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岩石学报 2011
The transformation of the terrain structures of the Tibet Plateau through large-scale strike-slip faults.
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Abstract:
There are about 13 large-scale strike-slip faults present in the Qinghai-Tibet Plateau and its adjacent area, which were mainly formed during three periods: the Early Paleozoic, the Triassic and the Cenozoic. The large-scale strike-slip faults that formed since the collision between the Indian block and the Asian plate (60~50Ma ago) are mainly located along both sides of the eastern and western Himalayan syntaxes, such as the Karakurom and the Chaman right-lateral strike-slip faults to the west and the Xianshuihe-Xiaojiang, the Jingshajiang-Ailaoshan-Red River and the Chongshang-Langchuangjiang left-lateral strike-slip faults, as well as the Jiali-Gaoligong and Sangaing right-lateral faults to the east. Their main deformations show an early ductile strike-slip shearing in the deep crust, followed by the transformation of ductile to ductile/brittle to brittle deformations during uplift process. However, in northern Tibet, it is shown as the reactivation of old strike-slip shear zones or suture zones such as the Altyn Tagh, Karakax shear zones and the East Kunlun suture zone, as well as the occurrence of the new brittle fault (e.g. the Haiyuan fault). In this paper, we will explain the characteristics of large-scale strike-slip faults formed during different geological periods and their roles on terrain amalgamation and collision orogeny within the Tibetan plateau, including "strike-slip" type folded orogeny, "transpression" type orogeny, "compression" type basin and range system, as well as relative displacement and lateral extrusion of terrains.