文献类型：期刊文献

英文题名：Deep physical structure and geotectonic implications of the eastern margin of the Qinghai-Tibet Plateau

作者：Li, Jun Wang, Xuben Qin, Qingyan Zhang, Gang Li, Dahu Zhou, Jun

第一作者：Li, Jun

通信作者：Li, J[1];Li, J[2]

机构：[1]Minist Educ, Key Lab Geodetect Informat Tech, Chengdu, Peoples R China;[2]Chengdu Univ Technol, Coll Geophys, Chengdu, Peoples R China;[3]Guizhou Inst Technol, Coll Resources & Environm Engn, Guiyang, Peoples R China;[4]Southwest Univ Sci & Technol, Sch Environm & Resource, Mianyang, Peoples R China;[5]Sichuan Earthquake Adm, Chengdu, Peoples R China

第一机构：Minist Educ, Key Lab Geodetect Informat Tech, Chengdu, Peoples R China

通信机构：corresponding author), Minist Educ, Key Lab Geodetect Informat Tech, Chengdu, Peoples R China;corresponding author), Chengdu Univ Technol, Coll Geophys, Chengdu, Peoples R China.

年份：2016

卷号：20

期号：4

起止页码：A1-A8

外文期刊名：EARTH SCIENCES RESEARCH JOURNAL

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000401074700001)】；

基金：We are grateful to Xuelin Cai and Jixin Deng for their helpful comments and constructive suggestions, while we extend our thanks to others for participating in the field work. The Chinese Bureau of Geological Survey (project 2016YFC0600308 and project 12120113095100) are acknowledged with thanks for financially supporting this work.

语种：英文

外文关键词：Eastern margin of Qinghai-Tibet Plateau; Bouguer gravity; Long period magnetotellurics; Crustal fluid; Apparent density

摘要：The eastern margin of the Qinghai-Tibet Plateau (QTP) is the focus of studies on eastward lateral extrusion of the latter's crustal material. This study aims to explore the structural response of the QTP's eastern crust-mantle to the extrusion, and the basis for the latter's geological structure. Data on the long-period magnetotelluric sounding of cross-tectonic units and Bouguer gravity were used to determine the physical structure of the crust-mantle at the plateau's eastern margin. The findings are as follows: (i) the apparent density structure indicates the large presence of a low-density material in the middle-lower crusts of the Songpan and Sichuan-Yunnan blocks at the QTP's eastern margin. On the other hand, the Yangtze cratonic block (Sichuan Basin) contains a material with a significantly higher density. To the west of the Longmenshan-Panxi tectonic zones, and along the lower crust at 40-50 km depth, is an obvious low-density zone aligned in a northeast-southwest orientation. (ii) The electrical structural model spanning Songpan block-Longmenshan tectonic zone-Yangtze block reveals three distinct electrical structural units along the cross-section bounded by the Longmenshan tectonic zone. The first is the Songpan block, which has high and low resistivity at the superficial layer and middle-lower crusts, respectively. Next is the Yangtze craton, which has a low and relatively higher resistivity at the superficial layer and middle-lower crusts, respectively. The third is the Longmenshan transitional tectonic zone, whose shallow layer and deep structure are characterized by an electrical structure with a thrust nappe towards the east, and a high-conductivity material extending to the lithospheric mantle, respectively. (iii) The apparent density and electrical structures indicate that the Panxi tectonic zone has a weakened structure in the lower crust; and (iv) physical properties of the QTP's deep structure show that its eastern margin may contain a middle-lower crustal fluid material with the attributes of high conductivity and low density. Its distribution is interrelated to the uplift mechanism and deep seismogenic activities at the QTP's eastern margin.