Coeval extension and compression in Late Mesozoic-Recent thin-skinned extensional tectonics in central Anatolia, Turkey
Coeval extension and compression in Late Mesozoic-Recent thin-skinned extensional tectonics in central Anatolia, Turkey
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DOI：
10.1016/j.jsg.2010.03.011
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发表时间：
2010-05-01
影响因子：
3.1
通讯作者：
Yurur, Mehmet Tekin
中科院分区：
文献类型：
--
作者：
Genc, Yurdal;Yurur, Mehmet Tekin
中央安纳托利亚地壳由高级变质岩组成，被第三系浅海-陆相沉积岩覆盖，卡帕多西亚为中中新世-近代火山活动。晚白垩世特提斯洋闭合后，板块碰撞后，在安纳托利亚中部的奈德和基尔赛希尔地区形成了核心杂岩。最近的地球物理研究表明，在安纳托利亚中部下方存在低地震速度带，解释为区域变薄和/或热地幔岩石圈，或软流圈上涌。我们给出了Konya和Yozgat之间一条类似于300公里的WSW-NNE向断面的新构造数据，表明中安纳托利亚新生代构造体制是伸展的，狭窄的褶皱/逆冲带曾被认为是重力运动导致的地壳会聚的证据。安纳托利亚中部的居里点深度图显示了一个大范围(直径140公里)的区域地壳隆起(约15公里)，我们认为这是由于软流层上涌所致。这些考虑表明：(1)中央安纳托利亚地壳通过伸展变形。像中央安纳托利亚断裂带这样的横流断裂适应了地壳通过传递断层进行的伸展：(2)晚白垩世后地壳伸展有利于热和低密度软流圈物质通过瑞利-泰勒不稳定现象解释的过程在卡帕多西亚就位；(3)在安纳托利亚中部，始新世后地壳水平大位移(我们估计至少50公里)不是通过先前提出的地壳收缩实现的，而是薄皮伸展构造；(4)特提斯缝合线需要审查，因为它们的牵引力可能会被后来的伸展位移所改变。(C)2010爱思唯尔有限公司。保留所有权利。
The central Anatolian crust is composed of high-grade metamorphic rocks covered by Tertiary shallow marine to continental sedimentary rocks, with a Middle Miocene-Recent volcanic activity in Cappadocia. After the Late Cretaceous closure of the Tethyan Ocean and following plate collision, core complexes formed in Nigde and Kirsehir regions of central Anatolia. Recent geophysical studies indicate the presence of low seismic velocity zones beneath central Anatolia, interpreted as regionally thinned and/or hot mantle lithosphere, or asthenospheric upwelling. We present new structural data covering a similar to 300 km WSW-NNE trending transect between Konya and Yozgat cities to suggest that central Anatolian Cenozoic tectonic regime is extensional and the narrow fold/thrust zones once taken as evidence of crustal convergence resulted from gravitational movements. Curie point depths map of central Anatolia shows a large-scale (diameter >140 km) upwarping (c. 15 km) of the regional crust we interpret as due to asthenospheric upwelling. These considerations suggest that (1) the central Anatolian crust deforms by extension. Transcurrent faults like the Central Anatolian Fault Zone accommodate the crustal stretching by transfer faulting: (2) post-Late Cretaceous crustal extension favored the placement of hot and low density asthenospheric material in Cappadocia by processes that may be explained by Rayleigh Taylor instability phenomenon; (3) In central Anatolia, large post-Eocene horizontal crustal displacements (we estimate a minimum of 50 km) are not achieved by crustal contraction as previously proposed but thin-skin extensional tectonics and (4) Tethyan suture lines need to be reviewed since their traces may be modified by later extensional displacements. (C) 2010 Elsevier Ltd. All rights reserved.