Geochemical and Pb–Sr–Nd isotopic composition of the ultrapotassic

volcanic rocks from the extension-related Camardı-Ulukısla basin,

Nigde Province, Central Anatolia, Turkey

Musa Alpaslana,*, Durmus Boztugb, Robert Freic, Abidin Temeld, Mehmet Ali Kurta

aMersin University, Department of Geology, Mersin, TurkeybCumhuriyet University, Department of Geological Engineering, 58140 Sivas, Turkey

cGeological Institute University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen, DenmarkdHacettepe University, Department of Geology, 06532 Ankara, Turkey

Received 10 August 2004; revised 4 May 2005; accepted 6 July 2005

Abstract

Major, trace element and Sr–Nd–Pb isotope data are presented for the ultrapotassic lavas and dykes from the Late Cretaceous-Early

Tertiary Ulukısla Basin in the Central Anatolia. All samples have geochemical characteristics belonging to Group III ultrapotassic rocks

(Foley, S.F., Venturelli, G., Green, D.H., Toscani, L., 1987, The ultrapotassic rocks: characteristics, classification and constraints for

petrogenetic models, Earth Science Reviews, 24, 81–134.). These rocks have unusually high contents of large-ion-lithophile elements (LILE)

(e.g. Ba up to 5900 ppm, K2O up to 8 wt% in lava and 10 wt% in dykes). Negative Nb and Ti anomalies and LREE enrichments relative to

HREE on chondrite normalized trace and rare earth element patterns indicate that subduction related material is present in the mantle source

region. Their high initial 87Sr/86Sr (0.70798–0.70917) and low 143Nd/144Nd (0,512109–0,512239) ratios suggest that they originated from an

enriched lithospheric mantle source with low Sm/Nd ratios. The elevated 207Pb/206Pb (15.743–15.797), low 143Nd/144Nd ratios and

geochemical features such as low Nb/La and elevated Ce/Sr ratios may reflect the involvement of sediments as a metasomatic agent for the

source region. The steep trend on the 207Pb/204Pb vs 206Pb/204Pb diagram also imply that the metasomatic component represents recycled

continent-derived material in the source region. Integration of the geochemistry with regional and local geological data suggest that the

ultrapotassic volcanic rocks from the Camardı-Ulukısla basin were derived from a lithospheric mantle material in a post-collisional

extension-related geodynamic setting following Late Mesozoic continental collision between the Eurasian plate and Tauride-Anatolide

platform, as a result of convergence between the Eurasian and Afro-Arabian plates.

q 2005 Elsevier Ltd. All rights reserved.

Keywords: Ultrapotassic volcanic rocks; Trace element geochemistry; Pb–Sr–Nd isotope geochemistry; Enriched mantle; Camardı-Ulukısla basin; Central

Anatolia; Turkey

1. Introduction

The Camardı-Ulukısla Basin is one of the Late

Cretaceous to early tertiary post-collisional central Anato-

lian basins (Fig. 1) (Goncuoglu et al., 1995; Erdogan et al.,

1996; Poisson et al., 1996; Boztug et al., 2003, 2004).

However, its development has been interpreted in various

ways in terms of geodynamics such as a fore-arc basin

1367-9120/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.

doi:10.1016/j.jseaes.2005.07.002

* Corresponding author.

E-mail address: malpaslan@mersin.edu.tr (M. Alpaslan).

(Gorur et al., 1998), a back-arc basin (Demirtaslı et al., 1984),

an island-arc related basin (Oktay, 1982; Bas et al., 1986; Isler,

1988), and a rifting-related basin (Boztug et al., 2001;

Clark and Robertson, 2002; Alpaslan et al., 2004). In

particular, Clark and Robertson (2002) has proposed that

the Camardı-Ulukısla basin is an intracontinental rifting-

related, transtensional basin developed after the late

Cretaceous closure of the Northern Neotethys. Clark and

Robertson (2002) have determined within-plate and also

subduction-related geochemical signatures for the wide-

spread basaltic to andesitic submarine volcanic rocks in the

Camardı-Ulukısla basin which are also documented by

Journal of Asian Earth Sciences 27 (2006) 613–627

www.elsevier.com/locate/jaes

Fig. 1. (a) Location of the study area and Neotethyan sutures of Turkey (Modified after Clark and Robertson, 2002). b: Major sedimentary basins of central

Anatolia. (Abbreviations: BP: Bolkar Carbonate Platform, NKM: Nigde-Kırsehir Massif, UB: Ulukısla basin, TB: Tuzgolu basin, HB: Haymana basin, KKB:

Kırıkkale basin, CB: Cankırı basin, YSB: Yozgat-Sorgun basin, KB: Kızılırmak basin, YB: Yıldızeli basin, RB: refahiye basin, SB: Sivas basin, SKB: Sarkısla

basin, EFZ: Ecemis Fault Zone) (After Clark and Robertson, 2002).

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627614

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627 615

Alpaslan et al. (2004) with the major, trace and Pb–Sr–Nd

isotope geochemical data.

Alpaslan et al. (2003) reported that the volcanism within

the Camardı-Ulukısla basin encompasses (1) sodic alkaline,

and (2) ultrapotassic compositions. The sodic alkaline

volcanic rocks from this basin are suggested to have been

derived from an enriched subcontinental lithospheric mantle

source (EMII-OIB) (Alpaslan et al., 2004). This paper

documents, for the first time, the petrological features of

ultrapotassic rocks in the Camardı-Ulukısla basin. We

present geochemical and Pb–Sr–Nd isotopic compositional

data in order to better understan the geological evolution of

this basin in central Anatolia.

2. Regional tectonic setting

Despite numerous studies in the Ulukısla basin, neither

the processes responsible for basin development nor the

regional tectonic setting have been reconciled by the

authors. The different interpretations are related to two

major areas of investigation: (1) the geodynamic setting of

the basin and whether it is (a) a fore-arc basin (Gorur et al.,

1998), (b) an island arc-related basin (Oktay, 1982; Bas

et al., 1986), (c) the prolongation of the Tauride platform

(Goncuoglu, 1986; Goncuoglu et al., 1995), (d) a back-arc

basin (Demirttaslı et al., 1984, or (e) rifting-related basin

(Boztug et al., 2001; Clark and Robertson, 2002; Alpaslan

et al., 2004) and (2) the location and subduction polarity of

the oceanic realm whose evolution has given rise to this

basin: (a) the Inner Tauride ocean subducted northwards

(Gorur et al., 1998) or southwards (Oktay, 1982), or (b) the

Northern Neotethys subducted northward (Goncuoglu,

1986; Dirik et al., 1999). Clark and Robertson (2002)

have proposed a recent explanation for the genesis of the

Camardı-Ulukısla basin and in-filling volcanic rocks on the

basis of geological, structural and geochemical data. They

suggest that the latest Cretaceous (Maastrictian) to late

Eocene Ulukısla basin formed by extension (or transtension)

following initial closure of what was probably a local strand

of the Northern Neotethys ocean (Inner Tauride Ocean).

