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STT-01 General contributions to tectonics and structural geology
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Cenozoic basin-range coupling of northwestern margin of the Tibetan plateau
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Jialiang Si, Key Laboratory for Continental Dynamics of MLR, Institute of Geology, Chinese Academy of Geological Sciences (China)
Haibing Li, Key Laboratory for Continental Dynamics of MLR, Institute of Geology, Chinese Academy of Geological Sciences (China)
Zhiming Sun, Key Laboratory of Crust Deformation and Processes, Institute of Geomechanics, Chinese Academy of Geological sciences (China)
Junling Pei, Key Laboratory of Crust Deformation and Processes, Institute of Geomechanics, Chinese Academy of Geological Sciences (China)
Jiawei Pan, Key Laboratory for Continental Dynamics of MLR, Institute of Geology, Chinese Academy of Geological Sciences (China)
Van Der Woerd Jerome, Institut de Physique du Globe de Strasbourg EOST (France)
Zhuli Qiu, Key Laboratory for Continental Dynamics of MLR, Institute of Geology, Chinese Academy of Geological Sciences (China)
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After the collision, the ongoing penetration of India plate into Eurasia plate produced intense northward squeezing and significantly affected the northwestern margin of the Tibetan plateau. The West Kunlun Mountain and Tianshan Mountain uplifted enormously; a series of drag folds and thrust folds developed in the front parts with the principal compressive stress from south to north according to joint statistics. In surrounding areas of the Tarim Basin like Sangzhu, the underthrusting of the basin beneath the mountains making the Paleozoic thrust over the Meso-Cenozoic strata as tectonic slices. Tarim Basin subsided significantly, wholly extruded eastward and developed the huge Cenozoic depression. The height difference between basin and mountains increased rapidly and the molasse accumulated up to several thousand meters in piedmont. According to several sections along the north margin of the West Kunlun Mountain, including Kekeya in Yecheng County, Keliyang, Sangzhu and Duwa in Pishan County, the molasse was mainly composed of sedimentary rocks at the bottom and of volcanic and metamorphic rocks at the top, indicating the accelerating of denudation. Both volume and intensity of deduction have decreased and weakened from west to east, indicating the possible easterly transitional evolution of tectonic uplift of the West Kunlun Mountain during late Cenozoic.
The foredeep of Southwest Tarim foreland basin broke and merged into the West Kunlun Mountain, Markit slope and Tazhong-Bachu frontal uplift zone survived, Selibuya-Marzartag fault as the boundary. Marzartag structural belt extends about 140km from west to east in NWW direction. The Paleogene strata of Mazartag section including gypsolith outcropped in the bottom, the younger purple red sandstone, siltstone and interlaid argillite all considerably folded. The Quaternary lacustrine sediments also developed significant deformation and back-thrusting features. It may be deduced that the convergence of India plate and Eurasia plate affected the northwestern margin of the Tibetan plateau so much that had spread to the hinterland of the Tarim Basin and continued into the late Quaternary.
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