geochronological evidence and tectonic s
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Geochronological evidence and tectonic significance
of Carboniferous magmatism in the southwest Trabzon
area, eastern Pontides, TurkeyAbdullah Kaygusuz
a, Mehmet Arslan
b, Wolfgang Siebel
c, Ferkan Sipahi
a& Nurdane
Ilbeylid
aDepartment of Geological Engineering, Gmhane University, TR-29000 Gmhane,
TurkeybDepartment of Geological Engineering, Karadeniz Technical University, TR-61080 Trabzon
Turkey
cInstitute of Geosciences, Universitt Tbingen, D-72074 Tbingen, GermanydDepartment of Geological Engineering, Akdeniz University, TR-070058 Antalya, Turkey
Version of record first published: 05 Apr 2012.
To cite this article:Abdullah Kaygusuz, Mehmet Arslan, Wolfgang Siebel, Ferkan Sipahi & Nurdane Ilbeyli (2012):
Geochronological evidence and tectonic significance of Carboniferous magmatism in the southwest Trabzon area, eastern
Pontides, Turkey, International Geology Review, 54:15, 1776-1800
To link to this article: http://dx.doi.org/10.1080/00206814.2012.676371
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International Geology Review
Vol. 54, No. 15, November 2012, 17761800
Geochronological evidence and tectonic significance of Carboniferous magmatism
in the southwest Trabzon area, eastern Pontides, TurkeyAbdullah Kaygusuza*, Mehmet Arslanb , Wolfgang Siebelc , Ferkan Sipahia and Nurdane Ilbeylid
aDepartment of Geological Engineering, Gmshane University, TR-29000 Gmshane, Turkey;bDepartment of GeologicalEngineering, Karadeniz Technical University, TR-61080 Trabzon, Turkey; cInstitute of Geosciences, Universitt Tbingen, D-72074
Tbingen, Germany; dDepartment of Geological Engineering, Akdeniz University, TR-070058 Antalya, Turkey
(Accepted 12 March 2012)
The northern and southern zones of the eastern Pontides (northeast Turkey) contain numerous plutons of varying ages andcompositions. Geochemical and isotopic results on two Hercynian granitoid bodies located in the northern zone of theeastern Pontides allow a proper reconstruction of their origin for the first time. The intrusive rocks comprise four distinctbodies, two of which we investigated in detail. Based on LAICPMS UPb zircon dating, the Derinoba and Kayadibigranites have similar 206Pb/238U versus 207Pb/235U Concordia ages of 311.1 2.0 and 317.2 3.5 million years for theformer and 303.8 1.5 million years for the latter. Aluminium saturation index values of both granites are between 0.95 and
1.35, indicating dominant peraluminous melt compositions. Both intrusions have high SiO2(7477 wt.%) contents and showhigh-K calc-alkaline and I- to S-type characteristics. Primitive mantle-normalized element diagrams display enrichment in K,Rb, Th, and U, and depletion in Ba, Nb, Ta, Sr, P, and Ti. Chondrite-normalized rare earth element patterns are characterizedby concave-upward shapes and pronounced negative Eu anomalies with Lacn/Ybcn =4.69.7 and Eucn/Eu
=0.110.59
(Derinoba), and Lacn/Ybcn = 2.75.5 and Eucn/Eu= 0.310.37 (Kayadibi). These features imply crystal-melt fractionation
of plagioclase and K-feldspar without significant involvement of garnet. The Derinoba samples have initial Nd valuesbetween 6.1 and 7.1 with Nd model ages andTDMbetween 1.56 and 2.15 thousand million years. The Kayadibi samplesshow higher initial Nd(I) values, 4.5 to 6.2, with Nd model ages between 1.50 and 1.72 thousand million years. Thisstudy demonstrates that the Sr isotope ratios generally display negative correlation with Nd isotopes; Sr isotope ratios werelowered in some samples by hydrothermal interaction or alteration. Isotopic and petrological data suggest that both graniteswere produced by the partial melting of early Palaeozoic lower crustal rocks, with minor contribution from the mantle.Collectively, these rocks represent a late stage of Hercynian magmatism in the eastern Pontides.
Keywords: Carboniferous magmatism; UPb zircon dating; SrNdPb isotope; high-K; southwest Trabzon; easternPontides; Turkey
Introduction
The Pontide tectonic unit (Ketin 1966) includes various
intrusive and extrusive rocks, many of which are related
to the convergence of Eurasia and Gondwana (Figure 1A).
These Permo-Carboniferous rocks (ogulu 1975; Topuz
et al. 2004, 2010; Dokuz 2011) are present as basement
complexes in a terrane formed from the Cretaceous
Palaeocene (Ylmazet al. 2000; Boztuget al. 2006; Ilbeyli
2008; Kaygusuz et al. 2008, 2009, 2010; Kaygusuz and
Aydnakr 2009; Karsl et al. 2010; Sipahi 2011) to the
Eocene (Boztug et al. 2004; Topuz et al. 2005; Ylmaz-Sahin 2005; Arslan and Aslan 2006; Karsl et al. 2007;
Eyboglu etal. 2010, Figure 1B). Rock compositions range
from low-K through high-K calc-alkaline metaluminous
peraluminous granitoids to alkaline syenites (Ylmaz and
Boztug 1996). Igneous activity apparently occurred in
*Corresponding author. Email:[email protected]
various tectonic settings ranging from arc-collisional to
syn-collisional and post-collisional regimes (Ylmaz and
Boztug 1996; Okay and Sahintrk 1997; Ylmaz et al.
1997; Yegingilet al. 2002).
About 40% of the exposed Palaeozoic basement rocks
of the eastern Pontides are made up of granitoids. Despite
extensive exposure, these granitoids have received lit-
tle attention so far (e.g. Ylmaz 1974; ogulu 1975).
Thus, knowledge regarding Palaeozoic geological pro-
cesses in northeast Turkey is still insufficient, and precise
geochronological data are rare, thereby hampering the
understanding of the tectonic and magmatic evolution ofthis region. We report on our systematic research of two
newly mapped intrusions, the Derinoba and Kayadibi gran-
ites. New field-based observations, as well as geochemical,
geochronological, and SrNdPb isotope data from these
ISSN 0020-6814 print/ISSN 1938-2839 online
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International Geology Review 1777
1 2 3 4 5 6 7
Kse
40
40
Krtn
Torul
Trabzon
Maka
Gm hane pluton
Da ba
BLACK SEA
Kse plton
8
39
Tonya
9 10
B
zdil
Black Sea
Mediterranean SeaCyprus
Eurasianplate
NAFZ
Arabian plate
African plate
AegeanSea
EAFZ
DSFZ
0 200 km
42
36
39
33
4527 3933
A
Fig.2
Fig1b
N
0 5 km
Figure 1. (A) Tectonic map of Turkey and surroundings (modified after Sengret al. (2003)). (B) Distribution of plutonic and volcanicunits in the eastern Pontides (modified from Gven (1993)). (1) Palaeozoic metamorphic rocks, (2) Palaeozoic granitoids, (3) LiassicDogger volcanic rocks, (4) MalmLower Cretaceous sedimentary rocks, (5) Upper Cretaceous volcanic rocks, (6) Upper Cretaceousgranitoids, (7) Tertiary calc-alkaline volcanic rocks, (8) Tertiary alkaline volcanic rocks, (9) Eocene granitoids, (10) alluvium. NAFZ,north Anatolian fault zone; EAFZ, east Anatolian fault zone.
rocks, are presented. This study aims to gain a betterunderstanding of the regional petrogenesis and tectonicenvironment.
Geological setting and regional geology
The eastern Pontides are commonly subdivided into anorthern zone and a southern zone (Figure 2A), basedon structural and lithological features (zsayar et al.1981; Okay and Sahintrk 1997). Pre-Late Cretaceous
sedimentary rocks are widely exposed in the southernzone, whereas Late Cretaceous and middle EocenelateMiocene volcanic and volcaniclastic rocks dominate thenorthern zone (Arslanet al. 1997; Senet al. 1998; Arslanet al. 2000; Sen 2007; Temizel et al. 2012). Liassic vol-canic rocks of the eastern Pontides lie unconformably ona Palaeozoic heterogeneous crystalline basement and arecross-cut by younger granitoids of Jurassic to Palaeoceneage (Ylmaz 1972; ogulu 1975; Okay and Sahintrk 1997;Topuzet al. 2010; Dokuz 2011) (Figure 1A). Volcanic and
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1778 A. Kaygusuzet al.
Simene P
Susuzkiran H
Mandagzobasi P
Kadrga P
Sehitkitan H
Tuzlakkaya H
07
N
05
27 29 31
09
03
11
13
15
17
Kefli P
Ardiclik H
Dikenli P
Budak P
Knalk H
Bayrmahalle P
Kurban H
Davunlu H
Kizilagac P
Arpaky
0 1km
Trabzon RizeOrdu
Samsun
NAFZ
Niksar
TokatSiran
Bayburt
Artvin
Erzurum
AXIAL ZONE
TAURID PLAT
NORTHERN ZONE
SOUTHERN ZONEEAFZ
N
41
37 38 39 40 41
0 60 km
Da ba
Palaeozoic metamorp Mainly Mesozoic sedimentary rocks
Platform carbonate rocks
Undifferentiated Mesozoic and Cenozoic rocks
Serpentinite
Palaeozoic granites
Fault
Late Cretaceous and Eocene arc gran.
Cretaceous and Eocene arc volc.rocks
Thrustf.Normal fault
BLACK SEA
M41
43
M40
M43
M46
T133
T134
T136
T137
T138
T139
T140
T135
M45
M44
Kiziluzum P
Sahmetlik P
Davunlu P
Karaorman H
Dikenli H
Karaaptal H
Derinoba P
Suluk H
Pazarkiran H
Celige H
Gez H
T5N12
T1N15
M42
Palaeozoic granites
Explanation
Upper Cretaceous granitoids
Kzlkaya Formation (dacite and pyroclastics)
(Upper Cretaceous)
atak Formation (andesite and pyroclastics)
(Upper Cretaceous)
Berdiga Formation (dolomitic limestone)
(Jurassic-Lower Cretaceous)
Hamurkesen Formation (basalt,andesite and pyroclastics) (Liassic)
M16
Kayadibi
(A)
(B)
M43 Sample location
Thrust
Fault
Road
Figure 2. (A) Major structures of the eastern Pontides (modified fromEyuboglu et al. (2007)).(B) Geological map of the study areawith sample locations and main settlements.
volcano-sedimentary rocks of Early and Middle Jurassic
age are tholeiitic in character (Arslan et al. 1997; Sen
2007). These rocks are overlain conformably by Middle
Late JurassicCretaceous neritic and pelagic carbonates.
