Shan Huang, Jiancheng Xie, Quanzhong Li, Likai Ge, Liu Yang, Jun Yan
{"title":"中国东部铜陵铜官山矽卡岩铜矿床石榴石的地质年代和地球化学:对成矿过程的启示","authors":"Shan Huang, Jiancheng Xie, Quanzhong Li, Likai Ge, Liu Yang, Jun Yan","doi":"10.1016/j.sesci.2024.100167","DOIUrl":null,"url":null,"abstract":"<div><p>Skarn Cu deposits are one of most important deposit-type in Middle-Lower Yangtze River region, eastern China, but skarn formation process remains unclear. Mineralogical, morphological and in situ geochemical data from the skarn stage of Tongguanshan skarn Cu deposit in Tongling region are systemically investigated, to reveal the timing, physical-chemical conditions, and fluid evolution during the skarn formation. The Tongguanshan garnets can be identified homogeneous and unzoned early generation garnet (GrtI), and oscillating zoned late generation garnet (GrtII) with the Fe-rich core (GrtII-Fe) and Al-rich edge (GrtII-Al). Garnet U–Pb dating results show that the Tongguanshan Cu mineralization was formed in 145.6 ± 4.4 Ma. In situ elemental composition results of the garnet samples indicate that they belong to grossular-andradite solid solution series, and are a magmatic-hydrothermal origin. The distinctly geochemical characteristics (e.g., Sn and U contents, (La/Yb)<sub>N</sub>, δEu and Y/Ho values) reveal that the physiochemical conditions from GrtI to GrtII-Fe, and GrtII-Fe to GrtII-Al stages in the Tongguanshan skarn formation were an increase and a decrease of fluid salinity and oxygen fugacity, closed to open and then to closed of fluid environment, and neutral-weakly acidic to acidic and acidic to neutral-weakly acidic of fluid pH, respectively. A comprehensive discriminant analysis indicates a fluid boiling occurred in the GrtI to GrtII-Fe stage of the Tongguanshan skarn Cu deposit, and there is little or no external fluid mixed during the skarn stage.</p></div>","PeriodicalId":54172,"journal":{"name":"Solid Earth Sciences","volume":"9 2","pages":"Article 100167"},"PeriodicalIF":2.0000,"publicationDate":"2024-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2451912X24000059/pdfft?md5=7a210b3f973ca909ba35c89b02ef9ee2&pid=1-s2.0-S2451912X24000059-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Geochronology and geochemistry of garnet from Tongguanshan skarn Cu deposit, Tongling, eastern China: insights into ore-forming process\",\"authors\":\"Shan Huang, Jiancheng Xie, Quanzhong Li, Likai Ge, Liu Yang, Jun Yan\",\"doi\":\"10.1016/j.sesci.2024.100167\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Skarn Cu deposits are one of most important deposit-type in Middle-Lower Yangtze River region, eastern China, but skarn formation process remains unclear. Mineralogical, morphological and in situ geochemical data from the skarn stage of Tongguanshan skarn Cu deposit in Tongling region are systemically investigated, to reveal the timing, physical-chemical conditions, and fluid evolution during the skarn formation. The Tongguanshan garnets can be identified homogeneous and unzoned early generation garnet (GrtI), and oscillating zoned late generation garnet (GrtII) with the Fe-rich core (GrtII-Fe) and Al-rich edge (GrtII-Al). Garnet U–Pb dating results show that the Tongguanshan Cu mineralization was formed in 145.6 ± 4.4 Ma. In situ elemental composition results of the garnet samples indicate that they belong to grossular-andradite solid solution series, and are a magmatic-hydrothermal origin. The distinctly geochemical characteristics (e.g., Sn and U contents, (La/Yb)<sub>N</sub>, δEu