内蒙古赤峰鸭鸡山钼(铜)矿床辉钼矿Re-Os年龄及其地质意义  

Re-Os isotope dating of molybdenite separates from the Yajishan Mo (Cu) deposit,Inner Mongolia,and its geological significance

作　　者：代军治[1,2] 谢桂青[2] 王瑞廷 任涛 王涛 

机构地区：[1]西北有色地质勘查局,陕西西安710054 [2]中国地质科学院矿产资源研究所,北京100037

出　　处：《中国地质》2012年第6期1614-1621,共8页Geology in China

基　　金：中国地质调查局地质大调查项目(1212010634001);"十二五"国家科技支撑计划课题(2011BAB04B05);公益性行业科研专项(201111007-3)联合资助

摘　　要：鸭鸡山钼(铜)矿床位于华北板块北缘西拉木伦钼铜成矿带南部,矿体受区内EW向和NE向走滑断裂控制,主要呈脉状或碎裂岩型赋存于二长花岗岩中,属石英脉型钼矿床。金属矿物主要是辉钼矿、黄铁矿和黄铜矿。运用Re-Os同位素定年法对该矿床辉钼矿进行年龄测试,测得7件不同类型辉钼矿样品的模式年龄加权平均年龄为(241.1±1.4)Ma,6件同类型样品等时线年龄为(240±3.8)Ma,表明成矿作用比较集中,成矿时间为早—中三叠世。结合鸭鸡山钼矿床辉钼矿、黄铜矿呈脉状、浸染状分布于二长花岗岩体中的特征,及前人已有的晚期蚀变年龄,作者认为赋矿二长花岗岩的形成时间为早—中三叠世。结合前人对区域上三叠纪构造岩浆作用的分析,认为鸭鸡山钼(铜)矿床的形成与古亚洲洋的闭合有关。The Yajishan Mo（Cu） deposit is located in southern Xilamulun Mo（Cu） metallogenic belt on the northern margin of North China block,which is one of the largest Mo metallogenic belts in China.Its major ore bodies occur in the vein like or cataclastic form in the monzonitic granite,strictly controlled by EW-and NE-striking faults.The deposit is obviously of the quartz vein type,and the sulfides in ore veins are dominated by molybdenite,pyrite and chalcopyrite and show veined and disseminated forms in the monzonitic granite.The authors carried out molybdenite Re-Os dating to better understand the mineralization time.Re-Os dating of seven different types of molybdenite separates from the major Mo mineralized bodies gave a weighted average model age of 241.1±1.4 Ma,and six samples of the same type yielded isochron age of（240±3.8） Ma.The Re-Os isochron age represents the ore-forming time of the Mo（Cu） deposit and constrains the age of the monzonitic granite to Early-Middle Triassic.This result not only provides new evidence for the study of molybdenum deposits in the Xilamulun Mo（Cu） metallogenic belt but also has important significance for discussing the large-scale mineralization in Early-Middle Triassic on the northern margin of North China block.The corresponding geodynamic background was the closure of the Paleo-Asian Ocean.

关 键 词：鸭鸡山钼(铜)矿 辉钼矿 RE-OS同位素 成矿年龄 

分 类 号：P597.3[天文地球—地球化学]