Mineral chemistry of isotropic gabbro and plagiogranite from the Central Anatolian Ophiolites in the Derinkuyu (Nevşehir, Central Anatolia) region

Abstract

The isotropic gabbro and plagiogranite belonging to the Central Anatolian Ophiolites, are exposed as stocks around Derinkuyu (Nevşehir). Plagiogranite, which cuts the isotropic gabbro, contains mafic microgranular enclaves (MME) belonging to these rocks. Gabbro and MME contain plagioclase, clinopyroxene and hornblende minerals. The isotropic gabbros are in hornblende-pyroxene and pyroxene-hornblende/hornblende gabbro compositions. Plagiogranite is composed of quartz, plagioclase and hornblende, and exhibits a tonalite composition. Mineral chemistry analysis results indicate that plagioclases in the gabbro, plagiogranite, and MME have compositions of andesine–bytownite (An47–85), andesine (An38–48), and labradorite–bytownite (An65–75), respectively. Clinopyroxenes (Mg#=0.73–0.84) and hornblendes (Mg#=0.57–0.79) are characterized by their high-Mg contents. Clinopyroxenes, diopside–augite (En37–43Fs12–15Wo42–47), and the hornblendes exhibit compositions of tschermakite–magnesio-hornblende. Clinopyroxene and hornblende data on the discrimination diagrams indicate the presence of an island arc for the source magma. Pyroxene and amphibole thermobarometry suggest that P–T crystallization conditions for clinopyroxene and hornblende 2.60–1.37 kbar 1199–1186°C and 1.95–1.09 kbar; 864–790°C, respectively. These data manifest that the magma of supra-subduction type ophiolite rise towards shallow lithospheric levels (9.2–3.9 km).

Keywords

• Isotropic gabbro
• Plagiogranite
• Mineral chemistry
• Supra-subduction zone
• Central Anatolia

Derinkuyu (Nevşehir, Orta Anadolu) yöresindeki Orta Anadolu Ofiyolitlerinden izotropik gabro ve plajiyogranitin mineral kimyası

Öz

Orta Anadolu Ofiyolitlerine ait izotropik gabro ve plajiyogranitler, Derinkuyu (Nevşehir) çevresinde stoklar halinde yüzeylemektedir. İzotropik gabroyu kesen plajiyogranit, bu kayaçlara ait mafik mikrogranüler anklavları (MME) içerir. Gabro ve MME plajiyoklaz, klinopiroksen ve hornblend mineralleri içerir. İzotropik gabrolar, hornblend-piroksen ve piroksen-hornblend/hornblend gabro bileşimlerindedir. Plajiyogranit, kuvars, plajiyoklaz ve hornblendden oluşur ve tonalit bileşimi gösterir. Mineral kimyası analiz sonuçları, gabro, plajiyogranit ve MME’deki plajiyoklazların sırasıyla andezin–bitovnit (An47–85), andezin (An38–48) ve labradorit–bitovnit (An65–75) bileşimlerine sahip olduğunu göstermiştir. Klinopiroksen (Mg#=0.73–0.84) ve hornblendler (Mg#=0.57–0.79) yüksek-Mg içerikleriyle karakteristiktir. Klinopiroksenler, diyopsit–ojit (En37–43Fs12–15Wo42–47) ve hornblendler çermakit–magnezyum-hornblend bileşimleri sergiler. Sınıflama diyagramlarında klinopiroksen ve hornblend verileri, kaynak magma için bir ada yayının varlığını göstermektedir. Piroksen ve amfibol termobarometrisi, klinopiroksen ve hornblend için P-T kristalleşme koşullarının sırasıyla 2.60–1.37 kbar; 1199–1186°C ve 1.95–1.09 kbar; 864–790°C olduğunu göstermektedir. Bu veriler, dalma-batma zonu üstü tipi ofiyolit magmasının sığ litosferik seviyelere (9.2–3.9 km) doğru yükseldiğini ortaya koymaktadır.

Anahtar Kelimeler

• İzotropik gabro
• Plajiyogranit
• Mineral kimyası
• Dalma-batma zonu üstü
• Orta Anadolu

