广东鹦鹉岭多金属矿床辉钼矿的Re-Os同位素定年及其意义  

Re-Os ISOTOPIC DATING OF MOLYBDENITES FROM THE YINGWULING POLYMETALLIC DEPOSIT IN GUANGDONG PROVINCE AND ITS GEOLOGICAL SIGNIFICANCE

作　　者：郑伟[1] 赵海杰[2] 陈懋弘[2] 徐林刚[2] 刘建新 罗大略 胡耀国 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [2]中国地质科学院矿产资源研究所,北京100037 [3]广东省地质建设工程集团公司,广东广州510080 [4]广东省地质调查院,广东广州510080

出　　处：《矿物岩石》2013年第3期38-46,共9页Mineralogy and Petrology

基　　金：国家自然科学基金项目(No.40930419);中国地质调查局地质调查工作项目(1212011120831);国家重点基础研究发题(2012CB416704)

摘　　要：通过对鹦鹉岭铜多金属矿床6件辉钼矿样品的Re-Os同位素定年,获得的模式年龄为82.96Ma～84.75Ma。其中1件矽卡岩型矿石中辉钼矿的187 Re-187 Os模式年龄为82.96Ma±1.2Ma,5件石英脉型矿石中辉钼矿的187 Re-187 Os模式年龄为83.78 Ma～84.75Ma,加权平均值为84.08 Ma±0.54 Ma,对应的等时线年龄为83.0 Ma±1.7 Ma,模式年龄和等时线年龄结果在误差范围内基本一致,指示鹦鹉岭多金属矿床的成矿时限为82.96Ma～84.75Ma,即形成于晚白垩世。鹦鹉岭矿床辉钼矿样品的Re含量较低,表明其成矿物质主要来自于壳源。该矿床形成于燕山晚期岩石圈伸展减薄环境。Six molybdenite samples are selected from the Yingwuling copper polymetallic deposit to perform the Re-Os dating. It yielded weighted average model ages of 82.96 Ma to 84. 75 Ma, with a narrow range variation. It was showed that the Re-Os dating of one sample collected from skarn-type ore yielded a model age of 82.96 Ma±1. 2 Ma,and five molybdenite samples collected from quartz-vein-type ore yielded model ages ranging from 83.78 Ma to 84. 75 Ma,with an aver- age of 84.08 Ma±0. 54 Ma,and give an isochron age of 83.0 Mail. 7 Ma. Evidently, model ages are compatible with isochron age in the error within the allowable range, so it constrains the abso- lute age of Yingwuling copper polymetallic deposit in 82.96 Ma±84.75 Ma,namely,the Late Cre- taceous is the main time for the formation of ore. The molybdenites from Yingwuling copper poly- metallic deposit have a low content of Re,indicating a crustal source for ore-forming materials. It was considered that the deposit formed in the Late Yanshanian lithospheric extensional and thinning environment.

关 键 词：RE-OS同位素定年 辉钼矿 鹦鹉岭多金属矿床 燕山晚期 广东 

分 类 号：P578.291[天文地球—矿物学] P597.3[天文地球—地质学]