学术
热液锆石U-Pb定年与石英脉型金矿成矿时代：评述与展望
毕诗健[1,2,3] 李建威[2,3] 赵新福[4]
[1]中国地质大学研究生院,武汉430074 [2]中国地质大学地质过程与矿产资源国家重点实验室,武汉430074 [3]中国地质大学资源学院,武汉430074 [4]香港大学地球科学系,香港
摘 要:
石英脉型金矿床是最重要的金矿床类型之一，对其成矿时代的精确测定却一直是一道难题。近年来同位素质谱技术的发展使得通过含金石英脉中热液锆石的U-Pb定年来精确限定石英脉型金矿床成矿时代成为可能。但含金石英脉中的锆石组成通常较复杂，除有热液锆石外，还可能出现从围岩中捕获的岩浆锆石和变质锆石。锆石成因和组成的这种复杂性，经常导致所获得的U-Pb年龄数据难以解释或缺乏明确的地质意义。因此石英脉型金矿床锆石U-Pb定年的关键是有效区分从成矿流体中直接生长的热液锆石和从围岩中捕获的岩浆锆石或变质锆石。通过锆石形貌、结构、微量元素组成（含稀土元素）、矿物或流体包裹体特征等的系统分析和综合研究，可以较好地区分含金石英脉中的不同成因锆石。在此基础上利用先进的SHRIMP或LA-ICP-MS锆石U-Pb分析技术对石英脉中的热液锆石进行微区原位定年，可以获得石英脉型金矿床可靠的成矿年龄。[著者文摘]
文章出处:
《地质科技情报》-2008年27卷1期 -69-76页
栏目信息:
分 类 号:
文献标识码:
A
文章编号:
1000-7849（2008）01-0069-08
相关文章:
Hydrothermal Zircon U-Pb Dating and Geochronology of Quartz Vein-Type Gold Deposits： A Review
BI Shi-jian ,LI Jian-wei ,ZHAO Xin-fu（ Graduate School ; lb. State Key Laboratory of Geological Processes and Mineral Resources ; Faculty o.f Earth Resources, China University of Geosciences , Wuhan 430074,China; Department of Earth Sciences ,Unviersity of Hongkong , Hongkong, China）
Abstract:
Quartz vein-type gold deposit is the most important type of gold deposits in the world. However, the lack of minerals suitable for most conventional isotopic dating methods constrains the direct and precise dating. Recent development in mass spectrometry makes it possible to determine the age of auriferous quartz veins by U-Pb dating of zircons from quartz veins. Unfortunately, hydrothermal zircons that grow directly from mineralizing fluids and inherited magmatic or metamorphic zircons from wall rocks may coex- ist in the same vein. Such complexity poses significant problem while interpreting the U-Pb data. Thus, the key for zircon U-Pb dating of quartz vein-type gold deposit will be to distinguish hydrothermal zircon precipitated from ore-forming fluids from the inherited zircons. Combined studies of zircon morphology, internal texture, trace elemental geochemistry （including rare earth element）, compositions of mineral and fluid inclusions will permit identification of hydrothermal zircons, which then can be precisely dated by SHRIMP or LA-ICP-MS methods to provide reliable age constraints of quartz vein-type gold deposits.[著者文摘]
Key words:
hydrothermal zircon;quartz-vein-type gold deposit; U-Pb dating; age of ore deposit
基金资助:
国家自然科学基金创新群体基金（40521001）;中国地质大学研究生学术探索和创新基金（CUGYJS0715）;地学类研究生创新中心项目（C-0611）
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