Origin of the pleonaste-bearing mafic–ultramafic rocks from the Armutlu peninsula, NW Turkey
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Turkish Journal of Earth Sciences
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Research Article
Turkish J Earth Sci
(2018) 27: 167-190
© TÜBİTAK
doi:10.3906/yer-1711-13
Origin of the pleonaste-bearing mafic–ultramafic rocks from the Armutlu peninsula,
NW Turkey
Mutlu ÖZKAN, Ömer Faruk ÇELİK*
Department of Geological Engineering, Faculty of Engineering, Kocaeli University, İzmit, Kocaeli, Turkey
Received: 14.11.2017
Accepted/Published Online: 20.03.2018
Final Version: 17.05.2018
Abstract: Al-rich spinels were rarely reported compared to Cr-spinels, which were mostly observed in ophiolitic rocks. Pleonaste [(Mg,
Fe2+)Al2O4], which is an Al-rich spinel, was observed in the ophiolitic mafic–ultramafic rocks tectonically located in the Early Cretaceous
accretionary complex, at the eastern part of the Armutlu peninsula, NW Turkey. The ophiolitic mafic–ultramafic rocks have cumulate
character, and most of them are represented by peridotite and pyroxenite. Pleonaste was observed in pyroxenites and gabbros of the
ophiolitic rocks. Pyroxenites consist mainly of clinopyroxene + orthopyroxene + amphibole ± olivine + spinel. Gabbros are composed
of clinopyroxene + orthopyroxene + amphibole + plagioclase + spinel. Pleonaste in these rocks lies parallel to the magmatic layers and
is distinguished by its emerald greenish color under the microscope. Pleonastes have high Al2O3 (59.65–62.24 wt.%) and low Cr2O3
(0.05–1.32 wt.%) contents with Mg# and Fe3+# ranging from 54.23 to 59.77 and 3.83 to 4.28, respectively. Petrographical observations
and the pressure–temperature (P-T) pseudosection modelling suggest that pleonaste in the mafic–ultramafic rocks from the study area
crystallized during magmatic processes. Presence of amphibole and Ca-rich (An % 85–88) plagioclase in these rocks suggests that the
ophiolitic rocks, located in the Early Cretaceous accretionary complex at the eastern part of Armutlu peninsula, formed from an arcrelated hydrous magma source.
Key words: Cumulate, ophiolite, pseudosection models, pyroxenite, spinel
1. Introduction
Spinel-group minerals (general formula: AB2O4) are
important geological tools to understand the petrogenetic
properties and geodynamic environment of the rocks in
which they occur in a wide compositional range (e.g.,
Dick and Bullen, 1984; Arai et al., 2011). Spinel (MgAl2O4)
and hercynite (Fe2+Al2O4) solid-solution series are the
aluminum-rich (Al-rich) two end-members of spinelgroup minerals. They rarely occur as pure end-members
in nature and if the substitution ratio of divalent Mg2+
and Fe2+ in these end-members is from 3 to 1, the mineral
is called pleonaste [(Mg0.25–0.75Fe0.25–075)Al2O4] (Deer et
al., 1992). In the present study Al-rich spinel is used as
a general name for spinel, hercynite, and pleonaste. The
Al-rich spinel solid solution series have been observed
in the amphibolite–granulite facies basic–ultrabasic and
pelitic rocks, the basic–ultrabasic magmatic rocks, and the
mantle xenoliths in volcanic rocks (e.g., Evans and Frost,
1975; Babu et al., 1997; Ho et al., 2000; Bucher and Frey,
2002; Topuz et al., 2004; Amortegui et al., 2011; Daczko
et al., 2012; Rodriguez et al., 2012; Gargiulo et al., 2013).
Diverse origins, such as magmatic, metamorphic, and
*Correspondence:
metasomatic, have been proposed for the Al-rich spinel
occurrences in these rocks (e.g., Evans and Frost, 1975;
Della-Pasqua et al., 1995; Claeson, 1998; Franz and Wirth,
2000; Berger et al., 2010; Daczko et al., 2012; Gargiulo et
al., 2013).
On the other hand, spinel-group minerals in the
ophiolite-related mafic–ultramafic rocks are commonly
represented by chromite, magnesium chromite, and
chrome-spinel (e.g., Dick and Bullen, 1984; Arai, 1994).
These types of spinels have commonly high Cr2O3 (>10
wt.%) and low to moderate Al2O3 (<55 wt.%) contents
with Cr# (100 × Cr/[Cr+Al]) > 10 and were observed in
mantle and cumulate rocks of many well-known ophiolites
(e.g., Kızıldağ, Eldivan, Refahiye, Troodos, and Semail
ophiolites) (e.g., Uysal et al., 2012; Topuz et al., 2013;
Chen et al., 2015; Rollinson and Adetunji, 2015; Çelik et
al., 2018). Consequently, our investigated spinel-group
minerals, which are Al-rich (~60 wt.%) and Cr-poor (<1.3
wt.%), are different from those of ophiolites.
This paper presents petrographical, whole rock (major,
trace, and rare earths elements) and mineral chemical
characteristics of the ophiolitic mafic–ultramafic rocks
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ÖZKAN and ÇELİK / Turkish J Earth Sci
located at the eastern end of the Armutlu peninsula. The
main objective of this paper is to investigate the origin of
the Al-rich spinel formed in mafic–ultramafic rocks of the
ophiolite.
the Intra-Pontide Suture Zone at Armutlu peninsula and
Almacık Mountain (e.g., Robertson and Ustaömer, 2004;
Akbayram et al., 2013) (Figures 1 and 2). Early Cretaceous
metamorphic age was obtained from phyllite of the
accretionary complex via Rb-Sr method (Akbayram et al.,
2013).
The ophiolitic rocks, which are the subject of this study,
are located in the Early Cretaceous accretionary complex and
are tectonically overlain by the oldest rocks of the region at
the east (Figure 2). These oldest rocks were metamorphosed
in amphibolite facies and are mainly represented by
amphibolite, micaschist, and quartzofeldspathic gneiss.
Late Proterozoic and Middle Ordovician U-Pb zircon
2. Geological framework
The investigated area is located at the eastern end of the
Armutlu peninsula in NW Turkey (Figure 1). The Armutlu
peninsula is located in the collisional belt of the İstanbul
and Sakarya zones, which are separated from each other by
the Intra-Pontide Suture Zone (Figure 1; Yılmaz et al., 1995;
Okay and Tüysüz, 1999). Greenschist facies metamorphism
was reported for the ophiolitic accretionary complex of
29o00
30o00
BLACK SEA
31o00
N
İstanbul
Düzce
MARMARA SEA
Sapanca
Lake
Sakarya
Sapanca
in
unta
o
M
cık
a
Alm
ARMUTLU PENINSULA
32 o
30 o
Geyve
Figure 2
İznik Lake
Sa
40 o
ka
ry
aR
Bursa
Aegean
Sea
İSTANBUL ZONE
Permian
OrdovicianCarboniferous
SAKARYA ZONE
Limestone, sandstone
conglomerate
Permo-Triassic
Granitoid
CarboniferousEarly Permian
Sandstone,
limestone, shale
N
0
40 km
Triassic
one
İstanbul stanbul Z
İ
Marmara
Sea
Intra-Pontide Suture
Sakarya Zone
Ankara
ive
r
Pre-Carboniferous
Jurassic and younger
rocks
Metabasite, phyllite,
marble and overlying
olistostromes
Granitoid
Gneiss, marble,
amphibolite
120 km
INTRA-PONTIDE SUTURE ZONE
Jurassic?Lower
Cretaceous
0
Black Sea
40 o
İzmit
Triassic
Latest
ProterozoicOrdovician
Metabasite, serpentinite,
phyllite, slate, metachert,
minor marble
Greywacke, shale matrix
and limestone,metabasalt,
serpentinite, chert blocks
Metasandstone, phyllite,
marble, minor metabasite
Metaultramafic, amphibolite,
gneiss, metagranitoid,
marble, metaquartzite
Figure 1. Geological map of the Armutlu peninsula and surroundings (Akbayram et al., 2013 and references therein). Inset shows the
Intra-Pontide suture zone separating the İstanbul and Sakarya zones.
168
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ÖZKAN and ÇELİK / Turkish J Earth Sci
0269000
N
0275000
15
85
50
M-039
65
55
M-102
65
M-045
İkramiye
Pliocene terrestial sediments
Upper Cretaceous
shallow marine sediments
Pre-Cambrian gneiss,
amphibolite and micaschist
Doğançay
ive
r
77
50
60
Quaternary alluvium
75
40
Nuriosmaniye
Early Cretaceous
Accretionary prism
4500000
M-048-049
55
80
M-043
M-105
M-117
M-101
ar
52
M-003-005
-113
ka
ry
35
M-051-052
M-006
Sa
25
Peridotite, pyroxenite
gabbro
Meta-volcanic rocks
Serpentinite, meta-gabbro,
meta-volcanic, marble,
phyllite, meta-chert,
meta-sandstone
Sample location
0
500
1000 m
Figure 2. Geological map of the study area.
crystallization ages (Okay et al., 2008; Akbayram et al., 2013)
from gneiss and Upper Triassic metamorphism ages (40Ar39
Ar method) from hornblendes of the amphibolites (Çelik et
al., 2009) were obtained from the oldest metamorphic rocks
of the region. All these rocks are unconformably covered by
Upper Cretaceous aged shallow marine and Pliocene aged
terrestrial sediments (Göncüoğlu et al., 1987).
The accretionary complex in the study area consists
mainly of serpentinites, serpentinized peridotites, mafic–
ultramafic cumulates, meta-gabbros, meta-volcanites,
meta-pelites, meta-cherts, and marbles (e.g., Göncüoğlu et
al., 1987). The meta-gabbros and marbles are tectonically
located with different sized blocks in the matrix (serpentinite
and meta-pelite) of the accretionary complex. Serpentinized
peridotites, which are commonly harzburgite in composition,
and meta-volcanites are observed as tectonic slices in the
accretionary complex.
Pleonaste is observed in the ultramafic and mafic
cumulate rocks. The ultramafic rocks in the study area
are more common than mafic rocks. While the ultramafic
cumulate rocks are represented by dunite, wehrlite,
clinopyroxenite, and websterite, the mafic cumulate
rocks are gabbros. Wehrlite and pyroxenite are the most
common rock types in the ultramafic cumulate rocks.
Rare pegmatitic gabbro dikes cut the ultramafic cumulate
rocks. Serpentinization and/or alteration are common
in the cumulate rocks but relatively fresh ultramafic and
mafic rocks can be found at many locations. Pyroxene and
olivine in the relatively fresh ultramafic cumulate rocks
show dark green and yellowish brown colors in the hand
samples. Cumulate rocks display well-developed magmatic
layers (Figure 3a). However, this phenomenon is not
clear in highly serpentinized ultramafic rocks and coarse
grained (>1 cm) pyroxenites. Cumulate nature of the
ultramafic rocks in the field is defined by the alternation of
fine-grained and black-colored peridotites with relatively
coarse-grained and green-colored pyroxenites (Figure 3b).
Cr-spinels in dunites and Al-rich spinel (pleonaste) in
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Figure 3. (a) Field view of pyroxenites and gabbros showing magmatic rhythmic layering. (b) Close up view of peridotite and pyroxenite
showing rhythmic layering. (c) Cr-spinels in dunite. (d) Pleonaste along the magmatic layers of pyroxenite. (e) Close view of the
magmatic layers of gabbro and pyroxenite.
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pyroxenites lie parallel to the magmatic banding (Figures
3c and 3d). Plagioclase and/or pyroxene-rich parts in the
mafic and ultramafic cumulates, with thicknesses varying
from a few millimeters to three meters, can be observed
in some locations (Figures 3a and 3e). Depending on the
increase in plagioclase, the rock passes from wehrlite and
pyroxenite to gabbros (Figures 3a and 3e). The gabbro
layers together with pyroxenites often show rhythmic
alternation.