Kaynakça

1. [1] Pearce JA, Lippard SJ, Roberts S. Characteristics and Tectonic Significance of Supra-Subduction Zone Ophiolites. Editors: Kokelaar BP, Howells MF. Marginal Basin Geology, Geological Society of London, Special Publications, 16(1), 77–94, Blackwell, London, UK, 1984.
2. [2] Dilek Y, Furnes H, Shallo M. “Suprasubduction zone ophiolite formation along the periphery of Mesozoic Gondwana”. Gondwana Research, 11(4), 453–475, 2007.
3. [3] Coleman RG, Peterman ZE. “Oceanic plagiogranite”. Journal of Geophysical Research, 80(8), 1099–1108, 1975.
4. [4] Floyd PA, Yaliniz MK, Goncuoglu MC. “Geochemistry and petrogenesis of intrusive and extrusive ophiolitic plagiogranites, Central Anatolian Crystalline Complex, Turkey”. Lithos, 42(3-4), 225–241, 1998.
5. [5] Yalınız MK, Göncüoğlu MC. “Clinopyroxene compositions of the isotropic gabbros from the Sarıkaraman Ophiolite: New evidence on supra-subduction zone type magma genesis in Central Anatolia”. Turkish Journal of Earth Sciences, 8(2), 103–111, 1999.
6. [6] Kocak K, Isık F, Arslan M, Zedef M. “Petrological and source region characteristics of ophiolitic hornblende gabbros from the Aksaray and Kayseri regions, central Anatolian crystalline complex, Turkey”. Journal of Asian Earth Sciences, 25(6), 883–891, 2005.
7. [7] Ilbeyli N. “Geochemical comparison of ultramafic-mafic cumulate rocks from the Central Anatolian Ophiolites, Turkey”. International Geology Review, 50(9), 810–825, 2008.
8. [8] Bağcı U. “The geochemistry and petrology of the ophiolitic rocks from the Kahramanmaraş region, southern Turkey”. Turkish Journal of Earth Sciences, 22(4), 536–562, 2013.