The Late Cretaceous series that unconformably overlies
these carbonate rocks is made up of sedimentary rocks
in the southern part and of volcanic rocks in the northern
part (Bektaset al. 1987; Robinsonet al. 1995; Ylmaz and
Korkmaz 1999).
Cretaceous volcanic rocks mainly belong to the tholei-
itic and calc-alkaline series. Eocene volcanic rocks uncon-
formably overlie the Late Cretaceous volcanic and/or
sedimentary series (Gven 1993; Ylmaz and Korkmaz
1999).
The altitude of the eastern Pontides (above sea level)
during the Palaeoceneearly Eocene era is attributed to
the collision between the Pontide arc and the Tauride
Anatolide platform (Okay and Sahintrk 1997; Boztug
https://www.researchgate.net/publication/228680926_Mid-Cretaceous_Olistostromal_Ophiolitic_Melange_Developed_in_the_Back-arc_Basin_of_the_Eastern_Pontide_Magmatic_Arc_Northeast_Turkey?el=1_x_8&enrichId=rgreq-50835883-ef5a-4fad-a4ad-11e2c9f99369&enrichSource=Y292ZXJQYWdlOzI0MTcxMzAzNztBUzoyMTgwMjE1NjI5ODI0MDFAMTQyODk5MTc5OTkxOA==https://www.researchgate.net/publication/228680926_Mid-Cretaceous_Olistostromal_Ophiolitic_Melange_Developed_in_the_Back-arc_Basin_of_the_Eastern_Pontide_Magmatic_Arc_Northeast_Turkey?el=1_x_8&enrichId=rgreq-50835883-ef5a-4fad-a4ad-11e2c9f99369&enrichSource=Y292ZXJQYWdlOzI0MTcxMzAzNztBUzoyMTgwMjE1NjI5ODI0MDFAMTQyODk5MTc5OTkxOA==https://www.researchgate.net/publication/228680926_Mid-Cretaceous_Olistostromal_Ophiolitic_Melange_Developed_in_the_Back-arc_Basin_of_the_Eastern_Pontide_Magmatic_Arc_Northeast_Turkey?el=1_x_8&enrichId=rgreq-50835883-ef5a-4fad-a4ad-11e2c9f99369&enrichSource=Y292ZXJQYWdlOzI0MTcxMzAzNztBUzoyMTgwMjE1NjI5ODI0MDFAMTQyODk5MTc5OTkxOA==https://www.researchgate.net/publication/228680926_Mid-Cretaceous_Olistostromal_Ophiolitic_Melange_Developed_in_the_Back-arc_Basin_of_the_Eastern_Pontide_Magmatic_Arc_Northeast_Turkey?el=1_x_8&enrichId=rgreq-50835883-ef5a-4fad-a4ad-11e2c9f99369&enrichSource=Y292ZXJQYWdlOzI0MTcxMzAzNztBUzoyMTgwMjE1NjI5ODI0MDFAMTQyODk5MTc5OTkxOA== -
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International Geology Review 1779
et al. 2004). Eocene volcanic and volcaniclastic rocks are
intruded by calc-alkaline granitoids of similar age (Arslan
and Aslan 2006; Karslet al. 2007; Eyubogluet al. 2011).
Post-Cretaceous magmatic rocks include Palaeocene plagi-
oleucitites in the southern zone (Altherret al. 2008), early
Eocene adakitic granitoids (Topuzet al. 2005), and mid-
dle to late Eocene calc-alkaline to tholeiitic, basaltic toandesitic volcanic rocks, as well as the cross-cutting gran-
itoids exposed throughout the eastern Pontides (e.g. Tokel
1977; Arslan et al. 1997; Karsl et al. 2007; Boztug and
Harlavan 2008; Temizel and Arslan 2009; Temizel et al.
2011).
The clastic input into locally developed basins is due
to post-Eocene uplift and erosion (Korkmaz et al. 1995).
Towards the end of the middle Eocene, the region is largely
above sea level. Minor volcanism and terrigeneous sedi-
mentation continues to the present (Okay and Sahintrk
1997). Miocene and post-Miocene volcanic history of the
eastern Pontides is characterized by calc-alkaline to mildly
alkaline volcanism (Aydn 2004; Ycel et al. 2011; Temizelet al. 2012).
The study area is located in the northern zone of
the eastern Pontides (Figure 1). Basement rocks consist-
ing of Palaeozoic granites (Derinoba, Kayadibi, Sahmetlik,
and Kzlaga) have been newly mapped and are being
reported for the first time in this study (Figure 2B).
The granites are unconformably overlain by Liassic vol-
canics (Figure 3A) consisting of basalts, andesites, and
their pyroclastic equivalents. These rocks are overlain
conformably by MiddleLate JurassicCretaceous carbon-
ates and Late Cretaceous volcanics. All these lithologies
are cut by Late Cretaceous granitoids.
Analytical techniques
A total of 15 samples were collected from the Derinobagranite and 5 samples from the Kayadibi granite (for sam-
ple location, see Figure 2B). Based on the petrographical
studies, 16 of the freshest and most representative rock
samples from the granites were selected for whole-rock
major, trace, and rare earth element (REE) analyses. Rock
samples were crushed in steel crushers and ground in an
agate mill to a grain size of
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1780 A. Kaygusuzet al.
were mounted on epoxy resin and polished until halfway
through. Cathodoluminescence images were acquired to
check the internal structures of individual zircon grains and
to ensure a better selection of analytical positions.
UPb zircon dating was carried out using LAICP
MS at the Geologic Lab Center, China University of
Geosciences (Beijing, China). A quadrupole ICPMS(7500a; Agilent Inc., Santa Clara, CA, USA) was con-
nected with a UP-193 solid-state laser (193 nm; Electro
Scientific Industries, Inc., Portland, OR, USA) and an
automatic positioning system. The laser spot size was
set to approximately 36 m, with an energy density of
8.5 J/cm2 and repetition rate of 10 Hz. Laser sampling
was according to the following procedure: 5 s pre-ablation,
20 s sample-chamber flushing, and 40 s sampling abla-
tion. The ablated material was carried into the ICPMS
by a high-purity He gas stream with flux of 0.8 l/min.
The entire laser path was fluxed with N2 (15 l/min) and
Ar (1.15 l/min) to increase energy stability. UPb isotope
fractionation effects were corrected using zircon 91500(Wiedenbecket al. 1995) as external standard. Zircon stan-
dard TEMORA (417 million years, Blacket al. 2003) was
also used as a secondary standard to monitor the devia-
tion of age measurement/calculation. A total of 10 analyses
of TEMORA yielded apparent 206Pb/238U ages of 417 to
418 million years. Isotopic ratios and element concentra-
tions of zircons were calculated using the GLITTER soft-
ware (ver. 4.4, Macquarie University, Sydney, Australia).
Concordia ages and diagrams were obtained using
Isoplot/Ex (3.0) (Ludwig 2003). Common lead was cor-
rected following the method of Andersen (2002).
Electron microprobe analyses on polished thin sections
were carried out at the New Mexico Institute of Miningand Technology, Socorro, NM, USA, using a Cameca
SX-100 electron microprobe with three wavelength-
dispersive spectrometers. Samples were examined using
backscattered electron imagery, and selected minerals were
quantitatively analysed. Elements analysed included F, Na,
Mg, Al, Si, P, S, Cl, K, Ca, Ti, Cr, Mn, Fe, Sr, and Ba.
An accelerating voltage of 15 kV and probe current of
20 nA were used, except for analyses using general glass
labels (i.e. chlorite), which utilized a 10 nA probe current.
Peak count numbers of 20 s were used for all elements,
except for F (40 s; amph/mica), F (60 s; glass), Cl (40 s), S
(30 s), Sr (60 s), and Ba (60 s). Background count numbers
were one half the peak count times. A point beam of 1 m
was used to analyse amphibole, pyroxene, epidote, FeTi
oxide, and zircon. A slightly defocused (10 m) beam was
used to analyse feldspar, mica, and chlorite to avoid losses
caused by sodium volatilization (Nielsen and Sigurdsson
1981). Analytical results are presented in Tables 13.
Sr, Nd, and Pb isotope compositions were measured on
a Finnigan MAT 262 multicollector mass spectrometer at
the Institute of Geosciences, Tbingen, Germany. For Sr
Nd isotope analyses, approximately 50 mg of whole-rock
powder was decomposed in 52% HF for 4 days at 140C
on a hot plate. Digested samples were dried and redis-
solved in 6 N HCl; these were dried again and redissolved
in 2.5 N HCl. Sr and Nd were separated by conventional ion
exchange techniques, and their isotopic compositions were
measured on single W and double Re filament configura-
tions, respectively. The isotopic ratios were corrected forisotopic mass fractionation by normalizing to 86 Sr/88Sr=
0.1194 and146Nd/144Nd= 0.7219. The reproducibility of87Sr/86Sr and143Nd/144Nd during the period of measure-
ment was checked by analyses of NBS 987 Sr and La Jolla
Nd standards, which yielded average values of 0.710235
0.000015 (2SD,n = 3) and 0.511840 0.000008 (2SD,
n = 5), respectively. Total procedural blanks were 2050 pg
for Sr and 4066 pg for Nd. The separation and purifi-
cation of Pb were carried out on Teflon columns with a
100 m (separation) and 40 m bed (cleaning) of Bio-
Rad AG1-X8 (100200 mesh) anion exchange resin using
an HBrHCl ion exchange procedure. Pb was loaded with
Si-gel and phosphoric acid into a Re filament and wasanalysed at about 1300C in a single-filament mode. A fac-
tor of 1 per atomic mass unit for instrumental mass
fractionation was applied to the Pb analyses, using NBS
SRM 981 as reference material. The total procedural blanks
for Pb during the measurement period were between 20 and
40 pg. Sample reproducibility was estimated at 0.02,
0.015, and0.03 (2) for206Pb/204Pb, 207Pb/204Pb, and208Pb/204Pb ratios, respectively.