3. Mineralogy and petrography
Ultramafic cumulate rocks are defined as dunite, wehrlite,
websterite, and pyroxenite based on petrographical
observations. Wehrlites, showing generally adcumulate
and mesocumulate textures, consist mainly of olivine
+ clinopyroxene + orthopyroxene ± spinel ± magnetite
minerals (Figure 4a). Serpentine, talc, chlorite, and
calcite were observed as secondary minerals. Olivine in
serpentinized dunite and wehrlite is found as rounded
crystals (Figure 4a). Spinel-group minerals show colors of
dark brown to light brown in dunites and of light brown
or greenish brown in wehrlites (Figure 4a). Pyroxenites
consist mainly of clinopyroxene ± orthopyroxene ±
olivine ± amphibole ± plagioclase ± spinel ± magnetite
minerals. They are commonly coarse-grained and
show orthocumulate and adcumulate textures (Figures
4b–4e). In some pyroxenites (e.g., M-041) amphibole,
plagioclase, and opaque minerals, which make up
about 2% of the mineral assemblage, lie parallel to
magmatic banding. Olivine in the pyroxenites occurred
both as intercumulus minerals among pyroxenes and
as inclusions in clinopyroxenes (Figures 4b and 4c).
Clinopyroxene inclusions and exsolution lamellas are seen
in orthopyroxenes of the coarse-grained websterites (e.g.,
M-043 and M-045). Amphibole (~10 modal %) showing
brown to light brown pleochroism is observed in some
websterites (Figure 4d). In some pyroxenites (e.g., M-113),
amphibole abundance reaches up to 15 modal %. The
amphiboles in the pyroxenites extend discontinuously
but parallel to the magmatic layering. Cumulate gabbros
show orthocumulate, adcumulate, mesocumulate,
and heteradcumulate textures. They consist mainly of
plagioclase ± clinopyroxene ± orthopyroxene ± amphibole
± spinel ± magnetite ± ilmenite (Figures 4f–4h). Although
gabbros are commonly fresh, some of them show alteration
with secondary minerals, such as epidote, chlorite, and
clay (Figure 4g). Amphibole is rarely observed in gabbros,
where it is coarse grained (Figure 4h).
Spinel minerals with pleonaste composition are
evident by green to dark green (emerald green) colors
(Figures 5a–5d). Pleonaste is usually observed as skeletonshaped xenomorphic crystals with dimensions up to 2
mm and extends parallel to the magmatic layering (Figure
5b). While the modal abundance of pleonaste is 20% in
the clinopyroxenites, it is about 1% or 2% in gabbros
and olivine bearing clinopyroxenites. Pleonaste is mostly
observed in between clinopyroxene and amphibole
minerals and it contains clinopyroxene inclusions (Figures
5c and 5d). This indicates that the pleonastes represent the
postcumulus phase and crystallize after the formation of
clinopyroxene.
4. Analytical methods
Mineral compositions were determined at the IGG-CNR
Padova (Italy) on a Cameca SX50 electron microprobe
(EPMA) using ZAF online data reduction and matrix
correction procedures. The beam current for analyzing
amphibole and plagioclase was set at 15 nA, whereas
pyroxenes and oxides were analyzed with a beam current
of 20 nA. The accelerating voltage was 15 kV in all cases.
Repeated analyses of standards indicate relative analytical
uncertainties of about 1% for major and 5% for minor
elements.
Mafic and ultramafic rocks were analyzed for major
and trace elements by XRF and ICP-MS (PerkinElmer
Elan DRC-e model), respectively, at the Kocaeli University
Analytical Geochemistry Laboratory in Kocaeli, Turkey.
Major oxides were measured on pressed powder pellets,
using a SKAYRAY EDX3600B model XRF spectrometer.
About 0.2 g of rock powder was fused with 1.4 g of LiBO2
and dissolved in 50 mL of 5% HNO3 for trace element
and rare earth element (REE) analyses. Loss on ignition
(LOI) was determined by heating a separate aliquot of rock
powder at 900 °C for ˃2 h.
5. Mineral chemistry
Electron microprobe analyses were performed on olivine,
orthopyroxene clinopyroxene, spinel-group minerals,
amphibole and plagioclase of wehrlite (M-101), websterite
(M-105), clinopyroxenite (M-113), and gabbro (M-006).
The light brown spinels in wehrlites are Cr-spinel in
composition and their Cr# and Mg# (100 × Mg/[Mg +
Fe2+]) range from 8.87 to 22.23 and from 62.43 to 75.69,
respectively. Cr-spinels have low TiO2 (<0.16 wt.%) and Fe3+#
(100 × Fe3+[Fe3+ + Cr + Al]) (1.73–3.98) values (Table 1).
The emerald greenish spinel of the clinopyroxenite
sample has high contents of Al2O3 (55.64–62.24 wt.%)
and low Cr2O3 (0.05–1.32 wt.%). The Mg# and Fe3+#
range from 54.23 to 59.77 and 3.83 to 4.28, respectively
(Table 1). In the spinel classification diagram the emerald
greenish spinels in the investigated rocks are pleonaste in
composition (Figures 6a and 6b).
Olivines from a wehrlite sample have low MnO
(0.09–0.18 wt.%) and CaO (0.00–0.03 wt.%) contents.
Forsterite (Fo) values of olivines in this rock range from
89.4 to 89.9. (Table 2). All orthopyroxenes in wehrlite,
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Figure 4. Microscopic views (XPL, crossed polarized light; PPL plane polarized light) of peridotites, pyroxenites and gabbros. (a) Crspinel-bearing wehrlite sample. (b) Interstial olivines in a pyroxenite sample. (c) Olivine inclusions in clinopyroxenes of a pyroxenite
sample (d) Amphibole-bearing pyroxenite with mesocumulate texture. (e) Orthocumulate texture from a pyroxenite. (f) A fresh gabbro
sample showing cumulate texture. (g) A gabbro sample exhibiting alteration. (h) Coarse grained amphibole-bearing gabbro sample.
Abbreviations: amp, amphibole; cpx, clinopyroxene; ep, epidote; ilm, ilmenite; ol, olivine; mag, magneitite; opx, orthopyroxene; pl,
plagioclase; spl, spinel.
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Figure 5. (a) Pleonaste showing emerald greenish color in clinopyroxenite. (b, c) Skeletal-shaped pleonastes with clinopyroxene
inclusion in clinopyroxenite. (d) Pleonaste occurrences in gabbro. Abbreviations: amp, amphibole; cpx, clinopyroxene; pl, plagioclase.
websterite, and clinopyroxenite samples are enstatite in
composition (Figure 7). While Mg# of orthopyroxene in
wehrlite ranges from 89.6 to 90.3, it varies between 80.9
and 81.0 for websterite and between 76.3 and 78.2 for
clinopyroxenites. Clinopyroxenes in the same rocks are
represented by diopside and augite composition (Figure
7). The Mg# of clinopyroxenes are high compared to those
of orthopyroxenes, ranging from 90.6 to 93.0 in the case
of wehrlite, 84.7 to 86.7 in the case of websterite, and 74.8
to 84.4 in the case of clinopyroxenite. Orthopyroxenes
and clinopyroxenes from mafic and ultramafic rocks
generally have high Al2O3 contents (Tables 3 and 4).
Al2O3 contents of clinopyroxene from a pleonaste-bearing
clinopyroxenite are especially high and reach up to 8.29
wt.%. While TiO2 contents of the clinopyroxenes in the
wehrlite and websterite range from 0.21 to 0.43, those of
the clinopyroxenite sample are between 0.53 and 0.90.
These compositional properties, especially for Al2O3 and
TiO2, of pyroxene minerals are very similar to those of
pyroxene minerals in pleonaste-bearing rocks from the
Eastern Alps (e.g., Melcher et al., 2002).
Amphiboles from websterite, clinopyroxenite, and
gabbro samples are defined as magnesiohastingsite,
tschermakite, and pargasite based on the classification
given by Leake et al. (1997) (Figure 8). Amphiboles are
represented by high Mg# (77–94), TiO2 (1.40–2.19 wt.%),
and Al2O3 (11.68–16.84 wt.%) values (Table 5). Plagioclases
in a gabbro are calcic in composition (An % 85–88) and
are classified as bytownite (Table 6).
6. Whole rock chemistry
Whole rock major, trace, and rare earth element (REE)
chemistry was performed on 13 samples of mafic and
ultramafic rocks. The results of the analyses are presented
in Table 7.
The LOI values of the rock samples are low and range
between 0.36 and 1.97 wt.%. These values are related to
the relative abundance of primary aqueous magmatic
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Table 1. Spinel analysis from wehrlite (M-101) and clinopyroxenite (M-113) samples.
Sample M-101
M-101
M-101
M-101
M-101
M-101
M-101
M-101
M-101
M-101
M-101
M-101
M-101
M-101
M-101
0.10
0.14
54.33
11.64
2.86
13.58
0.17
17.84
0.00
100.65
0.00
0.00
1.69
0.24
0.06
0.30
0.00
0.70
0.00
3.00
12.56
70.08
2.85
29.92
0.14
0.05
53.82
12.75
2.79
13.53
0.19
17.89
0.01
101.17
0.00
0.00
1.67
0.27
0.06
0.30
0.00
0.70
0.00
3.00
13.71
70.21
2.77
29.79
0.10
0.03
51.98
14.00
3.04
14.29
0.21
17.05
0.01
100.71
0.00
0.00
1.64
0.30
0.06
0.32
0.00
0.68
0.00
3.00
15.30
68.02
3.07
31.98
0.11
0.07
51.01
14.26
2.83
14.50
0.16
16.65
0.00
99.59
0.00
0.00
1.63
0.31
0.06
0.33
0.00
0.67
0.00
3.00
15.79
67.17
2.90
32.83
0.10
0.05
58.22
8.55
2.47
11.44
0.13
19.59
0.00
100.54
0.00
0.00
1.77
0.17
0.05
0.25
0.00
0.75
0.00
3.00
8.97
75.32
2.41
24.68
0.11
0.05
58.19
8.47
2.19
11.24
0.11
19.63
0.02
100.02
0.00
0.00
1.78
0.17
0.04
0.24
0.00
0.76
0.00
3.00
8.90
75.69
2.14
24.31
0.17
0.16
58.14
8.63
2.49
11.72
0.12
19.65
0.00
101.09
0.00
0.00
1.76
0.18
0.05
0.25
0.00
0.75
0.00
3.00
9.06
74.93
2.42
25.07
0.13
0.03
58.73
8.52
2.28
11.40
0.12
19.80
0.00
101.00
0.00
0.00
1.78
0.17
0.04
0.24
0.00
0.76
0.00
3.00
8.87
75.59
2.21
24.41
0.13
0.04
55.44
10.87
1.73
12.50
0.14
18.32
0.06
99.23
0.00
0.00
1.73
0.23
0.03
0.28
0.00
0.72
0.00
3.00
11.63
72.31
1.73
27.69
0.23
0.00
57.72
10.90
2.53
12.42
0.16
19.59
0.02
103.59
0.01
0.00
1.72
0.22
0.05
0.26
0.00
0.74
0.00
3.00
11.25
73.76
2.43
26.24
0.10
0.01
54.15
12.60
2.38
13.07
0.10
18.10
0.00
100.52
0.00
0.00
1.68
0.26
0.05
0.29
0.00
0.71
0.00
3.00
13.50
71.17
2.37
28.83
0.13
0.01
55.64
10.60
2.54
12.92
0.11
18.31
0.01
100.27
0.00
0.00
1.72
0.22
0.05
0.28
0.00
0.72
0.00
3.00
11.34
71.64
2.52
28.36
0.11
0.09
56.44
10.36
2.28
12.05
0.13
19.03
0.00
100.49
0.00
0.00
1.73
0.21
0.04
0.26
0.00
0.74
0.00
3.00
10.96
73.80
2.25
26.20
0.10
0.04
56.36
10.44
2.19
11.95
0.07
19.02
0.01
100.17
0.00
0.00
1.73
0.22
0.04
0.26
0.00
0.74
0.00
3.00
11.05
73.94
2.16
26.06
0.12
0.08
56.62
9.21
2.35
11.80
0.12
18.96
0.00
99.24
0.00
0.00
1.75
0.19
0.05
0.26
0.00
0.74
0.00
3.00
9.84
74.13
2.33
25.87
SiO2
TiO2
Al2O3
Cr2O3
Fe2O3
FeO
MnO
MgO
CaO
Total
Si
Ti
Al
Cr
Fe3+
Fe2+
Mn
Mg
Ca
Total
Cr#
Mg#
Fe3+#
Fe2+#
Table 1. (Continued).
