广西珊瑚钨锡矿床含钨石英脉中白云母^(40)Ar-^(39)Ar年龄及其地质意义

^(40)Ar-^(39)Ar dating of muscovite from tungsten-quartz veins in Shanhu tungsten-tin deposit and its geological significance

广西珊瑚钨锡矿床是中国南岭钨锡成矿带内的典型矿床之一,其矿石类型主要为钨锡石英脉型、钨锑萤石石英脉型及含钨石英角砾脉型等3种。本研究对采自该矿床长营岭75中段和35中段含钨石英脉的2件白云母样品进行了40Ar-39Ar快中子活化年龄测定,获得白云母的Ar-Ar坪年龄分别为(100.8±0.7)Ma和(102.7±1.7)Ma,等时线年龄分别为(100.2±1.3)Ma和(102.2±2.4)Ma,表明该矿床的成矿作用主要发生在100 Ma左右的白垩纪。该成果对进一步认识桂东北地区的钨锡成矿作用及其地球动力学背景具有重要意义。

The Shanhu tungsten-tin deposit in Guangxi is one of the typical Nanling-type WSn ore deposits in China.It contains 3 ore types,namely,wolframite-cassiterite-quartz veins,wolframite-stibnite-fluorite-quartz veins and ferberite-quartz breccia veins.40Ar-39Ar dating of two muscovite samples were collected from the 35 m and 75 m level respectively in Changyingling ore body,and the results yielded the plateau age and the isochron age of（100.8±0.7） Ma,（102.7±1.7） Ma,and（100.2±1.3） Ma,（102.2±2.4） Ma,respectively.These data suggest that the formation age of the Shanhu tungsten-tin deposit is about 100 Ma,i.e.,in Cretaceous.The results can help understand the geochronology of tungsten-tin mineralization in northeast Guangxi and the geological dynamic setting.