Results
Field relations and petrography
The resulting geological map contains four separate gran-
ite bodies, namely, Derinoba, Kayadibi, Sahmetlik, and
Kzlaga (Figure 2B). These intrusions form nearly NE
SW-elongated bodies in varying dimensions occupying
the highest peaks in the region. Generally, these are
bounded by the pre-Jurassic volcanic and pyroclastic
rocks to the east. Liassic volcanic and pyroclastic rocks
(Hamurkesen Formation) unconformably overlie the gran-
ite bodies (Figure 3A). In the west, granite bodies thrust
over Late Cretaceous volcanic and pyroclastic rocks (atak
and Kzlkaya Formations).
The Derinoba granite, located about 65 km southwest
of Trabzon, forms an EW-elongated body, with the longaxis extending from northeast to southwest (Figure 2B).
This granite body covers an area of approximately 13 km 2.
In the east, the granite is unconformably overlain by
Lower Jurassic volcanic and pyroclastic rocks, whereas
in the west, the granite thrusts over Late Cretaceous vol-
canic and pyroclastic rocks together with their cover rocks
(Figure 2B). The Derinoba granite is generally unde-
formed, but strongly altered and weathered. Rocks often
have a brick red to pink colour, except for strongly chlori-
tized zones that are greenish.
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International Geology Review 1781
Table1.
Microprobeanalyseso
fplagioclasesfromtheDerinobaandKaya
dibigranites.
Plagioclase
Rock
types
Derinobagranites
Kayadibigranites
Samples
T138-3c
T138-4rT138-5c
T138-6rT138-11c
T138-12rT135-1
rT135-2c
T135-7rT135-8c
T135-9rT
135-10c
M16-3c
M16-4c
M16-5c
M16-6rM16-9c
M16-10c
SiO2
68.0
9
68.1
6
68
.88
68.9
8
65.7
4
68.4
9
68.48
67.2
6
67.5
1
65.7
3
67.4
9
67.4
1
67.5
6
66.8
0
66.3
3
68.2
1
67.3
0
67.5
1
Al2O3
20.7
4
19.8
3
20
.31
20.4
1
22.3
7
21.0
9
20.02
21.4
1
20.3
0
21.3
9
19.5
6
20.2
7
20.6
7
20.6
8
21.0
5
20.9
7
21.1
7
20.8
0
FeOT
0.0
6
0.0
9
0
.14
0.0
3
0.2
8
0.0
5
0.04
0.2
3
0.0
5
0.2
5
0.0
6
0.1
4
0.0
5
0.1
4
0.0
8
0.0
9
0.1
1
0.0
8
CaO
0.7
7
0.2
7
0
.30
0.1
4
0.6
2
0.8
7
0.19
0.2
8
0.4
1
0.5
5
0.2
0
0.2
7
0.5
6
1.1
6
0.6
6
0.8
4
1.2
3
0.6
5
Na2O
11.3
2
11.1
6
11
.71
11.6
0
10.2
5
11.4
6
11.62
10.9
7
11.2
5
10.5
1
11.2
4
11.3
6
11.4
0
11.0
7
10.8
2
11.3
4
11.1
5
11.2
5
K2O
0.1
0
0.1
1
0
.10
0.1
1
1.1
8
0.3
1
0.14
0.9
0
0.2
7
1.0
8
0.1
3
0.4
0
0.2
3
0.2
8
0.6
0
0.1
6
0.1
7
0.2
3
BaO
0.0
2
0.0
6
0
.07
0.0
0
0.0
3
0.0
2
0.00
0.0
9
0.0
0
0.0
0
0.0
0
0.1
0
0.0
0
0.0
2
0.0
3
0.0
5
0.0
3
0.0
5
SrO
0.0
3
0.0
2
0
.01
0.0
2
0.0
6
0.0
7
0.05
0.0
2
0.0
0
0.0
5
0.0
0
0.0
4
0.0
3
0.0
4
0.0
3
0.0
2
0.0
0
0.0
5
Total
101.1
99.7
101
.5
101.3
100.5
102.4
100.5
101.2
99.8
99.5
98.7
100.0
100.5
100.2
99.6
101.7
101.2
100.6
Cationsonthebasisofeightoxygens
Si
2.9
5
2.9
9
2
.97
2.9
7
2.8
8
2.9
4
2.98
2.9
2
2.9
6
2.9
1
2.9
9
2.9
6
2.9
5
2.9
3
2.9
2
2.9
4
2.9
2
2.9
4
Al
1.0
6
1.0
2
1
.03
1.0
4
1.1
5
1.0
7
1.03
1.1
0
1.0
5
1.1
1
1.0
2
1.0
5
1.0
6
1.0
7
1.0
9
1.0
7
1.0
8
1.0
7
Fe2+
0.0
0
0.0
0
0
.01
0.0
0
0.0
1
0.0
0
0.00
0.0
1
0.0
0
0.0
1
0.0
0
0.0
0
0.0
0
0.0
1
0.0
0
0.0
0
0.0
0
0.0
0
Ca
0.0
4
0.0
1
0
.01
0.0
1
0.0
3
0.0
4
0.01
0.0
1
0.0
2
0.0
3
0.0
1
0.0
1
0.0
3
0.0
5
0.0
3
0.0
4
0.0
6
0.0
3
Na
0.9
5
0.9
5
0
.98
0.9
7
0.8
7
0.9
5
0.98
0.9
2
0.9
6
0.9
0
0.9
6
0.9
7
0.9
6
0.9
4
0.9
2
0.9
5
0.9
4
0.9
5
K
0.0
1
0.0
1
0
.01
0.0
1
0.0
7
0.0
2
0.01
0.0
5
0.0
1
0.0
6
0.0
1
0.0
2
0.0
1
0.0
2
0.0
3
0.0
1
0.0
1
0.0
1
Ba
0.0
0
0.0
0
0
.00
0.0
0
0.0
0
0.0
0
0.00
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
Sr
0.0
0
0.0
0
0
.00
0.0
0
0.0
0
0.0
0
0.00
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
Total
5.0
0
4.9
9
5
.01
4.9
9
5.0
1
5.0
2
5.00
5.0
2
5.0
0
5.0
2
4.9
9
5.0
1
5.0
1
5.0
1
5.0
1
5.0
1
5.0
1
5.0
1
An
3.5
8
1.3
0
1
.40
0.6
5
3.0
0
3.9
7
0.87
1.3
0
1.9
5
2.6
1
0.9
6
1.2
5
2.6
1
5.4
0
3.1
4
3.9
1
5.7
1
3.0
4
Ab
95.8
4
98.0
8
98
.06
98.7
6
90.1
7
94.3
7
98.33
93.6
3
96.5
4
91.2
2
98.3
2
96.5
3
96.1
1
93.0
5
93.4
4
95.2
3
93.3
5
95.6
8
Or
0.5
8
0.6
2
0
.53
0.5
9
6.8
3
1.6
6
0.80
5.0
8
1.5
1
6.1
7
0.7
2
2.2
2
1.2
8
1.5
5
3.4
3
0.8
6
0.9
4
1.2
8
Note:FeOTistotalironasFeO;r,rimofc
rystal;c,coreofcrystal.
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1782 A. Kaygusuzet al.
Table2.
Microprobeanalyseso
fK-feldsparsfromtheDerinobaandKayadibigranites.
K-feldspar
Rock
types
Derinobagranites
Kayadibigranites
SamplesT138-1cT138-2rT138-14cT138-15rT138-19cT138-20
rT135-3rT135-4cT135-5rT135-6cT135-11rT135-12rM16-1cM16-2
rM16-7rM16-8c
SiO2
64.6
2
64.7
1
64.2
7
65.2
5
63.8
5
63.70
63.9
9
63.9
1
63.9
1
63.7
8
63.3
0
64.0
6
63.8
8
64.03
64.3
8
64.1
9
Al2O3
18.9
9
18.8
6
18.8
4
19.1
8
19.1
7
19.20
18.5
5
18.5
1
18.5
9
18.8
2
18.3
1
18.8
1
18.6
9
18.77
18.8
3
18.6
1
FeOT
0.0
4
0.0
5
0.0
4
0.0
0
0.0
1
0.02
0.0
4
0.0
8
0.0
1
0.0
5
0.0
0
0.0
4
0.0
0
0.04
0.1
0
0.0
7
CaO
0.0
2
0.0
5
0.0
0
0.0
3
0.0
1
0.60
0.0
0
0.0
1
0.0
0
0.0
2
0.0
2
0.0
5
0.0
0
0.01
0.0
0
0.0
0
Na2O
0.3
0
0.4
0
0.0
0
0.6
1
0.2
6
0.29
0.6
9
0.5
3
0.3
5
0.6
3
0.3
4
0.4
3
0.3
6
0.31
0.4
3
0.4
7
K2O
16.1
9
15.8
4
16.4
8
15.9
1
16.1
3
16.18
16.0
9
16.2
0
16.4
7
16.0
0
16.2
3
16.3
1
16.5
0
16.51
16.5
2
16.4
9
BaO
0.1
8
0.2
1
0.2
0
0.2
1
1.1
3
0.09
0.1
6
0.2
3
0.3
9
0.4
9
0.0
0
0.4
3
0.3
3
0.16
0.1
4
0.0
5
SrO
0.0
0
0.0
2
0.0
1
0.0
2
0.0
5
0.01
0.0
2
0.0
0
0.0
0
0.0
6
0.0
3
0.0
5
0.0
1
0.02
0.0
1
0.0
2
Total
100.3
100.1
99.8
101.2
100.6
100.1
99.5
99.5
99.7
99.8
98.2
100.2
99.8
99.9
100.4
99.9
Cationsonthebasisofeightoxygens
Si
2.9
8
2.9
8
2.9
8
2.9
8
2.9
6
2.95
2.9
8
2.9
8
2.9
8
2.9
7
2.9
8
2.9
7
2.9
7
2.97
2.9
7
2.9
8
Al
1.0
3
1.0
3
1.0
3
1.0
3
1.0
5
1.05
1.0
2
1.0
2
1.0
2
1.0
3
1.0
2
1.0
3
1.0
3
1.03
1.0
3
1.0
2
Fe
2+
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.00
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.00
0.0
0
0.0
0
Ca
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.03
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.00
0.0
0
0.0
0
Na
0.0
3
0.0
4
0.0
0
0.0
5
0.0
2
0.03
0.0
6
0.0
5
0.0
3
0.0
6
0.0
3
0.0
4
0.0
3
0.03
0.0
4
0.0
4
K
0.9
5
0.9
3
0.9
7
0.9
3
0.9
5
0.96
0.9
6
0.9
6
0.9
8
0.9
5
0.9
8
0.9
7
0.9
8
0.98
0.9
7
0.9
8
Ba
0.0
0
0.0
0
0.0
0
0.0
0
0.0
2
0.00
0.0
0
0.0
0
0.0
1
0.0
1
0.0
0
0.0
1
0.0
1
0.00
0.0
0
0.0
0
Sr
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.00
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.0
0
0.00
0.0
0
0.0
0
Total
4.9
9
4.9
9
4.9
9
5.0
0
5.0
1
5.02
5.0
2
5.0
2
5.0
2
5.0
2
5.0
1
5.0
2
5.0
2
5.01
5.0
2
5.0
2
An
0.0
8
0.2
4
0.0
1
0.1
7
0.0
4
2.95
0.0
2
0.0
5
0.0
0
0.1
1
0.1
2
0.2
7
0.0
1
0.04
0.0
2
0.0
0
Ab
2.7
5
3.6
5
0.0
0
5.4
9
2.3
8
2.56
6.1
4
4.7
5
3.1
3
5.6
7
3.0
6
3.8
2
3.1
9
2.81
3.8
3
4.1
2
Or
97.1
7
96.1
1
99.9
9
94.3
4
97.5
8
94.50
93.8
4
95.2
0
96.8
7
94.2
1
96.8
2
95.9
2
96.8
0
97.15
96.1
5
95.8
8
Note:FeO
TistotalironasFeO;r,rim
ofcrystal;c,coreofcrystal.