Sample
M-101
M-101
M-101
M-101
M-101
M-101
M-113
M-113
M-113
M-113
M-113
M-113
SiO2
TiO2
Al2O3
Cr2O3
Fe2O3
FeO
MnO
MgO
CaO
Total
Si
Ti
Al
Cr
Fe3+
Fe2+
Mn
Mg
Ca
Total
Cr#
Mg#
Fe3+#
Fe2+#
0.13
0.14
45.73
19.06
3.67
15.96
0.29
15.25
0.01
100.25
0.00
0.00
1.49
0.42
0.08
0.37
0.01
0.63
0.00
3.00
21.85
63.02
3.85
36.98
0.13
0.11
45.65
20.17
3.24
15.86
0.18
15.50
0.00
100.85
0.00
0.00
1.48
0.44
0.07
0.37
0.00
0.64
0.00
3.00
22.86
63.54
3.38
36.46
0.10
0.07
45.10
19.95
3.77
15.72
0.23
15.32
0.02
100.27
0.00
0.00
1.48
0.44
0.08
0.36
0.01
0.63
0.00
3.00
22.88
63.46
3.95
36.54
0.12
0.01
48.37
17.40
3.17
14.77
0.16
16.33
0.00
100.33
0.00
0.00
1.55
0.37
0.06
0.34
0.00
0.66
0.00
3.00
19.44
66.34
3.26
33.66
0.12
0.13
44.72
20.18
3.78
16.19
0.18
15.09
0.01
100.39
0.00
0.00
1.47
0.44
0.08
0.38
0.00
0.63
0.00
3.00
23.23
62.43
3.98
37.57
0.14
0.02
45.03
20.14
3.30
16.04
0.17
15.07
0.02
99.93
0.00
0.00
1.48
0.44
0.07
0.37
0.00
0.63
0.00
3.00
23.08
62.61
3.48
37.39
0.12
0.03
61.34
0.05
4.30
18.62
0.10
15.02
0.02
99.60
0.00
0.00
1.91
0.00
0.09
0.41
0.00
0.59
0.00
3.00
0.05
58.99
4.28
41.01
0.10
0.01
62.24
0.05
3.92
18.41
0.16
15.35
0.03
100.27
0.00
0.00
1.91
0.00
0.08
0.40
0.00
0.60
0.00
3.00
0.05
59.77
3.87
40.23
0.13
0.00
61.88
0.06
4.05
18.50
0.16
15.23
0.00
100.00
0.00
0.00
1.91
0.00
0.08
0.41
0.00
0.59
0.00
3.00
0.07
59.47
4.00
40.53
0.09
0.03
59.65
1.27
3.85
20.36
0.15
13.53
0.05
98.99
0.00
0.00
1.89
0.03
0.08
0.46
0.00
0.54
0.00
3.00
1.41
54.23
3.91
45.77
0.11
0.03
60.04
1.32
4.14
20.03
0.14
14.00
0.03
99.83
0.00
0.00
1.88
0.03
0.08
0.44
0.00
0.55
0.00
3.00
1.45
55.48
4.16
44.52
0.11
0.02
60.80
1.02
3.83
20.05
0.18
14.12
0.01
100.14
0.00
0.00
1.89
0.02
0.08
0.44
0.00
0.56
0.00
3.00
1.11
55.67
3.83
44.33
174
ÖZKAN and ÇELİK / Turkish J Earth Sci
rrite
fe
magnesio
magnetite
Magnesioferrite 1.0
(MgFe2O4)
0.9
Magnesioferrite
Magnetite
0.8
Fe3+/(Al3++Fe3+)
0.7
magne
sio
Magnetite
(FeFe2O4)
(b)
chrom
ite
Al-magnetite
0.6
0.5
Ferrian-spinel
Ferrian-pleonaste
0.4
Ferrian picotite
0.3
hercyn
ite
chrom
ite
spinel
e
pleonast
Al3+-Fe3+ exchange
(a)
0.2
0.1
Spinel
(MgAl2O4) 0.0
0.0
Spinel
0.1
Pleonaste
0.2
0.3
0.4
0.5
Fe2+/(Mg2++Fe2+)
Hercynite
0.6
0.7
0.8
0.9
1.0
Hercynite
(FeAl2O4)
clinopyroxenite (M-113)
Mg2+-Fe2+ exchange
Figure 6. (a) The classification prism of spinel group minerals (Deer et al., 1992). (b) Chemical composition of spinel of pyroxenite on
the spinel classification diagram (Haggerty, 1991; Deer et al., 1992).
(amphibole) and alteration minerals (e.g., chlorite, calcite,
serpentine).
The Mg# of pyroxenites (85.28–89.10) are higher
than those of gabbros (53.87–78.43). Al2O3 contents
of pyroxenites vary from 2.10 and 4.61 wt.%. While
SiO2 contents of pyroxenite are represented in narrow
compositional range (49.0–51.59 wt. %), those of gabbro
samples show a wide range in composition and vary
between 44.2 and 50.1 wt.%. CaO (7.8–19.6 wt.%) and
MgO (19.3–28.1 wt.%) contents of pyroxenites have a wide
range in composition. Gabbros are represented also in
wide ranges of CaO (11.7–16.8 wt.%) and MgO (4.6–12.1
wt.%) contents.
Ultramafic cumulates (pyroxenites) in the chondritenormalized REE patterns diagram (Figure 9a) show an
almost flat pattern or slight enrichment from heavy REE
(HREE) to middle REE (MREE) (LuN/GdN = 0.6–1) and
stronger depletion from MREE to light REE (LREE) (SmN/
LaN = 1.5–5.8). However, they are different from average
depleted mid-ocean ridge mantle (DMM) with their
enriched REE patterns. All gabbro samples display convex
(SmN/LaN = 1.4–3.6; LuN/GdN = 0.6–0.9) and depleted
chondrite-normalized LREE patterns compared to normal
mid-ocean ridge basalts (N-MORB) (Figure 9c). They
show positive Eu (Eu*/Eu = 1.1–1.3) anomalies. On the
N-MORB normalized multi-element diagram, pyroxenites
and gabbros exhibit depleted compositional variations,
some of which (e.g., Th, U) are below the detection limit
(Figures 9b and 9d). In the same diagrams, ultramafic and
mafic rocks display large-ion lithophile element (LILE)
enrichment (e.g., K, Rb, Sr, Pb) relative to high-field-
strength elements (HFSE) (e.g., Nb, Ta, Zr, Ti) (Figures 9b
and 9d).
7. Discussion
Mafic–ultramafic rocks exhibit a cumulate nature with
their variable CaO and MgO contents and low contents of
incompatible elements such as Ti, P, and Zr. The positive
Eu* anomalies in the REE distribution patterns of gabbros
suggest plagioclase accumulation, indicating the cumulate
nature of these rocks. REE distribution patterns of mafic
rocks should be also different (convex REE pattern) due
to the modal abundance and type of the cumulus minerals
and the intercumulus melts (e.g., Melcher et al., 2002;
Holm and Preagel, 2006; Yang, 2006). The convex REE
patterns of gabbros suggest that amphibole and pyroxene
minerals were formed as cumulus minerals, which were
confirmed with petrographic observations. As whole rock
geochemical analysis from cumulate rocks do not represent
the primary melt composition, the mineral chemical data
were used to interpret the tectono-magmatic environment.
The presence of amphibole and Ca-rich plagioclase
in the investigated gabbros and pyroxenites suggests that
these rocks formed from a hydrous mantle source (e.g.,
Claeson and Meurer, 2004; Takagi et al., 2005; Ushioda
et al., 2014). It was reported that Al-rich spinel minerals
are common in arc-related environments (e.g., DeBari
and Coleman, 1989; Della-pasua et al., 1995; Claeson and
Meurer, 2004; Wu et al., 2014). Similarly, clinopyroxene
of the cumulate rocks (wehrlite and pyroxenite) suggests
that these rocks were derived from the magma with a
tholeiitic arc character (Figures 10a and 10b). The Al/Ti
175
176
0.00
3.00
89.46
10.38
Total
Fo
Fa
0.00
0.00
Ca
Na
1.80
1.80
Mg
0.21
Mn
10.51
89.29
3.01
0.00
0.00
0.21
0.00
Fe2+
0.00
10.40
89.40
3.01
0.00
0.00
1.80
0.00
0.21
0.00
1.00
10.16
89.67
3.00
0.00
0.00
1.80
0.00
0.20
0.00
0.00
0.00
1.00
10.29
89.53
3.00
0.00
0.00
1.79
0.00
0.21
0.00
0.00
0.00
0.99
10.03
89.77
3.01
0.00
0.00
1.81
0.00
0.20
0.00
0.00
0.00
10.68
89.19
3.00
0.00
0.00
1.79
0.00
0.21
0.00
0.00
0.00
1.00
10.39
89.44
3.00
0.00
0.00
1.80
0.00
0.21
0.00
0.00
0.00
0.99
10.18
89.65
3.01
0.00
0.00
1.80
0.00
0.20
0.00
0.00
0.00
10.30
89.55
3.00
0.00
0.00
1.79
0.00
0.21
0.00
0.00
0.00
1.00
0.00
10.38
89.48
3.01
0.00
0.00
1.80
0.00
0.21
0.00
0.00
0.00
0.99
0.00
9.88
89.95
3.00
0.00
0.00
1.79
0.00
0.20
0.00
0.00
0.00
1.00
0.00
10.30
89.48
3.01
0.00
0.00
1.80
0.00
0.21
0.00
0.00
0.00
0.99
0.00
10.32
89.54
3.01
0.00
0.00
1.80
0.00
0.21
0.00
0.00
0.00
0.99
0.00
0.01
49.70
9.95
89.88
3.00
0.00
0.00
1.80
0.00
0.20
0.00
0.00
0.00
1.00
0.00
0.01
49.31
0.16
0.00
0.00
0.00
0.00
Al
Cr
0.99
0.00
0.00
0.03
49.69
0.14
0.01
9.73
0.99
0.99
0.00
0.01
49.52
0.22
0.00
10.21
0.00
0.00
0.00
49.50
0.17
0.00
10.20
0.00
0.00
1.00
0.00
0.02
49.46
0.14
0.05
9.69
0.00
0.00
0.00
0.00
0.02
49.64
0.15
0.00
10.24
0.00
0.02
Si
0.01
0.00
49.19
0.16
0.00
10.14
0.00
0.01
Ti
0.00
0.00
49.29
0.17
0.01
10.04
0.00
0.00
100.79 100.14 100.66 100.75 100.61 100.63 100.85 100.79 99.81
0.00
0.00
49.42
0.12
0.00
10.18
0.00
0.00
0.00
0.00
49.26
0.19
0.06
10.52
0.00
0.01
100.43 100.31 100.70 100.55 100.40 99.84
0.01
49.43
0.18
0.00
9.85
0.00
0.00
40.57
Na2O
0.01
49.52
0.17
0.01
10.09
0.00
0.01
40.73
Total
0.02
49.17
0.20
0.03
9.98
0.00
0.00
40.70
49.31
0.20
0.05
10.26
0.00
0.01
41.19
0.00
MnO
0.01
10.32
0.00
0.00
40.73
MgO
0.16
FeO
0.00
0.02
40.99
CaO
0.00
10.19
Cr2O3
0.00
40.77
0.00
0.01
49.30
0.10
10.01
0.05
0.00
0.00
40.54
0.00
0.00
49.45
0.12
9.92
0.04
0.00
0.00
40.68
0.00
0.00
50.18
0.14
10.00
0.00
0.00
0.01
41.46
0.01
0.03
50.06
0.13
10.00
0.06
0.00
0.00
40.92
0.00
0.00
49.59
0.21
9.84
0.03
0.00
0.03
40.72
0.01
0.00
49.84
0.13
9.81
0.00
0.00
0.00
40.88
10.20
89.64
3.01
0.00
0.00
1.80
0.00
0.21
0.00
0.00
0.00
0.99
10.22
89.69
3.01
0.00
0.00
1.80
0.00
0.21
0.00
0.00
0.00
0.99
10.10
89.77
3.00
0.00
0.00
1.80
0.00
0.20
0.00
0.00
0.00
1.00
10.04
89.82
3.00
0.00
0.00
1.80
0.00
0.20
0.00
0.00
0.00
1.00
10.06
89.81
3.01
0.00
0.00
1.81
0.00
0.20
0.00
0.00
0.00
0.99
0.99
0.00
10.00
89.79
3.01
0.00
9.93
89.94
3.01
0.00
0.00
1.81
0.00
1.80
0.20
0.00
0.00
0.00
0.00
0.20
0.00
0.00
0.00
0.99
100.70 100.01 100.21 101.78 101.20 100.42 100.67
0.00
0.00
49.64
0.15
10.07
0.00
0.00
0.00
40.84
0.00
40.61
0.00
40.78
0.00
40.38
Al2O3
40.86
TiO2
40.92
40.59
40.77
SiO2
40.64
M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101 M-101
Sample
Table 2. Olivine analysis from wehrlite sample (M-101).
ÖZKAN and ÇELİK / Turkish J Earth Sci
ÖZKAN and ÇELİK / Turkish J Earth Sci
Ca2Si2O6(Wo)
Diopside
50
45
Hedenbergite
50
45
wehrlite (M-101)
websterite (M-105)
clinopyroxenite (M-113)
Augite
20
20
Pigeonite
5
Enstatite
50
Mg2Si2O6(En)
5
Ferrosilite
Fe2Si2O6(Fs)
Figure 7. Chemical composition of pyroxenes in wehrlites and
pyroxenites (after Morimoto (1988)).
atoms per formula units (apfu) ratio of clinopyroxenes in
these cumulate rocks is between 13 and 22, also suggesting
a tholeiitic arc character (e.g., Leterrier et al., 1982). The
crystallization of pyroxenes before the plagioclases in
gabbros, unlike the MORB-type crystallization trend,
supports the presence of the water-rich magmatic system
(e.g., Feig et al., 2006).
Spinel minerals in the arc-related rocks should be
represented by a wide range of composition. For example,
ultramafic and mafic rocks from the Chilas complex of
the Kohistan arc have Cr-spinel, Al-rich spinel, and Crbearing magnetite (e.g., Jan et al., 1992). Spinels in the
investigated ultramafic rocks show also a wide range in
composition. This should be related to thickness of the
Table 3. Orthopyroxene analysis from wehrlite (M-101), websterite (M-105), and clinopyroxenite (M-113) samples.
Sample
M-101
M-101
M-101
M-101
M-101
M-105
M-105
M-105
M-105
M-105
M-113
M-113
M-113
M-113
M-113
SiO2
55.96
56.84
56.02
55.27
55.38
54.26
54.13
54.15
54.78
54.16
50.79
50.52
50.61
51.16
50.28
TiO2
0.07
0.07
0.06
0.05
0.06
0.05
0.07
0.10
0.10
0.11
0.12
0.13
0.16
0.08
0.11
Al2O3
2.04
1.48
1.92
4.16
4.23
2.76
2.71
2.73
2.84
2.65
6.20
6.30
6.38
5.49
6.44
Cr2O3
0.22
0.16
0.26
0.27
0.43
0.23
0.25
0.24
0.31
0.23
0.08
0.07
0.10
0.11
0.11
FeO
6.99
6.90
6.95
6.39
6.82
12.56
12.80
12.60
12.55
12.44
14.06
13.95
13.78
13.84
14.96
MnO
0.16
0.23
0.12
0.14
0.14
0.32
0.28
0.26
0.34
0.30
0.27
0.17
0.28
0.23
0.21
MgO
34.09
34.99
34.38
33.43
33.84
29.84
29.78
29.87
29.93
29.81
27.36
27.02
27.10
27.46
27.17
CaO
0.42
0.38
0.38
0.68
0.66
0.49
0.49
0.46
0.43
0.44
0.75
0.87
0.96
0.77
0.52
Na 2O
0.00
0.00
0.00
0.03
0.04
0.01
0.02
0.01
0.04
0.00
0.02
0.04
0.00
0.01
0.03
K2O
0.02
0.01
0.01
0.00
0.00
0.00
0.00
0.01
0.00
0.00
0.02
0.01
0.00
0.01
0.00
Total
99.96
101.06
100.12
100.43
101.60
100.52
100.54
100.42
101.32
100.14
99.68
99.08
99.38
99.15
99.81
Si
1.94
1.95
1.94
1.90
1.89
1.92
1.92
1.92
1.92
1.92
1.83
1.83
1.83
1.85
1.82
Ti
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Al(iv)
0.06
0.05
0.06
0.10
0.11
0.08
0.08
0.08
0.08
0.08
0.17
0.17
0.17
0.15
0.18
AL(vi)
0.02
0.01
0.02
0.07
0.06
0.04
0.03
0.03
0.04
0.03
0.09
0.10
0.10
0.09
0.09
Cr
0.01
0.00
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.00
0.00
0.00
0.00
0.00
2+
0.20
0.20
0.20
0.18
0.19
0.37
0.38
0.37
0.37
0.37
0.42
0.42
0.42
0.42
0.45
Mn
0.00
0.01
0.00
0.00
0.00
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
Mg
1.76
1.79
1.77
1.72
1.72
1.57
1.57
1.58
1.57
1.58
1.47
1.46
1.46
1.48
1.46
Fe
Ca
0.02
0.01
0.01
0.03
0.02
0.02
0.02
0.02
0.02
0.02
0.03
0.03
0.04
0.03
0.02
Na
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
K
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Total
4.01
4.02
4.02
4.01
4.02
4.02
4.02
4.02
4.01
4.02
4.03
4.03
4.03
4.03
4.04
Vo
0.78
0.71
0.71
1.31
1.24
0.94
0.95
0.88
0.82
0.85
1.50
1.76
1.94
1.55
1.04
En
88.98
89.41
89.16
89.04
88.60
80.10
79.75
80.13
80.18
80.34
76.39
76.07
76.30
76.73
75.53
Fs
10.24
9.89
10.12
9.55
10.02
18.92
19.23
18.97
18.87
18.81
22.02
22.03
21.76
21.69
23.32
Mg#
89.68
90.04
89.81
90.32
89.84
80.90
80.57
80.86
80.95
81.03
77.63
77.55
77.81
77.96
76.41
177
178
2.42
1.89
0.01
99.76
1.90
Total
Si
0.62
0.94
0.04
0.00
0.00
0.90
0.93
0.04
Mn
Mg
Ca
Na
47.94
46.30
3.49
92.99
Wo
En
Fs
Mg#
0.00
0.88
0.07
Fe2+
4.03
0.07
0.02
Cr
K
0.02
0.05
Al(vi)
92.30
3.80
45.60
48.35
4.03
0.00
0.06
0.11
0.01
0.10
Ti
Al(iv)
Total
0.00
0.59
23.88
16.14
0.06
2.37
0.79
4.03
0.43
51.85
0.01
0.64
22.58
16.45
0.03
3.04
0.45
4.74
0.34
51.41
92.39
3.76
45.59
48.49
4.02
0.00
0.04
0.93
0.88
0.00
0.07
0.02
0.06
0.11
0.01
1.89
0.01
0.00
90.62
4.84
46.73
46.08
4.03
0.00
0.05
0.88
0.90
91.44
4.40
46.96
46.33
4.02
0.00
0.04
0.89
0.90
0.00
0.08
0.01
0.11
0.01
1.89
0.07
0.09
0.00
0.53
23.51
15.56
0.15
4.38
0.32
3.50
0.31
51.78
0.01
0.57
23.27
15.77
0.14
4.34
0.31
3.20
0.25
52.37
0.02
0.49
23.26
15.35
0.15
4.18
0.29
3.57
0.32
51.87
86.36
6.90
43.70
47.46
4.03
0.00
0.04
0.93
0.85
0.00
0.13
0.01
0.05
0.10
0.01
1.90
86.62
6.83
44.21
46.89
4.02
0.00
0.04
0.91
0.86
0.00
0.13
0.01
0.06
0.08
0.01
1.92
86.74
6.70
43.80
47.70
4.01
0.00
0.03
0.92
0.84
0.00
0.13
0.01
0.07
0.09
0.01
1.91
101.49 100.04 100.24 99.51
0.00
0.64
23.21
16.91
0.10
2.82
0.46
4.32
0.34
52.69
0.08
0.12
0.01
1.88
100.36 100.12 99.68
0.01
0.62
0.00
K2O
24.03
16.29
0.07
Na2O
16.57
23.88
MgO
CaO
2.23
0.03
0.53
Cr2O3
FeO
0.66
3.42
Al2O3
MnO
0.40
0.35
TiO2
4.02
51.85
52.12
SiO2
86.59
6.89
44.48
46.78
4.02
0.00
0.04
0.91
0.86
0.00
0.13
0.01
0.06
0.09
0.01
1.91
99.53
0.00
0.50
23.01
15.72
0.14
4.34
0.34
3.38
0.33
51.77
85.53
7.46
44.05
46.54
4.02
0.00
0.04
0.90
0.85
0.00
0.14
0.01
0.06
0.09
0.01
1.91
99.83
0.00
0.53
22.87
15.56
0.09
4.69
0.25
3.66
0.36
51.81
77.16
12.91
43.61
42.11
4.04
0.00
0.03
0.80
0.83
0.00
0.24
0.00
0.12
0.23
0.02
1.77
98.89
0.01
0.36
19.85
14.78
0.15
7.80
0.05
7.92
0.73
47.25
79.16
10.25
38.94
49.08
4.05
0.00
0.03
0.93
0.74
0.00
0.19
0.00
0.13
0.24
0.02
1.76
99.16
0.00
0.45
23.10
13.18
0.11
6.18
0.08
8.29
0.86
46.90
77.93
11.01
38.87
48.43
4.05
0.00
0.03
0.92
0.74
0.00
0.21
0.00
0.12
0.23
0.02
1.77
99.20
0.03
0.44
22.84
13.18
0.15
6.65
0.03
8.00
0.84
47.04
79.60
10.48
40.88
47.15
4.04
0.00
0.03
0.89
0.77
0.00
0.20
0.00
0.12
0.23
0.02
1.77
99.09
0.00
0.39
22.25
13.86
0.14
6.34
0.00
8.00
0.88
47.24
78.74
10.50
38.89
49.03
4.05
0.00
0.03
0.94
0.74
0.01
0.20
0.00
0.11
0.23
0.02
1.77
99.36
0.02
0.41
23.28
13.27
0.18
6.39
0.01
7.83
0.84
47.13
79.32
10.32
39.59
48.34
4.05
0.00
0.03
0.92
0.75
0.00
0.20
0.00
0.11
0.23
0.02
1.77
98.83
0.00
0.46
22.84
13.45
0.11
6.25
0.07
7.73
0.84
47.09
78.96
10.39
39.01
49.21
4.05
0.00
0.03
0.94
0.74
0.00
0.20
0.00
0.11
0.23
0.03
1.77
99.02
0.00
0.36
23.26
13.25
0.14
6.29
0.00
7.66
0.90
47.17
78.43
10.92
39.72
47.91
4.05
0.00
0.03
0.92
0.76
0.00
0.21
0.00
0.11
0.22
0.02
1.78
99.05
0.01
0.38
22.76
13.56
0.15
6.65
0.01
7.40
0.83
47.31
79.59
10.08
39.30
49.01
4.04
0.00
0.03
0.92
0.74
0.00
0.19
0.00
0.14
0.23
0.03
1.77
98.55
0.02
0.42
22.76
13.12
0.09
6.00
0.00
8.32
0.88
46.94
74.76
16.30
48.27
34.22
4.04
0.00
0.02
0.65
0.91
0.01
0.31
0.00
0.13
0.23
0.02
1.77
98.57
0.00
0.31
16.05
16.28
0.17
9.79
0.00
8.21
0.65
47.11
77.65
12.72
44.19
41.75
4.04
0.00
0.03
0.79
0.83
0.00
0.24
0.00
0.12
0.23
0.02
1.77
98.39
0.02
0.35
19.55
14.87
0.08
7.63
0.06
7.93
0.82
47.09
78.12
10.89
38.87
48.50
4.05
0.00
0.03
0.92
0.74
0.01
0.21
0.00
0.12
0.24
0.02
1.76
99.06
0.00
0.46
22.94
13.21
0.20
6.60
0.02
8.07
0.83
46.75
79.69
10.50
41.20
46.93
4.04
0.00
0.03
0.89
0.78
0.00
0.20
0.00
0.12
0.23
0.03
1.77
98.63
0.00
0.35
22.03
13.90
0.11
6.32
0.00
8.02
0.90
46.99
Sample M-101 M-101 M-101 M-101 M-101 M-105 M-105 M-105 M-105 M-105 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113
Table 4. Clinopyroxene analysis from wehrlite (M-101), websterite (M-105), and clinopyroxenite (M-113) samples.
