华东地质2026，Vol.47Issue(2)：247-265,19.DOI:10.16788/j.hddz.32-1865/P.2024.12.020
江南造山带的形成与演化:来自新元古代南桥辉绿岩的证据
Formation and tectonic evolution of the Jiangnan Orogen:evidence from the Neoproterozoic Nanqiao diabase
摘要
Abstract
The Jiangnan Orogen,situated on the southeastern margin of the Yangtze Block,represents the tectonic suture zone between the Yangtze Block and Cathaysia Block.The formation and evolution of this oro-genic belt remain significant research topics.This study presents LA-ICP-MS zircon U-Pb dating and petro-geo-chemical analyses of the Nanqiao diabase from the central Jiangnan Orogen,to investigate their petrogenesis and tectonic evolution implications.LA-ICP-MS zircon U-Pb dating indicates the Nanqiao diabase formed at ca.(839±7)Ma.The diabase exhibits low SiO2 content(48.4%-52.0%),relatively high MgO contents(6.96%-9.12%)and high Mg#values(70.3-79.1),and characteristic of tholeiitic series.Most samples demonstrate light rare earth element(LREE)depletion without significant Eu anomalies,while some samples display LREE enrichment with pronounced negative Eu anomalies.The rocks show enrichment in highly incompatible elements such as Rb and Th but depletion in moderately incompatible elements including Nb,Ta,Zr,Hf,and Ti.Geochemical analysis suggests that the Nanqiao diabase originated from decompression-induced upwelling of mantle material at rela-tively shallow depths(＜85 km),potentially associated with extension of a back-arc setting during subduction along the southeastern margin of the Yangtze Block.Integration with previous researches indicate a trench-arc-basin system developed along the southeastern margin of the Yangtze Block between 850 Ma and 820 Ma.The amalgamation between the Yangtze Block and the Cathaysia Block occurred at around 820-800 Ma.关键词
新元古代/江南造山带/南桥辉绿岩/岩石成因/构造演化Key words
Neoproterozoic/Jiangnan Orogen/Nanqiao diabase/petrogenesis/tectonic evolution分类
天文与地球科学引用本文复制引用
黄思访,贺振,罗亚萍,于芳,李洁,朱新玉,薛尔堃..江南造山带的形成与演化:来自新元古代南桥辉绿岩的证据[J].华东地质,2026,47(2):247-265,19.基金项目
河南省自然科学基金"皖南新元古代蛇绿岩中花岗岩脉成因及其对俯冲沉积物再循环的指示(编号:242300421663)"项目资助. （编号:242300421663）
