Geology and petrology of the Simav Magmatic Complex (NW Anatolia) and its comparison with the Oligo-Miocene granitoids in NW Anatolia: implications on Tertiary tectonic evolution of the region

摘要

The Oligo-Miocene granitic plutons and their related volcanic-subvolcanic successions form a NW-SE trending magmatic belt along the northern border of the Menderes Massif. This belt evolved within a nappe package consisting of the Menderes metamorphics, Sakarya Continent, Afyon Zone and Tavsanli Zone and also intruded this nappe package. The Ezine, Evciler, Eybek, Kozak, Alacam, Koyunoba, Egrigoz and the Baklan plutons em-placed along this belt and show similarities in their internal structures, emplacement mechanisms, and petrological characteristics. These different granitic plutons cut and stitch various combinations of the nappe package of the above-mentioned tectonic belts, and evolved during and following the Alpine collision. They all show characteristic map patterns of shallow-seated plutons and range from granite to monzogranite. The granitic plutons display calc-alkaline, Ⅰ-type and post-collisional geochemical characteristics. The Egrigoz, Koyunoba plutons and their subvolcanic-volcanic phases (Simav Magmatic Complex) were studied in detail. The geochemical characteristics and field occurences of the Simav Magmatic Complex were compared to the other magmatic associations in western Anatolia and it was determined that it is of collisional origin and not related to an extensional tectonic regime as suggested in some recent studies.