ÖZKAN and ÇELİK / Turkish J Earth Sci
14.33
22.34
0.42
0.00
99.03
1.79
0.21
13.80
23.22
0.42
0.00
98.40
MnO
MgO
CaO
Na2O
K2O
Total
0.01
0.18
0.11
0.00
Al(vi)
Cr
40.75
8.37
82.96
En
Fs
Mg#
4.04
49.29
Total
Wo
0.03
0.00
Na
K
0.77
0.94
Mg
Mn
Ca
0.16
0.01
2+
Fe
0.00
0.20
Al(iv)
81.55
9.49
41.94
46.98
4.04
0.00
0.03
0.89
0.80
0.01
0.11
0.21
0.02
1.80
0.02
Si
Ti
0.19
5.78
0.02
7.26
5.05
7.16
Al2O3
0.73
47.97
FeO
0.73
Cr2O3
47.78
SiO2
TiO2
82.38
8.74
40.88
48.88
4.04
0.00
0.03
0.93
0.78
0.01
0.17
0.00
0.11
0.20
0.02
1.80
98.33
0.00
0.39
23.01
13.83
0.17
5.27
0.08
7.08
0.66
47.83
82.89
8.48
41.08
49.10
4.04
0.00
0.03
0.94
0.79
0.00
0.16
0.00
0.10
0.19
0.02
1.81
98.82
0.00
0.36
23.45
14.10
0.13
5.19
0.01
6.72
0.65
48.20
83.21
8.27
40.98
49.65
4.04
0.00
0.02
0.95
0.79
0.00
0.16
0.00
0.09
0.20
0.02
1.80
98.59
0.00
0.29
23.69
14.05
0.13
5.05
0.06
6.49
0.78
48.06
82.59
8.51
40.39
49.54
4.05
0.00
0.03
0.95
0.77
0.00
0.16
0.00
0.11
0.22
0.02
1.78
98.80
0.00
0.41
23.57
13.81
0.09
5.19
0.05
7.34
0.85
47.48
82.27
8.99
41.70
48.25
4.04
0.00
0.02
0.94
0.81
0.01
0.17
0.00
0.07
0.16
0.02
1.84
98.52
0.02
0.28
23.28
14.46
0.21
5.56
0.06
5.22
0.65
48.78
84.43
7.61
41.29
49.96
4.03
0.00
0.02
0.95
0.79
0.00
0.15
0.00
0.10
0.18
0.02
1.82
98.54
0.00
0.30
23.76
14.11
0.16
4.64
0.04
6.34
0.74
48.45
78.64
10.80
39.74
47.58
4.04
0.00
0.04
0.90
0.75
0.01
0.20
0.00
0.13
0.22
0.02
1.78
98.78
0.00
0.48
22.22
13.34
0.25
6.46
0.11
7.89
0.71
47.32
78.99
10.36
38.95
48.95
4.04
0.00
0.03
0.93
0.74
0.00
0.20
0.00
0.12
0.21
0.02
1.79
99.11
0.00
0.45
23.04
13.18
0.16
6.25
0.08
7.57
0.72
47.68
79.84
10.01
39.65
48.64
4.05
0.00
0.03
0.93
0.76
0.00
0.19
0.00
0.11
0.21
0.02
1.79
98.55
0.02
0.44
22.95
13.44
0.13
6.05
0.14
7.31
0.67
47.39
78.43
11.67
42.43
44.65
4.04
0.00
0.02
0.85
0.81
0.00
0.22
0.00
0.11
0.21
0.02
1.79
98.94
0.03
0.33
21.16
14.45
0.09
7.08
0.09
7.44
0.64
47.64
79.45
10.35
40.01
48.17
4.04
0.00
0.03
0.92
0.76
0.01
0.20
0.00
0.11
0.21
0.02
1.79
98.96
0.00
0.38
22.76
13.59
0.19
6.27
0.13
7.32
0.65
47.67
79.64
10.12
39.61
48.83
4.04
0.00
0.03
0.92
0.75
0.01
0.19
0.00
0.12
0.21
0.02
1.79
98.40
0.00
0.37
22.81
13.30
0.16
6.06
0.11
7.37
0.72
47.50
79.08
10.67
40.32
47.58
4.04
0.00
0.03
0.91
0.77
0.00
0.20
0.00
0.11
0.21
0.02
1.79
98.74
0.00
0.38
22.47
13.68
0.10
6.45
0.10
7.37
0.72
47.47
79.54
10.17
39.53
48.97
4.04
0.00
0.03
0.93
0.75
0.01
0.19
0.00
0.11
0.21
0.02
1.79
98.87
0.01
0.35
23.11
13.41
0.16
6.15
0.07
7.37
0.74
47.50
80.48
9.64
39.74
49.35
4.04
0.00
0.02
0.94
0.76
0.00
0.18
0.00
0.11
0.21
0.02
1.79
98.94
0.00
0.33
23.35
13.51
0.06
5.84
0.13
7.29
0.76
47.67
80.25
10.14
41.20
47.33
4.04
0.00
0.03
0.91
0.79
0.00
0.19
0.00
0.10
0.20
0.02
1.80
98.54
0.04
0.35
22.47
14.06
0.10
6.16
0.12
6.71
0.68
47.85
80.00
10.05
40.22
48.36
4.04
0.00
0.03
0.92
0.76
0.00
0.19
0.00
0.11
0.21
0.02
1.79
98.78
0.01
0.36
22.79
13.63
0.12
6.07
0.09
7.41
0.76
47.54
79.88
10.03
39.83
48.84
4.04
0.00
0.02
0.92
0.75
0.01
0.19
0.00
0.12
0.22
0.02
1.78
98.73
0.01
0.34
22.91
13.43
0.17
6.03
0.15
7.54
0.76
47.38
79.40
10.31
39.74
48.59
4.04
0.00
0.03
0.93
0.76
0.00
0.20
0.00
0.11
0.22
0.02
1.78
99.12
0.00
0.36
23.02
13.53
0.13
6.26
0.13
7.41
0.79
47.50
79.48
10.31
39.92
48.38
4.04
0.00
0.03
0.92
0.76
0.00
0.20
0.00
0.11
0.21
0.02
1.79
98.21
0.00
0.36
22.69
13.46
0.14
6.19
0.05
7.28
0.77
47.26
83.88
8.16
42.45
48.33
4.04
0.00
0.02
0.94
0.82
0.00
0.16
0.00
0.08
0.17
0.02
1.83
98.61
0.00
0.28
23.29
14.71
0.11
5.04
0.09
5.51
0.62
48.96
Sample M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113
Table 4. (Continued).
ÖZKAN and ÇELİK / Turkish J Earth Sci
179
ÖZKAN and ÇELİK / Turkish J Earth Sci
0.0
tschermakite
0.5
ferrotschermakite
Diagram parameter
CaB>1.50
(Na+K)A<0.50
CaA<0.50
Si 5.5
Si 6.5
0.0
1.0
Mg/(Mg+Fe2+)
Mg/(Mg+Fe2+)
0.5
1.0
magnesiohastingsite
hastingsite
0.5
Diagram parameter
CaB>1.50
(Na+K)A>0.50
iv
Al>Fe 3+
Si 5.5
Si 6.5
0
pargasite
Mg/(Mg+Fe2+)
1.0
gabbro (M-006)
websterite (M-105)
clinopyroxenite (M-113)
ferropargasite
Diagram parameter
CaB>1.50
(Na+K)A>0.50
iv
Al
Si 5.5
Si 6.5
Figure 8. Chemical composition of amphiboles from pyroxenite and gabbro samples (after Leake et al. (1997)).
magmatic banding, ranging from centimeter to meter
scale, and re-fertilization of magma chambers in arcrelated environments.
Al-rich spinel minerals can be observed in diverse
rock types and there are different arguments regarding
their origins (e.g., Della-pasqua et al., 1995; Gargiulo et al.,
2013). For example, the presence of Al-rich spinels in pelitic
and basic–ultrabasic rocks is commonly taken as evidence
for amphibolite or granulite facies metamorphism (e.g.,
Evans and Frost, 1975; Bucher and Frey, 2002; Rodriguez
et al., 2012; Gargiulo et al., 2013). On the other hand, it
is stated that the Al-rich spinels can primarily crystallize
from basaltic melts (e.g., Della-pasqua et al., 1995; Babu et
al., 1997; Ho et al., 2000; Melcher et al., 2002; Amortegui
et al., 2011; Daczko et al., 2012), or formed by metasomatic
processes (e.g., Claeson, 1998; Franz and Wirth, 2000).
Al-rich spinels in magmatic or metamorphic rocks
can be observed in between minerals showing reaction
textures (e.g., corona texture). For example, pleonaste
is extensively observed in the reaction texture between
olivine and plagioclase in olivine-gabbro and troctolite
(e.g., Claeson, 1998; Jan et al., 1992; Berger et al., 2010;
Urraza et al., 2015; Khanchuk and Vysotskiy, 2016).
This reaction is expressed by:
(i) plagioclase + olivine ± H2O = clinopyroxene +
orthopyroxene + spinel ± amphibole.
However, we have not observed any such texture in our
pleonaste-bearing gabbros or pyroxenites.
It is suggested that the mineral phases with Al, such
as corundum, sapphirine, and garnet, which are mostly
formed during the metamorphic processes of basic–
ultrabasic rocks, are closely related to the Al-rich spinel
formation (e.g., Mukhopadhyay, 1991; Morishita et al.,
180
2001; Konzett et al., 2005; Yang, 2006). Some of the
proposed reactions are as follows:
(ii) corundum + clinopyroxene = spinel + plagioclase
(iii) sapphirine + clinopyroxene = spinel + plagioclase
(iv) garnet = orthopyroxene + spinel + plagioclase
(v) clinopyroxene + orthopyroxene + garnet + H2O =
amphibole + spinel.
Another reaction that produces pleonaste, (vi), involves
chlorite (Al-rich) in serpentinized ultramafic rocks (Evans
and Frost, 1975; Bucher and Frey, 2002).
(vi) chlorite = olivine + orthopyroxene + spinel + H2O
Pleonaste occurrence in the investigated rocks is
not related to the above-mentioned metamorphic or
metasomatic reactions, because corundum, sapphirine,
and garnet are not in the mineral association of the
pleonaste-bearing pyroxenite and gabbros. Moreover, the
reaction textures in the investigated rocks do not exist and
pleonaste is mostly observed together with clinopyroxenes.