The in-filling volcanic rocks in this basin exhibit within-

plate type basic to intermediate compositions with a

subduction signature recognized by trace element data

(e.g. relative Nb depletion) which was probably inherited

from prior Late Cretaceous subduction in the region (Clark

and Robertson, 2002). The subduction signature of the

alkaline volcanic rocks from the Camardı-Ulukısla basin

has also been reported by Alpaslan et al. (2003, 2004) based

on Pb–Sr–Nd isotope geochemical data.

3. Geological setting

Recent detailed regional and local geological settings of

the Camardı-Ulukısla basin have been published by Clark

and Robertson (2002) and Alpaslan et al. (2004). The

volcano-sedimentary rocks of the Camardı-Ulukısla basin,

having a thickness of more than 5 km, range in age from

Late Createcous to Early Oligocene. Volcanic rocks can

reach a thickness of up to 2 km (Clark and Robertson, 2002;

Alpaslan et al., 2004 and references therein). These rocks

unconformably overlie the Late Cretaceous Alihoca

ophiolite which was emplaced onto the Bolkar Carbonate

platform (Demirtaslı et al., 1984; Lytwn and Casey, 1995;

Dilek et al., 1999; Yetis et al., 1995; Fig. 2). The rock types

in the Camardı-Ulukısla basin include alternating conglom-

erate, sandstone, marl, pelagic limestone, reef limestone,

claystone and volcanics consisting of pillow lava, massive

lava flows and pyroclastics, which are collectively called the

Ulukısla formation (Fig. 2) with ages ranging from Late

Cretaceous to Early Eocene (Alpaslan et al., 2004). The

volcanic rocks within the Ulukısla formation comprise two

main types (1) sodic alkaline, and (2) ultrapotassic

(Alpaslan et al., 2003). Sodic alkaline volcanic rocks

occur as pillow lavas and massive lava flows, whereas

ultrapotassic volcanic rocks occur as massive lavas and

dykes. Sodic alkaline volcanic rocks alternate with

sedimentary units, and were intruded by dioritic, monzonitic

and trachytic dykes (Alpaslan et al., 2004; Kurt, 2004).

Ultrapotassic volcanic rocks include lava flows alternating

with sedimentary units towards the top of the sequence. In

some localities, ultrapotassic volcanics are also observed as

dykes that strike east to west, and intrude sedimentary units

and dykes mentioned above. Mineralogical and textural

characteristics of the ultrapotassic volcanic rocks from the

Ulukısla formation are shown in Table 1.

Major structural elements of the mapped area include

nearly EW trending thrust faults, NE–SW and NNE–SSW

trending left-lateral strike-slip faults and some ENE–WSW

folds (Fig. 2; Alpaslan et al., 2004). The Alihoca ophiolitic

unit has been thrusted onto the Bolkardag carbonate

platform from north to south (Fig. 2) prior to the opening

of the Camardı-Ulukısla basin. All the other structural

elements, such as E-W thrusts, ENE-WSW folds and NE–

SW faults affecting only the Ulukısla formation are

considered to reflect post-Eocene N-S compression. The

NNE-SSW trending fault in the SE portion of the mapped

area (Kamıslı fault) is the part of the well-known Ecemis

fault, one of the major neotectonic faults of the Anatolian

province formed by continued convergence between the

Eurasian and Arabian plates (Kocyigit and Beyhan, 1998;

Bozkurt, 2001; Jaffey and Robertson, 2001).

4. Analytical techniques

Seventeen rock samples were selected for geochemical

analysis (major and trace elements, REE) and five of them

for isotopic (Sr, Nd and Pb) analysis (Table 2).

For major element analyses, fused disks were prepared

by using six parts of lithium tetraborate and one part of rock

Fig. 2. Simplified geological map of the study area (after Alpaslan et al., 2003).

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627616

powder. The mixture was fused in crucibles of 95% Pt and

5% Au at 1050 8C for 60 min to form a homogenous melt.

The melt then was poured into a preheated mold and chilled

to a thick glass disk. Whole rock analyses were performed at

Hacettepe University using a PHILIPS PW 1480 X-ray

spectrometer calibrated using USGS rock standards. Trace

and rare earth element concentrations were analyzed at

ACME laboratories (Vancouver, CANADA) by ICP-MS

Table 1

Brief petrographical descriptions of the ultrapotassic volcanic rocks from the Cam

Sample no Lithology Mg-no Texture

11 Massive lava 53.76 Hypocrystalline-porphyry

77 Dyke 50.40 Aphanitic-microlitic

79 Dyke 43.98 Aphanitic-microlitic

81 Dyke 51.89 Aphanitic-microlitic

82 Dyke 49.68 Aphanitic-microlitic

92 Massive lava 50.85 Hypocrystalline porphyry

114 Massive lava 37.70 Hypocrystalline porphyry

155 Massive lava 46.57 Hypocrystalline porphyry

156 Massive lava 53.27 Hypocrystalline porphyry

157 Massive lava 58.64 Hypocrystalline porphyry

161 Massive lava 53.19 Hypocrystalline porphyry

163 Massive lava 50.41 Hypocrystalline porphyry

173 Massive lava 50.36 Hypocrystalline porphyry

217 Massive lava 54.77 Hypocrystalline porphyry

286 Massive lava 39.48 Hypocrystalline porphyry

290 Massive lava 62.42 Hypocrystalline porphyry

317 Massive lava 39.34 Hypocrystalline porphyry

356 Massive lava 50.63 Hypocrystalline porphyry

Explanation:cpx, clinopyroxene; plg, plagioclase; bi, biotite; ap, apatite; op, opaq

using a fusion method with better than G3% analytical

accuracy.

