Geological and geochemical characteristics of the Baogudi Carlintype gold district(Southwest Guizhou, China) and their geological implications  

作　　者：Songtao Li Yong Xia Jianzhong Liu Zhuojun Xie Qinping Tan Yimeng Zhao Minghua Meng Lijin Tan Rong Nie Zepeng Wang Guanghong Zhou Haiyan Guo 

机构地区：[1]State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]No.105 Geological Team,Guizhou Bureau of Geology and Mineral Exploration and Development,Guiyang 550018,China [4]Bureau of Geology and Mineral Exploration and Development Guizhou Province,Guiyang 550004,China [5]Guizhou Education University,Guiyang 550018,China [6]School of Pharmacy,Chengdu University of Traditional Chinese Medicine,Chengdu 611137,China

出　　处：《Acta Geochimica》2019年第4期587-609,共23页地球化学学报（英文）

基　　金：supported by the National Key R&D Program of Deeppenetrating Geochemistry (2016YFC0600607);Deep Mineral Resources Exploration and Exploitation (2017YFC0601500);the Geological Research Project of Bureau of Geology and Mineral Exploration and Development Guizhou Province (Qian Di Kuang Ke He (2017) No. 10);the National Science Foundation of China (Nos. 41802027, 41802088)

摘　　要：The newly discovered Baogudi gold district is located in the southwestern Guizhou Province,China,where there are numerous Carlin-type gold deposits.To better understand the geological and geochemical characteristics of the Baogudi gold district,we carried out petrographic observations,elemental analyses,and fluid inclusion and isotopic composition studies.We also compared the results with those of typical Carlin-type gold deposits in southwestern Guizhou.Three mineralization stages,namely,the sedimentation diagenesis,hydrothermal(main-ore and late-ore substages),and supergene stages,were identified based on field and petrographic observations.The main-ore and late-ore stages correspond to Au and Sb mineralization,respectively,which are similar to typical Carlin-type mineralization.The mass transfer associated with alteration and mineralization shows that a significant amount of Au,As,Sb,Hg,Tl,Mo,and S were added to mineralized rocks during the main-ore stage.Remarkably,arsenic,Sb,and S were added to the mineralized rocks during the late-ore stage.Element migration indicates that the sulfidation process was responsible for ore formation.Four types of fluid inclusions were identified in ore-related quartz and fluorite.The main-ore stage fluids are characterized by an H2O–NaCl–CO2–CH4±N2system,with medium to low temperatures(180–260℃)and low salinity(0–9.08%NaCl equivalent).The late-ore stage fluids featured H2O–NaCl±CO2±CH4,with low temperature(120–200℃)and low salinity(0–7.48%Na Cl equivalent).The temperature,salinity,and CO2and CH4concentrations of ore-forming fluids decreased from the main-ore stage to the late-ore stage.The calculated δ^13C,d D,and δ^18O values of the ore-forming fluids range from-14.3 to-7.0%,-76 to-55.7%,and 4.5–15.0%,respectively.Late-ore-stage stibnite had δ^34S values ranging from-0.6 to 1.9%.These stable isotopic compositions indicate that the ore-forming fluids originated mainly from deep magmatic hydrothermal fluids,with minor contributions from strata.CollecThe newly discovered Baogudi gold district is located in the southwestern Guizhou Province,China,where there are numerous Carlin-type gold deposits.To better understand the geological and geochemical characteristics of the Baogudi gold district,we carried out petrographic observations,elemental analyses,and fluid inclusion and isotopic composition studies.We also compared the results with those of typical Carlin-type gold deposits in southwestern Guizhou.Three mineralization stages,namely,the sedimentation diagenesis,hydrothermal（main-ore and late-ore substages）,and supergene stages,were identified based on field and petrographic observations.The main-ore and late-ore stages correspond to Au and Sb mineralization,respectively,which are similar to typical Carlin-type mineralization.The mass transfer associated with alteration and mineralization shows that a significant amount of Au,As,Sb,Hg,Tl,Mo,and S were added to mineralized rocks during the main-ore stage.Remarkably,arsenic,Sb,and S were added to the mineralized rocks during the late-ore stage.Element migration indicates that the sulfidation process was responsible for ore formation.Four types of fluid inclusions were identified in ore-related quartz and fluorite.The main-ore stage fluids are characterized by an H2O–NaCl–CO2–CH4±N2system,with medium to low temperatures（180–260°C）and low salinity（0–9.08%NaCl equivalent）.The late-ore stage fluids featured H2O–NaCl±CO2±CH4,with low temperature（120–200°C）and low salinity（0–7.48%Na Cl equivalent）.The temperature,salinity,and CO2and CH4concentrations of ore-forming fluids decreased from the main-ore stage to the late-ore stage.The calculated δ13C,d D,and δ18O values of the ore-forming fluids range from-14.3 to-7.0%,-76 to-55.7%,and 4.5–15.0%,respectively.Late-ore-stage stibnite had δ34S values ranging from-0.6 to 1.9%.These stable isotopic compositions indicate that the ore-forming fluids originated mainly from deep magmatic hydrothermal fluids,with minor contributions f

关 键 词：Elemental geochemistry Fluid inclusions Stable isotopes CARLIN-TYPE GOLD deposits Baogudi GOLD DISTRICT SOUTHWESTERN GUIZHOU 

分 类 号：P[天文地球]