Petrogenesis and geodynamics of plagiogranites from Central Turkey (Ekecikdag/Aksaray): new geochemical and isotopic data for generation in an arc basin system within the northern branch of Neotethys

In the Late Cretaceous, throughout the closure of the Neotethys Ocean, ophiolitic rocks from the A degrees zmir-Ankara-Erzincan ocean branch were overthrusted the northern margin of the Tauride-Anatolide Platform. The ophiolitic rocks in the Ekecikdag (Aksaray/Central Turkey) region typify the oceanic crust of the A degrees zmir-Ankara-Erzincan branch of Neotethys. The gabbros in the area are cut by copious plagiogranite dykes, and both rock units are intruded by mafic dykes. The plagiogranites are leucocratic, fine- to medium-grained calc-alkaline rocks characterized mainly by plagioclase and quartz, with minor amounts of biotite, hornblende and clinopyroxene, and accessory phases of zircon, titanite, apatite and opaque minerals. They are tonalite and trondhjemite in composition with high SiO2 (69.9-75.9 wt%) and exceptionally low K2O (< 0.5 wt%) contents. The plagiogranites in common with gabbros and mafic dykes show high large-ion lithophile elements/high-field strength element ratios with depletion in Nb, Ti and light rare-earth elements with respect to N-MORB. The plagiogranites together with gabbros and mafic dykes show low initial Sr-87/Sr-86 ratios (0.70419-0.70647), high AENd((T)) (6.0-7.5) values with Pb-206/Pb-204 (18.199-18.581), Pb-207/Pb-204 (15.571-15.639) and Pb-208/Pb-204 (38.292-38.605) ratios indicating a depleted mantle source modified with a subduction component. They show similar isotopic characteristics to the other supra-subduction zone (SSZ) ophiolites in the Eastern Mediterranean to East Anatolian-Lesser Caucasus and Iran regions. It is suggested that the Ekecikdag plagiogranite was generated in a short time interval from a depleted mantle source in a SSZ/fore-arc basin setting, and its nature was further modified by a subduction component during intra-oceanic subduction.


The Unaz Formation: A Key Unit in the Western Black Sea Region, N Turkey
Tuysuz, Okan; Yılmaz, İsmail Ömer; Svabenicka, Lilian; Kirici, Sabri (2012-01-01)
The Pontide magmatic belt in the Western Pontides, which developed in response to the northward subduction of the northern branches of the Tethys Ocean, consists of two different volcanic successions separated by an Upper Santonian pelagic limestone unit, the Unaz Formation. The first period of volcanism and associated sedimentation started during the Middle Turonian and lasted until the Early Santonian under the control of an extensional tectonic regime, which created horst-graben topography along the sout...
Zircon ages from the Beypazari granitoid pluton (north central Turkey): tectonic implications
Speciale, Pamela A.; Catlos, Elizabeth J.; Yildiz, G. Okan; Shin, Timothy A.; Black, Karen N. (Informa UK Limited, 2012-09-01)
The Beypazari granitoid is emplaced in a Late Cretaceous volcanic arc in north central Turkey and provides evidence for processes that occurred during the closure of the Neo-Tethys Ocean. Zircons from its northern granodiorite and quartz monzonite exposure are dated in rock thin section and display characteristic igneous zoning in cathodoluminescence (CL). Its oldest Late Cretaceous ages (95.4 +/- 4.2-91.3 +/- 6.5 Ma, U-238/Pb-206, +/- 1 sigma) time early crystallization from rising melts, but inspection of...
Ellero, Alessandro; Ottria, Giuseppe; Sayıt, Kaan; Catanzariti, Rita; Frassi, Chiara; Göncüoğlu, Mehmet Cemal; Marroni, Michele; Pandolfi, Luca (2015-01-01)
In the Central Pontides (Northern Turkey), south of Tosya, a tectonic unit consisting of not-metamorphic volcanic rocks and overlying sedimentary succession is exposed inside a fault-bounded elongated block. It is restrained within a wide shear zone, where the Intra-Pontide suture zone, the Sakarya terrane and the Izmir-Ankara-Erzincan suture zone are juxtaposed as result of strike-slip activity of the North Anatolian shear zone. The volcanic rocks are mainly basalts and basaltic andesites (with their pyroc...
Petrogenesis and tectonic setting of Cadomian felsic igneous rocks, Sandikli area of the western Taurides, Turkey
Guersu, Semih; Goencueoglu, M. Cemal (Springer Science and Business Media LLC, 2006-09-01)
In the Sandikli (Afyon) region, western Taurides, the Late Proterozoic rocks of the Sandikli basement complex are composed of low-grade meta-sedimentary rocks (Guvercinoluk Formation) intruded by felsic rocks (Kestel Cayi Porphyroid Suite, KCPS). The KCPS is a deformed and highly sheared, dome-shaped rhyolitic body with a granitic core. Quartz porphyry dikes intrude both the slightly metamorphic igneous and the sedimentary rocks of the basement complex. Both the quartz porphyries and rhyolites were converte...
Reconstruction of a Late Jurassic-Early Cretaceous carbonate platform margin with composite biostratigraphy and microfacies analysis (western Sakarya Zone, Turkey): Paleogeographic and tectonic implications
Atasoy, Serdar Görkem; Altıner, Demir (Elsevier BV, 2018-12-01)
During Late Jurassic-Early Cretaceous the Pontides were the site of a wide carbonate platform facing the Tethys ocean in the south. In the western Pontides the Upper Jurassic-Lower Cretaceous shallow marine carbonates abut the Tethyan Izmir-Ankara suture with no evidence for platform margin deposits. The Sivrihisar klippe 50 km south of the Izmir-Ankara suture preserves a record of the missing platform margin. In the Upper Jurassic-Lower Cretaceous carbonates exposed in this Sivrihisar klippe, two coeval bu...
Citation Formats
S. Köksal, F. Toksoy Köksal, and M. C. Göncüoğlu, “Petrogenesis and geodynamics of plagiogranites from Central Turkey (Ekecikdag/Aksaray): new geochemical and isotopic data for generation in an arc basin system within the northern branch of Neotethys,” INTERNATIONAL JOURNAL OF EARTH SCIENCES, pp. 1181–1203, 2017, Accessed: 00, 2020. [Online]. Available: