新疆西天山可克萨拉铁铜矿床辉钼矿Re-Os同位素测年及其地质意义  

The Molybdenite Re-Os Isotopic Dating of the Kekesala Fe-Cu Deposit in West Tianshan,Xinjiang and Its Geologic Significance

作　　者：李书领[1] 李永军[1,2] 吴乐[1] 王祚鹏 汪振宇[1] 张郁玲 

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054 [2]西部矿产资源与地质工程教育部重点实验室,陕西西安710054

出　　处：《西北地质》2017年第4期81-90,共10页Northwestern Geology

基　　金：国家自然基金委"伊宁石炭纪火山岩"项目(20120898)

摘　　要：可克萨拉铁铜矿床是西天山博罗科努多金属成矿带上的一个典型矽卡岩型矿床,产于呼斯特中酸性侵入岩与上奥陶统碳酸盐岩的接触带上。近年来,年代学研究表明,矿区中酸性侵入岩的成岩年龄集中于晚泥盆世,而矿石中辉钼矿的成矿年龄为早二叠世,成矿成岩年龄相差很大。为确定成矿时代,笔者采集矿区地表探槽中的辉钼矿样品,获得Re-Os同位素等时线年龄为(290±10)Ma,加权平均年龄为(287.8±0.9)Ma,时代为早二叠世。辉钼矿成矿年龄和围岩花岗岩类成岩年龄的显著差异,表明存在着2期岩浆或岩浆热液活动事件。可克萨拉矽卡岩型铁铜矿床可能与早期(晚泥盆世)中酸性岩浆侵入于灰岩地层发生接触交代作用有关;晚期(早二叠世)铜钼矿形成与沿断裂发育的构造-岩浆热液作用有关,并叠加于早期矽卡岩型矿床之上。As a typical skarn type deposit in the Boluokenu polymetallic belt, West Tianshan, Xinjiang, the Kekesala FeCu deposit was occurred at the contact zone between the Husite intermediate acid intrusions and Upper Ordovician carbonate. Inrecent years, the chronological studies indicate that the diagenetic age of intermediate acid intrusive rocks from this deposit are concentrated on Late Devonian.However, the metallogenic age of molybdenite is Early Permian, which varies in wide range. This paper has collected molybdenum samples from the surface trenches of this deposit to determine its metallogenic age.The results suggest that the ReOs isotopic isochron age is （290±10）Ma, and its weighted average age is （287 8±0 9）Ma, corresponding to Early Permian. The metallogenic age of molybdenite is significantly different from the diagenetic age of intermediate acid intrusive rocks, indicating two periods of magmatic or magmatic hydrothermal events in this studying area. The Kekesala skarn type FeCu deposit may be related to the contact metasomatism of the early stage （Late Devonian）intermediate acid magma intruded into the limestone formation; the late stage （Early Permian） CuMo deposit was formed by the tectonic magmatic hydrothermal effect occurred along with the fault, which was superimposed on the early stage skarn type deposit.

关 键 词：ReOs同位素测年 矽卡岩型铁铜矿床 可克萨拉 西天山 

分 类 号：P597[天文地球—地球化学]