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International Geology Review 1783
Table 3. Microprobe analyses of biotites from the Derinoba and Kayadibi granites.
Biotite
Rock types Derinoba granites Kayadibi granites
Samples T135-1 T135-2 T138-1 T138-2 M16-1 M16-2 T5-1 T5-2SiO2 35.47 36.36 36.58 37.79 35.90 36.10 36.11 37.10
TiO2 4.65 3.94 3.87 3.25 4.74 4.00 3.55 3.41Al2O3 13.52 13.11 12.96 13.36 12.78 13.12 13.34 13.20Cr2O3 0.01 0.00 0.01 0.01 0.00 0.02 0.01 0.00FeOT 23.18 24.73 24.94 21.25 23.42 24.43 24.64 22.50MnO 0.35 0.34 0.27 0.28 0.38 0.38 0.29 0.26MgO 10.01 11.25 9.25 10.31 11.76 11.44 11.43 10.62CaO 0.02 0.04 0.02 0.03 0.03 0.01 0.02 0.02Na2O 0.12 0.11 0.12 0.13 0.16 0.09 0.11 0.10K2O 8.24 7.42 8.08 9.06 8.30 8.32 8.02 8.74Total 95.57 97.30 96.10 95.47 97.47 97.91 97.52 95.95
Cations on the basis of 22 oxygensSi 5.50 5.54 5.66 5.80 5.47 5.49 5.51 5.70Ti 0.54 0.45 0.45 0.37 0.54 0.46 0.41 0.39Al 2.47 2.35 2.37 2.42 2.29 2.35 2.40 2.39Cr 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Fe2+ 3.00 3.15 3.23 2.72 2.98 3.10 3.14 2.89Mn 0.05 0.04 0.04 0.04 0.05 0.05 0.04 0.03Mg 2.31 2.55 2.14 2.36 2.67 2.59 2.60 2.43Ca 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00Na 0.04 0.03 0.04 0.04 0.05 0.03 0.03 0.03K 1.63 1.44 1.60 1.77 1.61 1.61 1.56 1.71Total 15.55 15.57 15.52 15.53 15.67 15.69 15.68 15.58
Mg/Mg+ Fe2+ 0.44 0.45 0.40 0.46 0.47 0.46 0.45 0.46Fe2+/Fe2+ +Mg 0.56 0.55 0.60 0.54 0.53 0.54 0.55 0.54
Note: FeOT is total iron as FeO.
The Kayadibi granites, as well as the two other stocks
referred to as Sahmetlik and Kzlaga, form small ellip-
tical bodies. Each of these bodies has an outcrop area ofapproximately 1 km2 (Figure 2A), overlain unconformably
by Lower Jurassic volcanic and pyroclastic rocks in the
east and thrust over Late Cretaceous volcanic and pyroclas-
tic rocks in the west (Figure 2A). All granites mentioned
are cut by Late Cretaceous granites and dacitic dikes and
domes (Figure 3B).
Studied samples (i.e. obtained from Derinoba and
Kayadibi) are medium- to coarse-grained monzogran-
ites, share several common petrographic features, and
are described together. These samples are composed of
equigranular K-feldspar, quartz, plagioclase, biotite, acces-
sory zircon, apatite, allanite, magnetite, and secondary
phases of sericite, chlorite, epidote, clay minerals, carbon-ates, and white mica (Figures 3C and 3D).
Plagioclase forms subhedral to euhedral, normally and
reversely zoned prismatic crystals. In some samples, it
is altered into sericite and clay minerals and partly into
epidote. Representative mineral analyses of plagioclase
crystals are provided in Table 1. Composition in all samples
is pure albite and varies from An1 to An4 in the Derinoba
granite, whereas in the Kayadibi granite, it is slightly less
rich in sodium and ranges from An3 to An6. K-feldspar
forms anhedral, rarely subhedral crystals of orthoclase and
perthitic orthoclase. Large K-feldspar oikocrysts contain
inclusions of abundant plagioclase, biotite, and opaqueminerals. Representative mineral analyses of K-feldspar
are presented in Table 2. Compositions range from Or94to Or99 in the Derinoba granite and Or96 to Or97 in the
Kayadibi granite (Table 2).
Biotite is euhedral to subhedral, is reddish-brown in
colour, and forms small prismatic crystals and lamel-
las. In most samples, biotite is strongly chloritized
or partially replaced by prehnite and/or pumpellyite.
Biotite sheets are frequently deformed around secondary
prehnite/pumpellyite grains. Primary inclusions in biotite
are magnetite, apatite, and zircon. Representative biotite
analyses are provided in Table 3. The Mg-number (Mg/Mg
+ Fe2+) varies from 0.40 to 0.46 in the Derinoba graniteand from 0.45 to 0.47 in the Kayadibi granite (Table 3).
TiO2contents are relatively high (3.254.74 wt.%).
Quartz is anhedral in shape and generally shows undu-
lose extinction. It locally forms large grains but also fills
the interstitial spaces left behind from early-crystallized
plagioclase and mafic minerals.
Apatite is the most common accessory mineral and
occurs as small prismatic and acicular crystals. Allanite
forms euhedral, reddish crystals in all samples. Zircon is
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1784 A. Kaygusuzet al.
observed as short euhedral and prismatic crystals. Opaque
minerals are mostly titaniferous magnetites that occur as
phenocrysts and microphenocrysts.
Whole-rock chemistry
Major, trace, and REE analyses of representative sam-
ples from the Derinoba and Kayadibi granites are given
in Table 4. In the classification diagram of Debon and Le
Fort (1982), all samples are plotted in the granite field
(Figure 4A). In the RbSrBa ternary diagram (Tarney and
Jones 1994), samples are plotted in the field of low BaSr
granitoids (not shown here).
Both granites span a narrow compositional range
(Table 4, Figure 4A). SiO2 ranges from 75 to 77 wt.%
in the Derinoba granite and from 74 to 75 wt.% in the
Kayadibi granite (Table 4). K2O/Na2O ratios vary between
0.98 and 1.45 (Derinoba) and 1.18 and 1.43 (Kayadibi).
The aluminium saturation index (ASI) (molar Al2O3/(CaO+ Na2O + K2O)) values of samples from the Derinoba
and Kayadibi granites are between 0.95 and 1.35, with
an average of 1.14. These figures indicate that the gran-
ites are dominantly peraluminous (Table 4, Figure 4B).
Both granites show subalkaline affinity and belong to the
high-K calc-alkaline series (Figure 5A). In the SiO2 ver-
sus ASI diagram (Figure 5B), the samples are plotted in
the I- to S-type granite fields. Some altered samples from
the Derinoba granite portray elevated ASI values. Harker
plots of selected major and trace elements (Figure 5C
5R) show systematic variations in element concentration.
The rocks define trends without a compositional gap. CaO,
MgO, Fe2O3(T), TiO2, P2O5, Ba, Sr, Th, Ni, and Y con-
tents decrease with increasing SiO2content, whereas K2O,
Al2O3, Zr, and Nb increase with increasing SiO2 content;
Na2O and Pb are nearly constant (Figure 5C5R).
In the primitive mantle-normalized trace element dia-
grams (Figure 6A6C), all samples from the Kayadibi and
Derinoba granites display marked negative anomalies in
Ba, Nb, Ta, Sr, P, and Ti, but positive anomalies in K
and partly Pb, which indicate fractionation of plagioclase,
K-feldspar, biotite, apatite, and FeTi oxides.
Chondrite-normalized REE patterns of the Kayadibi
and Derinoba granite samples (Figure 6D6F) are gener-
ally characterized by concave-upward shapes (Lacn/Ybcn= 2.79.7) and pronounced negative Eu anomalies
(Eucn/Eu) of 0.110.59, whereas the largest Eu-anomalies
appear in the Derinoba granite (Table 4). Compared
with other Palaeozoic granitoids of the eastern Pontides
(Figure 6C and 6F), the trace and REE patterns of the
Derinoba and Kayadibi granites resemble those of the
Gmshane pluton (Topuz et al. 2010). However, the
Derinoba and Kayadibi granites differ from the Gmshane
pluton in terms of the stronger negative Eu anomalies
(Figure 6F).
