacite after Green et al.
(2007), amphibole after Dale et al. (2000), chlorite after
Holland et al. (1998), biotite after Tajcmanová et al.
(2009), plagioclase after Newton et al. (1980), sanidine
after Thompson & Hovis (1979). Talc is assumed to be
an ideal solution, and zoisite, lawsonite and stilpnomelane have end-member compositions. Three representative samples with different bulk compositions
from body 4 were selected for P–T pseudosection calculation. The results are shown in Figs 9 & 10.
and andesitic compositions at varying fO2 and fH2O
indicate garnet and amphibole may coexist over a
pressure range of 15–25 kbar (Graham & Powell,
1984). The amphibole at the contact with the adjacent
garnet corona may be considered to be in local (or
domain) equilibrium; using the Grt–Hbl thermometer
of Graham & Powell (1984) for representative compositions of garnet and amphibole pairs gives 520 C
for sample 99KL-4e, 530 C for 99KL-4f, 620–645 C
for 99KL-4k (body 2), 500 C for 02KL-2 (body 3),
475 C for 02KL-4b (body 4) and 630 C for 02KL-5b
(body 5) with 50 C uncertainty [when KD = (Fe2+ ⁄
Mg)Grt ⁄ (Fe2+ ⁄ Mg)Hbl].
The pseudosections (Fig. 9) indicate that garnet
appears in the Ph + Amp + Zo + Qz assemblage at
the conditions of 550 C at 18 kbar to 600 C at 7 kbar
for 02KL-4b, and of 535 C at 16 kbar to 610 C
at 9 kbar for 02KL-4f. This paragenesis of Ph +
Amp + Grt + Zo + Qz has a large stability field
(Fig. 9a,c). For a high-FeO and low-SiO2 sample
(02KL-4e), Ph + Amp2 + Grt + Zo paragenesis is
stable in a limited field of 14.5–11.5 kbar and 550–
650 C. The appearance of omphacite in the assemblage Ph + Amp + Grt + Zo + Qz occurs between
620 C, 25 kbar to 700 C, 18 kbar for 02KL-4b, and
605 C, 23.5 kbar to 700 C, 17 kbar for 02KL-4f
(Fig. 9c). The P–T boundary between the assemblages
of Ph + Amp + Grt + Zo + Qz and Omp + Ph +
Amp + Grt + Zo + Qz has a negative slope. For
sample 02KL-4e, omphacite appears in the assemblage
Ph + Amp + Grt + Qz to the high temperature side
between 620 C, 27.5 kbar and 700 C, 19 kbar
(Fig. 9b). However, omphacite initially appears in the
assemblage of Bt + Omp + Amp + Grt at 19–
24.5 kbar and 550–500 C.
Stage I
Stage III
The first stage of amphibolite facies metamorphism
preserved mineral assemblage of Brs (or Mg–Hbl) +
Zo ± Qz. The presence of plagioclase inclusions in
garnet and prismatic omphacite patches surrounded by
garnet coronas (Fig. 4d) suggests that the amphibolite
initially contained plagioclase. The P–T conditions
cannot be well constrained by thermobarometry, but
from the pseudosection (Fig. 9a), the assemblage of
Chl + Amp2 (two amphiboles with different composition are present as immiscibility) + Ph + Zo + Qz
formed at <500 C and <12 kbar. The chlorite of this
stage may have been consumed during the growth of
garnet.
In this stage, all eclogitic minerals are well recrystallized
at eclogite facies conditions. The Fe2+–Mg exchange
thermometer (Powell, 1985; Krogh Ravna, 2000) and
Grt–Omp–Ph barometer (Krogh Ravna & Terry, 2004)
were employed to estimate P–T conditions. For the Grt–
Cpx thermometer, the Fe3+ in Omp = Na–Al–Cr. For
the application of the Grt–Omp–Ph barometer, the
ferric iron for clinopyroxene was calculated assuming
four cations and six oxygen
P atoms. The phengite formula was normalized to SiAlTiCrFeMnMg
= 12.00.
P
Garnet was normalized to
CaMnFeTotalMgAlTiCr = 5.00, where Ca + Mn + Fe + Mg = 3 and
Al + Ti + Cr + Fe3+ = 2.00. Here Fe3+ = 3.00–
(Al + Ti + Cr) and Fe2+ = Fetotal–Fe3+ (Krogh
Ravna & Terry, 2004).
