吉林长安堡钼(铜)矿床成矿时代及物质来源：来自辉钼矿Re-Os同位素证据

Origin and Geochronology of Chang 'anpu Mo-Cu Deposit in Jilin Province: Constraints from Molybdenite Re-Os Isotope Systematics

吉林省中东部地区地处中国东北部陆缘、兴蒙造山带的东段,目前已探明大中型钼矿床十余座,矿床类型有斑岩型、矽卡岩型和石英脉型。长安堡斑岩型钼（铜）矿床是吉林中部地区新发现的一座大型斑岩型矿床,成矿年代学研究工作至今尚未开展。本文在矿床地质特征研究的基础上,对矿区辉钼矿进行了Re-Os同位素体系的定年研究,获得辉钼矿模式年龄值为167.3±2.4-168.7±2.4 Ma,加权平均值为168.0±1.0 Ma（MSWD=0.16）,等时线年龄为168.0±6.2 Ma（MSWD=0.42）,表明长安堡钼（铜）矿床形成于中侏罗世,属中国北方燕山期大规模钼成矿期成矿,结合已发表的钼矿床高精度年代学数据,认为吉林中东部地区的钼成矿作用发生在早-中侏罗世（167-196 Ma）。矿区辉钼矿的Re含量介于25.17-34.80μg/g,平均值为29.54μg/g,指示了成矿物质具有壳幔混源、且更偏壳源特征,为准确认识该矿床的成矿物质来源提供了进一步的制约。这些成果对于研究吉林地区钼矿资源的成矿规律提供了科学依据。

The east-central part of Jilin Province, located on the continental margin of northeast China along the eastern Xing-Meng orogenic belt, hosts more than 10 large- and medium-scale Mo deposits. The major types of mineralization include porphyry, skarn, and quartz vein types. The Chang？ anpu Mo-Cu deposit is a newly discovered large-scale porphyry deposit in central Jilin Province ; the age of mineralization is unknown. The geological characteristics of the deposit were investigated and molybdenite Re- Os isotope dating was applied, to constrain the age of mineralization. The molybdenite Re-Os model ages range from 167.3 ±2.4 to 168.7 ±2.4 Ma with a weighted mean model age of 168. 0 ± 1. 0 Ma. The isochron age is 168. 0 ± 6. 2 Ma, which indicates that the Chang ’ anpu Mo-Cu deposit was formed in the Middle Jurassic, belonging to the large-scale Yanshanian molybdenum metallogenic period of North China. The Re content of the molybdenite varies from 25. 17 to 34. 80 μg/g, suggesting that the ore-forming materials may come from a crust-mantle mixed source and mainly from the crustal source. Combining published molybdenite Re-Os and zircon U-Pb ages in east-central Jilin Province, suggests that the Mo mineralization occurred in the Early-Middle Jurassic （ 167 - 196 Ma） , thereby providing a scientific basis for Moresources prospecting in Jilin.