甘肃北山红尖兵山钨矿床的^(40)Ar-^(39)Ar同位素年代学研究  

^(40)Ar-^(39)Ar geochronology of Hongjianbingshan tungsten deposit in Beishan Mountain,Gansu Province,China

作　　者：江思宏[1] 聂凤军[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京10037

出　　处：《矿床地质》2006年第1期89-94,共6页Mineral Deposits

基　　金：国家自然科学基金项目(编号:40073015);国家地质调查项目(编号:200310200001-01);科技攻关项目(2001BA609A-03)的资助

摘　　要：文章对红尖兵山钨矿云英岩中的白云母进行了40Ar-39Ar同位素年代学研究,获得的坪年龄为(216.6±1.6)Ma(2σ),等时线年龄为(215.2±2.8)Ma,MSWD=0.47,40Ar/36Ar初始比值为333±47。等时线年龄与坪年龄在误差范围内完全一致,可认为该结果近似代表了黑钨矿的形成时代,即红尖兵山的黑钨矿形成于印支期。Located in the western part of Hongshishan-Heiyingshan terrane within Kazakhstan plate, the Hongjian-bingshan deposit is one of the most important tungsten deposits in northwest China. Tungsten mineralization occurs mainly within Early Carboniferous rhyolite tuff and rhyodacite of Baishan Formation as topaz-quartz veins, and partly in monzogranite stocks as massive greisen blocks and stratoid layers. In order to obtain the ore-forming age, the authors measured the muscovite separated from the greisen in the Hongjianbingshan tungsten deposit by the ^40Ar-^39Ar incremental heating method, and the results yield a ^40Ar-^39Ar plateau age of （216.6 ± 1.6） Ma, an isochron age of （215.2 ± 2.8） Ma with MSWD being 0.47, and an initial ^40Ar-^39Ar value of 333 ± 47. As muscovite in greisen and that in wolfrarnite were formed almost simultaneously, the ^40Ar-^39Ar dating result of the muscovite can represent the precipitation age of the wolframite or the ore-forming age of the Hongjianbingshan tungsten deposit. It is shown that the ore-forming process of the Hongjianbingshan tungsten deposit was controlled by Indosinian magmatism. The authors believe that the dating data are of great significance in the study of the regional geological evolution, the investigation of the metallogeny of the metallic deposits and the exploration of the concealed tungsten deposits in the Beishan Mountain, Gansu Province.

关 键 词：地球化学 白云母 柏^40Ar-^39Ar同位素年龄 印支期 红尖兵山 甘肃北山 

分 类 号：P618.67[天文地球—矿床学] P597.3[天文地球—地质学]