In order to avoid large uncertainty, the relatively
homogeneous mineral compositions of normal
eclogites and eclogitic domains for coronal eclogites
were selected to estimate P–T conditions (Table 6).
First, the geothermobarometer for Grt–Cpx–Ph–
Coe ⁄ Qz parageneses was applied to the phengite-
Table 6. P–T estimates of the Kulet eclogites.
Body no.
1
1
1
1
2
3
4
5
a
Sample
T (C)
T (C)
99KL3-2c-c
99KL3-2c-r
99KL3-2g-c
99KL3-2g-m
99KL-4e
02KL-2
02KL-4f
02KL-5a
695
710
680
720
620
600
690
660–700b
740
780
700
750
710
785
640
680–710
P (kbar)
29.0
29.0
30.0
28.0
27.7
33.0
28.0
30.0c
Temperature calculated by Grt–Cpx thermometer (aPowell, 1985; bKrogh Ravna, 2000).
Pressure calculated from Krogh Ravna & Terry (2004); c, pressure assumed as 30 kbar.
Fe3+ = Na–Al–Cr for Cpx; Fetotal = Fe2+ for Grt.
Stage II
In the second stage, amphibolite transformed to
coronal eclogite by the growth of neoblastic garnet in
coronas along interface boundaries between amphibole
and other phases as well as the formation of eclogitic
domains. High P–T experimental studies for basaltic
(a)
(b)
Fig. 9. P–T pseudosections for eclogites
from body 4 calculated in NKCFNASH
system at aH2O = 1 using bulk composition
of eclogite (see Table 1) and a software
Perple-X by Connolly (2005, updated in
April 2010). FeOtotal is expressed as FeO. (a)
Coronal eclogite (02KL-4b): 1 Bt Chl Amp
Grt Law, 2 Bt Ph Amp Grt Law, 3 Bt Omp
Chl Ph Amp Grt, Law 4 Bt Chl ph Amp Grt
Law, 5 Ph Amp Grt law Qz, 6 Ph Amp Grt
Zo Law Qz. (b) transitional coronal eclogite
(02KL-4e): 1 Omp2 Chl Ph Amp Grt Law, 2
Bt Omp2 Amp Grt Law, 3 Bt Omp Amp Grt
Law, 4 Omp2 Chl Ph Amp Grt Law, 5 Bt
Omp Chl Ph Amp Grt Law, 6 Omp2 Chl Ph
Amp Gt law, 7 Chl Ph Amp Gt law, 8 Chl
Ph Amp Grt, 9 Omp Chl Ph Amp Grt Zo
Law, 10 Omp Chl Ph Amp2 Grt Zo, 11 Chl
Ph Amp Grt Zo Law, 12 Bt Chl Ph Amp
Grt, 13 Bt Chl Ph Amp2 Grt, 14 Chl Ph
Amp2 Grt, 15 Bt Ph Amp2 Grt, 16 Chl Ph
Amp2 Grt Zo Qz, 17 Ph Amp Grt Zo Qz, 18
Bt Chl Amp Pl Opx Qz. (c) normal eclogite
(02KL-4f): 1 Bt Chl Ph Amp Grt Zo Qz, 2 Bt
Chl Amp Grt Zo Qz, 3 Bt Chl Amp Grt Zo
Qz, 4 Ph Amp Law Coe Stp and 5 Ph Tlc
Amp Law Coe Stp. Amp2 and Omp 2: there
are two amphiboles or two clinopyroxenes of
different composition in the assemblage due
to immiscibility of solid solution. H2O is in
all assemblages in the pseudosections.
Mineral abbreviations are after Whitney &
Evans (2010). Star refers to the position at
700 C and 28 kbar.
(c)
36
Xprp 0.2
0.3
(a)
0.1
30
02KL-4b
0.35
0.3
24
0.4
18
0.3
0.5
P(bar)
Pressure (kbar)
0.35
0.35
0.3
12
0.2
Xprp
Xgrs
6
0
400
500
600
700
800
T (°C)
36
0.2
0.1
(b)
02KL-4e
0.15
0.2
Pressure (kbar)
30
24
0.3
0.4
18
0.5
0.6
12
0.35
0.3
Xprp
Xgrs
6
0
400
0.2
500
600
700
800
T (°C)
36
(c)
0.2
02KL-4f
0.2
0.3
30
0.4
Pressure (kbar)
0.3
0.4
24
0.45
18
12
6
0
400
Xprp
Xgrs
500
600
700
800
T (°C)
Fig. 10. Isopleths of Xprp and Xgrs for coronal eclogite (02KL4b) (a), transitional coronal eclogite (02KL-4e) (b) and normal
eclogite (02KL-4f) (c). Oblique rectangle, intercept P–T condition of Xprp and Xgrs isopleths.
