内蒙古沙麦钨矿白云母^(40)Ar/^(39)Ar年龄及其地质意义  

Muscovite ^(40)Ar/^(39)Ar Ages of the Shamai Tungsten Deposit in Inner Mongolia and Their Geological Sighificance

作　　者：吴皓然 李怀彬 李腊梅 黄华 张征 谢玉玲[2] WU Haoran;LI Huaibin;LI Lamei;HUANG Hua;ZHANG Zheng;XIE Yuling(Institute of Mineral Recourses Research,China Metallurgical Geology Bureau,Beijing 101300;Civil and Resource Engineering School,University of Science and Technology Beijing,Beijing 100083)

机构地区：[1]中国冶金地质总局矿产资源研究院,北京101300 [2]北京科技大学土木与资源工程学院,北京100083

出　　处：《地质与勘探》2022年第4期798-808,共11页Geology and Exploration

基　　金：中国地质调查局项目(编号:12120113056700);中国冶金地质总局“大兴安岭成矿带成果集成及成矿预测研究”项目(编号:CMGB202002)联合资助。

摘　　要：内蒙古沙麦钨矿床位于中亚造山带东段(或称兴蒙造山带),矿体主要赋存在黑云母二长花岗(斑)岩内,主要矿化类型为伟晶岩型和云英岩型。本文利用^(40)Ar/^(39)Ar同位素测年方法对沙麦钨矿成矿阶段形成的白云母进行了年龄测定,获得白云母Ar-Ar坪年龄为138.4±0.84 Ma,对应的正、反等时线年龄分别为137.32±0.73 Ma和137.35±0.73 Ma。所测坪年龄与正反等时线年龄具有很好的一致性,可以代表矿床钨矿体的形成年龄,表明该矿床的形成与沙麦地区燕山晚期的岩浆活动有关,这与区域上的成矿事件相吻合。结合区域地球动力学背景的研究成果,认为沙麦钨矿床形成于陆-陆碰撞造山后的陆内伸展环境。The Shamai tungsten deposit in Inner Mongolia is located in the eastern section of Central Asian orogenic belt(or Xing-Meng orogenic belt).The ore bodies mainly occur in biotite monzonite granite(porphyry),and the main mineralization types are pegmatite type and dolomite type.This paper presents precise ^(40)Ar/^(39)Ar ages of muscovite related to the mineralization by laser incremental ^(40)Ar/^(39)Ar analysis.Muscovite yielded a well-defined ^(40)Ar/^(39)Ar plateau age of 138.4±0.84 Ma,with normal and inverse isochron ages being 137.32±0.73 Ma and 137.35±0.73 Ma,respectively.The measured plateau age is consistent with the isochron and inverse isochron age,which can represent the formation age of tungsten ore body.It is indicated that the formation of the deposit is related to the Late Yanshanian magmatic activity in Shamai area,which is consistent with the regional metallogenic events.Combined with the research results of regional geodynamic background,it is speculated that the Shamai tungsten deposit may be formed in an intracontinental extensional environment after the continent-continent collision orogeny.

关 键 词：白云母^(40)Ar/^(39)Ar年龄 成矿时代 兴蒙造山带 沙麦钨矿床 内蒙古 

分 类 号：P575.9[天文地球—矿物学]