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Turkish Journal of Earth Sciences

DOI

10.3906/yer-1907-29

Abstract

The architecture, kinematics, and timing of fold-and-thrust belt development provide essential first-order constraints on the structural evolution of continental collision zones. The southern Sivas fold-thrust belt (SSFTB) is a ~300 × 50-km-long, ENEtrending contractional belt located in the Sivas Basin at the western end of the Arabia-Eurasia collision zone, and along the İzmir- Ankara-Erzincan and Inner Tauride suture zones. We present new geologic mapping and the first detailed structural characterization and seismotectonic evidence of active deformation along the western and central segments of the SSFTB that provide new insights into the timing and kinematics of deformation associated with collision and escape in Central Anatolia. The SSFTB is a dominantly north-vergent contractional belt that initiated during the late Eocene and experienced several punctuated episodes of shortening and exhumation, primarily during the late Oligocene and late Miocene. Structural mapping and balanced cross-sections reveal that minimum cumulative shortening increases from west (29%) to east (34%) along the belt, along with a gradual eastward increase in fold asymmetry and a progressive transition from fold-related to overturned fold-and-thrust-related shortening. The kinematics of the central and eastern SSFTB changed from north-vergent thrusting during the late Eocene and Oligocene to predominantly south-vergent during the Miocene. Contraction in the SSFTB ended by ~7-6 Ma and was followed by a switch to distributed and kinematically linked sinistral strike-slip and normal faulting along the northeastern segment of the Central Anatolian fault zone. Offset strain markers suggest a total of at least 1.7-2.4 km of left-lateral slip on the Deliler fault and ~940 m of normal slip on the Hınzır fault. The latest Miocene to Pliocene switch to intraplate strike-slip deformation marks a regional transition to westward tectonic escape of the Anatolian microplate.

Keywords

Sivas Basin, Central Anatolian fault zone, fold-thrust belt, shortening, collision, escape

First Page

834

Last Page

859

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