bearing eclogite, which yielded conditions of
27–33 kbar and 610–720 C for normal and coronal
eclogites. The uncertainty of the thermometer and
barometer are ±3 kbar and ±65 C, respectively
(Krogh Ravna & Terry, 2004). Pressure calculation is
difficult for phengite-free eclogite. In the case of
the phengite-free eclogite in coherent contact with
phengite-bearing eclogite, it is assumed that both were
formed at similar pressure as they have a similar
metamorphic history. For phengite-free eclogite from
body 5, a temperature range of 660 to 710 ± 65 C
was obtained at an average pressure of 30 kbar using
the Fe2+–Mg exchange thermometer of Grt–Cpx
(Krogh Ravna, 2000). For the phengite-bearing
eclogite at the estimated pressure, the Grt–Cpx
thermometer of Powell (1985) yielded a slightly high
temperature range of 640–785 C (Table 6), which is
similar to the temperature estimate for Kulet coesitebearing eclogite by Ota et al. (2000).
The amphibole-out line within the quartz stability
field occurs at lower P–T conditions of 675 C at
27.7 kbar to 750 C at 21.5 kbar than the zoisite-out line
(680 C at 28.5 kbar to 750 C at 26 kbar) for sample
02KL-4b (Fig. 9a). For sample 02KL-4f, the amphibole-out line is defined by higher P–T conditions (695 C
at 28.3 kbar to 750 C at 24 kbar) than the zoisite-out
line (675 C at 27.7 kbar to 750 C at 23 kbar). In contrast, zoisite-out occurs at much lower pressure
(<17 kbar), whereas amphibole disappears at higher
temperature (756 C at 28.5 kbar to 800 at 25 kbar) for
02KL-4e in comparison with other two samples.
In sample 02KL-4e, omphacite occurs as patches
consisting of numerous very fine-grained laths, suggesting that these tiny omphacite laths have not recrystallized to a coarser single crystal. So the isopleths
of Xgrs and Xrp in garnet were used to estimate the
peak P–T conditions. For sample 02KL-4e, the isopleths of Xgrs (19–20 mol.%) and Xprp (20–21 mol.%)
yield 26–27 kbar and 710–720 C. For sample 4f, the
Xgrs and Xprp are 0.18 and 0.23 mol.%, respectively
(in Table 4, only average or representative values are
shown). For sample 02KL-4b, both Xgrs and Xprp are
0.27 mol.%. The isopleths yield peak P–T conditions
of 35 kbar, 560 C for sample 02KL-4f and 35 kbar
610 C for sample 02KL-4b (Fig. 10a,b). The P–T
conditions for the final two samples imply that a
probable UHP assemblage Omp + Ph + Amp +
Grt + Law + Coe was present. However, lawsonite
and coesite were not found in the eclogites. This
inconsistency may result from some uncertainties of
the P–T pseudosection calculation; for example, all
iron is assumed as FeO that converted from Fe2O3 in
Table 1, the composition of garnet may vary in different textural domains and the fluid was saturated. In
addition, retrograde metamorphism may have modified the mineral assemblage; when pressure decreases
with increasing temperature, lawsonite broke down
and coesite was converted to quartz.
Stage IV
This stage is characterized by the replacement of eclogite
minerals by retrograde phases that only developed in
some eclogites. Garnet is surrounded by amphibole, and
phengite decreases in Si pfu or is replaced by biotite (e.g.,
in sample 99KL-3-2d) and in turn by chlorite. Omphacite is locally rimmed by symplectite of Amp ± Cpx ± Ab. This indicates a retrograde metamorphism of
amphibolite to greenschist facies. The P–T conditions
are roughly estimated as <6 kbar and <500 C based
on the presence of a retrograde assemblage of
Amp + Pl + Qz + Bt + Chl (see Fig. 9).
compositional difference may be attributed to magmatic
or metamorphic differentiation rather than different
tectonic setting in which they formed. Overall, the protoliths of the Kulet eclogites are interpreted to have
formed in a continental marginal basin setting similar to
eclogites from the Kumd-Kol and Barch-Kol areas, and
Sulu-Tjube and Saldat-Kol areas, in spite of some of
these eclogites having higher FeO ⁄ MgO ratios and
lower Al2O3 content (Fig. 11b,d).
