黑龙江省翠宏山钨钼多金属矿床辉钼矿Re-Os同位素定年及其地质意义  

Re-Os Isotopic Dating of the Molybdenite from the Cuihongshan W-Mo Polymetallic Deposit in Heilongjiang Province and Its Geological Significance

作　　者：郝宇杰[1] 任云生[1] 赵华雷[1] 邹欣桐 陈聪[1] 侯召硕[1] 屈文俊[2] 

机构地区：[1]吉林大学地球科学学院,长春130061 [2]国家地质实验测试中心,北京100037

出　　处：《吉林大学学报（地球科学版）》2013年第6期1840-1850,共11页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41272094);中国地质调查局项目(1212011085485);吉林大学研究生创新基金项目(20121075)

摘　　要：翠宏山钨钼多金属矿床是小兴安岭-张广才岭成矿带内一个重要的矽卡岩型矿床,钨、钼、锌均达大型规模。为确定该矿床的形成时代,对取自岩体内接触带钨钼矿体的7件辉钼矿样品进行了Re-Os同位素测年研究。结果表明:辉钼矿中Re质量分数为(0.376 9~0.973 7)×10-6,Os质量分数为(1.272~3.234)×10-9;获得的模式年龄为(199.0±3.1)^(203.9±3.8)Ma,加权平均年龄为(201.6±1.4)Ma(MSWD=0.80),等时线年龄为(198.9±3.7)Ma(MSWD=0.83)。结合区域成矿作用分析认为:翠宏山多金属矿床的形成时代为早侏罗世,与成矿带内的霍吉河和鹿鸣等斑岩型(细网脉型)钼矿床同属燕山早期大规模构造-岩浆-成矿事件的产物。根据本次辉钼矿Re-Os定年结果,结合前人在矿区内所测多个花岗岩体的锆石U-Pb年龄认为:与翠宏山多金属矿床具成因联系的岩体应为二长花岗岩、碱长花岗岩,成岩成矿作用与古太平洋板块俯冲有关。辉钼矿中Re质量分数、成矿岩体的物质源区综合研究表明,翠宏山多金属矿床的成岩成矿物质具有壳幔混源特征。The Cuihongshan deposit is one of important polymetallic deposits in the Lesser Xing＇an Range-Zhangguangeai Mountain polymetallic metallogenic belt. The tungsten, molybdenum and zinc resources in this deposit are over large-scale. To determine the metallogenic age of the deposit, Re - Os dating of 7 molybdenite samples from W- Mo ore bodies in the inner contact zone has been completed. The Re content in the molybdenite varies from （0. 376 9 - 0. 973 8） × 10-6 and Os content varies from （1. 272 -3. 234） ×10^-9. The model age of the molybdenite ranges from （199.0±3.1） Ma to （203.9±3.8） Ma, the weighted mean age is （201. 6＋1. 4） Ma （MSWD is 0. 80）, and the isochron age is （198.9±3. 7） Ma （MSWD is 0. 83）. Combined the isotopic dating with the regional mineralization characteristics, it＇s suggested that the Cuihongshan polymetallic deposit be formed in Early Jurassic period, contemporary with some large-scale porphyry molybdenum deposits as Huojihe and Luming in the Lesser Xing＇ an Range- Zhangguangcai Mountain metallogenic belt, and they are all resulted from the Early Yanshanian large-scale tectonic-magma-metallogenetic events. According to the molybdenite Re- Os ages and zircon U - Pb ages of some granitic rock bodies in the mine, we can conclude that the monzonite and alkali-feldspar granite were closely related to the W - Mo polymetallic mineralization. The content of Re in molybdenite minerals, together with data on material source of associated intrusion, suggests that the ore-forming materials should be derived mainly from the mixing source of the crust and the upper mantle.

关 键 词：Re—Os同位素定年 辉钼矿 金属矿床 小兴安岭-张广才岭成矿带 矽卡岩型矿床 

分 类 号：P611.1[天文地球—矿床学] P597.1[天文地球—地质学]