Ages, Distribution, and Evolution of Miocene Basalts, East-Central Anatolia

Abstract:

Widespread volcanic activity accompanied the transition from continental collision to escape in East-Central Anatolia during Miocene time. Regionally, Miocene volcanic rocks are concentrated along an elongate path roughly parallel to the Arabian suture zone. They are often geographically isolated and form large, broad edifices above the surrounding Anatolian Plateau. In some instances, Miocene volcanic rocks are intercalated with terrestrial basin sediments. It has been proposed that the initiation of this volcanism represents the onset of the major shift in the regional tectonic framework, and geochemical changes exhibited by these lavas could record the evolution of magma sources.

In order to constrain the regional initiation and evolution of syn- to post-collisional volcanism, and the mantle melting sources responsible for them, mafic samples were collected from Miocene volcanic fields between Malatya and Konya, Turkey, an area representing ~50,000 km². New ⁴⁰Ar/³⁹Ar geochronology data and geochemical data, coupled with stratigraphic relations and limited existing data for this region, show that mafic magmatism began in early Miocene time (~20 Ma) and continued through Pliocene time throughout east-central Anatolia. Our results will be interpreted with the overall context of understanding how the timing and geochemistry of Miocene volcanism relates to the transition between collision and escape tectonics.