南秦岭铧厂沟金矿床铬云母^(40)Ar/^(39)Ar年代学及其大地构造意义  

Fuchsite ^(40)Ar/^(39)Ar Geochronology of the Huachanggou Gold Deposit and its Tectonic Implications

作　　者：林振文[1,2,3] 周永章[1] 秦艳[3] 岳素伟[4] 

机构地区：[1]广东省地质过程与矿产资源探查重点实验室,广东广州510275 [2]广东省海洋地质调查院,广东广州510080 [3]中国科学院广州地球化学研究所矿物学与成矿学重点实验室,广东广州510640 [4]华南理工大学广州学院,广东广州510800

出　　处：《大地构造与成矿学》2017年第2期315-324,共10页Geotectonica et Metallogenia

基　　金：国家自然科学青年基金(41502070;41403032);全国危机矿山接替资源找矿项目(20089934)资助

摘　　要：南秦岭铧厂沟金矿床位于勉略缝合带以南的逆冲推覆带内,矿体呈透镜体或脉状产于新元古界蚀变细碧岩及泥盆系灰岩中,受控于近EW向叠瓦状逆冲断层及韧脆性剪切带。为了准确厘定其成矿时代,对矿区蚀变细碧岩型矿石和含矿石英脉中的铬云母进行了年龄测定。2件铬云母样品的^(40)Ar/^(39)Ar坪年龄分别为209.4±2.3 Ma和211.5±2.5 Ma,相应的等时线年龄211.4±3.6 Ma和215.3±3.9 Ma,与坪年龄在误差范围内一致。因此,铧厂沟金矿床的成矿年龄为212~209 Ma。结合铧厂沟金矿床的大地构造位置、矿床地质特征及成因类型,推测铧厂沟金矿床形成于扬子板块与秦岭微板块的碰撞过程,其成矿年龄代表了两板块发生碰撞的下限。The Huachanggou gold deposit in Shaanxi province is located at the south of Mianlue Suture Zone. The ore bodies, which are mainly controlled by a series of EW trending ductile-brittle shear zones and reverse faults, are hosted in the spilite and limestone. To constrain the metallogenic age, fuchsite 40Ar/39Ar geochronological analyses were carried out. Two fuchsite samples from the gold bearing quartz veins and altered spilite ore yielded 40Ar/39Ar isotopic plateau ages of 209.4±2.3 Ma and 211.5±2.5 Ma, respectively, representing the mineralization age of gold polymetallic sulfides. By summarizing the characteristics of ore geology and the geotectonic location, it can be inferred that the Huachanggou gold deposit was formed during the collision between the Yangtze Block and Qinling micro Block which might have been took place before 209 Ma.

关 键 词：铬云母40Ar/39Ar年代学 铧厂沟金矿床 造山型金矿床 勉略缝合带 秦岭造山带 

分 类 号：P597[天文地球—地球化学] P611[天文地球—地质学]