内蒙东部白土营子钼铜矿田的矿床地质特征、辉钼矿Re-Os年龄及其意义  

Geological characteristics and molybdenite Re-Os ages of the Baituyingzi Mo-Cu field, eastern Inner Mongolia and their geological implications

作　　者：孙燕[1,2] 刘建明[1] 曾庆栋[1] 褚少雄[1] 周伶俐[1,2] 吴冠斌[1,2] 高玉友[3] 沈文君[3] 

机构地区：[1]中国科学院矿产资源研究重点实验室中国科学院地质与地球物理研究所,北京100029 [2]中国科学院大学,北京100049 [3]核工业243大队,赤峰024006

出　　处：《岩石学报》2013年第1期241-254,共14页Acta Petrologica Sinica

基　　金：国家973项目(2013CB429800);国家自然科学基金项目(40972065)联合资助

摘　　要：白土营子斑岩型-石英脉型钼铜矿田是华北板块北缘西拉沐沦钼矿带南部新近发现的与岩浆热液活动密切相关的钼铜成矿系统。本文在矿床地质特征研究的基础上,对矿田内三个重要钼铜矿床开展了辉钼矿Re-Os同位素定年,初步获得:1)白土营子斑岩型钼铜矿床的成矿年龄为248.0±10Ma(MSWD=0.52,n=6);2)白马石沟石英脉型铜钼矿的成矿年龄为248.6±6.7Ma(MSWD=1.06,n=4);3)库里吐石英脉型钼铜矿的成矿年龄为245.0±4.3Ma(MSWD=0.71,n=5);这一结果揭示该矿集区的钼铜矿化发生在早三叠世。该成矿系统的形成适值早三叠世西伯利亚板块与华北板块碰撞造山过程的晚期,二长花岗斑岩的UST结构证明含矿流体来自岩浆作用。早三叠世钼铜成矿作用在华北板块北缘及邻区有一定的普遍性,找矿前景可观。The recently discovered Baituyingzi porphyry-quartz vein type Mo-Cu orefield from the Xilamulun Mo belt in the north margin of the North China Plate, is genetically related to magmatic hydrothermal activity. On the basis of detailed geologic research, molybdenite samples were selected from the three important Mo-Cu deposits for Re-Os isotopic analysis, and results are： 1） molybdenite samples from Baituyingzi porphyry ores yield an isochron age of 248.0±10Ma （MSWD=0.52, 2σ）; 2） samples from Baimashigou quartz vein ores yield an isochron age of 248.6±6.7Ma （MSWD=1.06, 2σ）; 3） samples from Kulitu quartz vein type Mo-Cu deposit yield an isochron age of 245.0±4.3Ma （MSWD=0.71, 2σ）. These ages indicate that the Mo-Cu mineralization in Baituyingzi area occured in Early Triassic. The Baituyingzi mineralization system was formed during the late stage of continental collision between North China Plate and Siberian Plate in Early Triassic, and the ore-forming fluids originated from the monzogranite porphyry, as indicated by UST （Unidirectional Solidification Texture）. The Early Triassic Mo-Cu mineralizations extensively occured in the northern margin of the North China Plate and its adjacent areas, and are potential for future exploration.

关 键 词：辉钼矿Re-Os年代学 斑岩型-石英脉型钼铜矿床 成矿规律 白土营子钼铜矿田 西拉沐沦钼矿带 

分 类 号：P597.3[天文地球—地球化学] P618.41[天文地球—地质学]