Sm–Nd, Pb and Sr isotopic data and concentrations were

obtained from 300 mg aliquots of the same powders. For

isotope dilution analysis of Sm and Nd, a mixed147Sm–150Nd spike was added. Dissolution of the samples

was achieved in two successive, but identical steps which

consisted of a strong 8 N HBr digestion followed by

ardı-Ulukısla basin, central Anatolia, Turkey

Phenocryst Groundmass

tic CpxCPlg. BiCCpxCApCOpCGl

– BiCPlgCSanCOpCGl

– BiCPlgCSanCOpCGl

– BiCPlgCSanCOpCGl

– BiCPlgCSanCOpCGl

tic PlgCCpx BiCPlgCCpxCApCOpCGl

tic PlgCCpx BiCCpxCPlgCOpCGl

tic PlgCCpx BiCCpxCPlgCApCOpCGl

tic PlgCCpx BiCCpxCPlgCApCOpCGl

tic PlgCCpxCOl BiCPlgCCpxCSanCOpCGl

tic PlgCCpx BiCCpxCPlgCOpCGl

tic PlgCCpx BiCPlgCCpxCSanCOpCGl

tic PlgCCpx BiCCpxCPlgCOpCGl

tic PlgCCpx BiCPlgCCpxCOpCGl

tic PlgCCpx BiCPlgCCpxCOpCGl

tic PlgCCpx BiCPlgCCpxCSanCApCOpCGl

tic PlgCCpx BiCCpxCPlgCApCOpCGl

tic PlgCCpx BiCPlgCCpxCApCOpCGl

ue; gl, glass; san, sanidine; ol, olivine.

Table 2

Major, trace, REE and Sr-, Nd- and Pb-isotopic compositions of the ultrapotassic volcanic rocks from the Camardı-Ulukısla basin, central Anatolia. Turkey.

(Major oxides as wt %. trace and rare earth elements as ppm,. tFe2O3 as total iron oxide as ferric iron, LOI as loss on ignition)

Sample 11 155 156 161 163 217 286 317 356

Longitude 37833 012 00N 37833 0040 00N 37833 039 00N 37833 050 00N 37833 049 00N 37830 042 00N 37834 015 00N 37834 010 00N 37833 050 00N

Latitude 34832 014 00E 34844 007 00E 34844 005 00E 34844 007 00E 34844 006 00E 34844 030 00E 34847 008 00E 34846 052 00E 34849 045 00E

SiO2 49.74 47.70 46.80 48.19 48.65 48.80 47.77 48.58 48.55

TiO2 1.18 1.28 1.15 1.30 1.27 1.45 1.55 0.96 1.11

Al2O3 17.65 17.93 17.60 18.34 17.95 17.56 17.05 18.59 18.62

tFe2O3 7.70 9.09 8.98 9.01 8.96 9.65 9.93 7.64 7.32

MnO 0.13 0.17 0.15 0.17 0.17 0.09 0.33 0.14 0.11

MgO 4.52 4.00 5.17 5.17 4.60 5.90 3.93 3.68 3.79

CaO 4.34 8.40 7.88 5.28 6.10 2.84 4.53 5.13 9.02

Na2O 2.32 2.38 2.20 2.38 2.35 2.14 2.12 2.58 2.36

K2O 5.81 4.80 4.69 5.25 5.40 7.14 8.47 5.25 4.75

P2O5 0.77 0.90 0.80 0.88 0.92 0.99 1.06 0.64 0.74

LOI 4.13 3.70 4.64 4.20 3.77 4.43 3.44 6.37 3.31

Total 98.29 100.35 100.06 100.17 100.14 100.99 100.18 99.56 99.68

Rb 177 177 135 170 191 128 280 182 149

Cs 4.30 7.20 9.40 6.80 9.50 1.00 2.60 4.80 0.60

Pb 46.40 38.80 27.90 29.30 32.50 29.90 26.90 52.70 17.40

Ba 3562 1735 2066 2458 2965 3162 5913 2036 1024

Sr 1050 1091 911 975 1233 865 976 984 867

Ta 1.10 0.80 0.70 0.90 0.90 1.10 1.20 1.50 1.00

Nb 22.6 20.6 17.5 22.8 22.2 23.8 23.8 35.4 19.7

Hf 6.10 5.10 4.40 5.70 5.80 5.00 5.20 7.20 5.30

Zr 280 226 189 245 236 209 232 312 197

Y 34 34 29 37 35 31 35 30 24

Th 30.60 31.50 26.80 36.90 34.90 25.70 23.40 36.60 22.30

U 5.40 5.90 3.90 5.70 6.10 4.30 4.50 5.70 3.70

La 107.30 129.80 108.80 139.50 135.60 124.80 103.30 121.60 88.30

Ce 208.20 245.40 207.20 264.90 258.00 238.20 194.80 222.70 158.70

Pr 23.76 26.63 22.67 28.51 27.20 25.67 20.97 22.13 16.53

Nd 90.20 97.60 84.30 107.80 103.20 96.20 79.90 86.20 67.40

Sm 15.20 16.20 14.00 17.30 17.00 15.10 16.20 13.80 10.90

Eu 3.23 3.80 3.18 3.92 3.76 3.52 2.28 3.26 2.66

Gd 10.39 11.56 9.86 12.74 12.76 9.73 9.46 9.58 7.43

Tb 1.30 1.32 1.26 1.44 1.58 1.25 1.21 1.13 0.91

Dy 7.04 6.57 5.66 7.31 7.28 5.92 6.22 5.81 4.49

Ho 1.06 1.07 0.89 1.18 1.20 1.07 1.12 0.96 0.84

Er 2.89 2.89 2.48 2.97 2.83 2.71 3.05 2.77 2.28

Tm 0.43 0.42 0.37 0.46 0.44 0.41 0.53 0.40 0.32

Yb 2.77 2.51 2.08 2.52 2.57 2.47 2.98 2.45 2.09

Lu 0.41 0.38 0.35 0.42 0.39 0.36 0.42 0.40 0.3387Sr/86Sr 0.709514 – 0.708264 0.708723 – – 0.708574 – –143Nd/144Nd 0.512221 – 0.512142 0.512198 – – 0.512271 – –206Pb/204Pb 18.920 – 18.975 18.965 – – 18.866 – –207Pb/204Pb 15.767 – 15.797 15.774 – – 15.743 – –208Pb/204Pb 39.415 – 39.566 39.495 – – 39.234 – –

Sample 92 290 173 157 77 79 81 82

Longitude 37835 010 00N 37835 012 00N 37835 011 00N 37835 013 00N 37835 032 00N 37834 017 00N 37845 048 00N 37833 047 00N

Latitude 34842 008 00E 34842 007 00E 34842 010 00E 34842 012 00E 34842 040 00E 34847 009 00E 34858 017 00E 34844 008 00E

