【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。更多还原

【Abstract】 Located in the western part of Hongshishan-Heiyingshan terrane within Kazakhstan plate, the Hongjianbingshan 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 wolframite 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.更多还原