In the (Zr+ Nb + Ce + Y) versus FeO/MgO tec-
tonic discrimination diagram of Whalen et al. (1987), the
Derinoba and Kayadibi granites fall within the I-type gran-
ite field (Figure 7A). Furthermore, the tectonic discrimina-
tion diagram ofBatchelor and Bowden (1985)(Figure 7B)
suggests a syn- to post-collisional geochemical signature
for both granites.
SrNdPb isotopes
Sr, Nd, and Pb isotope data for the Kayadibi and Derinoba
granites are given in Tables 5 and 6 and plotted in Figure 8.
Initial Sr, Nd, and Pb isotope ratios are calculated using
Rb, Sr, Sm, Nd, U, Th, and Pb concentration data obtained
from ICPAES and MS analyses, with the assumed granite
ages of 303 million years (Kayadibi) and 317311 million
years (Derinoba) (see below). Samples from the Kayadibi
and Derinoba granites show a relatively wide range of ini-
tial87
Sr/86
Sr ratios (0.69740.7079) and a narrow range ofNd(I) values (4.6 to 7.1). The corresponding Nd model
ages (TDM) of the granites are in the range 1.502.15 thou-
sand million years. Extremely low (87Sr/86Sr)(I) ratios
(0.69740.7003) are found in samples, showing evidence
for alteration, which may suggest that the RbSr system
is more severely influenced by hydrothermal alteration or
weathering than the SmNd isotope system.
No correlation exists betweenNd(I) and (87Sr/86Sr)(I)
but the Derinoba samples display lower Nd(I) val-
ues (7.1 to 6.1) and higher (87Sr/86Sr)(I) ratios
(0.70030.7079) than the Kayadibi samples [Nd(I) =
4.6 to 6.2, (87Sr/86Sr)(I) =0.69740.703] (Figure 8A).
In the SiO2versus (87Sr/86Sr)(I) and (143Nd/144Nd)(I)dia-grams (Figures 8B and 8C), the samples define nearly
horizontal trends, indicating fractional crystallization.
A slightly positive correlation, however, is shown in the
(143Nd/144Nd)(I)versus Nd plot (Figure 8D).
In Figure 8A, the Derinoba and Kayadibi granites
are compared with other Palaeozoic granites from the
eastern Pontides. As shown in this plot, the studied sam-
ples have similarNd(I) and (87Sr/86Sr)(I) ratios to those
from Gmshane pluton but lower (87Sr/86Sr)(I)ratios than
those of the Kse pluton. The Kse samples show a nega-
tive correlation betweenNd(I) and (87Sr/86Sr)(I), whereas
the Kayadibi, Derinoba, and Gmshane samples show no
obvious correlation between these two parameters.Samples from the Kayadibi and Derinoba granites have
similar (207Pb/204Pb)(I) = 15.5515.62, but have vari-
able (206Pb/204Pb)(I) = 17.2918.0 and (208Pb/204Pb)(I) =
36.3837.67 isotopic compositions (Table 6, Figures 8E
and 8F). In the (207Pb/204Pb)(I) versus (206Pb/204Pb)(I)
diagram (Figure 8E), the samples are plotted to the left
of the geochron and above the Northern Hemisphere
Reference Line (Hart 1984). In the (206Pb/204Pb)(I) versus
(207Pb/204Pb)(I) diagram (Figure 8F), the studied samples
https://www.researchgate.net/publication/228524545_Carboniferous_high-potassium_I-type_granitoid_magmatism_in_the_Eastern_Pontides_The_Gumushane_pluton_NE_Turkey?el=1_x_8&enrichId=rgreq-50835883-ef5a-4fad-a4ad-11e2c9f99369&enrichSource=Y292ZXJQYWdlOzI0MTcxMzAzNztBUzoyMTgwMjE1NjI5ODI0MDFAMTQyODk5MTc5OTkxOA==https://www.researchgate.net/publication/228524545_Carboniferous_high-potassium_I-type_granitoid_magmatism_in_the_Eastern_Pontides_The_Gumushane_pluton_NE_Turkey?el=1_x_8&enrichId=rgreq-50835883-ef5a-4fad-a4ad-11e2c9f99369&enrichSource=Y292ZXJQYWdlOzI0MTcxMzAzNztBUzoyMTgwMjE1NjI5ODI0MDFAMTQyODk5MTc5OTkxOA==https://www.researchgate.net/publication/228524545_Carboniferous_high-potassium_I-type_granitoid_magmatism_in_the_Eastern_Pontides_The_Gumushane_pluton_NE_Turkey?el=1_x_8&enrichId=rgreq-50835883-ef5a-4fad-a4ad-11e2c9f99369&enrichSource=Y292ZXJQYWdlOzI0MTcxMzAzNztBUzoyMTgwMjE1NjI5ODI0MDFAMTQyODk5MTc5OTkxOA==https://www.researchgate.net/publication/248358667_Petrogenetic_interpretation_of_granitoid_rock_series_using_multicationic_parameters_Chem_Geol_48_43-55?el=1_x_8&enrichId=rgreq-50835883-ef5a-4fad-a4ad-11e2c9f99369&enrichSource=Y292ZXJQYWdlOzI0MTcxMzAzNztBUzoyMTgwMjE1NjI5ODI0MDFAMTQyODk5MTc5OTkxOA==https://www.researchgate.net/publication/248358667_Petrogenetic_interpretation_of_granitoid_rock_series_using_multicationic_parameters_Chem_Geol_48_43-55?el=1_x_8&enrichId=rgreq-50835883-ef5a-4fad-a4ad-11e2c9f99369&enrichSource=Y292ZXJQYWdlOzI0MTcxMzAzNztBUzoyMTgwMjE1NjI5ODI0MDFAMTQyODk5MTc5OTkxOA==https://www.researchgate.net/publication/228524545_Carboniferous_high-potassium_I-type_granitoid_magmatism_in_the_Eastern_Pontides_The_Gumushane_pluton_NE_Turkey?el=1_x_8&enrichId=rgreq-50835883-ef5a-4fad-a4ad-11e2c9f99369&enrichSource=Y292ZXJQYWdlOzI0MTcxMzAzNztBUzoyMTgwMjE1NjI5ODI0MDFAMTQyODk5MTc5OTkxOA== -
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1786 A. Kaygusuzet al.
Tab
le4
.
(Con
tinued
).
Roc
ktypes
Der
ino
bagranite
s
Kayad
ibigran
ites
Samp
les
T135
M42
T138
T137
T140
M43
M45
T136
T134
M40
M41
T1
N15
T5
N12
M16
Dy
6.2
3
6.8
5
6.4
5
6.2
4
3.3
9
5.5
8
4.2
0
4.5
0
4.9
7
3.2
5
3.4
1
7.2
1
6.0
2
6.7
3
6.0
6
6.0
4
Ho
1.7
0
1.7
5
1.6
5
1.7
1
0.7
5
1.1
1
1.2
6
1.3
3
0.9
9
0.7
4
0.7
7
1.6
4
1.4
6
1.3
5
1.5
2
1.4
5
Er
4.7
3
3.9
8
4.7
6
3.1
0
2.3
3
3.2
2
3.1
8
3.1
0
2.9
7
2.2
4
2.3
8
4.6
8
4.2
6
4.2
0
4.8
6
4.5
4
Tm
0.4
3
0.5
8
0.7
1
0.6
2
0.3
7
0.4
9
0.5
2
0.5
0
0.4
5
0.3
6
0.3
9
0.5
7
0.6
2
0.6
5
0.7
1
0.7
8
Yb
3.9
0
3.9
5
4.3
3
4.2
0
2.5
4
3.0
6
3.1
0
3.1
5
2.9
2
2.5
4
2.5
9
4.8
3
4.6
2
4.4
9
4.6
5
4.5
7
Lu
0.5
6
0.5
0
0.5
8
0.5
2
0.3
8
0.4
6
0.4
4
0.4
7
0.4
3
0.3
6
0.3
9
0.6
8
0.6
1
0.6
2
0.6
4
0.5
3
Lac
n/Lu
cn
4.8
8
6.3
0
5.5
9
6.8
5
7.5
5
9.0
9
7.1
3
7.6
4
8.7
4
9.2
0
9.8
8
2.9
1
3.7
0
6.1
3
6.0
3
7.0
9
Lac
n/Sm
cn
3.4
3
3.8
9
3.4
2
4.0
9
3.5
2
3.8
2
3.6
0
4.0
2
4.5
1
3.9
1
4.9
3
1.8
6
2.6
4
3.7
9
3.6
1
4.0
5
Gd
cn
/Lu
cn
1.6
4
1.1
7
1.3
7
1.5
1
0.9
5
1.5
5
1.3
7
1.1
4
1.5
0
0.8
3
0.7
9
1.5
8
1.6
7
1.2
7
1.4
2
1.6
7
Lac
n/Yb
cn
4.5
7
5.2
0
4.8
8
5.5
3
7.3
7
8.9
2
6.6
0
7.4
4
8.4
0
8.5
1
9.7
1
2.6
7
3.1
9
5.5
2
5.4
2
5.3
7
Tb
cn
/Yb
cn
1.7
0
1.4
3
1.4
0
1.2
6
0.9
8
1.4
0
1.3
2
1.0
6
1.3
2
0.8
9
0.9
2
1.2
7
1.2
2
1.2
2
1.1
5
1.1
4
Eu
cn
/Eu
0.4
3
0.5
9
0.5
1
0.4
8
0.2
4
0.4
1
0.3
8
0.3
4
0.4
4
0.1
1
0.1
1
0.3
4
0.3
4
0.3
4
0.3
7
0.3
1
Mg
#
22
.58
19
.63
22
.22
23
.66
32
.52
29
.63
22
.86
13
.20
24
.68
9.3
2
10
.49
22
.64
20
.67
18
.18
24
.57
19
.87
ASI
1.1
2
1.1
0
0.9
8
1.0
7
1.2
6
1.2
2
1.2
2
1.1
7
1.1
8
1.3
5
1.3
0
1.1
5
1.0
7
0.9
5
1.0
2
1.0
9
K2
O/Na2
O
1.0
0
1.2
8
1.1
2
1.1
9
0.9
8
1.1
1
1.3
2
1.4
5
1.1
2
1.3
7
1.3
8
1.2
1
1.1
8
1.4
3
1.2
4
1.2
4
Rb/Sr
1.8
5
2.1
1
2.8
9
2.9
3
1.7
5
2.4
1
2.4
7
2.4
2
3.6
1
5.0
1
5.1
9
0.5
2
1.0
6
1.7
8
1.7
2
2.0
2
Sr/
Y
2.2
2
1.8
4
1.2
0
1.3
3
3.2
4
1.3
6
1.4
2
1.5
8
1.3
0
1.7
5
1.6
9
3.7
0
1.9
1
1.5
9
2.0
2
1.4
8
Nb/Ta
13
.22
12
.50
12
.91
15
.89
8.1
7
14
.60
15
.33
12
.27
15
.22
5.6
7
6.7
6
20
.50
14
.00
10
.40
12
.36
12
.69
Zr/
Hf
24
.33
24
.58
25
.33
28
.07
26
.29
31
.25
26
.38
34
.55
30
.32
47
.60
51
.41
27
.35
28
.79
28
.63
28
.69
24
.92
Th/U
4.7
3
4.5
0
4.3
4
4.4
4
6.7
7
5.4
8
5.4
3
5.1
7
5.3
7
2.4
8
2.5
9
13
.80
7.0
0
3.4
9
4.9
5
5.8
6
No
te:
Fe2
OT 3istotalironas
Fe2
O3;
LOIislosson
ign
ition;
Mg
#(Mg-n
um
ber
)=1
00
Mg
O/(Mg
O+
Fe2
OT 3);ASI=
mo
lar
Al
2O
3/(CaO+
Na2
O+
K2
O);Eu=
(Smcn+G
dcn
)/2;
(Lacn
/Lucn
)=
chon
dri
te-n
orma
lized
La/
Lura
tio
,ox
idesareg
iven
inw
t.%
,traceelemen
tsinppm;
ASI,alum
iniumsa
tura
tion
index
.
