Petrogenesis of Pegmatitic Gabbros of the Koçali Ophiolite (Southeast Türkiye): Implications for Boninitic Magmatism

Abdullah Sar; Mustafa Eren Rizeli; Mehmet Ali Ertürk

doi:10.54287/gujsa.1869691

Petrogenesis of Pegmatitic Gabbros of the Koçali Ophiolite (Southeast Türkiye): Implications for Boninitic Magmatism

Abstract

Pegmatitic gabbros belonging to the Koçali ophiolite, located within the southern belt ophiolites, are situated in the Southeastern Anatolia region. In this study, whole-rock geochemistry analyses were performed on pegmatitic gabbros of the Koçali ophiolite. This study aims to contribute to the petrogenesis of pegmatitic gabbros and the tectonic evolution of the Southeastern Anatolian Orogenic Belt by evaluating new data alongside previous studies. Geochemical data demonstrate that the studied rocks are tholeiitic and mostly boninitic. Pegmatitic gabbros exhibit spoon-shaped REE patterns with high MgO content and low TiO₂ values. However, low Ti/V values support a boninitic magma origin. The high Ba/La and Ba/Th ratios of the pegmatitic gabbros show a high-pressure, low-temperature, and fluid-rich environment consistent with a forearc setting. KG-1 sample indicates a boninitic magma origin with positive ƐNd_(t) (+2.9) and high ⁸⁷Sr⁸⁶Sr values (0.706666). KG-8 sample, in contrast, shows relatively enriched characteristics and an E-MORB-like affinity. When all data are evaluated together, it has been determined that the pegmatitic gabbros formed mainly from a boninitic magma source in the forearc environment of the supra-subduction zone.

Keywords

Supporting Institution

Fırat University Scientific Research Projects Coordination Unit (FUBAP)

Project Number

MF.24.43

Thanks

We would like to thank the Fırat University Scientific Research Projects Coordination Unit for their support of this study (MF.24.43).

References

Beyarslan, M. (2017). Supra-subduction zone magmatism of the Koçali ophiolite, SE Turkey. Journal of African Earth Sciences, 129, 390-402. http://doi.org/10.1016/j.jafrearsci.2016.11.030
Bingöl, A. F., Beyarslan, M., Lin, Y.-C., & Lee, H.-Y. (2018). Geochronological and geochemical constraints on the origin of the Southeast Anatolian ophiolites, Turkey. Arabian Journal of Geosciences, 11(18), 569. https://doi.org/10.1007/s12517-018-3880-0
Bohrson, W. A., & Spera, F. J. (2001). Energy-constrained open-system magmatic processes II: application of energy-constrained assimilation-fractional crystallization (EC-AFC) model to magmatic systems. Journal of Petrology, 42(5), 1019-1041. https://doi.org/10.1093/petrology/42.5.1019
Chen, C., Su, B-X., Wang, C. Y, Uysal, İ., & Yao, Z-S. (2021). Mantle melting models of the Kızıldağ ophiolite in SE Turkey: Two types of partial melting processes in the oceanic upper mantle of southern Neo-Tethys. Lithos, 398-399, 106348. https://doi.org/10.1016/j.lithos.2021.106348
Dilek, Y., & Furnes, H. (2011). Ophiolite genesis and global tectonics: geochemical and tectonic fingerprinting of ancient oceanic lithosphere. Geological Society of America Bulletin, 123(3-4), 387-411. https://doi.org/10.1130/B30446.1
Dilek, Y., & Thy, P. (2009). Island arc tholeiite to boninitic melt evolution of the Cretaceous Kizildag (Turkey) ophiolite: Model for multi-stage early arc forearc magmatism in Tethyan subduction factories. Lithos, 113(1-2), 68-87. https://doi.org/10.1016/j.lithos.2009.05.044
Ersoy, E. Y. (2013). PETROMODELER (Petrological Modeler): a Microsoft® Excel© spreadsheet program for modelling melting, mixing, crystallisation and assimilation processes in magmatic systems. Turkish Journal of Earth Sciences, 22(1), 115-125. https://doi.org/10.3906/yer-1104-6
Heckmann, P., Palinkaš, S. S., Hansen, H., Iacona-Marziano, G., Rajič, K., Forein, M., & Bergh, S. G. (2022). Petrogenesis of zoned and unzoned mafic pegmatites: An insight from the Palaeoproterozoic mafic-ultramafic Hamn intrusion, Northern Norway. Lithos, 428-429, 106818. https://doi.org/10.1016/j.lithos.2022.106818

