The deep background of large-scale,Mesozoic Cu-Au-W metallogenesis in northeastern South China:Constraints from Yingshan-Changshan wide-angle seismic reflection/refraction data  

作　　者：Jue HOU Tao XU Qingtian LV Zhiming BAI Yongqian ZHANG Zhiyu ZHANG Dan YANG 

机构地区：[1]State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [2]China Academy of Geological Sciences,Beijing 100037,China [3]Institute of Geophysics,China Earthquake Administration,Beijing 100081,China [4]Universityof Chinese Academy of Sciences,Bejing 100049,China [5]Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing 100029,China [6]Institute of Geology,China Academy of Geological Sciences,Beijing 100037,China [7]Institute of Mineral Resources,China Academy of Geological Sciences,Beijing 100037,China

出　　处：《Science China Earth Sciences》2022年第11期2202-2218,共17页中国科学（地球科学英文版）

基　　金：supported by the National Key R&D Program of China(Grant Nos.2019YFA0708602,2019YFA0708603,and 2016YFC0600201);the National Natural Science Foundation of China(Grant Nos.42130807,42074099);the China Geological Survey(Grant No.1212011220243)。

摘　　要：To investigate the geodynamic processes of Mesozoic large-scale mineralization in South China,we deployed a 350-km-long,wide-angle seismic reflection/refraction sounding profile between Yingshan in Hubei and Changshan in Zhejiang.This profile traverses the Cu-Au metallogenic belt in the middle and lower reaches of the Yangtze River(YMB),the Jiangnan W-polymetal metallogenic belt(JNMB),and the Qinhang Cu-polymetal metallogenic belt(QHMB).Our imaging results reveal various interesting velocity features along the profile.(1)The velocity structure is characterized by vertical layering and horizontal blocking;(2)the YMB is marked by high velocity and high V_(p)/V_(s) ratios in general with a significantly uplifted Moho interface and a thin crust of~31 km,and the lower crust contains high-velocity anomalies and has the characteristics of a crustmantle transition zone;(3)the JNMB is bounded by the Jiangnan fault and Jingdezhen-Huangshan fault and has low-velocity anomalies and low V_(p)/V_(s) ratios;and(4)the QHMB is characterized by high-velocity anomalies and high V_(p)/V_(s) ratios.The highvelocity anomalies in the YMB and QHMB represent relatively Cu-Au-rich mafic juvenile lower crust.The formation of this kind of crust is considered to be related to mantle-derived magma underplating or residues of Neoproterozoic oceanic crustal materials,and it also provided sources for large-scale Cu-Au mineralization in the Mesozoic.The JNMB has features similar to those of ancient crusts enriched in W-Sn,the partial melting of which played a leading role in the formation of the superlarge W deposits in this belt.Considering these results and other regional geological data,we propose that a large-scale oblique upwelling of the asthenosphere along the collisional belt of the Yangtze and Cathaysia blocks during the Mesozoic was the deep driving mechanism for the explosive mineralization of Cu,Au,and W in northeastern South China.The boundaries of the blocks or terrains and discontinuities of the lithosphere were the main channels f

关 键 词：Northeastern South China Metallogenic belt of the middle and lower reaches of the Yangtze River Wide-angle seismic reflection/refraction Yingshan-Changshan seismic profile Crustal velocity structure 

分 类 号：P618.2[天文地球—矿床学] P631.4[天文地球—地质学]