大兴安岭北段小柯勒河铜钼矿床硫化物Re-Os年龄及其地质意义  

Re-Os Isotopic Dating of Sulfides from the Xiaokelehe Cu-Mo Deposit in the Northern Part of the Great Xing’an Range,NE China,and its Geological Implications

作　　者：冯雨周 邓昌州 陈华勇[1] 李光辉 肖兵[1,2] 李如操 时慧琳 FENG Yuzhou;DENG Changzhou;CHEN Huayong;LI Guanghui;XIAO Bing;LI Rucao;SHI Huilin(CAS Key Laboratory of Mineralogy and Metallogeny,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,Guangdong,China;University of Chinese Academy of Sciences,Beijing 100049,China;Heilongjiang Institute of Geological Survey,Harbin 150036,Heilongjiang,China)

机构地区：[1]中国科学院广州地球化学研究所矿物学与成矿学重点实验室,广东广州510640 [2]中国科学院大学,北京100049 [3]黑龙江省地质调查研究总院,黑龙江哈尔滨150036

出　　处：《大地构造与成矿学》2020年第3期465-475,共11页Geotectonica et Metallogenia

基　　金：黑龙江省国土科研项目(201701)资助。

摘　　要：黑龙江省小柯勒河铜钼矿床为大兴安岭多金属成矿带北段新发现的矿床。矿体主要赋存于花岗闪长斑岩内,少量赋存于新元古代浅变质碎屑岩和侏罗纪‒白垩纪火山碎屑岩与花岗闪长斑岩的接触部位。矿床中发育显著的细脉浸染状、浸染状矿化,相关的钠‒钙化、钾化、绿泥石化、绢英岩化等热液蚀变十分发育且分布广泛。其中铜钼矿化与钾化蚀变关系最为密切,部分黄铜矿化与绿泥石化有关。本次研究选择与钾化关系密切的石英‒黄铁矿‒黄铜矿脉和石英‒辉钼矿±黄铁矿±黄铜矿脉中的黄铁矿和辉钼矿开展Re-Os同位素定年。结果表明,4件黄铁矿的Re-Os等时线年龄为153±11 Ma,4件辉钼矿的Re-Os同位素等时线年龄为148.5±1.5 Ma,加权平均年龄为147.9±1.1 Ma。综合考虑测年结果的一致性以及精度可靠性,认为小柯勒河铜钼矿床可能形成于148 Ma左右。结合区域动力学背景分析认为,小柯勒河铜钼矿床可能形成于蒙古‒鄂霍茨克洋闭合之后蒙古‒中朝地块与西伯利亚地块之间的后碰撞阶段,即由挤压向伸展转换的环境。The newly-discovered large-scale Xiaokelehe Cu-Mo deposit is located in the northern part of the Great Xing’an Range polymetallic belt.The ores are mainly hosted in the granodiorite porphyry and minor in the surrounding Neoproterozoic and Jurassic-Cretaceous sedimentary rocks.The mineralization styles are principally veinlet-disseminated and disseminated,accompanied by pervasive sodic-calcic,potassic,chlorite and phyllic alteration.The potassic alteration is the most important Cu-Mo mineralization stage.However,the following chlorite alteration is also associated with Cu mineralization.This study focused on Re-Os dating of pyrite and molybdenite from quartz-pyrite-chalcopyrite and quartz-molybdenite±pyrite±chalcopyrite veins,respectively,which are both associated with potassic alteration.The results show that the Re-Os isochron ages of four pyrite samples are 153±11 Ma,which are in good agreement with the isochron age(148.5±1.5 Ma)and weighted mean age(147.9±1.1 Ma)of four molybdenite samples within analytical errors.Our results show that a hydrothermal alteration-mineralization event occurred around 148 Ma.The Xiaokelehe Cu-Mo deposit was formed in a compression to extension tectonic transition setting associated with collisional orogeny between the Mongol-Sinokorea and Siberia continents.

关 键 词：RE-OS定年 成矿动力学 小柯勒河铜钼矿床 大兴安岭多金属成矿带 

分 类 号：P611[天文地球—矿床学] P597[天文地球—地质学]