Karaoğlan, F., Parlak, O., Robertson, A., Thöni, M., Klötzli, U., Koller, F., & Okay, A. İ. (2013). Evidence of Eocene high-temperature/high-pressure metamorphism of ophiolitic rocks and granitoid intrusion related to Neo-Tethyan subduction processes (Doğanşehir area, SE Anatolia). In: A. H. F. Robertson, O. Parlak, & U. C. Ünlügenç (Eds.), Geological Development of Anatolia and the Easternmost Mediterranean Region. Geological Society, London, Special Publications (vol. 372, pp. 249-272). https://doi.org/10.1144/SP372.21
Keskin, M. (2002). FC-Modeller: A Microsoft® Excel© Spreadsheet Program for Modeling Rayleigh Fractionation Vectors in Closed Magmatic Systems. Computers & Geosciences, 28(8), 919-928. https://doi.org/10.1016/s0098-3004(02)00010-9
Köksal, S. (2019). The Upper Cretaceous intrusive rocks with extensive crustal contribution in Hacımahmutuşağı Area (Aksaray/Turkey). Geologica Carpathica, 70(3), 261-276. https://doi.org/10.2478/geoca-2019-0015
McCulloch, M. T. & Gamble, J. A. (1991). Geochemical and Geodynamical Constrains on Subduction Zone Magmatism. Earth and Planetary Science Letters, 102(3-4), 358-374. https://doi.org/10.1016/0012-821X(91)90029-H
MTA. (2002). Türkiye’nin 1/500.000 ölçekli jeoloji haritası. Maden Tetkik ve Arama Genel Müdürlüğü, Ankara.
Okay, A. I. & Tüysüz, O. (1999). Tethyan sutures of northern Turkey. In: B. Durand, L. Jolivet, F. Horváth, & M. Séranne (Eds.), The Mediterranean Basins: Tertiary Extension within the Alpine Orogen. Geological Society, London, Special Publications (vol. 156, pp. 475-515). https://doi.org/10.1144/GSL.SP.1999.156.01.22
Parlak, O., Bağcı, U., Rızaoğlu, T., Ionescu, C., Önal, G., Höck, V., & Kozlu, H. (2020). Petrology of ultramafic to mafic cumulate rocks from the Göksun (Kahramanmaraş) ophiolite, southeast Turkey. Geoscience Frontiers, 11(1), 109-128. https://doi.org/10.1016/j.gsf.2018.11.004
Pearce, J. A., van der Laan, S. R., Arculus, R. J., Murton, B. J., Ishii T., Peate D. W., & Parkinson I. J. (1992). Boninite and harzburgite from Leg 125 (Bonin-Mariana forearc): a case study of magina genesis during the initial stage of subduction. In: P. Fryer, J. A. Pearce, L. B. Stokking et al. (Eds.), Proceedings of the Ocean Drilling Program, Scientific Results (vol. 125), College Station, TX, Ocean Drilling Program, (pp. 623-659). https://doi.org/10.2973/odp.proc.sr.125.172.1992
Pearce, J. A. (2008). Geochemical fingerprinting of oceanic basalts with applications to ophiolite classification and the search for Archean oceanic crust. Lithos, 100(1-4), 14-48. https://doi.org/10.1016/j.lithos.2007.06.016
Pearce, J. A., & Reagan, M. K. (2019). Identification, classification, and interpretation of boninites from Anthropocene to Eoarchean using Si-Mg-Ti systematics. Geosphere, 15(4), 1008-1037. https://doi.org/10.1130/GES01661.1
Reagan, M. K., Ishizuka, O. Stern, R. J., Kelley, K. A., Ohara, Y., Blichert-Toft, J., Bloomer, S. H., Cash, J., Fryer, P., Hanan, B. B., Hickey-Vargas, R., Ishii, T., Kimura, J.-I., Peate, D. W., Rowe, M. C., & Woods, M. (2010). Fore-arc basalts and subduction initiation in the Izu-Bonin-Mariana system. Geochemistry, Geophysics, Geosystems, 11(3). https://doi.org/10.1029/2009GC002871
