Geology, petrography and geochemistry of the subduction related volcanic rocks, west of Konya, Central Anatolia

Konya'nın KB'sı Neojen yaşlı volkanik breş, aglomera, tüfit, tüfve andesit, dasit ve bazaltik andezit lavlarıyla kaplıdır. Bazaltik andezitler yaklaşık olarak % 7-10 olivin, %3-5 klinopiroksen, %5-10 ortopiroksen, %60-70 plajiyoklaz ve % 5-J O opak mineral fenokrisialleri içerirken andezitik lavlar % 50-60 plajiyoklaz, % 10-15 hornblende, %5 biyotit, % 2 klinopiroksen, % l sanidin, %1 kuvars ve % 3 opak mineral oluşmaktadır. Dasitikkayaçlar%35-40 plajiyoklaz, % 10-15 kuvars, %15-20 hornblend, %10-12 biyotit, % 2-3 opak mineral, % 3 sanidin içerirler. Dasit ve andezitik kayaçlar salınım zonlanma ve elek dokusuna sahiptirler. Volkanik kayaçların bileşimi bazaltik andezitten dasite kadar değişir ve tipik bir kalkalkalin karakter gösterirler. Ana, ve iz element içeriklerinin değişimi hornblend, plajiyoklaz, piroksen, ve titanlı magnetitin fraksiyonel kristalleşmesine ileri sürmektedir. Plajiyoklaz farklılaşması zayıf negatif Eu anomalisinin gelişimi ile doğrulanmaktadır. Yüksek LREE/HREE ve LILE/HFSE oranlan çalışılan örneklerin aktif kıta kenarında dalma batma ile ilişkili bir magmadan oluştuğunu göstermektedir. Kayaçların oldukça farklılaşmış ve zengin REE grafiği bu kayaçların oluşumunda kıta kabuğunun içerildiğine işaret etmektedir.

Orta Anadolu da Konya' nın batısındaki dalmabatma ile ilişkili volkanik kayaçların jeolojisi, petroğrafisi, ve jeokimyası

The northwest of Konya is covered by Neogene volcanic breccias, agglomerates, tuffites, tuffs and lavas of andesite, dacite and basaltic andesite. The basaltic andesites contain about 7-10% of olivine, 3-5 % clinopy-roxene, 5-10 % orthopyroxene, 60-70 % plagioclase and 5-10 % opaque minerals while the andesitic lavas include 50-60 % plagioclase, 10-15 % hornblende, 5% biotite, 2 %, clinopyroxene, 1 % sanidine, l % quartz and 3 % opaque minerals. Main constituents in the dacitic rocks are plagioclase (35-40%), quartz (10-15 %), hornblende (15-20 %), biotite (10-12 %), opaque minerals (2-3%) and sanidine (3 %). The plagioclase in dacites and andesitic rocks have oscillatory zoning and sieve texture. The volcanic rocks range in composition from basaltic andesites to dacites with calc-alkaline character. Co-variation of major and trace element contents suggest fractional crystallization of hornblende, plagioclase, pyroxene and titaniferous magnetite. The plagioclase fractionation is confirmed by a slight development of negative Eu anomaly. High LREE/HREE and LILE/ HFSE ratios show that the samples were possibly formed from a subduction-related magma at active continental margin. The strong fractionated and riched REE patterns of the rocks indicate that the formation of these rocks may have involved continental crust.

