Abstract

DENG, Dejie; WANG, Changliu  and  PENG, Peihao. Basic Characteristics and Evolution of Geological Structures in the Eastern Margin of the Qinghai-Tibet Plateau. Earth Sci. Res. J. [online]. 2019, vol.23, n.4, pp.283-291.  Epub Apr 20, 2020. ISSN 1794-6190.  https://doi.org/10.15446/esrj.v23n4.84000.

Based on field geological survey and stratigraphic profile survey in the eastern margin of the Qinghai-Tibet Plateau, the basic characteristics and evolution of geological structure in the eastern margin of the Qinghai-Tibet Plateau are studied. The Dongyuan area of the Qinghai-Tibet Plateau is divided into the late Cenozoic period and the current period. During the Late Cenozoic, the Pliocene Xigeda lacustrine deposits develops from 4.2 MaBP to 2.6 MaBP, with 9 cold-warm climate change stages. There are 4.3 MaBP old glacial period in this area, and 5 extreme paleoclimate events in Quaternary. At present, the horizontal movement intensity and mode of different tectonic zones are determined by the northward extrusion, eastward extrusion and rotation around the eastern tectonic junction in the study area, and the stages of the movement state changing with time are related to the gestation and occurrence of extra-large earthquakes. At present, the three-dimensional crustal movement shows that the tectonic activity differentiation of mountain and basin, which is related to tectonic dynamic environment and deep material activity, is related to the compression, shortening and uplift of plateau mountain and the extension and subsidence of basin, reflecting the inheritance of neotectonic activity. Through practical analysis, it is found that the eastern margin of the Qinghai-Tibet Plateau is composed of Minshan fault block and Longmenshan structural belt. The left-lateral dislocation of Minjiang fault is roughly the same as the vertical dislocation. In Longmenshan tectonic belt, the right-lateral dislocation of Maowen-Wenchuan fault, Beichuan-Yingxiu fault and other main faults is the same as the vertical dislocation.

Keywords : Qinghai-Tibet Plateau; Eastern margin area; Geological structure; Basic characteristics; Evolution research; Crustal movement.

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