SiO2 51.35 53.79 53.21 48.06 52.84 53.40 52.85 52.52

TiO2 1.26 1.33 1.14 1.04 1.02 1.01 1.02 1.04

Al2O3 18.03 18.48 18.42 18.03 17.96 17.97 17.46 17.67

tFe2O3 6.91 4.28 4.48 7.43 7.29 7.29 7.07 7.08

MnO 0.14 0.13 0.07 0.20 0.16 0.15 0.17 0.15

MgO 3.61 3.59 3.47 5.32 3.74 3.02 3.85 3.53

CaO 2.70 2.04 2.25 10.27 1.89 1.78 1.77 1.67

Na2O 2.46 2.40 2.62 1.87 0.96 0.89 0.87 0.82

K2O 6.81 8.27 8.6 4.25 9.92 10.58 10.53 10.42

P2O5 0.48 0.79 0.42 0.68 0.57 0.49 0.52 0.50

LOI 4.43 2.91 3.64 3.29 2.99 2.43 3.08 2.79

Total 98.18 98.01 98.32 100.44 99.34 99.01 99.18 98.19

Rb 203 259 203 127 373 391 308 293

(continued on next page)

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627 617

Table 2 (continued)

Cs 28.20 3.20 2.2 4.50 3.20 2.80 1.50 2.40

Pb 53.30 27.40 22.50 21.80 23.20 25.90 27.90 30.20

Ba 2628 3681 2686 2292 3382 3501 3560 4174

Sr 572 480 945 1440 982 1078 635 566

Ta 1.90 0.90 1 0.70 1.20 1.30 1.10 1.10

Nb 36.4 17.3 16.8 18.4 26.7 27.3 25.4 26.5

Hf 7.40 7.50 7.4 4.60 7.10 7.30 6.40 7.10

Zr 302 274 265 193 313 324 300 314

Y 35 27 26 23 43 40 40 37

Th 41.90 31.10 32.1 29.20 32.80 34.30 30.90 32.20

U 4.50 5.20 5.1 3.87 6.40 5.80 4.60 5.70

La 141.50 128.80 125.3 124.0 114.40 110.30 95.30 111.40

Ce 264.50 222.10 221.6 212.80 219.40 210.40 194.90 218.40

Pr 27.84 22.75 21.9 23.20 26.39 24.32 22.58 24.09

Nd 98.60 87.50 86.5 87.50 99.10 95.80 86.10 88.80

Sm 15.20 13.20 13.4 15.20 16.40 15.70 15.40 14.90

Eu 3.18 2.72 2.69 3.24 3.63 3.48 3.33 3.19

Gd 10.21 7.99 7.86 10.14 12.30 11.57 11.33 10.60

Tb 1.41 1.00 0.98 1.23 1.67 1.57 1.60 1.47

Dy 6.82 5.00 4.68 5.57 7.73 7.62 7.26 7.46

Ho 1.11 0.85 0.87 0.92 1.31 1.35 1.22 1.26

Er 2.94 2.56 2.43 2.40 3.22 3.27 3.20 3.33

Tm 0.47 0.40 0.39 0.38 0.47 0.48 0.46 0.54

Yb 2.88 2.39 2.41 2.09 2.87 2.90 3.19 2.91

Lu 0.44 0.39 0.42 0.39 0.43 0.44 0.46 0.4487Sr/86Sr – – – – 0.709617 – – –143Nd/144Nd – – – – 0.512226 – – –206Pb/204Pb – – – – 18.937 – – –207Pb/204Pb – – – – 15.755 – – –208Pb/204Pb – – – – 39.402 – – –

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627618

HF–HNO3 and then by concentrated HCl. Lead leaching

experiments involved leaching with 1 N HCl for 5 min, after

which the leachate was pipetted off and processed as a

separate sample.

Chemical separation of Sr and REEs from whole rocks

was carried out on conventional cation exchange columns,

followed by additional separation using HDEHP-coated

beads (BIO-RAD) in 6 ml quartz glass columns. Purification

of the Sr fraction was achieved by a pass through micro-

columns containing SrSpece resin. REEs were further

separated using HDEHP-coated bio beads (BioRade)

loaded in a 6 ml glass stem column. Pb was separated

conventionally in 0.5 ml glass columns charged with anion

exchange resin, followed by a clean-up on 200 ml Teflonw

columns. A standard HBr–HCl–HNO3 elution recipe was

applied for both column steps. Total Pb procedural blanks

were !125 pg for the whole rock chemistry, which are

negligible relative to the amount of Pb recovered from each

sample. Mass spectrometric analyses were carried out on a

VG Sector 54-IT instrument at the Geological Institute,

University of Copenhagen.

The mean value for our internal JM Nd standard

(referenced against La Jolla) during the period of

measurement was 0.511115 for 143Nd/144Nd, with a 2s

external reproducibility of G0.000013 (five measurements).

Fractionation for Pb was controlled by repetitive analysis of

the NBS 981 standard (values of Todt et al., 1993) and

amounted to 0.103G0.007%/amu (2s; nZ5). Sr was

normalized to 86Sr/88Sr Z0.1194, and repetitive analyses

of the NBS 987 Sr standard yielded 87Sr/88Sr Z0.710248C/K0.000004 (2 s, nZ6).

5. Geochemistry

Major, trace, REE and Pb–Sr–Nd isotopic compositions

of the ultrapotassic massive lavas and dykes from the

Ulukısla formation are reported in Table 2.

Ultrapotassic igneous rocks are described by Foley et al.

(1987) as having high contents of K2OO3 wt %, MgOO3 wt%, and K2O/Na2OO2. They defined three subgroups,

corresponding to different geodynamic settings, based on

their chemical characteristics; Group I (anorogenic lam-

proites) are products of intracontinental plate magmatic

activity; Group II (kamafugites) are associated with

continental rifts such as the Uganda segment of the East

African Rift; Group III ultrapotassic rocks which include

eruptives from Italy (e.g. Hawkesworth and Vollmer, 1979;

Rogers et al., 1985) that occur during or after continental

collision following ocean-basin closure. The volcanic rocks

studied here can be classified as ultrapotassic rocks

according to the definiton of Foley et al. (1987) (Fig. 3).

