Geochemistry of the Middle Miocene Collision-Related Yamadaği ( Eastern Anatolia) Calc-Alkaline Volcanics, Turkey

Authors: TANER EKİCİ, MUSA ALPASLAN, OSMAN PARLAK, ALİ UÇURUM

Abstract: Major, trace element and K-Ar age determinations are reported for a suite from the Yamadağı volcanics in the Eastern Anatolia. The exposed rocks mainly consist of medium-potassium calc-alkaline basaltic andesites, andesites and dacites. Petrographical data exhibit disequilibrium mineral textures, such as resorption of the ferromagnesian phases, clinopyroxene-mantled orthopyroxene, and sieve-textured plagioclases. The Yamadağı volcanics have a calk-alkaline character, and trace element characteristics exhibit that the volcanics resemble subduction zone volcanics and/or volcanics assimilated by continental crust. K/Ar age determinations show that the Yamadağı volcanics were formed during the 12 ± 0.5 - 15 ± 0.5 Ma time interval. Geochemical characteristics of these volcanics can be attributed to complex petrogenetic processes, including magma mixing and crustal assimilation along with fractional crystallization.

Keywords: calc alkaline, volcanics, collision, Eastern Anatolia, Turkey

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