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International Geology Review 1787
40 50 60 70 80 90
SiO2(wt%)
0
5
10
15
Na2O
+K2O(wt%)
Suba
lkalin
eseries
Gabbro
Gabbroic
Diorite
Diorite
Tonalite
Granodiorite
GraniteMnzgbr
Mnzdi
Monzonit Qmonz
Syenite
Peridot
Gabbro
Foidgabbro
Foidmonzosyenite
Foidolit
Foidmonzogabbro
Quartzolite
(A)
Derinobagr.Kayadibigr.
0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5
A/CNK
0.7
0.8
0.91.0
1.1
1.2
1.3
1.4
1.5
A/NK
Peraluminous
Metaluminous
(B)
Peralkaline
Aluminous
Figure 4. (A) Chemical nomenclature diagram (Debon and Le Fort 1982) for samples from the Derinoba and Kayadibi granites. (B)A/CNK (Al2O3/CaO + Na2O + K2O) versus A/NK (Na2O + K2O) molar diagram showing the range in alumina saturation index (ASI)of Derinoba and Kayadibi granites.
form subparallel trends to the orogen curve (Zartman and
Doe 1981).
UPb zircon dating
LAICPMS UPb zircon dating results are presented in
Table 7 and shown in Concordia diagrams (Figure 9).
Zircons are colourless to light yellow, with long prismatic,
perfectly euhedral, and oscillatory zoning (Figure 10).
Zircon grains are mostly fine-grained (63125 m) and
have aspect ratios of about 1:3. Inclusions of apatite and
internal fractures are common. All these features indicate
that zircons are of magmatic origin. Some grains are cor-
roded and display altered domains. Only the uncorroded
inner parts of the grains are investigated for UPb isotopeanalyses. Most analyses give concordant age data. A total
of 23 spots from sample T138 (Derinoba) yield206 Pb/238U
ages ranging from 301 to 317 million years, with a
weighted mean age of 311.1 2.0 million years (MSWD=
1.4) (Table 7, Figure 9A), and 12 spots from another sam-
ple of this granite (T135) give 206Pb/238U ages between
310 and 325 million years, with a weighted mean age of
317.2 3.5 million years (MSWD = 1.7) (Figure 9B).
A total of 30 spots from sample M16 (Kayadibi) provide206Pb/238U ages between 300 and 306 million years, with a
weighted mean age of 303.8 1.5 million years (MSWD=
0.119) (Figure 9C). Thus, Lower Carboniferous ages are
established for both granites by UPb zircon dating, and
these ages are interpreted as magmatic emplacement ages.
Discussion
Age constraints
In previous works, the emplacement age of granitoids
in the eastern Pontides is mainly estimated from contact
relationships, stratigraphic criteria, or biostratigraphic data.
Such data, however, are often imprecise or difficult to
obtain due to rock deformation or tectonic displace-
ment. Thus, an age reassessment, in the light of new
geochronological data, is essential. Early geochronologicstudies on the Gmshane and Kse plutons, however,
have given ambiguous and inconsistent results between
107 and 535 million years (Delaloye et al. 1972; ogulu
1975; Moore et al. 1980; JICA 1986; Bergougnan 1987).
More recently, Topuz et al . (2010) reported concor-
dant UPb zircon and ArAr biotite/hornblende ages of
324 and 320 million years, respectively, for granite samples
from the Gmshane pluton. Almost concurrently, Ar
Ar biotite/hornblende/K-feldspar ages between 322 and
306 million years have been obtained for the Kse pluton
(Dokuz 2011).
Prior to this study, knowledge about the emplacement
age of the Kayadibi and Derinoba granites was insufficient
for the reconstruction of their geological history. From
contact relationships and stratigraphic criteria, an Upper
Cretaceous age has been conjectured (Gven 1993). The
new LAICPMS UPb zircon ages of these granites, how-
ever, range from 303.8 1.5 million years (MSWD =
0.12) to 317.2 3.5 million years (MSWD = 1.7).
These ages are more or less coeval with the emplacement
age of the Gmshane and Kse plutons (Topuz et al.
2010; Dokuz 2011). Hence, the Derinoba and Kayadibi
granites are interpreted as members of a larger coher-
ent pluton, referred to here as the eastern Pontide pluton.
Remnants of this pluton either extend below the cover ofthe volcanic and volcaniclastic rocks or are now partly
eroded.
Petrogenesis of the Derinoba and Kayadibi granites
Major and trace element compositional variations in the
Derinoba and Kayadibi granites suggest that fractionation
played a major role during the crystallization of the granitic
magmas (Figure 11). Fractionation of feldspar would also
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1788 A. Kaygusuzet al.
2.8
3.0
3.2
3.4
3.6
3.8
4.0
Na2
O(wt.%)
(C)
73 74 75 76 770.5
1.0
1.5
ASI
I-tipi
S-tipiPeralumin
Metalumin
(B)
72 74 76 78
SiO2(wt.%)
0.6
0.8
1.0
1.2
1.4
Ni(ppm)
(P)1.6
73 74 75 76 77
SiO2(wt.%)
20
25
30
35
40
45
Y(ppm)
(Q)
73 74 75 76 77
SiO2(wt.%)
8
12
16
20
Nb(ppm)
(R)
73 74 75 76 77
40
80
120
160
200
Rb(ppm)
(M)
73 74 75 76 770
4
8
12
16
Pb(ppm)
(N)
73 74 75 76 774
8
12
16
20
24
28
Th(ppm)
(O)
73 74 75 76 77
40
80
120
160
200
240
Zr(ppm)
(J)
73 74 75 76 77
400
500
600
700
800
900
Ba(ppm)
(K)
30073 74 75 76 77
20
40
60
80
100
120
140
Sr(ppm)
(L)
73 74 75 76 77
0.8
1.2
1.6
2.0
2.4
2.8
Fe2
O3
T(wt.%)
(G)
73 74 75 76 770.04
0.08
0.12
0.16
0.20
T
iO2
(wt.%)
(H)
73 74 75 76 77
0.02
0.04
0.06
P
2O
5(wt.%)
(I)
73 74 75 76 77
0.0
0.4
0.8
1.2
1.6
CaO(wt.%)
(D)
73 74 75 76 770.0
0.2
0.4
0.6
0.8
MgO(wt.%)
(E)
73 74 75 76 7711.6
12.0
12.4
12.8
13.2
13.6
Al2O
3(wt.%)
(F)
73 74 75 76 77
0
2
4
6
K2
O(wt.%)
Medium-K
High-K
Shoshonitic
Low-K
(A)
68 72 76 80
Figure 5. (AR) Variation diagrams of SiO2(wt.%) versus major oxides (wt.%) and trace elements (ppm) for samples from the Derinobaand Kayadibi granites. (A) K2O versus SiO2diagram with field boundaries between medium-K, high-K, and shoshonitic series accordingto Peccerillo and Taylor (1976). (B) ASI versus SiO2 with field boundaries between I-type and S-type according to Chappell and White(1974) and peraluminous and metaluminous fields of Shand (1947). ASI (aluminium saturation index) = molar Al2O3/(Na2O + K2O +CaO). Same symbols as in Figure 4.
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International Geology Review 1789
0.1
1.0
10.0
100.0
1000.0
Sam
ple/primitivemantle
Derinoba granite(A)
Ba U Ta La Pb S r Nd H f Eu Dy YbRb Th Nb K Ce Pr P Zr Sm Ti Y Lu
1
10
100
1000
Sample/chondrite
(F)
Ksepluton
Gmhane pluton
La Ce Pr Nd SmEuGdTb Dy Ho Er TmYb Lu
0.1
1.0
10.0
100.0
1000.0
Sam
ple/primitivemantle
Kayadibi granite(B)
Ba U Ta La Pb S r Nd Hf Eu Dy YbRb Th Nb K Ce Pr P Zr Sm Ti Y Lu
0.1
1.0
10.0
100.0
1000.0
Sample/primitivemantle
Ksepluton
Gmhane pluton(C)
Ba U Ta La Pb S r Nd H f Eu Dy YbRb Th Nb K Ce Pr P Zr Sm Ti Y Lu
1
10
100
1000
Sample/chondrite
(D) Derinoba granite
(La/Yb)cn
= 4.69.7
La Ce Pr Nd SmEuGdTb Dy Ho Er TmYb Lu
La Ce Pr Nd SmEuGd Tb Dy Ho Er TmYb Lu1
10
100
1000
Sample/chondrite
(E) Kayadibi granite
(La/Yb)cn
= 2.75.5
Figure 6. (AC) Primitive mantle-normalized trace element patterns (normalizing values from Sun and McDonough 1989) for samplesfrom the Derinoba and Kayadibi granites. (DF) Chondrite-normalized REE patterns (normalizing values from Taylor and McLennan1985). Symbols as in Figure 4.
