西藏斯弄多铅锌矿床地质特征及成因分析

Geologic Characteristics and Formation Analysis of Sinongduo Lead-Zinc Deposit in Tibet

斯弄多铅锌矿床的铅锌矿体赋存于石炭系昂杰组白云质灰岩、白云岩层间构造破碎带内,受构造破碎带控制。经过地质详查,在矿区内圈定出了九个铅锌矿体和九个铅锌矿化体,在KT1、KT2、KT3、KT5铅锌矿体,探获的铅锌金属资源量达到了中型规模,全矿体铅锌平均品位11.25%。矿石矿物主要为褐铁矿、异极矿、菱锌矿、方铅矿、白铅矿、铅矾。主要有益组分为铅锌,伴生有益组分主要为银,次为铜。矿床成因类型主要以构造破碎带裂隙充填交代型为主,矽卡岩型为辅。矿床工业类型为含银铜的铅锌矿床。

In Sinongduo Pb-Zn deposit, Pb-Zn ore bodies exist in and are controlled by the crushed structural zones within the dolomitic limestone and dolostone of the Carboniferous Angjie Formation. Through detailed geological surveys, nine Pb-Zn ore bodies and another nine Pb-Zn mineralized ore bodies in our study area are identified and mapped, respectively by means of pit prospecting with fine pits named here KT1, KT2, KT3, KT4 and KTS. Among them, medium-scale Pb-Zn metal resource is confirmed in the ore bodies of KT1, KT2, KT3 and KT5 with the average grade of all ore bodies estimating at 11.25~. The study shows that （1） the main beneficial elements are lead and zinc, and their associated beneficial elements are firstly silver, followed by copper; and （2） the genetic types of this ore deposit include filling-metasomaric type within certain faulted structural zones and skarn type, with the former accounting for the majority, and the commercial type of mineral deposits is silver-and copper-bearing lead-zinc deposits