Development of an Oblique Subduction Zone - Tectonic Evolution of the Tethys Suture Zone in Southeast Turkey

Abstract

The Southeast Anatolian orogen part of the Mediterraneari-Himalayan orogenic belt may be divided into three approximately E-W-trending zones. From south to north they are the Arabian platform an imbricated zone and a nappe zone. The eastern pail of the Arabian platform includes a lower Paleozoic to lower Miocene sedimentary sequence and ophiolitic rocks that were obducted on the platform during Late Cretaceous time. Also in the eastern part of the nappe zone consisting of lower and upper nappe packages three major Paleocene-Oligocene deformational phases occurred related to late-early Paleocene-early Eocene late Lutetian and late Oligocene nappe emplacements. These amalgamated nappes collided with the Arabian plate and were welded onto it at the latest stage of the orogenic evolution during late early Miocene time. The imbricated zone consists of units that were compressed and sandwiched between the nappes and the Arabian platform. In the nappe and imbricated zones various island-are volcanics and associated units developed related to the northward subduction of Neotethys during the Late Cretaceous to the late Oligocene. The ages of volcanic units decrease from west to east. This reflects oblique subduction of the ocean floorits remnant presently underlies the northerly nappes.