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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 68 (1984)

Issue: 4. (April)

First Page: 526

Last Page: 526

Title: Strike-Slip Tectonics, Related Basin Formation, and Sedimentology in Zones of Continental Escape: Turkey as a Case Study: ABSTRACT

Author(s): A. M. C. Sengor, Naci Gorur

Abstract:

Strike-slip movement on various scales and in diverse orientations is one of the most prominent modes of deformation in zones of continental convergence. Extreme heterogeneity and low shear strength of continental rocks are responsible for creating "escape routes" of bewildering complexity into free faces from nodes of constriction along irregular collision fronts. Since the Tortonian (11 Ma), the tectonics of Turkey has been dominated by its escape westward from the east Anatolian collision zone onto the oceanic lithosphere of the eastern Mediterranean, mainly along the north and east Anatolian transform faults (NAT & EAT), and at least two other southeast-concave strike-slip faults that branch off the NAT near Erzincan and Resadiye. The Aegean graben system is a bro d shear zone between the latter of these and the Grecian shear zone. At "triple junctions" involving the NAT/EAT and EAT/Dead Sea transform fault, space problems arise, giving rise to the Karliova and Adana/Cilicia basins, respectively. In Thrace, where the NAT takes a southwesterly bend, part of the resulting constraint is released by rifting in a northwest orientation that formed the Ergene basin. In addition, various pull-apart structures and "leaky" strike-slip faults contribute to the richness of strike-slip-related negative structures in Turkey. Some of these are of lithospheric dimensions and contain thousands of meters of sediment, whereas others formed within thinner crustal flakes above decollement horizons. Because escape tectonics necessarily involves subduction, arc-related trike-slip deformation may interfere with that indigenous to collision tectonics, as in south Turkey. Continental convergence eventually eliminates all subductable areas along the collision front and the structures generated by escape regimes may fall prey to compressional obliteration. In zones of complex and multiple continental collision such as Turkey, several episodes of escape tectonics may alternate with intracontinental compressional deformation, whereby the products of the older escape regimes would be very difficult to recognize. The present tectonics of Turkey constitutes an excellent guide to earlier episodes of escape tectonics in and around Turkey.

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