DISCUSSION
Processes involved in the formation of coronal and UHP
eclogites
Tectonic setting of protolith
All eclogites have similar basaltic composition and,
with one exception, fall in the tholeiite field of the SiO2
v. Zr ⁄ TiO2 diagram (Winchester & Floyd, 1977). The
REE patterns of the Kulet eclogites are similar to arc
tholeiite or E-MORB, but different from N-MORB
that is characterized by slight depletion in LREE relative to MREE and HREE. The trace element pattern
of sample 02KL-3 is almost the same as arc basalt. For
other samples the enrichment in Th and U and
depletion in Nb and Ta, are similar to arc basalt, but
negative Ba and Sr anomalies are not consistent with
arc basalt.
Previous studies on high-P mafic rocks from New
Caledonia and other HP ⁄ UHP terranes (such as
Western Alps and Sulu terranes) indicated that there
are no significant changes in HFSE and REE abundances during subduction-zone metamorphism (Becker
et al., 2000; Chalot-Prat et al., 2003; Spandler et al.,
2004; Liu et al., 2008). In this scenario, several discrimination diagrams are used to decipher the initial
tectonic setting of basaltic protolith (Fig. 11). For
comparison, previously reported data of eclogites from
the Kulet and Kumdy Kol domains (Yamamoto et al.,
2000b; Yui et al., 2010) are included. In the 2Nb–
Zr ⁄ 4–Y (Meschede, 1986) and FeO ⁄ MgO–TiO2
(Glassily, 1974) diagrams (Fig. 11a,b), most Kulet
eclogites plot in MORB and IAB fields. There are only
two normal eclogite samples with >2.5 wt% TiO2 that
plot in the OIB field in addition to one sample from
Yui et al. (2010). The Kulet eclogites have low Nb and
Ta, similar to IAB, but they have much lower Ba and
Sr than those of arc tholeiite. These features may
indicate that the protolith of the Kulet eclogite is neither typical MORB nor typical IAB. In the Th ⁄ Yb–
Nb ⁄ Yb diagram (Fig. 11c), samples show variable
displacement from the MORB–OIB array, but lie away
from the volcanic arc array indicative of crustal input
or crustal interaction with oceanic basalts. These features are typical for volcanic rocks formed at a continental margin or intra-oceanic arc setting (Pearce,
2008). Furthermore, in Al2O3 v. TiO2 diagram, all low
Ti basaltic rocks are in, or close to the field of back arc
basin basalt (Fig. 11d). Minor high Ti basaltic rocks
have affinities to either OIB or Fe–Ti basalt. Both highTi and low-Ti eclogites occur in an individual body. The
As described above, coronal eclogite is a major rock
type in most eclogitic bodies and is characterized by
the growth of garnet corona and fine-grained omphacite laths, and the formation of eclogitic domains
with the assemblage of Grt + Omp + Rt +
Qz ± Ph. It records two processes. (i) Corona1 garnet crystals initially grew along the interphase
boundaries between amphibole and adjacent phases,
such as zoisite and plagioclase. In addition, neoblastic
garnet and omphacite also formed within zoisite and
amphibole crystals (Fig. 4b,c). (ii) With increasing
pressure, the amphibole, zoisite and other amphibolite facies phases were completely replaced by eclogitic
minerals to form amphibole-free eclogite domains.
However, the garnet corona texture is still preserved
and omphacite occurs as aggregates or patches consisting of many fine-grained omphacite laths rather
than discrete coarser crystal (Fig. 4d). The possible
reactions for such transformation from amphibolite
to eclogite are:
Na2 ½AlSi3 O8 2 ¼ 2SiO2 þ 2NaAl[Si2 O6 Qz
Ab in P1
ð1Þ
Jd in Omp
Ca2 Al2:7 M0:3 ðSiO4 Þ½Si2 O7 ðOHÞ2
Zo
þNa0:5 ðCa1:5 Na0:5 Þ2 ðM4:6 Al0:4 Þ5 ½Si3:5 Al0:5 O11 2 ðOHÞ2
Amp
þ0:4SiO2 ¼ðCa0:6 M2:4 Þ3 Al2 ½SiO4 3 þNaAl½Si2 O6 Qz
Grt
þ2:5CaM½Si2 O6 þ0:4CaAl½AlSiO6 þ2H2 O
Omp
þ0:1Al2 O3
ð2Þ
where M = Mg, Fe.
