Anisotropy of magnetic fabrics of the Late Cenozoic sedimentary succession in the southern West Tianshan Mountain and their tectonic implications

被引：0
|
作者：
Chen X. [1 ,2 ,3 ]
Chen H. [2 ,3 ]
Lin X. [2 ,3 ]
Cheng X. [2 ,3 ]
Nie M. [1 ]
机构：
[1] Key Laboratory of Tectonic Controls on Mineralization and Hydrocarbon Accumulation of Ministry of Land and Resource, School of Earth Sciences, Chengdu University of Technology, Chengdu
[2] School of Earth Sciences, Zhejiang University, Hangzhou
[3] Research Center for Structures in Oil- and Gas-Bearing Basins, Ministry of Education, Hangzhou
来源：
Dizhi Xuebao/Acta Geologica Sinica | 2020年 / 94卷 / 06期
关键词：
Kashi depression; Late Cenozoic; Magnetic fabrics; Southern West Tianshan Mountain; Talas Fergana fault;
D O I：
10.19762/j.cnki.dizhixuebao.2020082
中图分类号：
学科分类号：
摘要：
The western part of Kashi Depression lies in the conjunction area of the Tarim Basin, the Pamir Syntax, and the south West Tian Shan. The thick sediments accumulated in this depression were derived from and preserve a record of late Cenozoic tectonic uplift of the south West Tian Shan. This paper presents results of anisotropy of magnetic susceptibility (AMS) analysis of the late Cenozoic Tierekesazi section in the foreland of the south West Tian Shan. The late Cenozoic successions of the Tierekesazi section are continental sediments with a general upward increase in particle size and show a progressive change from fluvial-lacustrine facies to fan delta facies, alluvial fan facies and diluvial fan facies. Rock magnetic results of the late Cenozoic successions indicate that the magnetic minerals are mainly hematite, except for the lower Pakabulake Formation, which is dominated by magnetite. Results of the late Cenozoic AMS suggest a syn-sedimentary fabric with weak-deformation. Since 22.1 Ma directions of tectonic strain in the foreland of the south West Tian Shan are mainly N-S directed compressional stress, which is consistent with the continuous convergence of the Pamir and the south West Tian Shan in the late Cenozoic. At the time of deposition of the Anjuan Formation and the Xiyu Formation, directions of compressional strain changed from N-S directed to NNE-SSW directed, likely reflecting the activities of the Talas-Fergana fault. Right slip of the Talas-Fergana fault (TFF) might absorb part of the deformation amount of the south West Tian Shan in the late Cenozoic, leading to smaller deformation in the foreland of the southern West Tian Shan than in the foreland area of the South Tian Shan in the east of the TFF. As a result, late Cenozoic foreland thrustings in the area east of the TFF were more active and better developed than in the foreland area west of the TFF. © 2020, Science Press. All right reserved.
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页码：1675 / 1688
页数：13
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