Tectonics of eastern anatolian plateau: Final stages of collisional orogeny in Anatolia

Abstract

The East Anatolian High Plateau, which is a part of the Alpine-Himalayan orogen, is a 200 km wide, approximately east-west trending belt surrounded by two peripheral mountains of the Anatolian Peninsula. The plateau is covered by thick, interbedded Neogene volcanic and sedimentary rocks. Outcrops of the underlying rocks are rare and, therefore, contrasting views were proposed on the nature of the basement rocks. New geological and geophysical data suggest the presence of an ophiolitic melange-accretionary complex under cover rocks of Eastern Anatolia. The Neogene cover units began to be deposited during the closure of the NeoTethyan Ocean that was located between the Pontide arc to the north, and the continental slivers drifted away from the Arabian Plate to the south. The bordering orogenic belts, the Pontides in the north, and the Bitlis-Zagros Mountains in the south have undergone entirely different evolution. The Eastern Anatolian orogen was formed during the later stages of the development of the surrounding orogenic belts. In this period, the melange-accretionary prism that occupied a large terrain behaved like a wide and thick cushion, which did not allow a head-on collision of the bordering continents. The NeoTethyan oceanic lithosphere was eliminated from the entire eastern Anatolia by northward subduction that lasted till the Late Eocene. The Eastern Anatolia began to rise when the northern advance of the Arabian Plate continued after the total demise of the oceanic lithosphere. The present stage of the elevation of the East Anatolian Plateau as a coherent block started during the Late Miocene.