9. [9] Yellappa T, Tsunogae T, Chetty TRK, Santosh M. “Mineral chemistry of isotropic gabbros from the Manamedu Ophiolite Complex, Cauvery Suture Zone, southern India: Evidence for neoproterozoic suprasubduction zone tectonics”. Journal of Asian Earth Sciences, 130, 155–165, 2016.
10. [10] Kadıoğlu YK, Deniz K, Koralay T, Güllü B. “Nature of the gabbro in Central Anatolia: Geological observation and spectroscopic applications, Turkey”. 19th International Multidisciplinary Scientific GeoConference (SGEM 2019), Albena, Bulgaria, 30 June–6 July, 2019.
11. [11] Parlak O, Bağcı, U, Rızaoğlu T, Ionescu C, Önal G, Höck V, Kozlu H. “Petrology of ultramafic to mafic cumulate rocks from the Göksun (Kahramanmaraş) ophiolite, southeast Turkey”. Geoscience Frontiers, 11(1), 109–128, 2020.
12. [12] Sato A, Imayama T, Dutta D, Kaneda Y, Watanabe S, Hasegawa T, Minami M, Wakasugi Y, Wakaki S, Yi K. “Supra-subduction zone magmatism and extreme mantle depletion in the Early Cretaceous Nidar Ophiolite Complex, NW India”. Gondwana Research, 147, 119–136, 2025.
13. [13] Kadıoğlu YK, Akçe MA, Deniz K, Koralay T, Güllü B. “Orta Anadolu Gabrolarının Kökeni ve U-Pb Yöntemi ile Yaşlandırılması”. Türkiye Bilimsel ve Teknik Araştırma Kurumu, Ankara, Türkiye, 116Y240, 2021.
14. [14] Okay AI, Tüysüz O. Tethyan Sutures of Northern Turkey. Editors: Durand B, Jolivet L, Horváth F, Séranne M. The Mediterranean Basins: Tertiary extension within the Alpine Orogen, Geological Society of London, Special Publications, 475–515, The Geological Society, London, UK, 1999.
15. [15] Lefebvre C, Peters MK, Wehrens PC, Brouwer FM, Van Roermund HLM. “Thermal history and extensional exhumation of a high-temperature crystalline complex (Hırkadağ Massif, Central Anatolia)”. Lithos, 238, 156–173, 2015.
16. [16] Göncüoğlu MC, Toprak GMV, Kuşcu İ, Erler A, Olgun E. “Orta Anadolu Masifinin Batı Bölümünün Jeolojisi, Bölüm 1: Güney Kesim”. Türkiye Petrolleri Anonim Ortaklığı, Ankara, Türkiye, 2909, 1991.
17. [17] Göncüoğlu MC, Türeli TK. “Orta Anadolu Ofiyoliti plajiyogranitlerinin petrolojisi ve jeodinamik yorumu (Aksaray-Türkiye)”. Doğa - Türk Yerbilimleri Dergisi, 2, 195–203, 1993.
18. [18] Yalınız MK, Göncüoğlu MC. “General geological characteristics and distribution of the Central Anatolian Ophiolites”. Yerbilimleri, 20, 19–30, 1998.
19. [19] Yaliniz MK, Floyd PA, Göncüoğlu MC. “Petrology and geotectonic significance of plagiogranite from the Sarıkaraman Ophiolite (Central Anatolia, Turkey)”. Ofioliti, 25(1), 31–37, 2000.
20. [20] Yalınız MK. “A geochemical attempt to distinguish forearc and back arc ophiolites from the “supra-subduction” Central Anatolian Ophiolites (Turkey) by comparison with modern oceanic analogues”. Ofioliti, 33(2), 119–129, 2008.
21. [21] Köksal S, Toksoy‑Köksal F, Göncüoğlu MC. “Petrogenesis and geodynamics of plagiogranites from Central Turkey (Ekecikdağ/Aksaray): New geochemical and isotopic data for generation in an arc basin system within the northern branch of Neotethys”. International Journal of Earth Sciences (Geologische Rundschau), 106, 1181–1203, 2017.
22. [22] MTA. Kayseri L33b1, L33b2, L33b3 and L33b4 sheets, 1/25.000 Scaled Geological Maps. 1990.
23. [23] Işık F. Ekecekyeniköy-Mamasun (Aksaray) Yeşilhisar (Kayseri) Arasının Jeolojisi ve Gabroyik-Granitoyidik Kayaçların Mineralojik-Petrografik ve Jeokimyasal İncelemesi. Doktora Tezi, Selçuk Üniversitesi, Konya, Türkiye, 2000.
24. [24] Seymen İ. “Kaman (Kırşehir) dolayında Kırşehir Masifi’nin stratigrafisi ve metamorfizması”. Türkiye Jeoloji Kurumu Bülteni, 24(2), 7–14, 1981.
25. [25] Whitney DL, Teyssier C, Dilek Y, Fayon K. “Metamorphism of the Central Anatolian Crystalline Complex, Turkey: influence of orogen-normal collision vs. wrench-dominated tectonics on P-T-t paths”. Journal of Metamorphic Geology, 19(4), 411–432, 2001.
26. [26] Whitney DL, Teyssier C, Fayon AK, Hamilton MA, Heizler M. “Tectonic controls on metamorphism, partial melting, and intrusion: timing and duration of regional metamorphism and magmatism in the Niğde Massif. Turkey”. Tectonophysics, 376 (1–2), 37–60, 2003.
27. [27] Whitney DL, Hamilton MA. “Timing of high-grade metamorphism in central Turkey and the assembly of Anatolia”. Journal of the Geological Society, 161(5), 823–828, 2004.
28. [28] van Hinsbergen DJJ, Maffione M, Plunder A, Kaymakcı N, Ganerød M, Hendriks BWH, Corfu F, Gürer D, de Gelder GINO, Peters K, McPhee PJ, Brouwer FM, Advokaat EL, Vissers RLM. “Tectonic evolution and paleogeography of the Kırşehir Block and the Central Anatolian Ophiolites, Turkey”. Tectonics, 35(4), 983–1014, 2016.
29. [29] Akıman O, Erler A, Göncüoğlu MC, Güleç N, Geven A, Türeli TK, Kadıoğlu YK. “Geochemical characteristics of granitoids along the western margin of the Central Anatolian Crystalline Complex and their tectonic implications”. Geological Journal, 28(3-4), 371–382, 1993.
30. [30] Aydın NS, Malpas J, Göncüoglu MC, Erler A. “A review of the nature of magmatism in Central Anatolia during the Mesozoic post collisional period”. International Geology Review, 43(8), 695–710, 2001.