The presence of Al-rich spinels and the absence of
garnet in the metabasic rocks indicate low pressures (<4
kbar) amphibolite or granulite facies conditions (e.g.,
Bucher and Frey, 2002; Rodriguez et al., 2012). However,
relatively high pressures have been inferred for the Al-rich
spinel-bearing mafic–ultramafic xenoliths of volcanic rocks
(e.g., Montanini et al., 1992; Ho et al., 2000). The high AlVI/
AlIV ratio (0.41–0.59) of clinopyroxenes from pleonastebearing pyroxenites suggests relatively high pressure
conditions for the crystallization (e.g., Wass, 1979). It was
reported that conditions of the magmatic crystallization
for these kinds of rocks, containing pleonaste, are between
5 and 12 kbar (e.g., DeBari and Coleman, 1989; Montanini
et al., 1992; Khanhcuk and Vysotskiy, 2016). Equilibrium
condition for the temperature of ultramafic cumulate
1.46
1.59
12.46
0.03
6.88
0.05
16.07
12.02
TiO2
Al2O3
Cr2O3
FeO
MnO
MgO
CaO
0.43
0.38
6.41
0.17
1.59
0.53
0.00
0.40
0.43
0.01
3.46
1.86
0.49
0.11
2.00
17.46
88.88
Al(vi)
Cr
2+
Ti
Al(iv)
3+
Si
Mn
Mg
Ca
Na
K
OH*
Sum
Cat#
Mg#
Fe
Fe
0.00
95.83
Total
1.77
90.30
17.45
2.00
0.10
0.49
1.86
3.52
0.01
0.50
1.56
0.16
6.44
96.55
0.52
1.75
0.60
Na2O
K2O
12.17
16.51
0.11
6.72
0.03
12.22
45.03
44.36
SiO2
90.75
17.47
2.00
0.10
0.50
1.87
3.48
0.01
0.36
0.50
0.04
0.44
1.68
0.18
6.32
95.12
0.56
1.76
11.99
16.05
0.06
7.01
0.33
12.30
1.65
43.40
87.34
17.50
2.00
0.10
0.52
1.89
3.46
0.00
0.50
0.35
0.03
0.51
1.58
0.16
6.42
96.52
0.53
1.86
12.26
16.15
0.02
7.05
0.22
12.34
1.44
44.66
92.52
17.43
2.00
0.10
0.52
1.82
3.52
0.00
0.28
0.57
0.00
0.47
1.59
0.15
6.41
98.02
0.55
1.89
12.06
16.79
0.04
7.23
0.03
12.43
1.40
45.59
89.33
17.49
2.00
0.10
0.53
1.87
3.47
0.01
0.41
0.42
0.03
0.49
1.64
0.17
6.36
96.21
0.53
1.88
12.12
16.14
0.12
6.92
0.26
12.53
1.54
44.17
90.70
17.46
2.00
0.09
0.53
1.84
3.47
0.01
0.36
0.52
0.02
0.46
1.62
0.16
6.38
96.48
0.49
1.91
11.99
16.26
0.10
7.29
0.16
12.32
1.45
44.52
88.99
17.46
2.00
0.09
0.49
1.88
3.46
0.01
0.43
0.42
0.01
0.50
1.61
0.17
6.39
96.06
0.50
1.76
12.14
16.10
0.09
7.05
0.11
12.39
1.57
44.33
90.63
17.45
2.00
0.12
0.50
1.84
3.48
0.01
0.36
0.47
0.09
0.43
1.61
0.17
6.39
97.33
0.67
1.80
12.04
16.39
0.06
6.96
0.78
12.17
1.55
44.92
88.67
17.49
2.00
0.11
0.52
1.86
3.47
0.00
0.44
0.41
0.07
0.45
1.60
0.16
6.40
97.28
0.60
1.88
12.19
16.31
0.04
7.11
0.62
12.15
1.50
44.87
90.98
17.43
2.00
0.09
0.50
1.83
3.51
0.01
0.35
0.51
0.07
0.40
1.56
0.16
6.44
97.09
0.51
1.81
12.02
16.52
0.06
7.18
0.60
11.68
1.48
45.24
91.55
17.43
2.00
0.10
0.51
1.83
3.45
0.01
0.32
0.54
0.09
0.43
1.63
0.16
6.37
97.00
0.54
1.83
11.95
16.23
0.12
7.16
0.78
12.27
1.49
44.63
92.04
17.43
2.00
0.09
0.50
1.84
3.52
0.01
0.30
0.53
87.90
17.61
2.00
0.07
0.68
1.86
3.20
0.02
0.44
0.49
0.01
0.63
0.41
0.07
2.02
0.20
5.98
97.12
0.40
2.44
12.10
14.95
0.16
7.79
0.11
15.65
1.86
41.66
1.59
0.15
6.41
97.85
0.47
1.84
12.19
16.74
0.09
7.07
0.63
12.02
1.41
45.40
88.51
17.63
2.00
0.07
0.70
1.86
3.22
0.01
0.42
0.53
0.02
0.60
2.05
0.21
5.95
97.45
0.39
2.52
12.12
15.08
0.07
7.90
0.14
15.73
1.93
41.56
89.79
17.60
2.00
0.07
0.68
1.86
3.22
0.02
0.37
0.58
0.01
0.60
2.05
0.21
5.95
97.14
0.36
2.43
12.10
15.08
0.16
7.86
0.08
15.69
1.90
41.47
90.30
17.60
2.00
0.08
0.69
1.84
3.23
0.01
0.35
0.61
0.01
0.59
2.06
0.20
5.94
97.51
0.41
2.48
12.03
15.18
0.08
8.02
0.06
15.74
1.89
41.60
88.15
17.63
2.00
0.07
0.68
1.88
3.21
0.01
0.43
0.56
0.01
0.57
2.06
0.20
5.94
97.66
0.38
2.46
12.26
15.04
0.12
8.29
0.11
15.59
1.90
41.50
88.67
17.64
2.00
0.07
0.70
1.88
3.24
0.01
0.41
0.53
0.02
0.58
2.06
0.21
5.94
97.07
0.38
2.50
12.18
15.14
0.07
7.84
0.15
15.59
1.92
41.31
86.40
17.64
2.00
0.07
0.68
1.88
3.18
0.01
0.50
0.43
0.01
0.65
2.04
0.21
5.96
96.69
0.40
2.43
12.17
14.78
0.09
7.68
0.10
15.83
1.97
41.25
88.46
17.61
2.00
0.07
0.67
1.87
3.22
0.01
0.42
0.50
0.01
0.63
2.04
0.21
5.96
96.16
0.37
2.38
12.06
14.92
0.07
7.63
0.06
15.60
1.89
41.17
87.31
17.69
2.00
0.07
0.72
1.89
3.22
0.01
0.47
0.50
0.01
0.58
2.08
0.21
5.92
97.25
0.41
2.59
12.26
15.02
0.11
8.01
0.08
15.71
1.91
41.16
88.30
17.64
2.00
0.07
0.68
1.89
3.23
0.01
0.43
0.52
0.01
0.60
2.07
0.21
5.93
97.22
0.39
2.46
12.26
15.06
0.11
7.89
0.09
15.75
1.92
41.29
88.45
17.64
2.00
0.08
0.68
1.89
3.22
0.01
0.42
0.50
0.02
0.62
2.08
0.21
5.92
96.82
0.41
2.43
12.22
15.00
0.07
7.63
0.16
15.94
1.92
41.04
Sample M-105 M-105 M-105 M-105 M-105 M-105 M-105 M-105 M-105 M-105 M-105 M-105 M-105 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113
Table 5. Amphibole analysis from websterite (M-105), clinopyroxenite (M-113), and gabbro (M-006) samples.
ÖZKAN and ÇELİK / Turkish J Earth Sci
181
182
0.01
3.24
1.89
0.67
0.07
2.00
17.62
89.08
Mn
Mg
Ca
Na
K
OH*
Sum
Cat#
Mg#
86.59
17.67
2.00
0.09
0.69
1.89
3.23
0.00
0.50
0.62
2.03
0.40
Al(vi)
Fe2+
0.59
Al(iv)
0.21
5.97
0.00
2.06
Ti
0.42
0.21
Si
96.47
0.48
0.01
5.94
Total
0.54
96.74
K2O
12.19
2.44
Fe3+
0.39
Na2O
Cr
12.22
2.38
CaO
14.98
0.02
86.63
17.68
2.00
0.09
0.69
1.91
3.25
0.00
0.50
0.41
0.01
0.62
2.06
0.21
5.94
96.62
0.46
2.44
12.33
15.04
0.03
89.27
17.66
2.00
0.07
0.66
1.93
3.29
0.01
0.40
0.50
0.02
0.57
2.12
0.22
5.88
95.01
0.40
2.31
12.24
15.00
0.08
88.55
17.62
2.00
0.08
0.66
1.88
3.24
0.00
0.42
0.50
0.01
0.62
2.06
0.22
5.94
96.16
0.42
2.36
12.11
14.98
0.02
87.38
17.64
2.00
0.08
0.66
1.89
3.23
0.01
0.47
0.43
0.01
0.64
2.03
0.21
5.97
95.94
0.45
2.35
12.13
14.88
0.10
7.40
89.00
17.63
2.00
0.08
0.66
1.88
3.23
0.02
0.40
0.52
0.01
0.62
2.06
0.20
5.94
96.10
0.46
2.36
12.07
14.93
0.12
7.60
88.83
17.61
2.00
0.07
0.66
1.88
3.26
0.01
0.41
0.49
0.00
0.61
2.02
0.21
5.98
95.85
0.37
2.34
12.08
15.06
0.08
7.43
0.00
15.37
93.27
17.58
2.00
0.07
0.64
1.86
3.32
0.01
0.24
0.71
0.01
0.52
2.05
0.19
5.95
96.23
0.40
2.30
12.01
15.42
0.09
7.86
0.09
15.15
89.06
17.65
2.00
0.08
0.67
1.90
3.30
0.02
0.41
0.47
0.01
0.60
2.03
0.20
5.97
95.61
0.41
2.38
12.18
15.20
0.14
7.15
0.08
15.28
88.03
17.64
2.00
0.07
0.67
1.90
3.24
0.01
0.44
0.47
0.01
0.63
2.06
0.21
5.94
95.54
0.39
2.36
12.15
14.89
0.05
7.43
0.06
15.65
86.32
17.69
2.00
0.08
0.67
1.93
3.23
0.01
0.51
0.36
0.02
0.65
2.08
0.22
5.92
96.44
0.45
2.40
12.41
14.96
0.06
7.21
0.14
15.97
87.22
17.66
2.00
0.09
0.66
1.92
3.23
0.01
0.47
0.36
0.02
86.34
17.71
2.00
0.09
0.66
1.95
3.18
0.01
0.50
0.33
0.01
2.20
0.72
2.10
0.24
5.80
94.94
0.49
2.31
12.37
14.49
0.08
6.76
0.08
16.84
2.19
0.68
0.23
5.90
95.82
0.46
2.33
12.29
14.85
0.08
6.85
0.19
16.19
2.09
88.96
17.56
2.00
0.10
0.63
1.84
3.11
0.01
0.39
0.68
0.00
0.63
2.07
0.18
5.93
96.50
0.52
2.25
11.86
14.44
0.07
8.84
0.02
15.85
1.66
40.99
88.00
17.58
2.00
0.10
0.65
1.84
3.11
0.01
0.42
0.64
0.01
0.63
2.06
0.18
5.94
96.61
0.52
2.31
11.86
14.42
0.06
8.80
0.11
15.77
1.67
41.09
85.28
17.62
2.00
0.10
0.65
1.88
3.08
0.01
0.53
0.55
0.00
0.64
2.06
0.19
5.94
96.95
0.54
2.31
12.11
14.30
0.05
8.95
0.00
15.90
1.71
41.08
88.61
17.55
2.00
0.10
0.59
1.86
3.13
0.01
0.40
0.65
0.00
0.62
2.06
0.18
5.94
96.40
0.52
2.12
12.01
14.49
0.07
8.72
0.01
15.74
1.68
41.04
85.88
17.64
2.00
0.10
0.63
1.91
3.10
0.01
0.51
0.60
0.01
0.60
2.09
0.17
5.91
96.48
0.53
2.25
12.24
14.32
0.07
9.11
0.06
15.71
1.55
40.64
88.80
17.63
2.00
0.10
0.64
1.89
3.13
0.02
0.39
0.74
0.01
0.55
2.15
0.17
5.85
96.62
0.53
2.29
12.14
14.47
0.13
9.33
0.05
15.77
1.56
40.35
88.61
17.60
2.00
0.09
0.64
1.87
3.12
0.02
0.40
0.71
0.01
0.55
2.10
0.18
5.90
96.39
0.48
2.28
12.00
14.42
0.17
9.17
0.08
15.50
1.65
40.65
87.56
17.60
2.00
0.09
0.65
1.86
3.12
0.01
0.44
0.67
0.01
0.59
2.07
0.17
5.93
96.88
0.47
2.33
12.04
14.47
0.07
9.19
0.05
15.61
1.59
41.05
94.38
17.57
2.00
0.08
0.65
1.84
3.20
0.01
0.19
0.94
0.00
0.47
2.17
0.17
5.83
95.14
0.43
2.28
11.73
14.67
0.11
9.25
0.01
15.35
1.57
39.76
91.97
17.54
2.00
0.07
0.63
1.83
3.17
0.01
0.28
0.82
0.00
0.56
2.06
0.16
5.94
97.12
0.41
2.26
11.94
14.86
0.09
9.13
0.01
15.55
1.46
41.43
15.08
7.58
0.08
15.68
2.02
39.32
0.12
7.30
0.06
15.60
1.88
40.47
MgO
7.53
0.07
15.67
1.83
40.81
MnO
7.59
0.14
15.51
1.73
40.68
7.77
0.11
15.67
1.93
40.96
FeO
0.04
15.56
1.88
41.18
0.08
1.93
41.19
15.63
2.00
40.92
Cr2O3
2.01
41.03
Al2O3
1.94
40.96
1.97
1.90
TiO2
40.02
41.20
41.18
SiO2
41.06
M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113
Sample
Table 5. (Continued).