The most important reaction is the dehydration
reaction (2) leading to the disappearance of hydrous
phases to form normal eclogites. The coronal garnet in
transitional rocks shows three zoning types depending
on many factors, such as the position of nucleation,
chemical gradient of intergrains, intergranular and
volume diffusion, etc. For example, neoblastic garnet
within zoisite has higher grs and lower prp components than that at interphase boundaries (see Fig. 7b),
as the zoisite provided sufficient Ca and Al for its
formation. According to the pseudosections of Fig. 9,
2Nb
4
This study
Body 3
body 4
Body 5
A
3
B
C
OIB
2
0
E
0
Y
1
2
3
4
5
TiO2
y
10
IAB
1
D
Zr/4
(b)
MO
RB
(a)
FeO/MgO
A: WPA
B: WPAB + WPT
C: E-MORB
D: WPT + VAB
E: VAB +
N-MORB
ar
ra
(c)
22 (d)
ra
ar
-O
18
M
O
Al2 O3
RB
Magmacrust
interaction
Th/Yb
Kumdy-Kol
Barch-Kol
Kulet
Saldat-Kol
Sulu-Tjube
Previous
studies
20
IB
lca
Vo
1
y
c
ar
ni
c
OIB
E-MORB
0.1
BABB MORB
16
OIB
14
N-MORB
12
Ti-Fe basalt
0.01
0.1
10
1
10
100
Nb/Yb
0
1
2
3
4
5
TiO2
Fig. 11. Four discrimination diagrams for the Kulet eclogites: (a) 2Nb-Zr ⁄ 4-Y (Meschede, 1986), (b) FeO ⁄ MgO v. TiO2 (Glassily,
1974), (c) Th ⁄ Yb v. Nb ⁄ Yb (Pearce, 2008) and (d) Al2O3 v. TiO2 (modified after Spandler et al., 2004). BABB, back arc basin basalt;
IAB, island arc basalt; MORB, mid-ocean ridge basalt; E-MORB, enriched MORB; N-MORB, normal MORB; OIB, oceanic island
basalt; VAB, volcanic arc basalt; WPAB, within plate alkaline basalt; WPT, within plate tholeiite. The data from previous studies
expressed by open diamond and circle after Yui et al. (2010), and others after Yamamoto et al. (2000b).
although garnet and omphacite appear at this stage,
amphibole and zoisite have not yet completely disappeared.
With the advance of eclogitization, the coalescence
and coarsening processes of garnet and omphacite
occurred. The garnet aggregates changed from coronas
through strongly poikiloblastic to recrystallized
polygonal grains; concomitantly, the grain size increases. Such mineralogical and textural transformations are also well documented in the Yangkou coesitebearing eclogite block in eastern China by Zhang &
Liou (1997). During the coalescence and coarsening
processes of garnet, many tiny inclusions of quartz,
omphacite, rutile with minor taramite and plagioclase
were trapped (Fig. 3a,b; Table 2). Meanwhile, omphacite lath aggregates were recrystallized into coarser
single crystals in spite of a few omphacite aggregates
still persisting in some eclogites. These processes led to
the formation of fully recrystallized normal eclogite.
Although no coesite inclusions were found in either
eclogitic garnet or omphacite coesite inclusions in
garnet occur in some country rocks (such as coesitebearing metapelite with Grt + Ph + Ky + Coe ⁄ Qz
assemblage) of the Kulet eclogite (Shatsky et al., 1998;
Masago et al., 2009) and in closely associated whiteschist (Parkinson, 2000). Our peak P–T estimates of
27–33 ± 3 kbar and 610–720 ± 65 C for the Kulet
eclogite are compatible with the maximum P–T estimate (33 kbar and 750 C) for the nearby country
rocks (Masago et al., 2009) and most estimates for the
Kulet eclogites by Ota et al. (2000). All the lines of
evidence indicate that the Kulet eclogite was subjected
to in situ UHP metamorphism, and the Kulet area is a
part of the Kokchetav UHP metamorphic belt.