FG
OGT
1000100
Zr + Nb + Ce + Y(ppm)
1
10
100
FeOT/MgO
A-tipi
(A)
1
2
3
46
1-Mantle fractionates2-Pre-plate collision3-Post-collision uplift4-Late-orogenic5-Anorogenic
0 500 1000 1500 2000 2500 3000
R1 = 4Si11(Na + K)2(Fe + Ti)
0
500
1000
1500
2000
2500
R2=6Ca+2Mg+Al
7
6-Syn-collision7-Post-collision
5
(B)
Figure 7. (A) FeO/MgO versus (Zr+ Nb + Ce + Y) classification diagram (Whalen et al. 1987) for the Derinoba and Kayadibigranites. (B) R1 versus R2 diagram of Batchelor and Bowden (1985). R1 = 4Si 11(Na + K) 2(Fe + Ti); R2 = 6Ca + 2 Mg + Al.Symbols as in Figure 4.
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1790 A. Kaygusuzet al.
Table5.
SrandNdisotopedata
fromtheDerinobaandKayadibigranites.
Sample
Type
Age
(millionyears)
Rb
(ppm)
Sr
(ppm)87Rb/86Sr87Sr/86Sr
2m
(87Sr/86Sr)(I)
Sm(ppm)
Nd
(ppm)147Sm/144Nd143Nd/144Nd2m
(143Nd/144
Nd)(I)
Nd(I)a
TDM
b
Derinoba
T135
Granite
317
109.4
0
59.1
0
5.3
683
0.7
31657
9
0.7
0744
4.8
5
23.1
0
0.1
275
0.5
12158
10
0.5
118
9
6.5
7
1.6
5
M43
Granite
317
109.0
0
45.5
0
6.9
510
0.7
37003
9
0.7
0564
5.6
8
26.8
0
0.1
287
0.5
12181
7
0.5
119
1
6.1
7
1.6
3
T136
Granite
317
108.0
0
48.7
0
6.4
346
0.7
36909
9
0.7
0788
4.4
3
21.6
0
0.1
245
0.5
12158
7
0.5
119
0
6.4
5
1.6
0
T137
Granite
311
111.0
0
41.2
0
7.8
175
0.7
37215
12
0.7
0262
6.1
6
30.1
0
0.1
243
0.5
12179
7
0.5
119
3
6.0
8
1.5
6
T138
Granite
311
114.0
0
39.4
0
8.3
957
0.7
37461
12
0.7
0030
7.7
6
31.3
0
0.1
505
0.5
12182
7
0.5
118
8
7.0
7
2.1
5
Kayadibi
T5
Granite
303
156.2
0
65.2
0
6.9
485
0.7
32976
9
0.7
0301
7.0
9
35.1
0
0.1
226
0.5
12172
8
0.5
119
3
6.2
3
1.5
5
N12
Granite
303
145.6
0
64.9
0
6.5
052
0.7
30215
8
0.7
0217
7.1
6
35.7
0
0.1
218
0.5
12195
9
0.5
119
5
5.7
5
1.5
0
N15
Granite
303
128.3
0
61.1
0
6.0
872
0.7
27663
9
0.7
0142
8.1
2
36.3
0
0.1
358
0.5
12210
8
0.5
119
4
6.0
0
1.7
2
M16
Granite
303
118.5
0
58.8
0
5.8
393
0.7
22586
9
0.6
9741
8.6
4
36.5
0
0.1
437
0.5
12300
9
0.5
120
1
4.5
5
1.7
2
Notes:aNd(I)valuesarecalculatedbasedonpresent-day
147Sm/144Nd=
0.1
967and143Nd/144Nd=
0.5
12638(JacobsenandWa
sserburg1980).
bSingle-stagemodelage(TDM),calc
ulatedwithdepletedmantlepresent-dayparame
ters
143Nd/144Nd=
0.5
13151and147Sm/144Nd=
0.2
19.
Table6.
PbisotopedatafromtheDerinobaandKayadibigranites.
Sample
Type
Age(millionyears)
Pb(ppm)
U(ppm)
Th(p
pm)
206Pb/204Pb
(206Pb/204Pb)(I)
207Pb/204Pb
(207Pb/204Pb)(I)
208Pb/204
Pb
(208Pb/204Pb)(I)
Derinoba
T135
Granite
317
7.3
0
4.0
0
18.90
19.0
9
17.3
1
15.6
7
15.5
8
39.12
36.3
8
T136
Granite
317
12.7
0
2.8
0
14.50
18.7
1
18.0
0
15.6
6
15.6
2
38.86
37.6
7
Kayadibi
T5
Granite
303
11.0
0
6.9
0
24.10
19.2
4
17.2
9
15.6
5
15.5
5
39.09
36.8
8
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International Geology Review 1791
(87Sr/86Sr)I
15
10
5
0
5
Nd(I)
Gmhane pluton
Kse pluton
(A)
KayadibiDerinoba
0.693 0.696 0.699 0.702 0.705 0.708 0.711 0.714 SiO2(wt%)
0.6800
0.6900
0.7000
0.7100
0.7200
(87Sr/86Sr)I
(B)
FC
AFC
74 75 76
SiO2(wt.%)
0.5116
0.5118
0.5120
0.5122
(143Nd/144Nd)I
(C)
74 75 76
Nd
0.5118
0.5119
0.5119
0.5120
0.5120
0.5120
(143Nd/144Nd)I
(D)
20 24 28 32 36 40
(206
Pb/204
Pb)I
15.3
15.4
15.5
15.6
15.7
15.8
15.9
16.0
(207Pb/204Pb)I
UC
LC
EMII
EMI
HIMU
NHRL
Geochron (E)
17 18 19 20 21 22
17 18 19 20 21
(206
Pb/204
Pb)I
15.3
15.4
15.5
15.6
15.7
15.8
(207Pb/204Pb)I
Upper crust
Orogen
Mantle
Lower crust
(F)
Figure8. (A) Nd(I)versus (87Sr/86Sr)(I)diagram for theDerinoba and Kayadibigranites.(BD) (
87Sr/86Sr)(I)and (143Nd/144Nd)(I)versus
SiO2and Nd plots, respectively. (E and F) Pb isotope correlation plots of the Derinoba and Kayadibi granites. EMI, enriched mantle type
I (Zindler and Hart 1986); HIMU, high-( = 238U/204Pb, Lustrino and Dallai 2003); EMII, enriched mantle type II (enriched in Sr);LC, lower crust; NHRL, Northern Hemisphere Reference Line (Hart 1984); UC, upper crust. Mantle (MORB), orogen, upper crust (UC),and lower crust (LC) evolution lines are from Zartman and Doe (1981). Symbols as in Figure 4.
result in the depletion of Ba and Sr. Negative Eu anoma-
lies and a decrease in Sr with increasing silica (Figure 5L)
indicate that plagioclase is an important fractionating
phase. The rocks show similar REE patterns, with a general
increase of both light and heavy REEs with increasing
SiO2(Figure 6). The magnitude of the negative Eu anoma-
lies increases with increasing SiO2 contents, suggesting
fractionation of plagioclase for both granites. Fractionation
of FeTi oxide may be responsible for the negative anomaly
in Ti. The negative anomaly in P is most probably the
result of apatite fractionation (Figure 6). Garnet may have
not been involved in magma genesis (Table 4); chondrite-
normalized REE patterns show almost no fractionation
between middle and heavy REE, and Sr/Y ratios are low
(i.e. 1.23.7).
The Derinoba and Kayadibi granites are high-K calc-
alkaline rocks, and their primitive mantle-normalized
spider diagrams are characterized by pronounced neg-
ative Ba, Sr, Ti, and Nb anomalies and enrichment
in Rb, K, and La. These are typical features of syn-
orogenic crustal-derived granitoids. Moderate to high
Rb/Sr ratios (0.55.2) and high K2O (3.24.8 wt.%) and
SiO2(7477 wt.%) contents are consistent with the deriva-
tion from a metasedimentary or felsic micaceous crustal
source (cf. Van de Flierdt et al. 2003; Jung et al. 2009).
Moreover, Nb/Ta ratios vary from 5.7 to 20.5 (average
value = 12.7), Zr/Hf from 24.3 to 51.4 (average = 30.5),
and Th/U from 2.5 to 13.8 (average = 5.40). These
geochemical signatures also suggest the derivation of these
magmas from the partial melting of crustal rocks.
The ASI values indicate strongly peraluminous com-
position, as expected for melts derived by partial melting
of continental crustal rocks. Hence, a derivation from
crustal sources is apparent. The heterogeneity of the initial
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International Geology Review 1793
Table7.
(Continued).