ÖZKAN and ÇELİK / Turkish J Earth Sci
ÖZKAN and ÇELİK / Turkish J Earth Sci
Table 5. (Continued).
Sample
M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-113 M-006 M-006 M-006 M-006 M-006 M-006
SiO2
40.37
40.61
40.66
40.77
40.80
40.48
40.80
40.56
39.82
40.55
40.20
40.32
40.29
40.04
40.82
TiO2
1.64
1.68
1.60
1.66
1.53
1.58
1.70
1.67
1.56
2.96
2.95
1.81
2.73
3.11
2.76
Al2O3
15.48
15.54
15.54
15.32
15.34
15.82
15.55
15.78
15.86
15.66
15.82
16.74
16.04
15.66
15.52
Cr2O3
0.07
0.01
0.05
0.08
0.11
0.08
0.05
0.07
0.11
0.00
0.02
0.02
0.01
0.02
0.01
FeO
9.37
9.28
8.64
8.63
8.85
8.46
8.78
8.72
8.35
12.25
12.58
12.03
11.91
12.64
11.59
MnO
0.09
0.04
0.08
0.12
0.07
0.06
0.11
0.12
0.11
0.19
0.15
0.12
0.11
0.17
0.10
MgO
14.43
14.27
14.23
14.31
14.49
14.44
14.41
14.45
14.43
12.39
12.32
12.57
12.30
12.20
12.33
CaO
12.15
12.13
12.17
11.99
11.86
12.20
12.17
11.99
12.09
10.70
10.85
10.85
11.24
10.72
11.19
Na2O
2.29
2.29
2.29
2.31
2.19
2.26
2.30
2.29
2.26
2.58
2.61
2.59
2.44
2.52
2.31
K2O
0.53
0.54
0.53
0.51
0.47
0.54
0.53
0.58
0.56
0.64
0.55
0.66
0.68
0.58
0.61
Total
96.41
96.40
95.80
95.70
95.70
95.93
96.38
96.21
95.14
97.91
98.05
97.72
97.74
97.65
97.24
Si
5.88
5.91
5.96
5.97
5.95
5.91
5.94
5.90
5.86
5.85
5.80
5.80
5.84
5.80
5.94
Ti
0.18
0.18
0.18
0.18
0.17
0.17
0.19
0.18
0.17
0.32
0.32
0.20
0.30
0.34
0.30
Al(iv)
2.12
2.09
2.04
2.03
2.05
2.09
2.06
2.10
2.14
2.15
2.20
2.20
2.16
2.20
2.06
Al(vi)
0.53
0.58
0.64
0.61
0.58
0.63
0.60
0.60
0.61
0.51
0.49
0.64
0.58
0.47
0.60
Cr
0.01
0.00
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.00
0.00
0.00
0.00
0.00
0.00
Fe
3+
0.69
0.60
0.47
0.53
0.71
0.54
0.54
0.64
0.61
0.85
0.88
0.97
0.67
0.91
0.60
Fe
2+
0.45
0.53
0.59
0.53
0.37
0.49
0.52
0.42
0.41
0.63
0.64
0.48
0.77
0.62
0.81
Mn
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0.01
0.02
0.02
0.02
0.01
0.02
0.01
Mg
3.13
3.10
3.11
3.12
3.15
3.14
3.12
3.13
3.16
2.66
2.65
2.70
2.66
2.63
2.67
Ca
1.89
1.89
1.91
1.88
1.85
1.91
1.90
1.87
1.91
1.65
1.68
1.67
1.75
1.66
1.74
Na
0.64
0.65
0.65
0.65
0.62
0.64
0.65
0.64
0.64
0.72
0.73
0.72
0.69
0.71
0.65
K
0.10
0.10
0.10
0.10
0.09
0.10
0.10
0.11
0.10
0.12
0.10
0.12
0.13
0.11
0.11
OH*
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
Sum Cat# 17.64
17.64
17.66
17.63
17.56
17.65
17.64
17.62
17.65
17.49
17.51
17.52
17.56
17.48
17.51
Mg#
85.47
84.14
85.58
89.45
86.45
85.62
88.17
88.46
80.82
80.58
85.00
77.55
80.84
76.78
87.51
rocks is between 660 and 920 °C, based on the twopyroxene geothermometer of Wells (1977) and Brey and
Köhler (1990).
In previous studies, the ophiolitic mafic–ultramafic
rocks of the study area were interpreted to be
metamorphosed in epidote–amphibolite (Akbayram et
al., 2013) or amphibolite facies (Yılmaz et al., 1995). As
can be seen, both the textural/mineralogical properties
and wide range of temperature/pressure conditions do
not clarify whether the investigated rocks were subjected
to metamorphism. P-T pseudosection modeling was
performed on a gabbro sample to test whether the ophiolitic
rocks of the study area were subjected to metamorphism
in amphibolite or granulite facies conditions.
7.1. Pseudosection modelling
Pseudosection modeling, which is one of the most
important methods for obtaining thermobarometric
information on rocks, has been widely used over the
last decade. It allows interpretation about the textural
evolution and mineral compositions of rocks in terms of
pressure–temperature (P-T) paths (Powell and Holland,
2008).
P-T pseudosections have been calculated for the
amphibole-bearing gabbro sample. Thermodynamic
modelling of mineral assemblages and compositions
was carried out using the Theriak/Domino software (de
Capitani and Brown, 1987; de Capitani and Petrakakis,
2010) with the internally consistent thermodynamic
183
ÖZKAN and ÇELİK / Turkish J Earth Sci
Table 6. Plagioclase analysis from gabbro (M-006) sample.
Sample
M-006
M-006
M-006
M-006
M-006
M-006
M-006
M-006
M-006
M-006
M-006
SiO2
45.14
45.41
45.36
45.55
45.69
45.68
45.70
45.72
45.22
45.31
45.72
TiO2
0.01
0.00
0.00
0.00
0.03
0.01
0.00
0.01
0.02
0.02
0.01
Al2O3
34.38
34.42
34.38
34.26
34.23
34.31
34.10
34.09
34.39
34.24
33.77
Cr2O3
0.00
0.03
0.03
0.00
0.01
0.00
0.00
0.00
0.00
0.00
0.01
FeO
0.16
0.10
0.11
0.14
0.06
0.15
0.09
0.08
0.10
0.10
0.16
MnO
0.03
0.00
0.01
0.03
0.02
0.00
0.00
0.05
0.02
0.00
0.00
MgO
0.01
0.01
0.00
0.02
0.00
0.02
0.00
0.00
0.00
0.01
0.04
CaO
17.59
17.75
17.76
17.46
17.44
17.37
17.50
17.60
17.98
17.54
17.39
Na2O
1.40
1.46
1.38
1.56
1.53
1.55
1.51
1.50
1.29
1.55
1.62
K2O
0.15
0.03
0.03
0.01
0.00
0.01
0.00
0.04
0.02
0.04
0.02
Total
98.88
99.21
99.05
99.04
99.01
99.10
98.90
99.09
99.02
98.80
98.73
Si
2.11
2.11
2.11
2.12
2.12
2.12
2.13
2.12
2.10
2.11
2.13
Ti
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Al
1.89
1.88
1.88
1.88
1.87
1.88
1.87
1.87
1.89
1.88
1.86
Cr
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Fe 2+
0.01
0.00
0.00
0.01
0.00
0.01
0.00
0.00
0.00
0.00
0.01
3+
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Mn
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Mg
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Fe
Ca
0.88
0.88
0.88
0.87
0.87
0.86
0.87
0.88
0.90
0.88
0.87
Na
0.13
0.13
0.12
0.14
0.14
0.14
0.14
0.14
0.12
0.14
0.15
K
0.01
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
0.00
Total
5.02
5.02
5.01
5.01
5.01
5.01
5.01
5.01
5.01
5.02
5.01
Ab
12.50
12.94
12.28
13.94
13.68
13.88
13.51
13.33
11.47
13.73
14.38
An
86.60
86.85
87.53
86.01
86.30
86.06
86.49
86.46
88.44
86.07
85.50
Or
0.90
0.20
0.18
0.05
0.02
0.06
0.00
0.22
0.09
0.21
0.12
dataset given by Holland and Powell (1998; created in
November 2003 update). Solution models for feldspars
are taken from Holland and Powell (2003) and Baldwin
et al. (2005); epidote is from Holland and Powell (1998);
garnet, ilmenite, and liquid are from White et al. (2007);
clinopyroxene and amphibole are from Diener et al. (2007);
and orthopyroxene is from White et al. (2002, 2007). The
calculation was undertaken in the Na2O–CaO–FeO–
MgO–Al2O3–SiO2–H2O–TiO2 chemical model system.
Due to absence of MnO- or K2O-bearing mineral phases
(e.g., garnet and mica), these components are neglected for
simplicity. The LOI value (1.70 wt.%) was considered H2O
because the mineral phase containing H2O in the rock was
only amphibole and no other aqueous alteration minerals
(e.g., chlorite and epidote) were present in the rock.
The normalized molar percent composition of the
rock is given in the pseudosection graphic (Figure 11).
184
Pseudosection calculations were conducted at 600–950
°C and 3–10 kbar to cover the amphibolite and granulite
facies conditions. Calculated XAn isoplets of plagioclase
have been also shown in the pseudosection of the gabbro
sample (Figure 11). Amphibole, plagioclase, and ilmenite
minerals are present in all areas of the graphic. However,
some minerals (e.g., olivine, garnet, epidote) that are not
seen in the mineral paragenesis of the rock are present in the
equilibrium mineral assemblage of the diagram. Moreover,
while the XAn content of the plagioclase of the gabbro
ranges from 0.85 to 0.88, the isopleths of the plagioclase
on the P-T pseudosection never reach 0.85, even at high
temperature conditions (Figure 11). Since the equilibrium
mineral assemblage of the gabbro is incompatible with the
pseudosection, the pleonaste-bearing ophiolitic mafic–
ultramafic rocks were not subjected to amphibolite or
granulite facies conditions.
ÖZKAN and ÇELİK / Turkish J Earth Sci
Table 7. Whole rock (% wt.) trace and rare earth element (ppm) analyses for ultramafic and mafic cumulate rocks from the Armutlu
peninsula.
