Three-dimensional P-wave Velocity Structure Modelling of the Middle and Lower Reaches of the Yangtze River Metallogenic Belt: Crustal Architecture and Metallogenic Implications

作     者：CHEN Anguo LÜ Qingtian ZHOU Taofa DU Jianguo DING Juan YAN Jiayong LU Zhitang CHEN Anguo;Lü Qingtian;ZHOU Taofa;DU Jianguo;DING Juan;YAN Jiayong;LU Zhitang

作者机构：School of Resources and Environmental EngineeringHefei University of TechnologyHefei 230009China Geological Survey of Anhui ProvinceHefei 230001China Chinese Deep Exploration Center(SinoProbe Center)Chinese Academy of Geological SciencesBeijing 100037China Anhui Earthquake AgencyHefei 230031China 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2020年第94卷第6期

页      面：1808-1821页

核心收录：

学科分类：081801[工学-矿产普查与勘探] 081802[工学-地球探测与信息技术] 081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：funded by grants from the Key Project of the National Natural Science Foundation of China(No.41630320) the National Key Research and Development Program of China(No.2016YFC0600200) the Hefei Postdoctoral Science Foundation 

主　　题：3D P-wave velocity structure double-difference seismic tomography crust-upper mantle Dabie Orogen Middle and Lower Reaches of the Yangtze River Metallogenic Belt 

摘      要：In this study,we compiled and analyzed 69310 P-wave travel-time data from 6639 earthquake *** events(M≥2.0)occurred from 1980 s to June 2019 and were recorded at 319 seismic stations(Chinese Earthquake Networks Center)in the study *** adopted the double-difference seismic tomographic method(tomo DD)to invert the 3-D P-wave velocity structure and constrain the crust-upper mantle architecture of the Middle and Lower Reaches of the Yangtze River Metallogenic Belt(MLYB).A 1-D initial model extracted from wide-angle seismic profiles was used in the seismic tomography,which greatly reduced the inversion *** results indicate that reliable velocity structure of th e uppermost mantle can be obtained when Pn is involved in the *** results show that:(1)the pattern of the uppermost mantle velocity structure corresponds well with the geological partitioning:a nearly E-W-trending low-velocity zone is present beneath the Dabie Orogen,in contrast to the mainly NE-trending low-velocity anomalies beneath the Jiangnan *** suggest the presence of thickened lower crust beneath the orogens in the study *** contrast,the Yangtze and Cathaysia blocks are characterized by relatively high-velocity anomalies;(2)both the ultra-high-pressure(UHP)metamorphic rocks in the Dabie Orogen and the low-pressure metamorphic rocks in the Zhangbaling dome are characterized by high-velocity *** upper crust in the Dabie Orogen is characterized by a low-velocity belt,sandwiched between two high velocity zones in a horizontal direction,with discontinuous low-velocity layers in the middle *** keel of the Dabie Orogen is mainly preserved beneath its northern *** infer that the lower crustal delamination may have mainly occurred in the southern Dabie Orogen,which caused the mantle upwelling responsible for the formation of the granitic magmas emplaced in the middle crust as the low-velocity layers observed *** deep-level compression