60
Coexistence of coronal and normal eclogites
Kulet
Ko
l
Ku
m
dy
w
Metapelite (Masago et al., 2009)
Eclogite (this study)
Eclogite (Ota et al., 2000)
White schist (Zhang et al.,
1997; Parkinson, 2000)
160
km
-1
50
o
C
Kumdy-Kol
5
Dia-bearing rock
(Shatsky et al., 1985;
Zhang et al., 1997)
Dia
Gr
UHP
w
EC
III
sLw
III
30
120
Dry-EC
Coe
Qz
Ep-EC
80
AM-EC
II
20
Depth (km)
40
Pressure(kbar)
The coexistence of coronal and normal eclogites in a
single body in the Kulet UHP unit is a remarkable feature. The pseudosections (Fig. 9) show that the P–T
conditions of zoisite- and amphibole-out vary with different bulk composition. For instance, at 28 kbar, the
transitional coronal eclogite 02KL-4e [with higher FeO
(+TiO2) and lower MgO and SiO2 compared with samples 2KL-4b & 4f], the temperature of amphibole-out
from the assemblage Omp + Ph + Amp + Grt + Qz
is 760 C and zoisite-out is at much lower P–T (Fig. 9b).
The normal eclogite (02KL-4f) has the highest SiO2
(52.27 wt%) and the lowest FeOtotel (8.77 wt%) for
which this amphibole-out is 700 C at 28 kbar. For the
coronal eclogite (02KL-4b) containing high CaO
(12.44 wt%) and Zo (>15 vol%), zoisite-out is at higher
pressure than amphibole-out (Fig. 9a). Two observed
assemblages Omp + Ph + Amp + Grt + Qz for
coronal eclogite 4e and Omp + Ph + Grt + Coe ⁄ Qz
for normal eclogite 02KL-4f coexist at 700 C and
28 kbar in the pseudosections of the two samples. For
sample 02KL-4b, the observed mineral assemblage
of Omp + Ph + Grt + Zo + Amp + Qz is slightly
different from the calculated assemblage (Omp + Ph +
Grt + Zo + Qz) at 700 C and 28 kbar in the pseudosections; however, the observed assemblage would occur
at 25 C lower temperatures. These indicate that the
coexistence of coronal and normal eclogites in a single
body in the Kulet UHP unit is chiefly controlled by bulk
composition of eclogite.
BS
Ep-EC
40
EA
10
I
GS
200
400
AM
IV
600
GR
800
1000
T (°C)
Tectonic implications
Fig. 12. P–T path of the Kulet eclogite. P–T boundaries of
various metamorphic facies are indicated: GR, granulite, AM,
amphibolite, EA, epidote amphibolite, BS, blueschist schist, GS,
greenschist. The subdivisions of eclogite (EC) of amphibole
eclogite (Amp-EC), epidote eclogite (Ep-EC), lawsonite eclogite
(Lws-EC) and dry eclogite are also indicated. The P–T data and
retrograde path of Kumdy-Kol UHP rocks are from Shatsky
et al. (1995) and Zhang et al. (1997). The peak P–T conditions of
the Kulet whiteschist are after Zhang et al. (1997) and Parkinson
(2000).
As discussed above, the Kulet protoliths and most
other HP–UHP rocks in the western diamond-bearing
domain initially formed in a passive continent marginal basin. Moreover, eclogites of basaltic composition are widespread in the Kokchetav massif, especially
in unit II, suggesting that significant volcanic (or plutonic) activity took place during the late Proterozoic,
and the transitional crust displays features suggesting a
volcanic rifted margin.