Rizeli, M. E. (2023a). Primary Data on Chromitites of Mantle Peridotites around Kulp and Baykan (SE Anatolia): Mineral Chemistry Compositions of Spinels. In: 3rd International Graduate Studies Congress, (pp. 978).
Rizeli, M. E. (2023b). Mineral chemistry and petrogenesis of chromitites from the Koçali Ophiolite (SE Turkey). In: 2nd International Conference on Engineering, Natural and Social Sciences, (pp. 148).
Rizeli, M. E. (2023c). Chemistry of Cr-spinel in podiform chromitites from Islahiye Ophiolite (Gaziantep, SE Anatolia). In: 2. International Conference on Advances and Innovations in Engineering, (pp. 31-32).
Rizeli, M. E., Bingöl, A. F., Wang, K.-L., & Lee, H.-Y. (2023). Abyssal and forearc features of mantle peridotites in the Guleman ophiolite in SE Turkey. Lithos, 436-437, 106958. https://doi.org/10.1016/j.lithos.2022.106958
Robertson, A. H. F., Parlak, O., Ustaömer, T., Taslı, K., & Dumitrica, P. (2021). Late Palaeozoic-Neogene sedimentary and tectonic development of the Tauride continent and adjacent Tethyan ocean basins in eastern Turkey: New data and integrated interpretation. Journal of Asian Earth Sciences, 220, 104859. https://doi.org/10.1016/j.jseaes.2021.104859
Robertson, A. H. F. (2002). Overview of the Genesis and Emplacement of Mesozoic Ophiolites in the Eastern Mediterranean Tethyan Region. Lithos, 65(1-2), 1-67. https://doi.org/10.1016/S0024-4937(02)00160-3
Sapancı, Ö., Tokat, G., Eraslan N. K., Karakaya, A. O., Gücer, M. A., & Çimen, O. (2023). Geochemical and radiometric data for mafic rocks from the Guleman Ophiolite (SE, Turkey): New insights on the geodynamic evolution of the southern Neo-Tethyan ocean. Lithos, 442-443, 107071. https://doi.org/10.1016/j.lithos.2023.107071
Sun, S.-s., & McDonough, W. F. (1989). Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In: A. D. Saunders, & M. J. Norry (Eds.), Magmatism in the Ocean Basins. Geological Society, London, Special Publications (vol. 42, pp. 313-345). https://doi.org/10.1144/gsl.sp.1989.042.01.19
Yang, W.-B., Niu, H.-C., Shan, Q., Luo, Y., Sun, W.-D., Li, C.-Y., Li, N.-B., & Yu, X.-Y. (2012). Late Paleozoic calcalkaline to shoshonitic magmatism and its geodynamic implications, Yuximolegai area, western Tianshan, Xinjiang: Gondwana Research, 22(1), 325-340. https://doi.org/10.1016/j.gr.2011.10.008
Yang, Y., Zhao, L., Zhang, J., Xu, Q., & Cao, P. (2022). An Ordovician ophiolitic complex in West Junggar, NW China: Implications for subduction initiation and oceanic arc evolution of the Paleo-Asian Ocean. Gondwana Research, 111, 122-141. https://doi.org/10.1016/j.gr.2022.07.012
Yıldırım, N. (2018). Koçali Karmaşığını (Adiyaman) Oluşturan Okyanusal Birimlerin Petrolojik Özellikleri ve Tektonik Önemi. PhD Thesis, Çukurova University.
Yılmaz, Y. (2019). Southeast Anatolian Orogenic Belt revisited (geology and evolution). Canadian Journal of Earth Sciences. 56(11), 1163-1180. https://doi.org/10.1139/cjes-2018-0170