31. [31] Ilbeyli N, Pearce JA, Thirlwall MF, Mitchell JG. “Petrogenesis of collision related plutonic in Central Anatolia, Turkey”. Lithos, 72(3-4), 163–182, 2004.
32. [32] Kadıoğlu YK, Dilek Y, Foland KA. Slab Break-of and Syncollisional Origin of the Late Cretaceous magmatism in the Central Anatolian crystalline complex, Turkey. Editors: Dilek Y, Pavlides S. Postcollisional Tectonics and Magmatism in the Mediterranean Region and Asia, Geological Society of America, Special Paper, 381–415, Boulder, CO, USA, 2006.
33. [33] Köksal S, Göncüoğlu MC. “Sr and Nd isotopic characteristics of some S-, I and A-type granitoids from Central Anatolia”. Turkish Journal of Earth Sciences, 17(1), 11–127, 2008.
34. [34] Orhan A, Demirbilek M. “Kapadokya bölgesi (Nevşehir, Orta Anadolu) kalk-alkalen ve alkalen plütonik/ subvolkanik kayaçların petrografik ve jeokimyasal özellikleri”. Türkiye Jeoloji Bülteni, 61(1), 23–50, 2018.
35. [35] Divilioğlu E, Orhan A. “Avanos (Nevşehir, Orta Anadolu) yöresindeki Geç Kretase yaşlı alkalen plütonik ve subvolkanik kayaçların jeokimyası, mineral kimyası ve kristallenme koşulları”. Türkiye Jeoloji Bülteni, 66(2), 159–188, 2023.
36. [36] Köksal S, Romer RL, Göncüoglu MC, Toksoy-Köksal F. “Timing of postcollisional H-type to A-type granitic magmatism: U-Pb titanite ages from the Alpine central Anatolian granitoids (Turkey)”. International Journal of Earth Sciences (Geologische Rundschau), 93(6), 974–989, 2004.
37. [37] Boztuğ D, Tichomirowa M, Bombach K. “207Pb–206Pb single-zircon evaporation ages of some granitoid rocks reveal continent-oceanic island arc collision during the Cretaceous geodynamic evolution of the central Anatolian crust, Turkey”. Journal of Asian Earth Sciences, 31(1), 71–86, 2007.
38. [38] Orhan A, Akçe MA, Divilioğlu E. “Nevşehir-Niğde Bölgesi Plütonik Kayaçların Mineral Bileşimleri ve Kristalizasyon Koşullarının (P-T) Araştırılması”. NEÜBAP Bilimsel Araştırma Projesi, Nevşehir, Türkiye, ABAP21F22, 2022.
39. [39] Wang X, Hou T, Wang M, Zhang C, Zhang Z, Pan R, Marxer F, Zhang H. “A new clinopyroxene thermobarometer for mafic to intermediate magmatic systems”. European Journal of Mineralogy, 33(5), 621–637, 2021.
40. [40] Ridolfi F, Renzulli A, Puerini M. “Stability and chemical equilibrium of amphibole in calc-alkaline magmas: an overview, new thermobarometric formulations and application to subduction-related volcanoes”. Contributions to Mineralogy and Petrology, 160(1), 45–66, 2010.
41. [41] Streckeisen A. "Classification and nomenclature of plutonic rocks recommendations of the IUGS subcommission on the systematics of igneous rocks". Geologische Rundschau, 63(2), 773–786, 1974.
42. [42] Morimoto N. “Nomenclature of pyroxenes”. Mineralogy and Petrology, 39(1), 55–76, 1988.
43. [43] Burns LE. “The Border Ranges ultramafic and mafic complex, south central Alaska: cumulate fractionates of island arcs volcanics”. Canadian Journal of Earth Sciences, 22(7), 1020–1038, 1985.
44. [44] Leake BE, Woolley AR, Arps CES, Birch WD, Gilbert MC, Grice JD, Hawthorne FC, Kato A, Kisch HJ, Krivovichev VG, Linthout K, Laird J, Mandarino JA, Maresch WV, Nickel EH, Rock NMS, Schumacher JC, Smith DC, Stephenson NCN, Ungaretti L, Whittaker EJW, Youzhi G. “Nomenclature of amphiboles: Report of the subcommittee on amphiboles of the International Mineralogical Association, Commission on New Minerals and Mineral Names”. The Canadian Mineralogist, 35(1), 219–246, 1997.
45. [45] Deer WA, Howie RA, Zussman J. An Introduction to Rock Forming Minerals. 1st ed. New York, USA, John Wiley and Sons, 1966.
46. [46] Ustalić S, Nemec O, Milovská S, Putiš M, Babajić E, Kurylo E, Ružička P. “Amphibole group minerals in the Ozren Massif Ophiolites of Bosnia and Herzegovina as petrogenetic indicators”. Minerals, 14(3), 239, 2024.
47. [47] Le Bas MJ. “The role of aluminium in igneous clinopyroxenes with relation to their parentage”. American Journal of Science, 260(4), 267–288, 1962.
48. [48] Leterrier J, Maury RC, Thonon P, Girard D, Marchal M. “Clinopyroxene composition as a method of identification of the magmatic affinities of paleovolcanic series”. Earth and Planetary Science Letters, 59(1), 139–154, 1982.
49. [49] Droop GTR, “A general equation for estimating Fe3+ concentrations in ferromagnesian silicates and oxides from microprobe analyses, using stoichiometric criteria”. Mineralogical Magazine, 51(361) 431–435, 1987.
50. [50] Beccaluva L, Macciotta G, Piccardo GB, Zeda O. “Clinopyroxene composition of ophiolite basalts as petrogenetic indicator”. Chemical Geology, 77(3-4), 165–182, 1989.
51. [51] Arculus RJ, Wills KJA. “The petrology of plutonic blocks and inclusions from the Lesser Antilles island arc”. Journal of Petrology, 21(4), 743–799, 1980.
52. [52] Helz RT. “Phase relations of basalt in their melting range at PH2O=5 kb as a function of oxygen fugacity: Part I. mafic phases”. Journal of Petrology, 14(2), 249–302, 1973.
53. [53] Elthon D. “Petrology of the gabbroic rocks from the Mid-Cayman Rise spreading center”. Journal of Geophysical Research, 92(B1), 658–682, 1987.