In Table 2, SiO2 content range from 46.80 to 53.79 wt%;

K2OO3 wt% (4.25–10.58), MgOO3 wt% (3.02–5.90 wt%),

Fig. 3. a—K2O–SiO2; b—K2O–Na2O and c—CaO–Al2O3 diagrams for

the ultrapotassic volcanic rocks (Group I, II and III fields after Foley et al.,

1987; massive lavas: filled, dykes: open).

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627 619

K2O/Na2OO2 (2.01–12.71) in the ultrapotassic massive

lavas and dykes of the Ulukısla formation from

the Camardı-Ulukısla basin in central Anatolia. All the

data points of the studied volcanic rocks fall into the Group

III field of Foley et al. (1987) (Fig. 3c).

SiO2 content of the ultrapotassic volcanic rocks ranges

from 46.80 to 53.79% with high Al2O3. Dykes are poorer

than the lava flows in terms of P2O5, CaO and Na2O

contents. K2O/Na2O ratios of the dykes (10.33–12.71) are

much higher than those of the lava flows (2.01–4.0).

Mg-numbers of the lava flows and dykes range from

39.48–62.42 to 49.68–51.89, respectively (see Table 1). The

low contents of MgO (! 5.90 wt%) and Ni (!30 ppm) of

the ultrapotassic massive lavas and dykes of the Ulukısla

formation from the Camardı-Ulukısla basin in central

Anatolia indicate differentiation processes. When plotted

against SiO2 (Fig. 4), tFe2O3, TiO2, MgO, CaO, and P2O5

display negative correlations, while K2O shows a positive

correlation (Fig. 4). The transitional metal elements such as

Ni and V correlate negatively with SiO2, although the trends

are not well defined in Fig. 4. These major and trace element

trends are broadly consistent with fractional crystallization

of clinopyroxene, Fe–Ti oxides, apatite and biotite (possibly

phlogopite), all of which are present as phenocrysts in the

ultrapotassic volcanic rocks (see Table 1).

The large ion lithophile elements (LILE), particularly

Ba (1735–5913 ppm) in all rock samples and Rb (293–

391 ppm) in the dykes, are significantly enriched relative to

high field strength elements (HFSE) and HREE

accompanied by distinct negative anomalies for Nb and

Ti (Fig. 5a). The Nb-depletion distinguishes the Ulukısla

ultrapotassic rocks from typical OIB (Fig. 5a). The patterns

of the Ulukısla ultrapotassic volcanic rocks in Fig. 5 are

similar to those of subduction related mafic rocks or

continental intraplate basalts that have been significantly

contaminated or derived from a lithospheric mantle that

was modified by earlier subduction processes (Hawkes-

worth and Vollmer, 1979; Venturelli et al., 1984; Kempton

et al., 1991; Dostal et al., 2003). They resemble the profiles

of other subduction-related potassic lavas (e.g. Contini et

al., 1993; O’Brienetal., 1995; Dostal et al., 1998). Trace-

element patterns for the Ulukısla ultrapotassic volcanic

rocks also show small depletions in Zr and Hf (Fig. 5a).

These depletions relative to LREE enrichment are taken to

indicate that subduction related material has present in the

mantle source region (Kempton et al., 1991; Tingey et al.,

1991). In particular, high Rb/Sr (0.17–0.42) and K/Ti

(6.29–14.03) ratios relative to asthenospheric melts

including MORB and OIB suggest metasomatism by

hydrous fluids that leached incompatible elements from

subducted material and formed phlogopite in the overlying

lithospheric mantle (Tingey et al., 1991). High Ce/Yb

(71–92) ratios imply that a small percentage of melt was

also added (Tingey et al., 1991) but high Ba/Rb ratios are

difficult to interpret. Cs contents are relatively low

(Table 2), but Cs is very mobile and may have left the

subduction system at an early stage (Ayers, 1997), or

during late hydrothermal alteration (Mitchell, 1995).

All ultrapotassic volcanic rocks within the Camardı-

Ulukısla basin are considerably enriched in LREE (La O150 times primitive mantle) relative to primitive mantle

whereas the HREE are less enriched (Yb: 4.97–6.02 times

primitive mantle), resulting in LaN/YbN ratios that range

from 26 to 37. All samples have similar patterns, which tend

to be flatten out in the region of LREE, and flatten for the

HREE (Fig. 5b). They exhibit slight negative Eu anomalies

(mean Eu/Eu*Z0.80). Similar REE patterns have been

previously reported for some ultrapotassic rocks from

Fig. 4. Major element-SiO2 variation diagrams fro the ultrapotassic volcanic rocks (symbols as in Fig. 3).

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627620

central Italy (e.g. Hawkesworth and Vollmer, 1979; Rogers

et al., 1985) and NW Italy (Venturelli et al., 1984).

6. Pb–Sr–Nd isotopic compositions

The Pb–Sr–Nd isotopic compositions of analyzed

samples are given in Table 2. Ultrapotassic volcanic rocks

have high radiogenic initial (calculated at 50 Ma) 87Sr/86Sr

(0.70798–0.70917) and non-radiogenic 143Nd/144Nd ratios

corresponding to 3Nd values between K4.32 and K9.07 that

require a large time-integrated LREE enrichment. As

illustrated in Fig. 6, the lavas plot in the enriched quadrant

of a conventional Sr–Nd isotope diagram, where they

overlap the field defined by the Roccamonfina ultrapotassic

volcanic rocks from Central Italy (Hawkesworth and

Vollmer, 1979).

The 206Pb/204Pb ratios are restricted, lying within the

range of 18.866–18.975. 207Pb/204Pb (15.743–15.797)

and 208Pb/204Pb (39.234–39.566) ratios are unusually

radiogenic and plot well above the Northern Hemisphere

Reference Line (NHRL; Hart, 1984) in conventional Pb

isotope diagrams (Fig. 7), implying that they must have had

a complex evolution.

7. Petrogenetic discussion

The ultrapotassic rocks from the Camardı-Ulukısla basin

are characterized by high contents of total alkalis

Fig. 5. (a) Primitive mantle-normalized trace element patterns for studied volcanic rocks (N-MORB and OIB from Sun and Mc Dunough (1989), and upper

crust -UC from Taylor and McLennan, 1985) and (b) REE patterns. Normalizing values after Sun and Mc Dunough (1989).

Fig. 6. Nd-Sr isotopic space for the ultrapotassic volcanic rocks of the

Ulukısla basin [Oceanic basalt fields from White (1985), end-members

from Zindler and Hart (1986), Italian volcanic rocks from Hawkesworth

and Vollmer (1979)] (symbols as in Fig. 3).

