Gang Chen, Xiuqing Yang, Changhui Ke, Yanwen Tang, Maohong Chen
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In this study, we newly identified Carboniferous tuffs and syn-volcanic faults in the footwall, and exhalites in the hanging-wall. Hematite from the Cu ores yielded a U-Pb age of 320 ± 15 Ma (MSWD = 2.1, <i>n</i> = 57), and hydrothermal dolomite yielded a Sm-Nd isochron age of 308.1 ± 4.6 Ma (<i>n</i> = 7; MSWD = 0.94), which constrains the timing of mineralization at Yushui. These ages are coeval with the Carboniferous host rocks. Combining the evidence from the geological features (syn-volcanic faults, volcanic rocks, exhalites) and hematite trace element compositions, we suggest that the Yushui is a shallow marine VMS (volcanogenic massive sulfide) deposit. The Sr-Nd isotope composition of hydrothermal dolomite (<i>ε</i><sub>Nd</sub> ~−12) indicates that the ore-forming materials were originated from the crustal basement. The Yushui copper deposit was likely formed during the Late Carboniferous continental back-arc extension in eastern South China. The regional extension may have caused enhanced heat flow, which promoted fluid convection in the basement rocks. In addition, we suggest that volcanic rocks and disseminated chalcopyrite-pyrite mineralization in the Lower Carboniferous quartz sandstone and exhalites are good indicators for regional VMS prospecting.</p>","PeriodicalId":18682,"journal":{"name":"Mineralium Deposita","volume":null,"pages":null},"PeriodicalIF":4.4000,"publicationDate":"2023-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The shallow marine VMS copper deposit of Yushui, Eastern Guangdong, South China: evidence from geology, geochronology, and geochemistry\",\"authors\":\"Gang Chen, Xiuqing Yang, Changhui Ke, Yanwen Tang, Maohong Chen\",\"doi\":\"10.1007/s00126-023-01232-5\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Many massive sulfide deposits have been discovered in the Upper Paleozoic rift-related volcaniclastic sequence in South China, among which the Yushui copper deposit is the most important due to its high grade. The deposit has been variably attributed as SEDEX (sedimentary exhalative) or MVT (Mississippi valley type). The Yushui copper deposit in Guangdong (South China) contains stratiform bornite-chalcopyrite orebodies (102.1 kt Cu @ 3.5%, 186.6 kt Pb @ 4.29%, 117.6 kt Zn @ 2.91%, and 339 t Ag @ 112 g/t) developed along the contact between Upper Carboniferous dolostone and Lower Carboniferous pebbly quartz sandstone, which indicates a shallow marine deposition environment. The Yushui deposit comprises an upper massive sulfide orebody and a lower stockwork orebody with intense alteration. In this study, we newly identified Carboniferous tuffs and syn-volcanic faults in the footwall, and exhalites in the hanging-wall. Hematite from the Cu ores yielded a U-Pb age of 320 ± 15 Ma (MSWD = 2.1, <i>n</i> = 57), and hydrothermal dolomite yielded a Sm-Nd isochron age of 308.1 ± 4.6 Ma (<i>n</i> = 7; MSWD = 0.94), which constrains the timing of mineralization at Yushui. 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引用次数: 0
摘要
在华南地区上古生界与裂谷有关的火山碎屑层序中发现了许多块状硫化物矿床,其中以玉水铜矿床最为重要,其品位较高。该矿床可分为SEDEX型(沉积喷淋型)和MVT型(密西西比河谷型)。广东玉水铜矿床沿上石炭统白云岩与下石炭统含砾石英砂岩接触发育层状斑铜矿-黄铜矿体(Cu = 102.1 kt @ 3.5%, Pb = 186.6 kt @ 4.29%, Zn = 117.6 kt @ 2.91%, Ag = 339 t @ 112 g/t),为浅海沉积环境。玉水矿床由上部块状硫化物矿体和下部蚀变强烈的网状矿体组成。本次研究在下盘新发现了石炭系凝灰岩和同火山断裂,在上盘新发现了呼出物。铜矿石中赤铁矿的U-Pb年龄为320±15 Ma (MSWD = 2.1, n = 57),热液白云岩的Sm-Nd等时年龄为308.1±4.6 Ma (n = 7);MSWD = 0.94),限制了玉水成矿的时间。这些年龄与石炭系寄主岩年龄相同。综合地质特征(同火山断裂、火山岩、喷出物)和赤铁矿微量元素组成,认为玉水为浅海火山岩块状硫化物矿床。热液白云岩Sr-Nd同位素组成(εNd ~−12)表明成矿物质来源于地壳基底。豫水铜矿床可能形成于华南东部晚石炭世大陆弧后伸展期。区域伸展可能使热流增强,促进了基底岩石中的流体对流。此外,下石炭统石英砂岩和呼出岩中的火山岩和浸染型黄铜矿成矿是区域VMS找矿的良好标志。
The shallow marine VMS copper deposit of Yushui, Eastern Guangdong, South China: evidence from geology, geochronology, and geochemistry
Many massive sulfide deposits have been discovered in the Upper Paleozoic rift-related volcaniclastic sequence in South China, among which the Yushui copper deposit is the most important due to its high grade. The deposit has been variably attributed as SEDEX (sedimentary exhalative) or MVT (Mississippi valley type). The Yushui copper deposit in Guangdong (South China) contains stratiform bornite-chalcopyrite orebodies (102.1 kt Cu @ 3.5%, 186.6 kt Pb @ 4.29%, 117.6 kt Zn @ 2.91%, and 339 t Ag @ 112 g/t) developed along the contact between Upper Carboniferous dolostone and Lower Carboniferous pebbly quartz sandstone, which indicates a shallow marine deposition environment. The Yushui deposit comprises an upper massive sulfide orebody and a lower stockwork orebody with intense alteration. In this study, we newly identified Carboniferous tuffs and syn-volcanic faults in the footwall, and exhalites in the hanging-wall. Hematite from the Cu ores yielded a U-Pb age of 320 ± 15 Ma (MSWD = 2.1, n = 57), and hydrothermal dolomite yielded a Sm-Nd isochron age of 308.1 ± 4.6 Ma (n = 7; MSWD = 0.94), which constrains the timing of mineralization at Yushui. These ages are coeval with the Carboniferous host rocks. Combining the evidence from the geological features (syn-volcanic faults, volcanic rocks, exhalites) and hematite trace element compositions, we suggest that the Yushui is a shallow marine VMS (volcanogenic massive sulfide) deposit. The Sr-Nd isotope composition of hydrothermal dolomite (εNd ~−12) indicates that the ore-forming materials were originated from the crustal basement. The Yushui copper deposit was likely formed during the Late Carboniferous continental back-arc extension in eastern South China. The regional extension may have caused enhanced heat flow, which promoted fluid convection in the basement rocks. In addition, we suggest that volcanic rocks and disseminated chalcopyrite-pyrite mineralization in the Lower Carboniferous quartz sandstone and exhalites are good indicators for regional VMS prospecting.
期刊介绍:
The journal Mineralium Deposita introduces new observations, principles, and interpretations from the field of economic geology, including nonmetallic mineral deposits, experimental and applied geochemistry, with emphasis on mineral deposits. It offers short and comprehensive articles, review papers, brief original papers, scientific discussions and news, as well as reports on meetings of importance to mineral research. The emphasis is on high-quality content and form for all articles and on international coverage of subject matter.