文章摘要
吴皓然.内蒙古沙麦钨矿白云母40Ar/39Ar年龄及其地质意义[J].地质与勘探,2022,58(4):798-808
内蒙古沙麦钨矿白云母40Ar/39Ar年龄及其地质意义
Muscovite 40Ar/39Ar ages of the Shamai tungsten deposit in Inner Mongolia and their geological significance
投稿时间:2021-01-04  修订日期:2022-05-10
DOI:10.12134/j.dzykt.2022.04.009
中文关键词: 白云母40Ar/39Ar年龄 成矿时代 兴蒙造山带 沙麦钨矿床 内蒙古
英文关键词: muscovite 40Ar/39Ar age, ore-forming age, Xing-Meng orogenic belt, Shamai tungsten deposit, Inner Mongolia
基金项目:中国地质调查局项目(编号:12120113056700)和“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
作者单位E-mail
吴皓然 中国冶金地质总局矿产资源研究院北京北京科技大学土木与资源工程学院北京 lihuaibing@cmgb.cn 
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中文摘要:
      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40Ar/39Ar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。
英文摘要:
      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 40Ar/39Ar ages of muscovite related to the mineralization by laser incremental 40Ar /39Ar analysis. Muscovite yielded a well-defined 40Ar /39Ar 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.
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