Timing of post-obduction granitoids from intrusion through cooling to exhumation in central Anatolia, Turkey

Abstract

The Middle to Late Cretaceous central Anatolian granitoids intrude the supra-subduction zone-type central Anatolian ophiolite and medium- to high-grade metasediments of central Anatolian crystalline complex and are overlain by Late Palaeocene to Early/Middle Eocene sediments. Their single-zircon Pb-207-Pb-206 evaporation ages define three clusters: (I) Cenomanian-Turonian (weighted-mean age: 94.9 +/- 3.4 Ma), (2) Turonian-Santonian (85.5 +/- 5.5 Ma) and (3) Campanian (74.9 +/- 3.8 Ma). Their hornblende and biotite Ar-40-Ar-39 and K-Ar cooling ages cluster around 80-65 Ma. The close hornblende and biotite ages reflect rapid exhumation of a mid-crustal section during the Campanian-Maastrichtian. Early to Middle Palaeocene (57-62 Ma) apatite fission-track age clusters date the tail end of this exhumation episode. It is proposed that the central Anatolian granitoid melts were generated in a post-collisional extensional setting following the docking of an oceanic island arc onto the Tauride-Anatolide platform. Campanian-Maastrichtian to Early/Middle Palaeocene rapid exhumation event is considered to result from continent-continent collisions between Eurasian plate and the Tauride-Anatolide platform along the Izmir-Ankara-Erzincan suture zone. (C) 2008 Elsevier B.V. All rights reserved.