The Influence of the Closure of the East Paleo-Tethys Ocean on Southern South China:Evidences from Kinematics and^(40)Ar/^(39)Ar Geochronology of the Rongxian Ductile Shear Zone in Southeastern Guangxi  

作　　者：HUANG Wenqiang LI Saisai XIN Liangwei FENG Zuohai ZHANG Hongrui GENG Jieli LIU Kun SHI Chunyan 

机构地区：[1]Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources by the Province and Ministry,Guilin University of Technology,Guilin,Guangxi 541004,China [2]College of Earth Sciences,Guilin University of Technology,Guilin,Guangxi 541004,China [3]Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China [4]College of Tourism and Landscape Architecture,Guilin University of Technology,Guilin,Guangxi 541004,China

出　　处：《Acta Geologica Sinica(English Edition)》2024年第5期1125-1140,共16页地质学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.42262026,42072259).

摘　　要：The Triassic was a crucial period in the tectonic evolution of the South China Block.Research on tectonic deformation during this period provides information on intracontinental orogenic mechanisms in South China.In this study,alongside thermochronological analyses,we examine the macroscopic and microscopic structural features of the Rongxian ductile shear zone,located south of the Darongshan granite in the southeastern part of Guangxi Province,on the southern margin of South China.Sinistral shear is indicated by the characteristics of rotatedσ-type feldspar porphyroclasts,stretching lineations defined by elongated quartz grains and the orientations of quartz c-axes.LA-ICP-MS U-Pb dating of zircons from two samples of granitic mylonite and one of granite yielded ages of ca.256 Ma.Furthermore,two samples of granitic mylonite yield muscovite^(40)Ar/^(39)Ar plateau ages of 249-246 Ma.These results indicate that the Rongxian ductile shear zone resulted from Early Triassic deformation of the late Permian Darongshan granite.This deformation was likely related to the closure of the eastern Paleo-Tethys Ocean and the subsequent collision of the South China and Indochina blocks,during the early stage of the Indosinian orogeny.

关 键 词：ductile shear zone ^(40)Ar/^(39)Ar geochronology TRIASSIC South China Block East Paleo-Tethys Ocean 

分 类 号：P534.51[天文地球—古生物学与地层学] P542[天文地球—地质学] P597.3