内蒙古碾子沟钼矿床SHRIMP锆石U-Pb年龄、硫同位素组成及其地质意义  

SHRIMP zircon U-Pb dating and sulfur isotope compositions of Nianzigou molybdenum deposit in Inner Mongolia and their geological significance

作　　者：张作伦 刘建明[2] 曾庆栋[2] 

机构地区：[1]中铁资源集团中铁资源地质勘查有限公司,北京100039 [2]中国科学院地质与地球物理研究所矿产资源研究重点实验室,北京100029

出　　处：《矿床地质》2011年第6期1122-1128,共7页Mineral Deposits

基　　金：国家自然科学基金面上项目(40972065);国家重点基础研究项目(2006CB403507)的资助

摘　　要：内蒙古碾子沟钼矿床位于中亚-蒙古巨型造山带东段,是一中型石英脉型钼矿床,矿体赋存于燕山期中粗粒黑云母二长花岗岩内的断裂带中,矿体与岩体空间关系密切。文章对赋矿围岩和主要金属硫化物分别开展了单颗粒SHRIMP锆石U-Pb定年和硫同位素测试。获得的黑云母二长花岗岩加权平均年龄为(152.4±1.6)Ma(MSWD=0.28);8件辉钼矿δ34S值为3.50‰~6.23‰,平均为4.38‰;8件黄铁矿δ34S值为4.60‰~8.83‰,平均为5.62‰。结合相关研究成果进一步确定成矿(154.3±3.6 Ma)与黑云母二长花岗岩密切相关,成矿物质来源于岩浆,与黑云母二长花岗岩的形成过程密切相关。The Nianzigou ore deposit is a medium-size quartz vein type molybdenum deposit occurring in the Central Asian-Mongolian belt of Inner Mongolia. Its major ore bodies are a^ociated spatially with the Yanshanian medium-coarse grained biotite monzogranite. In order to investigate the relationship between mineralization and dia- genesis, the authors applied the SHRIMP dating technique to determining U-Pb ages of zircons from the biotite monzogranite. 13 analyses yielded a 2o6 pb/23s U weighted mean age of （ 152.4 ± 1.6） Ma （MSWD = 0.28 ）, which suggests that the biotite monzogranite was formed in the Late Jurassic. In addition, this age is quite close to the molybdenite Re-Os isochronic age of （154.3 ± 3.6） Ma. Sulfur isotope analyses of molybdenite and pyrite yielded 8 34S values ranging from 3.50‰ to 6.23‰, averaging 4.38‰, and from4.60‰ to 8.83‰, averaging 5.62‰, respectively. The δ34S values of the molybdenite and pyrite have characteristics of magma sulfur. Comprehensive studies indicate that the mineralization was in close relation with the diagenesis.

关 键 词：地球化学 石英脉型钼矿 SHRIMP锆石U-PB年龄 S同位素 碾子沟 内蒙古 

分 类 号：P618.65[天文地球—矿床学]