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627 621

(O6.12 wt%), particularly K2O (O4.25 wt%). Their

mantle-normalized trace-element patterns are distinctly

enriched in LILE including Ba and Th, and in LREE

relative to HREE and HFSE, but with negative anomalies

for Nb and Ti (Fig. 5). The primitive mantle-normalized

patterns of some of the Ulukısla ultrapotassic volcanic rocks

are significantly different from those of magmas which are

assumed to be generated within the asthenosphere, namely

MORB and OIB (Fig. 5), which peak at Nb and have no

negative Ti anomaly (Sun and Mc Dunough,1989). The

parental magmas of these ultrapotassic rocks, therefore,

cannot be generated by partial melting of a primitive upper

mantle. The radiogenic isotope characteristics of these rocks

(Fig. 6) include elevated initial radiogenic 87Sr/86Sr

(between 0.70796 and 0.70917) ratios and distinctive non-

radiogenic 3Nd (between K6.52 and K9.07) values that are

close to the EM II mantle component. Thus, the petrogenetic

discussions of the ultrapotassic volcanic rocks of the

Fig. 7. Pb isotope covariation diagrams for studied volcanic rocks a:206Pb/204Pb vs 208Pb/204Pb ratios diagram and b: 206Pb/204Pb vs 207Pb/204Pb

ratios diagram. NHRLZ Northern Hemisphere Reference Line (Hart,

1984). CIMZCentral Indian MORB (Mahoney et al., 1989). Field for the

Pasific MORB is from White et al. (1987). Oceanic sediment from White

et al. (1985), Woodhead and Fraser (1985) and Ben Othman et al. (1989);

The approximate fields for DMM, EMI and EMII are from Zindler and Hart

(1986). (symbols as in Fig. 3).

Fig. 8. 3Nd vs La/Nb diagram. The MORB and mantle end-members BSE,

DM and PREMA are from Zindler and Hart (1986). The composition of

fluid released from subducted oceanic crust is estimated from the highest

Nd and La/Nb ratio measured for oceanic island basalts (OIB, White and

Patchett, 1984). The continental crustal field is from Taylor and McLennan

(1985). (symbols as in Fig. 3)

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627622

Camardı-Ulukısla basin should take into account (1)

fractional crystallization and crustal contamination, (2)

source characteristics, and (3) geodynamic interpretation in

light of local and regional geological settings.

7.1. Fractional crystallization and crustal contamination

Major and trace element variations when plotted against

SiO2 as presented in Fig. 4 are consistent with fractionation

of clinopyroxene, Fe–Ti oxides, apatite and biotite, all of

which are present as phenocrysts in the ultrapotassic rocks

of the Ulukısla basin. In addition, increasing 87Sr/86Sr

isotopic ratios are coupled with increasing incompatible

element contents (e.g. K) and decreasing compatible

elements (e.g. Ni, and V). These characteristics suggest

that fractional crystallization was involved in differentiation

of the ultrapotassic rocks of the Ulukısla basin.

The ultrapotassic volcanic rocks from the Camardı-

Ulukısla basin are enriched in LILE and LREE relative to

continental crust and MORB and/or OIB. Crustal contami-

nation would lead to a decrease of LREE and an increase of

HREE in the magma, leading to a flatter slope for the REE

patterns. Thus, contamination of OIB-or MORB-type

magma by crustal material could not have produced the

ultrapotassic volcanic rocks from the Camardı-Ulukısla

basin. Assimilation of crustal material is inconsistent not

only with the high LILE and LREE contents, but also with

relatively low Rb/Sr and Rb/Ba ratios. In addition, radio-

genic Sr and Pb, and unradiogenic Nd ratios of the

ultrapotassic lavas of the Camardı-Ulukısla basin depart

drastically from those of convecting asthenosphere. Simi-

larly, the high La/Nb (3.5–7.5) and low 3Nd (K6 to K9)

values of these rocks reveal that they cannot be produced by

simple mixing between continental crust, oceanic island

basalt (OIB) and asthenospheric magmas (Fig. 8). Further-

more, relatively primitive ultrapotassic lavas (!50% SiO2

and O4% MgO) yield a steeply sloping array on a La/Yb vs

La diagram, which is characteristic of a partial melting

trend, but not a fractionation trend (Fig. 9). It is, therefore,

concluded that trace element, REE and isotopic compo-

sitions of the ultrapotassic volcanic rocks from the Camardı-

Ulukısla basin were largely inherited from and reflect the

mantle source.

7.2. Source characteristics

Partial melting of a heterogenous-mantle source has been

called on to produce a wide spectrum of alkaline magmas

from potassic to ultrapotassic compositions (Rogers et al.,

1985; Peccerillo, 1992, 1999; Conticelli et al., 1992). A

Fig. 9. La vs La/Yb diagram of the relatively primitive rocks for studied

volcanic rocks (symbols as in Fig. 3)

Fig. 10. Ba/Nb vs La/Nb for ultrapotassic volcanic rocks from the Ulukısla

basin and some potassic lithospheric melts. Data sources: N-MORB, OIB

and PM (Primitive mantle) from Sun and Mc Dunough, 1989); phlogopite

peridotite (Phlog Per) from Erlank et al. (1987), phlogopite lamproites GB

(Gaussberg), LH (Leucite Hills) and SB (Smooky Butte) from Mitchell and

Bergman (1991); micaceous kimberlites from Mitchell (1986), pelagic

sediments from Taylor and McLennan (1985). (symbols as in Fig. 3).

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627 623

phlogopite-bearing lithospheric mantle, metasomatized by

subduction-related fluids or melts, is thougt to be the source

of these magmas (Conticelli and Peccerillo, 1992; Peccer-

illo, 1999). Small-scale heterogeneity is commonly con-

sidered to be due to the presence of a vein network

permeating the upper-mantle peridotite (Foley, 1992); the

veins are inferred to be rich in clinopyroxene together with

accessory phases, such as phlogopite, titanates and oxides,

uncommon in normal peridotitic mantle assemblages.

Hybridization mechanisms between the partial melt of

wall-rock peridotite and vein components are supposedly

responsible for the generation of the alkaline magmas

(Foley, 1992). The highly potassic nature of the studied

volcanic rocks require that a K-rich mineral, such as

phlogopite, was present in the upper mantle and melted to

produce the ultrapotassic magmas. The variable potassium

contents probably reflect melting of different amounts of

phlogopite. However, phlogopite is not a typical mantle

mineral and its presence in the upper mantle reveals

compositional anomalies (Peccerillo, 2003).