The fault-bounded western and eastern domains
exhibit different peak metamorphic P–T conditions
(Fig. 12). Diamond-bearing metasedimentary rocks
and eclogites in the western domain recrystallized at
40–60 kbar 800–1000 C (Shatsky et al., 1995; Zhang
et al., 1997; Maruyama & Parkinson, 2000) and
underwent partial melting during the initial stages of
exhumation (Hermann et al., 2001; Korsakov & Hermann, 2006; Ragozin et al., 2009). In contrast, eclogites, whiteschists and garnet-bearing mica schists in the
eastern domain were metamorphosed at 27–36 kbar,
and 680–780 C (Zhang et al., 1997; Ota et al., 2000;
Masago et al., 2009; this study). Thus, there is 120–
220 C difference between the two domains. The
geological relationships are not well known between
various units because of geographic inaccessibility and
poor outcrops. According to Dobretsov et al. (1995),
the Kokchetav massif is a mega-mélange composed of
various slices and blocks formed under different P–T
conditions. Theunissen et al. (2000a,b) followed the
mega-mélange concept and distinguished the KumdyKol diamond-bearing western domain from the Kulet
coesite-bearing eastern domain separated by a NEtrending Chaglinka fault zone. The western domain
exhibits a sheath-like fold structure, and was subjected
to early melting, whereas the eastern domain has a
sheet-like geometry. These domains were subjected to
different structural and exhumation histories (Theunissen et al., 2000b). On the other hand, Maruyama &
Parkinson (2000) and Kaneko et al. (2000) postulated
a single wedge extrusion model to explain exhumation
of the UHP–HP units. Combining the Kumdy-Kol and
Kulet terranes into a single UHP unit, they proposed
that the primary structure of the Kokchetav massif
involves subhorizontal, sandwich-like sheets. The
UHP–HP units are separated from the low-P Daulet
unit at the bottom by a reverse fault and from weakly
and unmetamorphosed sedimentary strata on the top
by subhorizontal normal faults. The HP–UHP belt
represents a thrust sheet exhumed from upper mantle
(1) Continental rifting
NE
Siberian
platform (SP)
Ocean
Kazakhstanian
continent (KC)
SW
KC
SW
(2) Passive margin formation
NE
Ocean
SP
(3) Continental subduction
KC
SP
Continental lithosphere
Upper mantle
100 km
Sediments
Oceanic crust
ab
(4) Deep subduction
and slab breakoff
Based on our own and previously published geological,
geochronological and geochemical data, we propose a
tentative tectonic model to explain the formation and
exhumation of the Kulet UHP metamorphic rocks as
illustrated in Fig. 13. In the Late Proterozoic, a small
ocean lay between the Siberian platform and the
Kazakhstanian continent – possibly created by continental rifting (Fig. 13-1). A thick terrigenous
sedimentary wedge formed along the SW continental
slope and margin of the ocean (Massakovsky &
Dergunov, 1985). Concurrently, significant volcanic
(or plutonic) activity produced considerable amounts
of mafic igneous rocks associated with the passive
continent marginal sediments (Fig. 13-2). The marginal sediments + mafic and supracrustal rocks of the
Kazakhstanian continent (or the Kokchetav microcontinent) were subducted to mantle depths along with
a downgoing oceanic lithosphere. During the prolonged subduction of continental lithosphere, two or
more slabs may have formed and subducted to different depths (Fig. 13-3), where they were subjected to
UHP metamorphism at 537–527 Ma (Claoue-Long
et al., 1991; Hermann et al., 2001; Katayama et al.,
2001). At least two UHP slabs (diamond- and coesitegrade) and one HP unit were subsequently exhumed,
most probably due to buoyancy (e.g., Ernst, 2006)
immediately after a hypothesized breakoff of the
down-going oceanic lithosphere (Fig. 13-4). Finally,
discrete HP–UHP slabs were retrograded under different P–T conditions at mid-crust levels in Late
Cambrian time (Fig. 13-5).
Attending early exhumation of the diamond-grade
western domain, partial melting of some of the metasedimentary rocks at mantle depths took place at or
later than 526 Ma (Ragozin et al., 2009). Exhumation
of the subducted slabs occurred during 526–507 Ma, as
H
U
Mantle wedge
A new tectonic model
P
sl
depths to shallower crustal levels by subhorizontal
tectonic extrusion towards the north and emplaced
onto the low-P Daulet unit.
Based on the peak pressure estimate, the Kulet domain was only subducted to mantle depths of
100 km, much shallower than that (180 km) of the
Kumdy-Kol domain. These characteristics suggest the
high-T diamond-bearing Kumdy-Kol domain (unit I)
and the coesite-bearing Kulet domain (unit II) may
represent two discrete UHP slices separated by faults.
Relatively shallow subduction and rapid exhumation
may explain the low-T metamorphism of the Kulet
unit. However, geochronological data are necessary to
constrain the timing of subduction and exhumation of
the Kulet unit. Such multiple UHP slices with different
P–T estimates within a single UHP belt or stack of
nappes during exhumation of UHP continental crust
have been documented in the Dabie-Sulu UHP terrane
(Liu et al., 2009; Zheng et al., 2009) and in the DoraMaira massif (Michard et al., 1993).
