云开地块东南缘永宁韧性剪切带年代学及其对金成矿的控制:来自白云母40Ar-39Ar年龄约束  

40Ar/39Ar Geochronology of the Yongning Ductile Shear Zone in the Southeastern Margin of Yunkai Terrain,Yangchun,Guangdong

作　　者：李出安 庄文明 林振文 周岱 LI Chu-An;ZHUANG Wen-Ming;LIN Zhen-Wen;ZHOU Dai(Guangdong Marine Geological Survey,Guangzhou 510080,Guangdong,China;Wuhan Center of China Geological Survey(Central South China Innovation Center for Geosciences),Wuhan 430205,Hubei,China)

机构地区：[1]广东省海洋地质调查院,广东广州510080 [2]中国地质调查局武汉地质调查中心(中南地质科技创新中心),湖北武汉430205

出　　处：《华南地质》2022年第3期542-549,共8页South China Geology

基　　金：中国地质调查局项目(12120113012700);国家自然科学基金项目(41772019)。

摘　　要：吴川-四会断裂带内的永宁韧性剪切带是云开地块的东南边界,查明该剪切带形成时代对于研究区域地质演化及韧性剪切带型金矿成因具有重大意义。构造运动学特征分析表明,永宁韧性剪切带具有左行逆冲剪切的特征。本文通过对永宁韧性剪切带糜棱岩中的白云母开展单矿物^(40)Ar-^(39)Ar定年,获得坪年龄为227.38~232.77Ma,等时线年龄为229.94~232.47Ma,表明永宁韧性剪切带形成于晚三叠世早期,为印支期第一阶段活动的产物,多期活动的北东向剪切带在空间上直接或间接控制了银金矿床的分布。The Yongning ductile shear zone within the Wuchuan-Sihui fault zone is the southeastern boundary of the Yunkai Massif,and the determination of the age of the formation of this shear zone is of great significance to the study of regional geological evolution and the genesis of ductile shear zone type gold deposits.Tectonic kinematic characterization indicates that the Yongning ductile shear zone is characterised by left-slip thrusting shear.In this paper,we carried out the^(40)Ar-^(39)Ar dating on single mica grains from the Yongning ductile shear zone,and obtained the plateau ages of 227.38~232.77 Ma and the isochron ages of 229.94~232.47 Ma,indicating that the Yongning ductile shear zone was formed in the early Late Triassic and was a product of the first stage of Indosinian event.The multi-stage active NE shear zone controlled the distribution of Ag-Au deposits directly or indirectly.

关 键 词：云开地块 吴川-四会断裂带 永宁韧性剪切带 左行走滑 白云母40Ar-39Ar测年 印支运动 

分 类 号：P597[天文地球—地球化学] P618.51[天文地球—地质学]