and Y/Ho values) reveal that the physiochemical conditions from GrtI to GrtII-Fe, and GrtII-Fe to GrtII-Al stages in the Tongguanshan skarn formation were an increase and a decrease of fluid salinity and oxygen fugacity, closed to open and then to closed of fluid environment, and neutral-weakly acidic to acidic and acidic to neutral-weakly acidic of fluid pH, respectively. A comprehensive discriminant analysis indicates a fluid boiling occurred in the GrtI to GrtII-Fe stage of the Tongguanshan skarn Cu deposit, and there is little or no external fluid mixed during the skarn stage.</p></div>\",\"PeriodicalId\":54172,\"journal\":{\"name\":\"Solid Earth Sciences\",\"volume\":\"9 2\",\"pages\":\"Article 100167\"},\"PeriodicalIF\":2.0000,\"publicationDate\":\"2024-05-17\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.sciencedirect.com/science/article/pii/S2451912X24000059/pdfft?md5=7a210b3f973ca909ba35c89b02ef9ee2&pid=1-s2.0-S2451912X24000059-main.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Solid Earth Sciences\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2451912X24000059\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Solid Earth Sciences","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2451912X24000059","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
摘要
矽卡岩铜矿床是中国东部长江中下游地区最重要的矿床类型之一,但矽卡岩形成过程尚不清楚。本文系统研究了铜陵地区铜官山矽卡岩铜矿床矽卡岩阶段的矿物学、形态学和原位地球化学资料,揭示了矽卡岩形成的时间、物理化学条件和流体演化过程。铜官山石榴石可分为均质无分带早期石榴石(GrtI)和振荡分带晚期石榴石(GrtII),其中GrtII-Fe为富铁核,GrtII-Al为富铝边。石榴石U-Pb年代测定结果表明,铜官山铜矿化形成于145.6 ± 4.4 Ma。石榴石样品的原位元素组成结果表明,它们属于毛玻璃-闪长岩固溶体系列,属于岩浆-热液成因。明显的地球化学特征(如 Sn 和 U 含量、(La/Yb)N、δEu 和 Y/Ho 值)揭示了铜官山矽卡岩岩层从 GrtI 到 GrtII-Fe,以及 GrtII-Fe 到 GrtII-Al 阶段的理化条件分别是流体盐度和氧富集度的上升和下降,流体环境的封闭到开放再到封闭,流体 pH 值的中性-弱酸性到酸性和酸性到中性-弱酸性。综合判别分析表明,铜官山矽卡岩铜矿床在GrtI至GrtII-Fe阶段发生了流体沸腾,在矽卡岩阶段几乎没有外部流体混合。
Geochronology and geochemistry of garnet from Tongguanshan skarn Cu deposit, Tongling, eastern China: insights into ore-forming process
Skarn Cu deposits are one of most important deposit-type in Middle-Lower Yangtze River region, eastern China, but skarn formation process remains unclear. Mineralogical, morphological and in situ geochemical data from the skarn stage of Tongguanshan skarn Cu deposit in Tongling region are systemically investigated, to reveal the timing, physical-chemical conditions, and fluid evolution during the skarn formation. The Tongguanshan garnets can be identified homogeneous and unzoned early generation garnet (GrtI), and oscillating zoned late generation garnet (GrtII) with the Fe-rich core (GrtII-Fe) and Al-rich edge (GrtII-Al). Garnet U–Pb dating results show that the Tongguanshan Cu mineralization was formed in 145.6 ± 4.4 Ma. In situ elemental composition results of the garnet samples indicate that they belong to grossular-andradite solid solution series, and are a magmatic-hydrothermal origin. The distinctly geochemical characteristics (e.g., Sn and U contents, (La/Yb)N, δEu and Y/Ho values) reveal that the physiochemical conditions from GrtI to GrtII-Fe, and GrtII-Fe to GrtII-Al stages in the Tongguanshan skarn formation were an increase and a decrease of fluid salinity and oxygen fugacity, closed to open and then to closed of fluid environment, and neutral-weakly acidic to acidic and acidic to neutral-weakly acidic of fluid pH, respectively. A comprehensive discriminant analysis indicates a fluid boiling occurred in the GrtI to GrtII-Fe stage of the Tongguanshan skarn Cu deposit, and there is little or no external fluid mixed during the skarn stage.