Geochemistry, Zircon U-Pb Geochronology, and Tectonic Setting of the Taayla±‡ay Granitoids, Eastern Anatolia, Turkey

Abstract

The TaAYlA +/-double dagger ay granitoids are located in the East Anatolian Accretionary Complex (EAAC), eastern Turkey, and consist of I-type (gabbro, diorite, quartz diorite, monzodiorite, quartz monzodiorite) and S-type (tonalite, granodiorite, monzogranite, granite) granitoid rocks. Whole rock major and trace element data define different two rock assemblages on Harker diagrams. They also suggest that these two different rock assemblages was created from calc-alkaline hybrid magma source which is consisted of the litospheric mantle-derived mafic magma and lower continental crust-derived felsic magma with mixing and assimilation fractional crystallization and assimilation processes. The high average Rb/Nb ratio of the I-type rocks from the TaAYlA +/-double dagger ay granitoids indicates that the additive of lower continental crust material during the mixing of mafic and felsic magma more than litospheric mantle material. The TaAYlA +/-double dagger ay granitoids display enrichment in large ion litophile elements (LILE) (Cs, Rb, Ba, U, Th, Pb), light rare earth element (LREE) (I-type; La-N/Yb-N = 7.38-17.53; S-type; La-N/Yb-N = 6.27-26.73), and depleted in high field strength element (HFSE) (Nb, Ta, P, Ti) implying a subduction-related magmatic signature. The zircon U-Pb geochronological data (granodiorite, 19.7 +/- 0.3 Ma; monzogranite, 20.3 +/- 0.3 Ma) obtained from the TaAYlA +/-double dagger ay granitoids reveal that the continent-continent collision between the Arabian and Eurasian plates along the Bitlis-Zagros suture zone occurred in Early Miocene (Burdigalian) or before Miocene.