投稿时间：2022-06-14
修订日期：2022-09-30
网络发布日期：2023-03-07
中文摘要:安徽西湾铅锌矿床位于长江中下游成矿带庐枞矿集区北部，是近年来在该地区发现的首个赋存于三叠系周冲村组碳酸盐地层中的大型隐伏铅锌矿床，目前该矿床的成矿流体演化及矿床成因研究较为薄弱，制约了该地区铅锌矿床成矿理论与地质勘探。文章根据矿床地质特征，结合镜下鉴定，认为矿床中硫化物主要形成于石英碳酸盐硫化物阶段及碳酸盐硫化物阶段。闪锌矿原位微量元素分析和包裹体测温数据显示，石英碳酸盐硫化物阶段闪锌矿Fe、Mn含量相对较高，Ga、Ge、Cd含量相对较低，该阶段闪锌矿的均一温度为207~236℃，流体盐度w(NaCleq)范围为7.45%~11.81%；碳酸盐硫化物阶段的闪锌矿相对贫Fe和Mn，Cd、Ga和Ge含量相对较高，其闪锌矿均一温度为164~189℃，流体盐度w(NaCleq)为0.88%~5.56%。此外，西湾矿床西南部的样品以石英碳酸盐硫化物阶段的闪锌矿为主，而东北部的样品以碳酸盐硫化物阶段为主，流体包裹体均一温度结果表明矿床成矿温度从西南（183~240℃）向东北方向呈降低趋势（160~209℃），说明成矿流体由西南向东北方向移动。西湾矿床闪锌矿Zn/Cd比值（平均146）与矽卡岩矿床Zn/Cd值（104~214）相符，远低于火山沉积型矿床闪锌矿Zn/Cd值（417~531）及沉积岩容矿的矿床闪锌矿Cd/Zn值（250~330），且石英碳酸盐硫化物阶段闪锌矿In/Ge变化范围大（0.01~571）、Cd/Fe小于1，w(Mn)为（105~3201）×10-6的特征也与远源矽卡岩型矿床闪锌矿特征相符。结合矿床地质特征，文章认为西湾铅锌矿床应属于远源矽卡岩矿床。
Abstract:The Xiwan Pb-Zn deposit is located in the North of the Luzong basin in the Middle-Lower Yangtze River Metallogenic Belt. It is the first large-scale concealed Pb-Zn deposit hosted in the Triassic Zhouchongcun Formation in the Luzong basin discovered in recent years. Because the genesis is not clear, which restricts the understanding of Pb-Zn metallogenic theory and geological exploration in this area. According to the geological characteristics of the deposit and microscopic identification results, we think that the main mineralization was produced in quartz-carbonate sulfide stage and carbonate-sulfide stage. Trace element analysis and homogenization temperature of fluid inclusions show that sphalerites in quartz-carbonate sulfide stage are relatively rich in Fe and Mn, low in Ga, Ge and Cd. The homogenization temperature of sphalerite in quartz-carbonate sulfide stage is 207~ 236℃ with salinity w(NaCleq) of 7.45%~11.81%. The sphalerites of carbonate-sulfide stage are poor in Fe and Mn, rich in Cd, Ga and Ge. The homogenization temperature of sphalerite in this stage is 164~189℃, and the fluid salinity w(NaCleq) is 0.88%~5.56%. The sphalerite in the Southwest part of the deposit was dominantly formed in the quartz-carbonate sulfide stage, whereas that in the Northeast part was formed in the carbonate-sulfide stage. It also shows that the ore-forming temperature decreases from the southwest (183~240℃) to the Northeast (160~ 209℃), indicating that the ore-forming fluid migrates from the Southwest to the Northeast. The Zn/Cd value (average 146) of sphalerite are similar to skarn deposit, different from those of volcanic-sedimentary deposit (417~ 531) and sedimentary-hosted deposit (250~330). The In/Ge (0.01~571) and Cd/Fe (<1) ratios and Mn content ((105~3201)×10-6) of the sphalerite in the quartz-carbonate sulfide stage are also similar with the distal skarn deposit. We therefore think that the Xiwan Pb-Zn deposit should be a distal skarn deposit.
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基金项目:本文得到国家自然科学基金项目（编号：41820104007、42072321），安徽省地勘基金重点项目“无为县西湾铁多金属矿普查”（编号：2018-1-1）以及安徽省公益性质工作项目“安徽省铅锌矿中关键金属镉的资源潜力调查评价”（编号：2021-g-2-11）联合资助
引用文本：
兰秉玉,袁峰,邓宇峰,程培生,李晓晖,张建明,李壮.2023.安徽西湾铅锌矿床闪锌矿原位微量元素组成及成矿流体特征[J].矿床地质,42(1):192~210LAN BingYu,YUAN Feng,DENG YuFeng,CHENG PeiSheng,LI XiaoHui,ZHANG JianMing,LI Zhuang.2023.In situ trace element composition of sphalerite and ore-forming fluid characteristics of Xiwan Pb-Zn deposit, Anhui Province[J].Mineral Deposits42(1):192~210
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