Continental lithosphere
100 km
200 km
Slab
breakoff
Dyke/intrusives
Volcanics
Passive margin
Eclogite
Dia-bearing rock
(5) Exhumation
Fig. 13. Schematic diagram showing a preliminary tectonic
model for the evolution of the Kokchetav HP-UHP massif. (1)–
(2), Continent rifting created a small oceanic basin and a passive
margin (between oceanic and continental crust) in the Late
Proterozoic. (3)–(4) Continental lithosphere and its overlying
passive marginal sediments and mafic rocks were subducted to
mantle depths of 180–200 km and subjected to UHP metamorphism at 530 Ma. (5) Exhumation of UHP slabs following
the breakoff of oceanic lithosphere took place at 526–507 Ma
(Herman et al., 2001; Katayama et al., 2001; Ragozin et al.,
2009); the HP-UHP slices were extruded to and recrystallized at
crustal depths during exhumation.
indicated by cooling ages of biotite and white mica
(Shatsky et al., 1999; Theunissen et al., 2000a) and U–
Pb ages of retrograde domain of zircon from diamondbearing rocks (Hermann et al., 2001); a much younger
age of 507 Ma for the latest amphibolite facies overprinting was also recorded in retrograde domains of
zircon from Kumdy-Kol diamond-bearing rocks
(Katayama et al., 2001). Doming, extension and erosion might have played an important role in the final
stage of exhumation and amphibolite- to greenschist
facies recrystallization (Maruyama & Parkinson, 2000;
Dobretsov & Shatsky, 2004; Ernst, 2006). The tectonic
juxtaposition of the western diamond-bearing, eastern
coesite-bearing UHP and adjacent HP slices occurred
during this exhumation.
As most geochronological data for UHP and retrograde metamorphism mentioned above are for western, diamond-grade UHP rocks, the tectonic model
mentioned above should be considered as a very tentative. Systematic geochronological study of prograde
and retrograde amphiboles as well as U–Pb zircon ages
of Kulet eclogitic rocks described above are essential to
delineate more precisely the timing for subduction and
exhumation of the eastern coesite-grade Kulet domain.
CONCLUSIONS
Detailed petrological and geochemical studies of five
Kulet eclogite bodies give rise to the following conclusions:
1 The Kulet eclogite is rare in recording a continuous
transformation sequence from amphibolite through
transitional rock (coronal eclogite) to fully recrystallized normal eclogite, and the coexistence of
coronal and normal eclogites in a single body. The
P–T pseudosections indicate that the coexistence of
two-type eclogites with different texture and mineral
assemblage is chiefly controlled by bulk composition
when they have had same metamorphic evolution.
2 All eclogites from the Kulet area have similar
basaltic composition (tholeiite). Major and trace
element data of various eclogites suggest that their
protoliths were formed in a passive continent marginal basin.
3 The Kulet eclogite experienced four stages of
metamorphic evolution: (I) pre-eclogite stage (an
amphibolite facies metamorphism), (II) transition
from amphibolite to eclogite, (III) a peak eclogite
stage with prograde transformation from coronal
eclogite to UHP eclogite and (IV) retrograde metamorphism of amphibolite to greenschist facies. P–T
estimates of various stages yielded a clockwise P–T
path and peak P–T conditions of 27–33 ± 3 kbar
and 610–720 ± 65 C and 27–35 kbar 560–720 C
using Omp–Grt–Ph thermobarometer and isopleths
of Xgrs and Xgrs of garnet, respectively.
4 The difference in peak P–T conditions between the
western Kumdy-Kol domain (40–60 kbar, 800–
1000 C) and the eastern Kulet domain (27–36 kbar,
650–780 C) is attributed to different structural
evolution and subduction depths of two thrust UHP
slices. The tectonic juxtaposition of the two UHP
slices and adjacent HP slices took place during
exhumation. The very tentative tectonic model needs
to be significantly improved by the structural and
geochronologic studies in the future.
ACKNOWLEDGEMENTS
This research was supported by NSF EAR-0003355,
EAR-0506901, EAR-0810969 and was partially sup 2012 Blackwell Publishing Ltd
ported by National Science Council of Taiwan. We
sincerely appreciate J. Gillotti and an anonymous reviewer for their helpful comments. We thank H.-P.
Schertl for kindly providing many useful information
and references, and W.G. Ernst for helpful review and
discussion related to tectonic model. Finally, we thank
D. Robinson for his editorial correction and suggestions for revision.
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SUPPORTING INFORMATION
Additional Supporting Information may be found in
the online version of this article:
Table S1. Mineral compositions of eclogites from
body 1.
body 2.
bodies 3 and 5.
Please note: Wiley-Blackwell are not responsible for
the content or functionality of any supporting materials supplied by the authors. Any queries (other than
missing material) should be directed to the corresponding author for the article.
Received 30 March 2011; revision accepted 22 March 2012.

Tale of the Kulet eclogite from the Kokchetav Massive, Kazakhstan

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