Measuredratios
Correctedages(millionyears)
Spot
207Pb/206Pb
1
20
7Pb/235U
1
206Pb/238U
1
208Pb/
232Th
1
238U/232Th
1
207Pb/206P
b1
207Pb/235U
1
206Pb/238U1
208Pb/232Th1
M16-0
5
0.0
53
0.0
0134
0.3
51
0.0
0893
0.0
48
0.0
0065
0.0
16
0.0
0031
2.1
42
0.0
2
323
34
305
7
303
4
318
6
M16-0
7
0.0
55
0.0
0151
0.3
65
0.0
1006
0.0
48
0.0
0066
0.0
14
0.0
0029
1.4
81
0.0
1
409
37
316
7
303
4
290
6
M16-0
8
0.0
53
0.0
0137
0.3
55
0.0
092
0.0
48
0.0
0065
0.0
16
0.0
0031
1.7
88
0.0
2
337
35
309
7
305
4
312
6
M16-0
9
0.0
53
0.0
0158
0.3
52
0.0
1052
0.0
48
0.0
0067
0.0
15
0.0
0032
1.4
58
0.0
1
315
43
306
8
305
4
307
6
M16-1
0
0.0
55
0.0
0144
0.3
6
0.0
0951
0.0
48
0.0
0065
0.0
15
0.0
0031
1.7
39
0.0
2
392
35
313
7
302
4
310
6
M16-1
1
0.0
54
0.0
0148
0.3
6
0.0
0984
0.0
48
0.0
0066
0.0
14
0.0
0028
1.2
65
0.0
1
369
37
312
7
304
4
279
6
M16-1
2
0.0
56
0.0
0165
0.3
7
0.0
1093
0.0
48
0.0
0067
0.0
16
0.0
0035
2.1
78
0.0
2
320
109
305
12
303
4
303
4
M16-1
4
0.0
53
0.0
0165
0.3
48
0.0
1078
0.0
48
0.0
0067
0.0
16
0.0
0036
1.7
71
0.0
2
322
45
303
8
300
4
325
7
M16-1
5
0.0
52
0.0
0139
0.3
47
0.0
0925
0.0
48
0.0
0066
0.0
16
0.0
0032
1.8
25
0.0
2
293
36
302
7
304
4
313
6
M16-1
6
0.0
57
0.0
0181
0.3
78
0.0
1199
0.0
49
0.0
0069
0.0
15
0.0
0034
1.3
88
0.0
1
473
45
326
9
305
4
305
7
M16-1
7
0.0
53
0.0
0145
0.3
53
0.0
0963
0.0
48
0.0
0066
0.0
16
0.0
0034
2.0
36
0.0
2
330
37
307
7
304
4
328
7
M16-1
8
0.0
53
0.0
0154
0.3
55
0.0
1026
0.0
49
0.0
0067
0.0
16
0.0
0035
1.7
07
0.0
2
327
41
308
8
306
4
322
7
M16-1
9
0.0
53
0.0
0144
0.3
53
0.0
0956
0.0
48
0.0
0066
0.0
12
0.0
0025
1.2
6
0.0
1
329
37
307
7
304
4
243
5
M16-2
0
0.0
53
0.0
0161
0.3
52
0.0
1065
0.0
48
0.0
0067
0.0
15
0.0
0032
1.7
81
0.0
2
331
43
306
8
303
4
295
6
M16-2
1
0.0
54
0.0
0144
0.3
58
0.0
0958
0.0
48
0.0
0066
0.0
15
0.0
003
1.6
53
0.0
2
365
36
311
7
304
4
291
6
M16-2
2
0.0
54
0.0
0192
0.3
58
0.0
1262
0.0
48
0.0
007
0.0
16
0.0
0045
3.6
57
0.0
4
366
53
311
9
304
4
320
9
M16-2
3
0.0
53
0.0
0146
0.3
56
0.0
0966
0.0
48
0.0
0066
0.0
13
0.0
0027
1.5
75
0.0
2
349
37
309
7
304
4
253
5
M16-2
4
0.0
55
0.0
0165
0.3
66
0.0
1089
0.0
48
0.0
0067
0.0
16
0.0
0034
1.6
4
0.0
2
417
42
317
8
303
4
311
7
M16-2
5
0.0
53
0.0
0145
0.3
52
0.0
0962
0.0
48
0.0
0066
0.0
15
0.0
0032
1.3
46
0.0
1
319
38
306
7
304
4
297
6
M16-2
6
0.0
52
0.0
0182
0.3
49
0.0
12
0.0
48
0.0
007
0.0
15
0.0
0034
0.9
63
0.0
1
302
52
304
9
304
4
298
7
M16-2
7
0.0
53
0.0
0166
0.3
53
0.0
1089
0.0
48
0.0
0068
0.0
16
0.0
0038
1.9
22
0.0
2
333
44
307
8
304
4
326
8
M16-2
8
0.0
54
0.0
016
0.3
57
0.0
1055
0.0
48
0.0
0067
0.0
14
0.0
0031
1.3
91
0.0
1
351
42
310
8
305
4
277
6
M16-2
9
0.0
56
0.0
0168
0.3
77
0.0
1115
0.0
49
0.0
0068
0.0
15
0.0
0034
1.8
48
0.0
2
461
41
325
8
306
4
293
7
M16-3
0
0.0
53
0.0
0169
0.3
53
0.0
1113
0.0
48
0.0
0068
0.0
15
0.0
0034
0.9
71
0.0
1
320
46
307
8
305
4
299
7
Notes:Errorsare1.
206Pb/
238Uagevaluesareusedinthetextastheweightedmean.
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1794 A. Kaygusuzet al.
290
300
310
320
330
340
0.046
0.048
0.050
0.052
0.054
207Pb/
235U
206Pb
/238U
Data point error ellipses are 68.3% conf
Mean = 317.2 3.5 million years,
95% conf. n= 11, MSWD = 1.7
T135 Derinoba granite (B)
290
294
298
302
306
310
314
318
0.0455
0.0465
0.0475
0.0485
0.0495
0.0505
0.32 0.34 0.36 0.38 0.40 0.42 0.44 0.46
0.30 0.32 0.34 0.36 0.38 0.40 0.42
207Pb/
235U
206Pb/238U
Data point error ellipses are 68.3% conf
Mean = 303.8 1.5 million years
95% conf. n= 28 MSWD = 0.119
M16 Kayadibi granite (C)
290
300
310
320
330
0.045
0.047
0.049
0.051
0.053
0.30 0.32 0.34 0.36 0.38 0.40 0.42 0.44
207Pb/
235U
206Pb/238U
Data point error ellipses are 68.3% conf
Mean = 311.1 2.0 million years,
95% conf. n= 23, MSWD = 1.4
T138 Derinoba granite (A)
Figure 9. (AC) Concordia diagrams showing LAICPMS UPb zircon dating results from (A and B) Derinoba granite (samplesT138 and T135) and (C) Kayadibi granite (sample M16).
(A) T138 (B) M16
100 m100 m
Figure 10. (A and B) Cathodoluminescence images of typical zircons from (A) Derinoba granite (sample T138) and (B) Kayadibi granite(sample M16).
Sr isotope values is also consistent with this interpreta-
tion. However, the granites have undergone deformation
and alteration to variable degrees. Therefore, a prudent
assumption is that the measured Rb/Sr and 87Sr/86Sr
ratios have been modified to a certain extent, at least in
some samples. Extremely low (87Sr/86Sr)(I) values (e.g.
0.69740.7003) have been found in samples, showing signs
of aqueous alteration. Therefore, these values do not pro-
vide a significant geological meaning. On the other hand,
Nd isotope ratios are known to be more robust during
alteration and provide less ambiguous constraints on the
origin of these rocks. Initial 143Nd/144Nd isotope values
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International Geology Review 1795
Sr
10
100
1000
Rb
Pl
Kf
Bi
Cpx Hb
(A)
10 100 1000 10 100 1000
Sr
10
100
1000
Ba
Pl
Kf
Bi
CpxHb (B)
Figure 11. (A and B) Variation of (A) Rb versus Sr and (B) Ba versus Sr. Fractionation vectors were calculated according to the partitioncoefficients listed in Rollinson (1993). Symbols as in Figure 4.
(0.511880.51201) of the studied granites are homoge-
neous with negative Nd(I) values (4.6 to 7.1), con-
firming the derivation of granitic magma from crustal
sources.
Experimental data on high-K calc-alkaline granitoid
rocks show that such rocks can be produced by melt-ing different crustal sources (e.g. Roberts and Clemens
1993). Furthermore, partial melting yields compositional
differences among magmas produced by melting com-
mon crustal rocks, such as amphibolites, tonalitic gneisses,
metagreywackes, and metapelites under variable melting
conditions (e.g. Patio-Douce 1999). This compositional
variation can be visualized in terms of major oxide ratios
(Figures 12A12D) or molar oxide ratios (Figures 12E
12G). The plots in Figures 12A12F show that partial
melts derived from metapelites and metagreywackes source
rocks have higher molar (Na2O + K2O)/(FeOT + MgO
+ TiO2) and K2O/Na2O ratios as well as lower molar
CaO/(MgO + FeOT) and Na2O, relative to those originated
from the mafic to intermediate source rocks (Figure 12).
Most samples from the Derinoba and Kayadibi granites
plot in the metagreywackes field (Figure 12) and show
high molar (Na2O + K2O)/(FeOT + MgO + TiO2) and
molar K2O/Na2O ratios but relatively low CaO/(MgO +
FeOT). In the Al2O3/TiO2 versus CaO/Na2O diagram
(Figure 12H), the granites show varying CaO/Na2O val-
ues, which indicate the protolith composition of a mixture
of sandstone and argillaceous rocks. These features, asso-
ciated with relatively low Mg-number values (933), sug-
gest melt production from lower crustal metasedimentary
source rocks. A similar origin is suggested for granophyresfrom the Gmshane pluton (Topuzet al. 2010).
Geodynamic implications
Hercynian plutonism in Turkey is confined spatially to the
Pontides, specifically to its eastern portion (Figure 1B).
The subduction polarity and geotectonic evolution of
the eastern Pontide orogenic belt are still controversial.
The various models proposed for the subduction polar-
ity of the eastern Pontides can be grouped into three:
(i) Adamia et al. (1977) and Ustamer and Robertson
(1996) suggested that the eastern Pontides developed by the
northward subduction of the Palaeotethys, which was situ-
ated to the south of the magmatic arc, from the Palaeozoic
until the end of the Eocene; (ii) Sengr and Ylmaz
(1981) proposed that the Palaeotethys was situated to the
north of the Pontides, and hence southward subductionoccurred from the Palaeozoic until the Middle Jurassic,
whereas northward subduction occurred subsequently from
the Upper Cretaceous until the end of the Eocene; (iii)
Dewey et al. (1973), Bektas et al. (1999), and Eyuboglu
et al. (2007) suggested that southward subduction contin-
ued uninterruptedly from the Palaeozoic until the end of
the Eocene.
Researchers are likewise debating whether the eastern
Pontides belong to Gondwana or Eurasia (Laurussia)
(Sengret al. 1980; Sengr and Ylmaz 1981; Robertson
and Dixon 1984; Robinsonet al. 1995; Okay and Sahintrk
1997; Ylmaz et al . 1997; Wehrmann et al . 2010).
The oceanic domain between Gondwana and Eurasia
(Laurussia) is known as the Palaeotethys. The location
of the eastern Pontides during the late Palaeozoic era
is contentious. Some authors have suggested that the
eastern Pontides formed part of the active nor