大厂锡多金属矿田铜坑-长坡92号矿体Rb-Sr测年及其地质意义  

Rb-Sr Dating of the No.92 Orebody of the Tongkeng-Changpo Deposit in the Dachang Tin-Polymetallic Ore Field,Guangxi,and its significance

作　　者：蔡明海[1] 梁婷[2] 韦可利[3] 黄惠明[3] 刘国庆[4] 

机构地区：[1]广西大学资源与环境学院,南宁530004 [2]长安大学地球科学与国土资源学院,西安710054 [3]柳州华锡集团有限责任公司,广西柳州545006 [4]宜昌地质矿产研究所,湖北宜昌443003

出　　处：《华南地质与矿产》2006年第2期31-36,共6页Geology and Mineral Resources of South China

基　　金：中国地质调查局地质调查项目(200310200072)

摘　　要：铜坑-长坡锡石硫化物矿床是广西大厂锡多金属矿田中一个规模最大、特征最为典型的超大型锡矿床,矿体呈脉状、层状两种形式产出,其中的92号层状矿体是该矿床中规模最大的一个矿体。本文应用Rb-S等时线法获得92号矿体成矿年龄为93.4±7.9 Ma(1σ),这一年龄值不仅与矿田中部龙箱盖黑云母花岗岩的SHR IMP锆石U-Pb年龄93±1 Ma吻合,而且在测试误差范围内与前人所获得的龙头山100号矿体、铜坑-长坡91号矿体以及亢马矿床的成矿年龄基本一致,表明区内锡多金属成矿作用发生在燕山晚期。92号矿体成矿流体的87Sr/86Sr初始值为0.71351±0.00100,与龙箱盖黑云母花岗岩87Sr/86Sr的初始值0.7110接近。成矿年龄与成矿流体的87Sr/86Sr初始值均表明铜坑-长坡92号矿体的成矿作用与龙箱盖岩体具有一定的成生联系。The Tongkeng-Changpo cassiterite-sulphide deposit, located in Guangxi autonomous region of south China, is a giant and typic deposit in the Dachang polymetallic tin ore field. It is composed of vein-type ore bodies at upper part and stratiform ones at bottom. The No. 92 stratiform orebody is the biggest one of the Tongkeng-Changpo deposit. The Rb-Sr isochron dating of fluid inclusions of quartz of No. 92 ore body is 93. 4 ± 1.3Ma（1σ）. This age is not only consistent with that of the Cretaceous Longxianggai biotite granite, but also coincident with that of the No. 100 ore body of the Longtoushan deposit, No. 91 ore body of the Tongkeng-Changpo ore body and the Kangma deposit. It indicates that they formed in late Yanshan movement. The initial 87^Sr/86^Sr of ore fluid of the No. 92 ore body is 0. 71352 ±0.00016, which is close to the value 0.7110 of the Longxianggai biotite granitite, and this also indicates that the mineralization of the No. 92 ore body probably has a genetic relationship with the Longxianggai magmatic body.

关 键 词：铜坑-长坡矿床 92号矿体 Rb-Sr测年 广西大厂 

分 类 号：P618.4[天文地球—矿床学]