Details

Primary Language

English

Subjects

Igneous and Metamorphic Petrology

Journal Section

Research Article

Authors

Abdullah Sar ^*
0000-0002-9752-7807
Türkiye

Mustafa Eren Rizeli
0000-0003-3725-3063
Türkiye

Mehmet Ali Ertürk
0000-0003-1197-9202
Türkiye

Publication Date

June 30, 2026

Submission Date

January 22, 2026

Acceptance Date

March 27, 2026

Published in Issue

Year 2026 Volume: 13 Number: 2

DOI

https://doi.org/10.54287/gujsa.1869691

IZ

https://izlik.org/JA73ZC79CS

Cite

RIS / Bibtex

APA

Sar, A., Rizeli, M. E., & Ertürk, M. A. (2026). Petrogenesis of Pegmatitic Gabbros of the Koçali Ophiolite (Southeast Türkiye): Implications for Boninitic Magmatism. Gazi University Journal of Science Part A: Engineering and Innovation, 13(2), 582-600. https://doi.org/10.54287/gujsa.1869691

AMA

1.Sar A, Rizeli ME, Ertürk MA. Petrogenesis of Pegmatitic Gabbros of the Koçali Ophiolite (Southeast Türkiye): Implications for Boninitic Magmatism. GU J Sci, Part A. 2026;13(2):582-600. doi:10.54287/gujsa.1869691

Chicago

Sar, Abdullah, Mustafa Eren Rizeli, and Mehmet Ali Ertürk. 2026. “Petrogenesis of Pegmatitic Gabbros of the Koçali Ophiolite (Southeast Türkiye): Implications for Boninitic Magmatism”. Gazi University Journal of Science Part A: Engineering and Innovation 13 (2): 582-600. https://doi.org/10.54287/gujsa.1869691.

EndNote

Sar A, Rizeli ME, Ertürk MA (June 1, 2026) Petrogenesis of Pegmatitic Gabbros of the Koçali Ophiolite (Southeast Türkiye): Implications for Boninitic Magmatism. Gazi University Journal of Science Part A: Engineering and Innovation 13 2 582–600.

IEEE

[1]A. Sar, M. E. Rizeli, and M. A. Ertürk, “Petrogenesis of Pegmatitic Gabbros of the Koçali Ophiolite (Southeast Türkiye): Implications for Boninitic Magmatism”, GU J Sci, Part A, vol. 13, no. 2, pp. 582–600, June 2026, doi: 10.54287/gujsa.1869691.

ISNAD

Sar, Abdullah - Rizeli, Mustafa Eren - Ertürk, Mehmet Ali. “Petrogenesis of Pegmatitic Gabbros of the Koçali Ophiolite (Southeast Türkiye): Implications for Boninitic Magmatism”. Gazi University Journal of Science Part A: Engineering and Innovation 13/2 (June 1, 2026): 582-600. https://doi.org/10.54287/gujsa.1869691.

JAMA

1.Sar A, Rizeli ME, Ertürk MA. Petrogenesis of Pegmatitic Gabbros of the Koçali Ophiolite (Southeast Türkiye): Implications for Boninitic Magmatism. GU J Sci, Part A. 2026;13:582–600.

MLA

Sar, Abdullah, et al. “Petrogenesis of Pegmatitic Gabbros of the Koçali Ophiolite (Southeast Türkiye): Implications for Boninitic Magmatism”. Gazi University Journal of Science Part A: Engineering and Innovation, vol. 13, no. 2, June 2026, pp. 582-00, doi:10.54287/gujsa.1869691.

Vancouver

1.Abdullah Sar, Mustafa Eren Rizeli, Mehmet Ali Ertürk. Petrogenesis of Pegmatitic Gabbros of the Koçali Ophiolite (Southeast Türkiye): Implications for Boninitic Magmatism. GU J Sci, Part A. 2026 Jun. 1;13(2):582-600. doi:10.54287/gujsa.1869691