The range of variation in the trace element

(LREE/HFSE) and isotopic characteristics of the relatively

primitive magmas from Ulukısla basin might to be

attributed to small scale mantle heterogeneity. In particular,

variation in the trace element ratios (LREE/HFSE) might be

attributed to variable roles in the residuum for accessory

phases (e.g. phlogopite, apatite) or differences in the relative

proportion of veins and peridotitic wall-rock components,

which contribute to the melt. The partition coefficients for

LREE in apatite dominate those of LREE in the other

mineral phases in the veins (e.g. clinopyroxene); thus apatite

controls the LREE characteristics (Ionov et al., 1997). The

presence of apatite in the residuum of partial melting of the

veins could produce the negative anomaly at P (Fig. 5).

Relatively primitive rocks of the Ulukısla ultrapotassic

volcanic rocks have a negative P anomaly, suggesting that

apatite was stable and not completely melted out from the

vein component in the mantle source.

Relatively higher (Tb/Yb)N ratios in the relatively

primitive rocks suggest that garnet was still present in the

source residuum. The partition coefficient of Yb in garnet is

higher than that of Tb (Zack et al., 1997); thus the (Tb/Yb)N

ratio of a partial melt is high when garnet is present in the

mantle source.

Genesis of the ultrapotassic magmas requires the

presence of phlogopite in the source (Perini et al., 2004).

Assuming a veined mantle, with phlogopite accommodated

in the veins, the variations in K2O content, and in particular

the K2O/Na2O ratio, of the magmas can be explained in

terms of different proportions of the vein with respect to the

wall-rock component entering the partial melts. The K20/

Na2O ratio of the massive lavas (2.01–3.99) is much lower

than those of the dykes (10.88–12.70), suggesting a higher

wall-rock component/vein (phlogopite) component ratio in

the genesis of the ultrapotassic rocks of the Ulukısla basin.

In addition, lava flows have lower 87Sr/86Sr ratios than the

dykes (Table 2). Production of magmas with high radio-

genic Sr isotopic compositions requires the presence in the

source of appreciable amount of minerals with high Rb/Sr

ratios such as mica, causing evolution of radiogenic Sr over

time. Lower 87Sr/86Sr ratios in the lava flows might also be

the result of a high wall-rock/vein component ratio during

partial melting; the effect of the wall-rock is to lower the87Sr/86Sr ratios of the vein component.

On the Ba/Nb vs. La/Nb graph (Fig. 10), the ultrapotassic

volcanic rocks of the Camardı-Ulukısla basin plot far from

the asthenospheric melts (MORB and OIB), but near a trend

defined by potassic rocks from some provinces derived from

subcontinental lithospheric mantle, such as lamproites and

kimberlites (Mitchell, 1995; Mitchell and Bergman, 1991).

Therefore, the observed trend of the ultrapotassic volcanic

Fig. 11. Sr, Nd, Pb isotope covariation diagrams for ultrapotassic volcanic

rocks of Ulukısla basin. (a) 87Sr/86Sr vs 206Pb/204Pb diagram. (b)143Nd/144Nd vs 206Pb/204Pb diagram. Sources for data Pacific and Atlantic

MORB-Cohen et al. (1980), Cohen and O’Nions (1982), Ito et al. (1987)

and White et al. (1987); oceanic sediments-White et al. (1985), Woodhead

and Fraser (1985) and Ben Othman et al. (1989); DM, Depleted MORB

Mantle; EM1 and EM2, Enriched Mantle 1 and 2; HIMU, High U/Pb

Mantle-from Hart et al. (1992). (symbols as in Fig. 3).

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627624

rocks of the Camardı-Ulukısla basin cannot be produced by

any model involving partial melting from a four-phase

peridotite (MORB or OIB) source with crustal contami-

nation, but it requires a distinct mantle source.

The presence of the negative HFSE anomalies in the

ultrapotassic rocks of the Camardı-Ulukısla basin is similar

to island arc volcanic rocks (Wilson, 1989). These

depletions relative to strong LILE and LREE enrichments

are taken to denote that subduction-related material is

present in the mantle source (Kempton et al., 1991).

However, extreme enrichments in Ba, Th and U compared

to K and Rb in lava flows are not characteristics of island arc

volcanism. High Ba/Nb and La/Nb ratios, which are higher

than those of island arc volcanic rocks and crustal values,

and positive anomalies for Ba, Th and U require source

enrichments in these elements and point to different degrees

of involvement of a subduction component in the genesis of

the Ulukısla volcanic rocks. Modern pelagic sediments have

high values in Ba, Th and U (Tatsumi et al., 1986) and are

capable of modifying mantle compositions accordingly.

With regard to the HFSE anomalies of the ultrapotassic

volcanic rocks of the Ulukısla basin, their extremely high

LILE/HFSE ratios clearly suggest that these two groups of

elements were fractionated with respect to each other at

some stage of the potassic magma generation or during

metasomatism. This fractionation could have been produced

by the presence of a residual HFSE-bearing phase (Foley

and Wheller, 1990; Conticelli and Peccerillo, 1992). This

hypothesis agrees with the narrow range of the HFSE

contents of the ultrapotassic volcanic rocks (Table 2). This

relationship could be easily generated by variable degrees of

partial melting with HFSE buffered at low values by

residual titanates. Alternatively, the high LILE/HFSE

values may result from addition to the sources of different

amounts of fluids or melts already depleted in HFS

elements, which caused variable enrichments in LIL

elements, leaving HFSE at their original concentrations.

Ancient subduction events might have caused large scale

recycling of the subducted slab. During these events,

incompatible element-rich sediments and fluids may have

entered into the lithospheric mantle causing enrichment in

LILE. The addition of LILE via a fluid phase to mantle

peridotite is consistent with the relatively high solubilities

of these elements in hydrous fluids (Tatsumi et al., 1986).

The addition of HFSEs via a fluid phase is generally

considered unlikely due to low solubilities of these elements

in hydrous fluids (Stoltz et al., 1996). Low Nb/U (3.32–8.08)

and Ce/Pb (4.48–9.84) ratios and high La/Nb (3.43–7.45)

and Ba/Nb (51–248) ratios may have been resulted from

metasomatism due to fluid dominated process.

