Evolution and Origin of Granitoid Magmas Related to the Closure of Neo-Tethys in Eastern Taurus (Turkey)

Abstract

Granitoids cutting the sheeted dyke complex (Göksun metaophiolite), the Elbistan ensimatic island arc volcanoclastic sequence of Neocomian age and the Kabaktepe metamorphites (Bitlis/Pötürge metamorphites) of Paleozoik-Lower Triassic age respectively, outcrop around Afsin-Elbistan-Göksun. The units deposited during Upper Cenonian-Eocene overlie these older units with an angular unconformity starting with a basal conglomerate. In the study area, outcropped granitoids have not been developed during island arc eruptions. These granitoids take place on the collision belts of the subduction zone formed by the N-S directed compressional forces of late Cretaceous started in Lower Cretaceous and increased after Neocomian. Their development is due to the increasing crustal thickness and sinking of the island arc deposits and its basement which is oceanic crust during Coniacian-Upper Santonian. Granitoids are the differentiated products of anatectic magma (diorite, monzonite, syenite, tonalite, granodiorite, granite, alcaline granite and silexite). Which is formed from melting of oceanic (Göksun metaophiolite) and crustal (Kabaktepe metamorphites) rocks together or sepertly at high temperatures. This anatectic magma is named and defined as Afsin magmatism for the first time. However, except these wide spread granitoids intrusions in Eastern Taurus, it was also observed that seme granitic rocks (diorite, monzonite, syenite, tonalite, granodiorite, granite and alcaline granite). Which don't show any intrusive features and magmatic phase. They formed by recrystallization from metamorphites rocks, island arc volcanoclastic deposits and ophiolites (gabbro, sheeted dyke complex and volcanosedimentary rocks) insitu. Granitoids were subjected the low grade regional metamorphism (greenschist facies) probably in Upper Santonian-Campanian.