Late Mesozoic Tectono-stratigraphic evolution of the Hekimhan Basin and the environs (central eastern Anatolia): implications for the eastern Taurides and Gürün Curl

The east-west trending Taurides form a curved area in central eastern Anatolia known as the Gürün Curl. In order to understand the origin of the Gürün Curl and Tauride evolution in general, the results of a new field study of this region have been synthesized together with previously published data. We suggest that the geodynamic evolution of the area began with the likely presence of a Tethys Ocean transform fault. This fault separated the Taurides into the Akdere Sector in the west and the Munzur Sector in the east in the Late Cretaceous. During the late Santonian–early Campanian, ophiolites obducted onto the Munzur Sector, while platform sediments continued to accumulate in the Akdere Sector. This was followed by the development of an Andean-type arc-type magmatism (the Baskil Arc) during the early–middle Campanian in the Munzur Sector. Continued closure of the Tethys led to the collision of the Bitlis Massif in the south of the Munzur Sector in the Campanian. This, in turn, resulted in continental subduction and slab roll-back that was controlled by a Subduction Transform Edge Propagator (STEP) Fault that lay on the original transform fault between the Akdere and Munzur sectors. Because the subducted slab was free at its western corner, the western edge rolled back faster than in the east, leading to an asymmetrical extensional regime on the upper plate that created the late Campanian Hekimhan Basin. While these geodynamic events were taking place in the Munzur Sector, the Akdere Sector was in a platform setting. During the Palaeocene, the Late Mesozoic units of the Akdere Sector began to overthrust on the Hekimhan Basin and the ophiolites. Following the Palaeocene, all these tectonostratigraphic units were covered by Eocene sediments around the Gürün Curl of which the modern appearance was completed by the Miocene to Recent movements along the strike-slip faults.

呈东西走向的陶里德造山带（Taurides）在安纳托利亚中东部形成一处被称为居伦弧（Gürün Curl）的弯曲构造区域。为阐明居伦弧的成因及陶里德造山带的整体演化历程，本研究整合了该区域最新野外调查成果与已公开发表的相关数据。研究认为，该区域的地球动力学演化始于特提斯洋（Tethys Ocean）转换断层的存在。晚白垩世时期，该断层将陶里德造山带分为西部的阿克代尔分区（Akdere Sector）与东部的蒙祖尔分区（Munzur Sector）。桑托期晚期-坎潘期早期，蛇绿岩套（ophiolites）仰冲到蒙祖尔分区之上，而阿克代尔分区则持续发育台地沉积。随后在坎潘期早-中期，蒙祖尔分区发育了安第斯型弧岩浆作用（Andean-type arc magmatism）——巴斯吉尔弧（Baskil Arc）。坎潘期，特提斯洋持续俯冲闭合，导致位于蒙祖尔分区南部的比特利斯地体（Bitlis Massif）发生碰撞。此次碰撞进而引发了大陆俯冲与板片回撤（slab roll-back），该过程受位于阿克代尔分区与蒙祖尔分区之间原转换断层之上的俯冲转换边缘传播断层（Subduction Transform Edge Propagator，STEP Fault）所控制。由于俯冲板片的西端处于自由状态，其西侧的回撤速度快于东侧，进而在上盘形成不对称伸展环境，造就了坎潘期晚期的赫基姆汉盆地（Hekimhan Basin）。当蒙祖尔分区发生上述地球动力学事件时，阿克代尔分区仍处于台地构造环境。古新世（Palaeocene）时期，阿克代尔分区的晚中生代地层开始向赫基姆汉盆地与蛇绿岩套之上逆冲推覆。古新世之后，居伦弧周边的所有构造地层单元（tectonostratigraphic units）均被始新世（Eocene）沉积地层覆盖；现今的构造格局则是在中新世（Miocene）至现代沿走滑断层（strike-slip faults）的活动作用下最终定型的。