东天山卡拉塔格地区月牙湾铜镍硫化物矿床磁黄铁矿Re-Os同位素测定及其地质意义  

Re-Os Isotopic Dating of Pyrrhotite from Yueyawan Cu-Ni Sulfide Deposit in Kalatage Area of East Tianshan Mountain and Its Geological Significance

作　　者：吕晓强[1] 毛启贵[1] 郭娜欣[2] 李月臣[1] 孙燕[1] Lii Xiaoqiang;Mao Qigui;Guo Naxin;Li Yuechen;Sun Yan(Beijing Institute of Geology for Mineral Resources,Beijing 100012,China;Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]北京矿产地质研究院,北京100012 [2]中国地质科学院矿产资源研究所,北京100037

出　　处：《地球科学》2020年第9期3475-3486,共12页Earth Science

基　　金：国家重点研发计划项目(No.2017YFC0601201);中国地质调查局地质调查项目(No.DD20160071);中央高校基本科研业务费项目(No.310827171123)。

摘　　要：新疆哈密月牙湾铜镍矿是近年来在东天山卡拉塔格地区新发现的岩浆型铜镍硫化物矿床.为确定该矿床的成岩、成矿时代及其成矿作用,利用锆石LA-ICP-MS U-Pb定年和硫化物Re-Os同位素等时线定年方法,分别对主含矿岩相橄榄辉长岩和矿石中的磁黄铁矿进行了年龄测定.橄榄辉长岩中锆石的206Pb/238U年龄为255~292 Ma,加权平均值为274±2.4 Ma,代表了橄榄辉长岩的成岩年龄;矿石中磁黄铁矿Re-Os同位素等时线年龄为271.9±9.5 Ma,代表了硫化物熔离成矿的年龄;187Os/188Os初始值为0.279 6±0.008 9,γOs值为117~126,指示在岩浆侵位及硫化物熔离成矿过程中有地壳物质加入.月牙湾镁铁质岩浆的成岩、成矿作用发生于早二叠世,与东天山黄山-图拉尔根一带典型铜镍硫化物矿床为同一时期的产物.The Yueyawan Cu-Ni deposit is a newly discovered magmatic Cu-Ni sulfide deposit in Kalatage area of East Tianshan Mountain. In order to restrict the metallogenic age of the Yueyawan Cu-Ni deposit, LA-ICP-MS U-Pb and Re-Os isotopic dating had been conducted for zircons and pyrrhotite from the ore-forming olivine gabbro, respectively. The206 Pb/238U ages of zircons range from 255 Ma to 292 Ma, and yield an average weighted age of 274±2.4 Ma, which represents the diagenetic age of olivine gabbro. The isochron age of the Re-Os isotopic dating of pyrrhotite is 271.9±9.5 Ma, which represents the age of Cu-Ni mineralization. The initial187Os/188Os ratio is 0.279 6±0.008 9, and γOsvalue is 117-126, indicating that crustal materials had been involved into the sulfide mineralization. The diagenesis and metallogenesis of mafic magma in Yueyawan occurred in Early Permian,contemporary with the typical Cu-Ni sulfide deposits in Huangshan-Tulaergen area of East Tianshan Mountain.

关 键 词：镁铁质杂岩体 Re-Os同位素测定 铜镍硫化物矿床 月牙湾 东天山 矿床学 

分 类 号：P618[天文地球—矿床学]