Petrochemistry of the Oyaca-Kedikayasi (Ankara) dacites as evidence for the post-collisional tectonic evolution of north-central Anatolia, Turkey


Bozkurt E. , Kocyigit A., Winchester J., Holland G., Beyhan A.

GEOLOGICAL JOURNAL, vol.34, no.3, pp.223-231, 1999 (Journal Indexed in SCI) identifier

Abstract

The Lower Miocene Oyaca and Kedikayasi dacite stocks, unconformably overlain by Plio-Quaternary sedimentary and volcanic rocks, intrude a southward-verging imbricate thrust zone within the izmir-Ankara-Erzincan Suture Zone (IAESZ), approximately 50 km SW of Ankara. These stocks crop out as two petrographically distinguishable plagioclase, hornblende and biotite-phyric dacites. Xenoliths petrographically similar to the Kedikayasi dacite occur within the Oyaca stock, suggesting that the Kedikayasi stock is older; if so, the venting from the magma chamber may have removed the upper, more evolved magma first.