云南富乐铅锌矿床地质、地球化学及成因  

Geology,geochemistry and ore genesis of the Fule Pb-Zn deposit,Yunnan Province,Southwest China

作　　者：崔银亮 周家喜[2] 黄智龙[2] 罗开[2,4] 念红良 叶霖 李珍立[2,4] CUI YinLiang;ZHOU JiaXi;HUANG ZhiLong;LUO Kai;NIAN HongLiang;YE Lin;LI ZhenLi(Yunnan Nonferrous Metals Geological Bureau, Kunming 650051, China;Stake Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy Sciences, Guiyang 550081, China;Faculty of Land Resource and Engineering, Kunming University of Science and Technology, Kunming 650093, China;University of Chinese Academy Sciences, Beifing 100049, China;No. 317 Geological Part, Yunaan Nonferrous Metals Geological Bureau, Qujing 655000, China)

机构地区：[1]云南省有色地质局,昆明650051 [2]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,贵阳550081 [3]昆明理工大学国土资源工程学院,昆明650093 [4]中国科学院大学,北京100049 [5]云南省有色地质局三一七队,曲靖655000

出　　处：《岩石学报》2018年第1期194-206,共13页Acta Petrologica Sinica

基　　金：国家重点基础研究发展规划项目(2014CB440905);国家重点研发计划项目(2017YFC0602502);国家自然科学基金重点项目(41430315);云南省有色地质局与中科院地化所合作科研项目(2015001A)联合资助

摘　　要：富乐铅锌矿床位于扬子陆块西南缘的川滇黔铅锌成矿域东南部,受弥勒-师宗-水城区域性深大断裂构造控制,矿体呈似层状隐伏于中二叠统阳新组层间构造带内,赋矿围岩为白云岩。矿石矿物主要为闪锌矿,方铅矿和黄铁矿次之,含少量黄铜矿和黝铜矿等,脉石矿物主要为方解石和白云石。矿石构造主要有致密块状、浸染状和网脉状,金属矿物主要呈自形、半自形或他形粒状结构,其次为交代残余结构。已累计探明Pb+Zn金属资源量超过50万吨,平均品位大于10%Pb+Zn,最高达60%Pb+Zn,并伴随大量Cu和分散元素(如Cd、Ga、Ge等),显示其成矿环境极为特殊。本次工作通过详细的矿床地质和C-O、S及Pb同位素地球化学研究,旨在揭示该矿床的成矿物质来源及矿床成因。方解石的δ^(13)C值介于1.25‰~2.01‰之间,均值为1.64‰,与海相碳酸盐岩相似,而高于地幔和沉积有机质;δ^(18)O值为17.21‰~17.74‰,均值为17.49‰,介于海相碳酸盐岩(沉积有机质)和地幔之间。这表明方解石的C很可能来自碳酸盐岩围岩,而O同位素很可能受到流体与围岩间的水/岩相互作用影响。硫化物的δ^(34)S值介于10.04‰~16.43‰之间,均值为14.12‰,显示富集重S同位素的特征,表明成矿流体中S主要来源于沉积地层中的膏岩层,是海水硫酸盐岩热化学还原作用的产物。单颗粒方铅矿的^(206)Pb/^(204)Pb=18.5295~18.6100(均值为18.5640),^(207)Pb/^(204)Pb=15.6938~15.7024(均值为15.6974),^(208)Pb/^(204)Pb=38.5690~38.6568(均值为38.6008),其变化范围很窄,且与区域沉积岩和基底变质岩范围重叠,表明成矿金属Pb主要由沉积地层和基底岩石共同提供。综合矿床地质以及C-O、S和Pb同位素资料,本文认为富乐是一个形成于三叠纪拉张向挤压再向伸展的构造体制转换背景下、以碳酸盐岩为容矿围岩、受背斜和层间构造控制的层控、后生、富分散元素和高品位铅锌矿床,�The Fule Pb-Zn deposit is located in the western margin of the Yangtze Block, South China. This deposit structurally occurs in the Mile-Shizong-Shuicheng regional fault and is an important part of the Sichuan-Yunnan-Guizhou （SYG） Pb-Zn metallogenic province. Ore body is buried and occurs along the interlayer tectonic belt as stratiform shape. Sulfide ore is hosted by the middle Permian Yangxin Formation dolostone. Ore minerals are mainly sphalerite, minor galena and pyrite, with rare chalcopyrite and tetrahedrite, and gangue minerals are dominantly calcite and dolomite. Sulfide ore has massive, veined or disseminated structures with granular （euhedral, subhedral and anhedral） and metasomatic relict textures. There are more than 5 million tones （Mt） of sulfide ore, grading 〉10% Zn＋Pb, and can up to 60% Zn＋Pb. This paper presents the detailed ore deposit geology, and C-O, S and Pb isotopic data, aiming to reveal the sources of mineralizing elements and ore genesis. Calcite has δ13C values ranging from 1.25‰ to 2.01‰, mean 1.64‰, which are similar to those of marine carbonate rocks, but are higher than those of mantle and sedimentary organic matters. However, δ18O values of calcite range from 17.21‰ to 17.74‰ （mean 17.49‰）, which are lower than those of carbonate rocks and organic matters, but are higher than those of mantle. Such C-O isotopic data suggests that the source of C is carbonate wall rocks, and O isotope signatures are generated by water/rock interaction between fluids and carbonate rocks. δ34S values of sulfide minerals range from 10.04‰ to 16.43‰ （av. 14.12‰）, indicating a feature of heavy S isotopes-enriched and the sources of reduced S in the hydrothermal fluids are originated mainly from evaporites within sedimentary strata by thermal-chemical sulfate reduction （TSR）. Single-grain galena has 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios ranging from 18.530 to 18.610 （av. 18.564）, 15.694 to 15.702 （av. 15.697） and 38.569 to 38.657 （av. 38

关 键 词：矿床地质 同位素地球化学 成矿物质来源 矿床成因 富乐铅锌矿床 华南 

分 类 号：P597.2[天文地球—地球化学] P618.42[天文地球—地质学]