吉尔吉斯斯坦Taldybulak Levoberezhny(左岸)金矿地质特征及金属矿物学研究  

Geological characteristics and ore minerals of the Taldybulak Levoberezhny gold deposit,Kyrgyzstan

作　　者：席伟 夏小洪 吴艳爽 叶甜[1,2,3,4] 李诺 XI Wei;XIA Xiaohong;WU Yanshuang;YE Tian;LI Nuo(State Key Laboratory of Desert and Oasis Ecology and Xinjiang Research Centre for Mineral Resources;Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences,Orumqi 830011,China;2.Xinjiang Key Laboratory of Mineral Resources and Digital Geology,Orumqi 830011,China;3.University of Chinese Academy of Sciences,Beijing 100049,China;4.Altynken Limited Liability Company,Zijin Mining Group,Bishkek 720481,Kyrgyzsta)

机构地区：[1]荒漠与绿洲生态国家重点实验室和新疆矿产资源研究中心 [2]中国科学院新疆生态与地理研究所,新疆乌鲁木齐830011 [3]新疆矿产资源与数字地质实验室,新疆乌鲁木齐830011 [4]中国科学院大学,北京100049 [5]紫金矿业集团奥同克有限责任公司,吉尔吉斯斯坦比什凯克720481

出　　处：《地学前缘》2018年第5期135-150,共16页Earth Science Frontiers

基　　金：中国科学院西部之光项目(2015-XBQN-A-05);国家重点基础研究发展计划"973"项目(2014CB448000;2014CB440802);国家自然科学基金项目(41572070);新疆维吾尔自治区引进高层次人才专项

摘　　要：Taldybulak Levoberezhny(又称左岸)矿床位于吉尔吉斯斯坦北天山东段,是区内第三大金矿(金储量130t,平均品位6.9g/t)。长期以来,该矿床矿物学研究薄弱,成因类型存在争议,已有观点包括斑岩型、造山型、多阶段叠加成矿等。野外地质调查及室内岩相学鉴定发现:金矿化同时受韧性剪切带和岩体控制,局部显示一定的顺层特征;常见矿石类型包括浸染-细脉浸染型、石英-电气石-硫化物型、块状硫化物型、稀疏浸染型、方解石-硫化物脉型等;相关围岩蚀变以硅化、绢云母化、电气石化、碳酸盐化最为强烈,可见绿泥石化、绿帘石化、泥化等。电子探针分析发现,左岸金矿同时发育可见金和不可见金。前者包括银金矿(w(Au)=67.90%~80.86%,w(Ag)=14.24%~30.76%)、含银自然金(w(Au)=88.95%,w(Ag)=8.09%)等,以包体金、裂隙金或粒间金形式赋存于黄铁矿中。后者可赋存于黄铁矿和黄铜矿中(w(Au)=0.16%~0.33%)。不同类型矿石中黄铁矿的形态、结构、成分存在一定差异,显示了叠加成矿的可能性。浸染状-细脉浸染型矿石中黄铁矿以中粗粒(30~1 300μm,多数>200μm)、半自形-自形立方体为主,基本无碎裂或碎裂不明显,可含有自然金、银金矿或硅酸盐包体;成分上具有中等的As(0.03%~1.72%,平均0.66%)、Co(0.06%~0.19%,平均0.13%)、Te(0.03%~0.06%,平均0.04%)含量和As/S、Fe/S、Co/As比值,基本不含Cu、Pb、Zn、Ag。石英-电气石-硫化物型矿石中黄铁矿多呈中粗粒(30~2 000μm)、半自形-它形粒状,往往发生碎裂,并被黄铜矿、方铅矿等矿物交代;部分颗粒可含有银金矿或硅酸盐包体;总体具有较高的As(0.05%~2.05%,平均0.97%)、Co(0.05%~0.34%,平均0.15%)含量和As/S、Fe/S比值,Co/As比值较低。块状硫化物型矿石中黄铁矿多呈半自形-它形粒状产出,但粒度变化较大(250~3 000μm或者30~300μm);化学成分上以较高的As(0.05%~2.20%,平均1.21%)、Te(0.04%~0.09%,平均0.06%)含The Taldybulak Levoberezhny deposit（130 t@6.9 g/t）is the third largest gold deposit in northern Tienshan,Kyrgyz.Since its discovery in 1963,no detailed mineralogical studies has been done,especially on ore minerals in the deposit.The ore genesis is still under debate over the proposed origins including porphyry,orogenic or multi-stage overprint.In this contribution,through detailed field survey and petrographic observation,we discovered that gold mineralization was mainly controlled by both shear zones and later intrusion with ore bodies parallel to the strata.The ores can be divided into at least five types according to texture and composition：dissemination-stockwork（hosted in intrusions such as monzogranite）,quartztourmaline-sulfide,massive ores,dissemination（hosted in altered metamorphic rocks）and calcite-sulfide vein types.Related hydrothermal alterations are dominated by silicic,sericite,tourmaline and calcite alterations with minor chlorite and epidote alterations or argillation.Electron microprobe analysis（EMPA）revealed both visible and invisible gold in the ores.The visible gold includes electrum（Au：67.90%-80.86%;Ag：14.24%-30.76%）and silver-bearing native gold（Au：88.95%;Ag：8.09%）,and occur as micro-mineral inclusions enclosed in pyrite or distributed along pyrite boundaries or fractures,while the invisible gold resides in pyrite or chalcopyrite containing 0.16%-0.33% Au.Pyrite from different types of ores display variable morphology,texture and composition.In the dissemination-stockwork ores hosted in monzogranite,pyrite generally occurs as medium-coarse sized（30-1300μm,mostly200μm）subhedral to euhedral cubic grains;it may contain native gold,electrum or silicate inclusions,with little or no cracks;commonly,moderate amounts of As（0.03%-1.72%,averaging 0.66%）,Co（0.06%-0.19%,averaging 0.13%）and Te（0.03%-0.06%,averaging 0.04%）,with moderate As/S,Fe/S and Co/As ratios and limited Cu,Pb,Zn and Ag are present.In the quartz-tourmaline-sulfide ores,the medium-co

关 键 词：黄铁矿 金 电子探针分析 叠加成矿 Taldybulak Levoberezhny(左岸)金矿 西天山 

分 类 号：P618.51[天文地球—矿床学] P578.2[天文地球—地质学]