广西三黎Pb-Zn-Ag矿床的地质特征及S-Pb同位素研究  

Geological Characteristics and Isotopic ( Sulfur and Lead) of the Sanli Pb-Zn-Ag Deposit in the Central Guangxi Province,South China

作　　者：张伟[1,2] 蔡伊[3,4] 张乾[4] 

机构地区：[1]南京大学内生金属矿床成矿机制研究国家重点实验室地球科学与工程学院,江苏南京210093 [2]江西省地质矿产勘查开发局九一二大队,江西鹰潭335001 [3]贵州师范大学生态文明研究中心,贵州贵阳550001 [4]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵州贵阳550002

出　　处：《东华理工大学学报（自然科学版）》2017年第4期314-322,共9页Journal of East China University of Technology(Natural Science)

基　　金：矿床地球化学国家重点实验室"十二五"项目群(SKLODGZY125-04);国家自然科学基金面上项目(41372105)

摘　　要：为了查明三黎矿床的成因,进行了野外地质调查和S-Pb同位素研究。地质调查表明,矿体主要受断裂控制,呈脉状、透镜状和串珠状产出;矿石物质成分简单,主要以方铅矿、闪锌矿和石英为主,伴生少量磁黄铁矿、辉银矿和方解石;矿石结构包括压碎结构、中粒结构、自形粒状结构和半自形粒状结构;矿石构造包括块状、角砾状、肾状和浸染状构造。S-Pb同位素表明,矿石硫化物的S同位素分布较为均一,其δ^(34)SV-CDT值介于-0.57‰^+3.46‰之间,呈塔式分布于0附近(平均值为+1.52‰),为典型的岩浆(或深部)硫;矿石硫化物的Pb同位素与区域晚白垩世岩浆岩较为一致,却明显低于寒武系砂页岩和高于志留纪岩浆岩,暗示着矿石Pb及金属元素很可能起源于晚白垩世岩浆作用。因此,三黎矿床很可能为与晚白垩世岩浆作用密切相关的热液型矿床。结合区域矿化特征,推测矿床最有可能为晚白垩世大规模成矿作用的产物,目前正开采的矿体仅为矽卡岩型矿化的末梢,其深部存在巨大的找矿潜力。The Sanli deposit is located in the central part of the Damingshan tungsten and copper polymetallic belt, central Guangxi. Current explorations have revealed that ore bodies occurred in form as vein and lense controlled by faults and fractures, showing that it has good prospecting potential. None of geochemical word has been done on this deposit, S and Pb isotopic composition of metal sulfides are measured to study the ore-forming metal sources and metallogenesis. On the basis of detailed field geological investigation, the main metal minerals are selected from different part of this deposit to study mineralogical features and S and Pb isotopes. Results ： Ore minerals are simple, and mainly comprised of galena and sphalerite, with a minor amount of pyrrhotite and argentite; gangue minerals predominately consist of quartz and minor calcite. Ores predominately include typical crush, medium grained, euhedral and hypidiomorphic granular texture and massive, brecciated, kidney and impregation structure, respectively. Sulfur isotopic data of ore sulfides in the deposit vary in δ^34SV-CDT from -0. 57‰ to ＋ 3.46‰, with an average value of ＋ 1.52‰, indicating a magmatic origin. Lead isotopic composition of ore sulfides from the Sanli deposit are different with that of the Cambrian sandstone and shale and Silurian magmatic rocks, but consistent with that of the Late Cretaceous magmatic rocks, which suggests that lead and metals are probably derived from the Late Cretaceous magmatism. The Sanli deposit should be of magmatic-hydrothermal origin and a distal part of possible huge quartz vein and skarn Pb-Zn-In mineralization, thus indicating a vast exploration potential.

关 键 词：成矿作用 地质特征 地球化学 同位素 大明山 

分 类 号：P597[天文地球—地球化学]