二连-东乌旗中段新发现的乌和尔楚鲁图斑岩型钼矿床Re-Os同位素年龄及其地质意义  

Re-Os Isotopic Dating of Newly Discovered Porphyric Mo Deposit in the Central Section of Erenhot-Dong Ujimqin Qi and Its Geological Significance

作　　者：俞礽安 张锋 唐永香[2] 刘晓雪 谢瑜 曲凯 李志丹 屈文俊[3] 

机构地区：[1]中国地质调查局天津地质调查中心,天津300170 [2]天津地热勘查开发设计院,天津300250 [3]国家地质实验测试中心,北京100037

出　　处：《地质学报》2016年第1期139-150,共12页Acta Geologica Sinica

基　　金：中国地质大调查项目(编号1212011120720;12120113057400)联合资助的部分成果

摘　　要：在二连-东乌旗成矿带最新发现的乌和尔楚鲁图钼矿床位于二连贺根山断裂带南侧,是近年来在内蒙古中部地区找到的一处中型钼矿床。钼矿体赋存于燕山期花岗斑岩体与二叠纪地层的内外接触带中。矿床有明显的蚀变分带特征,即钾化、硅化、黄铁绢英岩化、绿泥石化、碳酸盐化等,具有典型的斑岩型钼矿床特征。本文对乌和尔楚鲁图钼矿床中选取的5件辉钼矿样品进行了Re-Os同位素定年,获得模式年龄介于158.1~161.6Ma,等时线年龄值为158±2 Ma（MSWD=1.16）,根据辉钼矿模式年龄和成矿岩体成岩年龄,乌和尔楚鲁图钼矿床的成岩成矿时代较为接近,均为中侏罗世,表明乌和尔楚鲁图钼矿属燕山期构造-岩浆活动的产物。通过与二连-东乌旗成矿带中矿区外围其他钼矿床同位素年龄数据对比分析,说明二连浩特—锡林浩特地区钼多金属成矿作用具有多期次成岩成矿特点,而大规模斑岩型钼矿成矿作用集中在燕山期。Located in the southern side of Erlian-Hegen mountain belt, Wheerchu is a newly discovered medium- sized Mo deposit in the Erlian-Dongwuqi ore belt of center Inner Mongolia. Molybdenum mineralization consists of quartz-molybdenite veinlets and stockworks which occur within the Yanshan Period granite stock or along its contact zone with Permian strata. Hydrothermal alteration is well developed and is composed of potassic feldspar alteration, silici{ication, beresitization, carbonatation and chloritization, indicating typical of porphyry Mo deposits. Re-Os dating of 5 molybdenite samples from the main ore body shows that the model age is 158.1 --161.6 Ma and the isochron ages is 158±2 Ma （MSWD= 1.16）. Re-Os dating and the U-Pb dating indicate that the diagenetic age and mineralization age are close and belong to Middle Jurassic. Thus the Wheerehu molybdenum deposit was formed at the early Yanshan period and related to the tectonic-magmatic activities. In consideration of other isotopic age data from the molybdenum deposits in adjacent areas, it can be inferred that magmatism-mineralization of the molybdenum deposit exists more stage in the Erenhot-XilinHot area, the large-scale porphyry Mo metallogenesis concentrated in the Yanshan period.

关 键 词：RE-OS同位素 钼矿床 燕山期 乌和尔楚鲁图钼矿床 内蒙古 

分 类 号：P618.65[天文地球—矿床学] P597.3[天文地球—地质学]