Rock
Ultramafic cumulates
Sample
M-048
M-052
M-102
M-003
M-043
M-045
M-105
Mafic cumulates
M-005
M-006
M-049
M-051
M-114
M-117
SiO2
TiO2
Al2O3
Fe2O3tot
MnO
MgO
CaO
Na2O
K2O
Cr2O3
LOI
Total
49.30
0.18
2.10
5.45
0.14
22.48
18.06
0.18
0.07
0.13
1.97
100.06
49.00
0.30
3.15
6.65
0.15
20.51
19.60
0.19
0.06
0.12
0.50
100.24
49.24
0.27
3.49
5.45
0.18
20.71
19.43
0.46
0.08
0.26
0.57
100.14
50.25
0.32
4.59
5.21
0.17
20.19
18.87
0.59
0.06
0.15
0.44
100.83
50.12
0.17
3.08
9.60
0.26
28.07
7.79
0.19
0.06
0.31
1.00
100.64
51.59
0.23
3.04
8.39
0.22
24.64
11.72
0.20
0.02
0.23
0.36
100.66
50.99
0.37
4.61
6.48
0.18
19.30
17.08
0.36
0.14
0.22
0.51
100.24
50.07
0.57
13.51
6.91
0.15
11.19
13.67
2.45
0.08
0.04
1.10
99.74
44.23
1.15
24.53
5.82
0.06
4.56
13.45
2.62
0.92
0.02
1.70
99.05
46.01
0.28
15.13
6.76
0.10
12.10
16.76
1.05
0.07
0.05
1.41
99.74
47.76
1.97
14.41
12.74
0.19
7.51
11.74
3.05
0.14
0.04
0.62
100.18
49.75
0.35
13.85
6.06
0.14
11.13
15.67
1.60
0.13
0.07
1.03
99.79
44.56
1.95
13.88
13.97
0.21
9.25
11.77
2.75
0.11
0.05
1.41
99.91
79.28
382.77
0.20
22.25
8.60
b.l.
b.l.
0.06
2.57
0.21
b.l.
0.55
b.l.
b.l.
334.00
61.06
474.46
0.09
32.93
10.19
7.16
b.l.
0.02
1.40
0.38
b.l.
0.30
b.l.
b.l.
297.80
56.59
292.85
0.46
63.23
13.21
6.05
0.21
0.10
0.41
0.46
0.01
0.21
b.l.
b.l.
308.37
97.18
1358.94
1.32
19.55
3.65
b.l.
b.l.
0.14
3.34
0.07
0.00
0.41
b.l.
b.l.
173.27
80.85
174.12
0.14
17.12
5.52
b.l.
b.l.
0.04
1.13
0.12
b.l.
0.39
b.l.
b.l.
247.00
70.76
663.85
0.62
70.47
13.56
17.61
0.17
0.02
7.30
0.61
b.l.
0.49
b.l.
b.l.
301.64
41.48
93.16
0.77
158.51
12.13
19.05
0.79
0.12
5.51
0.66
0.06
0.71
b.l.
b.l.
253.85
41.12
69.31
14.31
712.34
15.03
5.95
0.72
0.68
81.70
0.46
0.04
0.53
b.l.
b.l.
459.51
62.66
155.94
0.74
299.38
6.02
b.l.
b.l.
0.04
8.69
0.14
b.l.
0.46
b.l.
b.l.
232.34
58.69
64.96
4.68
414.70
37.42
55.31
2.18
4.00
35.74
1.68
0.14
0.34
b.l.
b.l.
541.55
58.66
79.62
5.16
256.96
41.21
56.53
2.18
8.59
32.70
1.62
0.10
0.21
b.l.
b.l.
660.72
51.00
211.28
5.25
179.48
14.10
10.05
0.10
0.08
13.70
0.36
b.l.
0.48
b.l.
b.l.
283.94
0.47
2.08
0.46
3.43
1.11
0.32
1.32
0.25
1.60
0.33
0.92
0.13
0.78
0.11
0.80
0.43
0.28
1.71
88.28
0.59
2.84
0.63
3.97
1.56
0.51
1.87
0.36
2.41
0.52
1.46
0.21
1.32
0.20
0.91
0.32
0.25
1.32
88.49
0.33
1.01
0.18
1.04
0.38
0.13
0.47
0.09
0.58
0.13
0.38
0.06
0.39
0.06
0.91
0.60
0.56
1.09
85.28
0.53
1.80
0.30
1.66
0.56
0.16
0.67
0.13
0.89
0.19
0.56
0.08
0.54
0.08
0.80
0.70
0.61
1.16
85.33
1.87
6.32
1.10
6.09
1.82
0.54
1.99
0.35
2.13
0.43
1.24
0.17
1.04
0.15
0.87
1.28
0.66
1.98
85.51
1.30
3.61
0.58
3.02
1.14
0.58
1.47
0.30
2.06
0.45
1.28
0.18
1.16
0.17
1.37
0.81
0.74
1.09
76.25
1.30
4.00
0.73
4.72
1.69
0.73
2.07
0.40
2.65
0.56
1.58
0.22
1.31
0.19
1.18
0.71
0.50
1.50
60.80
0.26
0.96
0.20
1.38
0.59
0.29
0.79
0.16
1.04
0.22
0.59
0.08
0.48
0.07
1.30
0.38
0.28
1.46
78.00
2.23
8.27
1.59
9.78
3.65
1.45
4.49
0.89
5.89
1.27
3.59
0.50
3.14
0.47
1.10
0.51
0.39
1.30
53.87
1.70
7.36
1.49
9.48
3.54
1.29
4.53
0.91
6.07
1.31
3.79
0.53
3.37
0.49
0.99
0.42
0.31
1.19
78.43
0.66
1.95
0.37
2.59
1.04
0.54
1.41
0.29
1.96
0.42
1.24
0.17
1.11
0.16
1.37
0.36
0.41
1.08
56.75
Trace elements (ppm)
Co
Ni
Rb
Sr
Y
Zr
Nb
Cs
Ba
Hf
Ta
Pb
Th
U
V
62.67
349.47
0.06
16.37
3.76
b.l.
b.l.
0.05
0.66
b.l.
b.l.
0.15
b.l.
b.l.
181.75
Rare earth elements (ppm)
La
Ce
Pr
Nd
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu
Eu/Eu*
(La/Yb)N
(La/Sm)N
(Sm/Lu)N
Mg#
0.14
0.58
0.13
0.88
0.41
0.14
0.52
0.10
0.68
0.13
0.38
0.05
0.30
0.05
0.96
0.33
0.22
1.50
89.10
0.23
1.13
0.25
1.87
0.86
0.31
1.07
0.21
1.39
0.29
0.78
0.10
0.64
0.09
0.97
0.26
0.17
1.60
85.94
b.l: below detection. [Mg# = Molecular MgO/(MgO+FeO*)]
185
ÖZKAN and ÇELİK / Turkish J Earth Sci
102
101
(a)
(b)
average DMM
100
10-1
100
10-1
ultramafic cumulate
Rock / N-MORB
Rock / C1 Chondrite
ultramafic cumulate
101
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
102 (c)
N-MORB
E-MORB
10-2
Rb Th Nb K Ce Pr Nd Zr Eu Gd Dy Ho Tm Lu
Ba U Ta La Pb Sr Sm Hf Ti Tb Y Er Yb
102
(d)
mafic cumulate
mafic cumulate
Rock / N-MORB
Rock / C1 Chondrite
101
100
101
10-1
100
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Rb Th Nb K Ce Pr Nd Zr Eu Gd Dy Ho Tm Lu
Ba U Ta La Pb Sr Sm Hf Ti Tb Y Er Yb
10-2
Figure 9. (a, c) Chondrite-normalized REE patterns for ultramafic and mafic rocks. (b, d) N-MORB-normalized multi-element diagrams
of the same rocks. Normalizing values after Sun and McDonough (1989). Depleted MORB Mantle (DMM) values after Workman and
Hart (2005).
18
(a)
16
Non-orogenic
0.05
(b)
Arc
cum relate
u la d
te t
ren
d
0.06
14
12
10
0.03
Alz
Ti+Cr (apfu)
0.04
0.02
orogenic
0.01
6
d
ted
rela e tren
ft
i
R
lat
u
cum
4
wehrlite (M-101)
8
websterite (M-105)
2
0.00
clinopyroxenite (M-113)
0
0.6
0.7
0.8
0.9
Ca (apfu)
1.0
1.1
0.0
0.5
1.0
1.5
TiO2 (wt.%)
2.0
2.5
3.0
Figure 10. (a) The Ti + Cr versus Ca classification diagram (after Leterrier et al. (1982)). (b) Alz (percentage of tetrahedral sites occupied
by Al) versus TiO2 in clinopyroxenes (after Loucks (1990)). apfu: Atoms per formula units.
186
ÖZKAN and ÇELİK / Turkish J Earth Sci
pl+amp+ilm
present in all fields
(% Mol) Si(37.97)Ti(0.74)Al(24.82)Fe(4.18)Mg(5.84)Ca(12.37)Na(4.35)O(?)H(9.73)
ep
qz
H2O
H
gr
cp t
ep x
Garnet in
ol
cpx
melt
H 2O
6
ep
ido
te
in
7
cpx
H2O
0.7
0.6
ep
H2O
cpx
amp
melt
H2O
cpx
melt
ol
cpx
melt
0.8
Pressure (Kbar)
cpx
ep
H
2O
0.75
8
grt
cpx grt, cpx,
melt melt
H2O
grt
cpx
H 2O
2O
0.5
9
grt, ep, qz
ep
H2O
pg
qz
grt, ep,
H2O
H2O
0.8
0.4
10
5
0.75
ol
cpx
H2O
Melt in
Olivine in
4
3
600
650
700
750
800
Temperature (°C)
850
900
950
Figure 11. P-T pseudosection for gabbro sample, calculated by Theriak/Domino software
in the NCFMASTH system. Red dashed lines are the XAn isopleths of plagioclase.
Abbreviations used in the diagram follow Whitney and Evans (2010).
8. Conclusions
Dunite, wehrlite, clinopyroxenite, websterite, and
gabbros are the most common rock types in the
ophiolite of the accretionary complex at the eastern
part of the Armutlu peninsula. These rocks in the field
exhibit well-developed magmatic layers, which are the
main characteristic of mafic and ultramafic cumulate
rocks. The cumulate nature of the rocks is evident
in their textural (orthocumulate, adcumulate, and
mesocumulate) and geochemical characteristics (e.g.,
positive Eu anomaly).
Pleonaste in the clinopyroxenites and gabbros is
distinguished by its emerald greenish color under
the microscope. Pleonaste minerals in the mafic and
ultramafic cumulate rocks lie parallel to the magmatic
banding and are commonly observed as the skeletonshaped xenomorphic crystals, some of which have
clinopyroxene inclusions. Pleonaste-bearing rocks
consist mainly of clinopyroxene + orthopyroxene +
amphibole ± olivine ± plagioclase + spinel. Unlike
spinel minerals in ophiolitic rocks, Al-rich spinels with
pleonaste composition have high contents of Al2O3
(55.64 – 62.24 wt.%) and low Cr2O3 (0.05–1.32 wt.%).
Petrographical characteristics and the P-T
pseudosection modeling show that the mafic–ultramafic
rocks of the region were not metamorphosed in the
amphibolite or granulite facies. Amphibole minerals and
Ca-rich plagioclase in the mafic–ultramafic cumulates
(An % 85–88) are the important evidence of a hydrous
magma source. Moreover, clinopyroxene compositions
suggest that the mafic–ultramafic cumulates were
derived from the arc-related tholeiitic magma source.
Acknowledgments
This work is a part of the MSc study by Mutlu Özkan.
We thank Rahmi Melih Çörtük and Serdal Karaağaç for
their assistance during the field study. Andrea Marzoli
is thanked for electron microprobe analyses. We also
thank Aral Okay, İbrahim Uysal, and the anonymous
reviewers for their helpful suggestions.
187
ÖZKAN and ÇELİK / Turkish J Earth Sci
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