On the other hand, Miller et al. (1999) argued that the

low Ti/Y and negative 3Nd values in some ultrapotassic

rocks are a feature of recycled continental material

subducted back into the upper mantle and suggests a

major contribution from sediment-contaminated litho-

spheric mantle in the generation of these magmas. The

ultrapotassic volcanic rocks of the Camardı-Ulukısla basin

also have these characteristics (low Ti/Y (217G76 and

negative 3Nd values). The relatively elevated 207Pb/204Pb

and 208Pb/204Pb ratios and the steep trend on the 207Pb/204Pb

vs 206Pb/204Pb diagram (Fig. 7) suggest involvement of an

old radiogenic component which could be recycled

continent-derived material in the source region of these

volcanic rocks. Furthermore, the elevated 87Sr/86Sr and the

negative correlation between 206Pb/204Pb ratios and Nd

isotopic compositions in the ultrapotassic volcanic rocks

from the Camardı-Ulukısla basin could be attributed to

oceanic sediment involvement in the source region

(Fig. 11). In addition, the Ce/Pb ratio ranges from 4.49 to

9.85 which is lower than those of oceanic basalts (MORB

and OIB, Hofmann et al., 1986), but typical of a subducted

sediment component which has a low Ce/Pb ratio due to

their high Pb contents (Hofmann et al., 1986; Ben Othman

et al., 1989). The sedimentary geochemical signature is also

reflected in the low Sr/Nd (6.37–16.46), low Nb/La

(0.13–0.27) and elevated Ce/Sr (0.2–0.46) ratios.

M. Alpaslan et al. / Journal of Asian Earth Sciences 27 (2006) 613–627 625

7.3. Geodynamic interpretation

The eruption of the post-collisional ultrapotassic

magmas in the Ulukısla basin clearly post-dates continental

collision between the Eurasian plate (EP) and Tauride-

Anatolia platform (TAP) in Late Mesozoic time. The

negative Nb, Ta and Ti anomalies in the incompatible

element patterns of the Ulukısla ultrapotassic volcanic rocks

(Fig. 5a) suggest that subduction processes were probably

responsible for metasomatism of their lithospheric mantle

source region. The subduction imprint of trace-element

distribution of the ultrapotassic volcanic rocks from the

Camardı-Ulukısla basin may result from a relatively young

enrichment in the mantle source due to late Mesozoic Neo-

tethyan subduction related to the convergence system

between the EP and TAP, or it may represent lithospheric

mantle previously enriched above some prior subduction

zone. The melting of such an enriched mantle in a post-

collisional extensional regime following late Mesozoic

Neo-tethyan subduction can explain the major, trace and

REE characteristics of the ultrapotassic rocks of the

Camardı-Ulukısla basin, but it cannot readily account for

the unusual isotopic compositions of these rocks. In

particular, non-radiogenic Nd isotopic compositions require

an ancient, LREE-enriched component. Similarly, the

radiogenic Sr isotopic compositions imply either time-

integrated, long-term enrichment of Sr in the source or a

primary high initial Sr isotopic ratio which is inherent to this

part of the mantle. Different hypothesis can be envisaged to

explain the distinctive isotopic features of this mantle

source. It should have retained high U/Pb and Th/Pb ratios

for sufficient enough time to develop high 206Pb/204Pb and208Pb/204Pb ratios. A similar situation could occur by

subducted material being is brought into the mantle and

successively recycled either into the melting region, as

commonly suggested for enriched components found in the

source of OIB (Zindler and Hart, 1986; Chauvel et al.,

1992), or into the subcontinental portion of the upper

mantle, which is suspected to participate in the melting

process in continental environments and thought to be

capable of developing strong geochemical and isotopic

heterogeneities (Menzies and Hawkesworth, 1987). The Nd

model ages relative to depleted mantle range from 1.14 to

1.36 Ga. Because the Sm/Nd ratio of a magma is generally

lower than that of its source, these depleted mantle model

ages represent minimum ages of enrichment; it can be

speculated that the age refers to ancient subduction-related

metasomatism of the mantle beneath this part of Anatolia.

Conversely, the Nd model ages may simply reflect the

antiquity of the subducted component and imply nothing

about the timing of metasomatism, especially when

sediments are added to the source region (Civetta et al.,

1998). Elevated Sr and unradiogenic Nd isotopic ratios,

along with Pb isotopic ratios (Fig. 11), require oceanic

sediment involvement in the source region of these

ultrapotassic volcanic rocks. Therefore, it can be concluded

that the trace elements and isotope geochemistry of these

volcanic rocks indicate source enrichments by Neo-tethyan

subduction in Late Mesozoic time.

8. Concluding remarks

The geochemical and isotopical characteristics of the

ultrapotassic lavas require strongly metasomatized mantle

sources that were enriched in incompatible elements. Trace

element characteristics of the ultrapotassic rocks of the

Ulukısla basin indicate the presence of some residual minerals,

i.e. apatite, in the source region. It is suggested here that the

mantle lithosphere beneath the Camardı-Ulukısla basin was

metasomatized during Late Mesozoic subduction of Neo-

tethyan crust beneath Tauride-Anatolide platform (TAP)

related to the Neo-Tethyan convergence system between

Eurasia plate (EP) and Tauride-Anatolide platform (TAP).

Enriched isotopic compositions and incompatible and REE

systematics of these volcanic rocks could have originated by

fluids and subducted sediments during the subduction process.

Ultrapotassic volcanic rocks within the Camardı-Ulukısla

basin formed as a part of the complex geodynamic evolution of

this area. Regional and local geological data given by Clarke

and Roberston (2002) and Alpaslan et al. (2003, 2004) suggest

that the eruption of the extension-related ultrapotassic

magmas in the Camardı-Ulukısla basin clearly post-dates the

Late Mesozoic continental collision between the Eurasia plate

(EP) and Tauride-Anatolide Platform (TAP). On the other

hand, alkaline volcanic rocks pre-dating these rocks within the

Ulukısla basin also represent melting of a subcontinental

lithospheric mantle source (Alpaslan et al., 2003, 2004), but

differ from the Ulukısla ultrapotassic rocks by their less

evolved isotopic compositions and higher Ti/K ratios,

suggesting different mantle source characteristics for the

different domains of Central Anatolia.

Acknowledgements

This study was funded by Scientific and Technical

Research Council of Turkey (TUBITAK) under the Project

of YDABCAG 100Y010. Authors thank the Danish Isotope

Center for Geology where the isotopic analyses have been

performed. Dr. Alan COOPER (Otago, New Zealand) is

kindly thanked for his reading and correction the manu-

script. Authors also thank to Dr. Ioan Seghedi (Romania)

and Dr. Donna Whitney (USA) for their constructive

comments and recommendations as refrees.

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