大颗粒辉钼矿Re-Os同位素失耦现象及^(187)Os迁移模式研究  

Decoupling of Re and Os and migration model of ^(187)Os in coarse-grained molybdenite

作　　者：李超[1] 屈文俊[1] 杜安道[1] 

机构地区：[1]国家地质实验测试中心,北京100037

出　　处：《矿床地质》2009年第5期707-712,共6页Mineral Deposits

基　　金：国家科技支撑计划"南岭地区有色-贵重金属综合勘查技术研究"课题(2006BAB01B03);中国地质大调查"我国重要矿产和区域成矿规律研究"项目(1212010633903);"中国成矿体系综合研究"项目(1212010634002);"我国西部重要成矿区带矿产资源潜力评估"项目(编号200420190004)的联合资助

摘　　要：对采自西华山钨矿的大颗粒辉钼矿样品的不同部位进行了取样,并对其年龄分别进行精确厘定,得到了不同的Re-Os模式年龄值,验证了失耦现象的存在。从原理上对失耦现象及其成因进行了解释,并在前人成果的基础上,探索性地提出了187Os可能的迁移模型。取样方式的不同会对辉钼矿的模式年龄产生很大影响,因此,在实际应用中一定要严格遵循"多取样,细磨碎"的原则,这对于能获得科学真实的与地质背景相符的Re-Os同位素地质年龄,从而深入探讨矿床成矿作用具有重要意义。Different parts of coarse-grained molybdenite from the Xihuashan tungsten deposit were sampled and dated, which yielded different Re-Os apparent ages and hence confirmed the decoupling of Re and 187Os within molybdenite. The decoupling phenomenon and its cause were explained, and a tentative migration model of 187Os within coarse-grained molybdenite was established. The results show that the difference in sampling methods might exert remarkable influence on the Re-Os apparent age. In order to reduce the influence of decoupling on Re-Os dating, more molybdenite samples should be collected, and the samples should be ground into homogeneous powder （200 meshes）. Only in this way can scientific and accurate Re-Os ages be obtained.

关 键 词：地球化学 RE-OS年龄 失耦现象 迁移模式 辉钼矿 钨矿床 西华山 

分 类 号：P597.1[天文地球—地球化学]