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Boynton, W. W., 1984. Cosmochemistry of the rare elements. Rare Earth Geochemistry. Elsevier, Amsterdam, 63-107s.
Cabanis, B. and Lecolle, M. 1989. Le diagramme La/10,Y/15, Nb/8: un outil pour la discrimination des series volcaniques et la mise en evidence des procussus de melanges et/ ou de contamination crustale. C.R.Acad. Sci.Paris, 309, 2023-2029.
Cox, K. J.D. Bell and R.J. Pankhurst 1979. The interpretation of igneous rocks. London: George Allen and Unwin, London, 450 pp.
Eren, Y., 1993. Eldes-Gökçeyurt-Derbent-Sögütözü (Konya) Arasinin jeolojisi, Ph.D. Thesis, Selçuk University, Konya, 224 p (Unpublished).
Gill, J. B., 1981. Orogenic andesites and Plate tectonics. Springer-Verlag, New York, 370 pp.
Harris, N.B.W., Pearce , J.A and Tindle, A.G., 1986. Geochemical characteristics of collision zone magmatism. In. Coward, M.p 6 Ries, A. C. (eds) Collision Tectonics. Geol . Soc. London Spec. Publ., 19,67-81.
Hollister, L.S. and Gancarz. A. J., 1971. Compositional sector-zoning in clinopyroxene from the Narce area, Italy. Am. Miner., 56, 959-79.
Irvine, T. N. and Baragar, W. R. A. 1971. A guide to the chemical classification of the common volcanic rocks. Can. J.of Earth Sci., 8, 523-548.
Keller, J., Junk, D., Burgath, K. and Wolff, F., 1977. Geologie und petrologie des neogenen kalkalkali vulkanismus von Konya (Erenler Dağ- Alaca Dağ- Massiv, Zentral- Anatolien). Geol. Jb., B25, 37- 117,Hannover.
Kurt, H., 1994. Petrography and Geochemistry of Kadınhanı (Konya) area, Central Turkey. PhD., Glasgow, University (Unpuplished), U.K., 191.
Kurt, H., 1996. Evolution of the Kadınhanı (Konya) dacite rocks; petrographical and geochemical evidences for crystal fractionation and possible magma mixing. Geosound, 28, 23-33.
Leat, P.T., Jackson, S.E., Thorpe, R.S.and Stillman, C.J.I986. Geochemistry of bimodal basalt subalkaline/ peralkaline rhyolite provinences within the southern British Caledonides. J. Geoi. Soc. London, 143,259-276.
Nakamura, N., 1973. Origin of sector-zoning in igneous clinopyroxenes. Am. Min., 58, 986-990.
Özcan, A., Göncüoğlu, M.C., Turhan, N., Şentürk,K., Uysal, Ş. Ve Işık, A., 1990: Konya - Kadınhanı-Ilgın dolayının temel jeolojisi, MTA, Rap.No: 9535 (yayınlanmamış), Ankara.
Özkan, A. M., 1998. Konya batısındaki Neojen çökellerinin stratigrafisi ve sedimantolojisi, Doktora tezi, Selçuk Üniversitesi, Konya, 228 p (yayınlanmamış).
Pearce, J. A., 1983. Role of the sub-continental lithosphere in magma genesis at active continental margins. In:Hawkesworth C. J. (eds), Continental basalts and mantle xenoliths.-Shiva, Nantwich, 230- 249pp.
Pearce, J.A., Gorman, B.E. and Birkett, T.C., 1977. The relationship between major element chemistry and tectonic environment of basic and intermediate volcanic rocks. Earth Planet Scie. Let., 36., 121-132.
Pearce, J.A.,1982. Trace element characteristics of lavas from destructive plate boundaries. ln:Thorpe,R.S.(eds) Andesites: Orogenic andesites and related rocks. Wiley, Chichester, 525-548pp.
Sun, S.S. 1980. Lead isotope study of young volcanic rocks from mid-ocean ridges, ocean islands and island arcs, Phil. Trans. R. Soc. London., A297, 409-455.
Taylor, Y.and McLennan, S.M. 1985. The continental crust: Its Composition and Evolution. Blackwell, Oxford, 312p.
Temel, A., Gündoğdu, M. N., and, Gourgaud,A., 1998, Petrological and geochemical characteristics of Cenozoic high-K calc-alkaline volcanism in Konya, Central Anatolia, Turkey, Journal of Vole, and Geothermal Res., 85, Issues 1-4, p 327-354.
Tsuchiyama, A., 1985. Dissolution kinetics of plagioclase in melt of the system diopsite-albite-anorthite and the origin of dusty plagioclase in andesites. Contrib. Mineral. Petrol., 84, 1-16.
Villemant, B., Jaffrezic, HL Joron, J.L. and Treuil, M. 1981. Distribution coefficients of major and trace elements: fractional crystallization in the alkali basalt series of Chaine des Puys (Massif Central, France). Geochim. Cosmochim. Acta, 45, 1997-2016.
Watters, B.R. and Pearce , J.A.I987. Metavolcanic rocks of the La Ronge Domain in the Churchill Province, Saskatchewan:geochemical evidence for a volcanic arc origin. Geological Society Special Publication, 33, 167-182.
Winchester J. A. and Floyd P. A., 1977. Geochemical distributions of different magma series and their differentiation products using immobile elements, Chem. Geo., 20, 325-343.
Wood, D. A., Joron, J.L., Treuil M., Norry M. and Tamey J., 1979 a. Elemental and Sr isotope variations in basic lavas from Iceland and the surrounding ocean floor. Contrib. Mineral. Petrol., 70, 319-339.
Wood, D.A., joron, J.L. and Treuil, M.1979b. Areappraisal of use of trace elements to classify and discriminate between magma series erupted in different tectonic settings. Earth and planetary Science letters, 46, 326-336.
Wood, D.A. 1980. The application of a Th-Hf-Ta diagram to problems of tectonomagnetic classification and to establish the nature of crustal contamination of basaltic lavas of the British Tertiary volcanic provence. Earth and Planetary Science Letters, 50, 11-30.