矿床地质2025，Vol.44Issue(3)：635-657,23.DOI:10.16111/j.0258-7106.2025.03.007
福建漳平凤山矽卡岩型萤石矿床石榴子石特征及其意义
Characteristics and significance of garnet from Fengshan skarn fluorite deposit,Zhangping,Fujian Province
摘要
Abstract
The Fengshan skarn fluorite deposit is located at the eastern margin of the Late Paleozoic depression basin in southwest Fujian Province.The discovery of this large-scale fluorite deposit is one of the important achievements of non-metallic prospecting projects in southwest Fujian Province in recent years.The results show that the Feng-shan garnet has two generations(Grt Ⅰ and Grt Ⅱ)and belongs to the andradite-grossular solid solution series(And7.00～100Gro0～93.00Spa0.44～42.62).The component of Grt Ⅰ is close to the andradite endmember(And89.56Gro10.39Spa1.77),with depletion of high field strength elements(Nb,Zr,Hf,Ta,Th,Ti,etc.)and a right-dipping rare earth element pattern with a positive Eu anomaly,whereas the component of Grt Ⅱ is close to the grossular endmember(And11.69Gro88.28Spa24.36)and displays enrichment of high field strength elements and a left-dipping"M"-type rare earth element pattern,with a negative Eu anomaly.The Grt Ⅰ is also significantly enriched in trace elements such as W(249×10-6～950×10-6)and Sn(448×10-6～1699×10-6),which suggests a potential for W mineralization.This is further supported by the presence of minor scheelite in skarn ores.Garnet texture and composition features indi-cate that the formation condition of garnet has changed from a relatively open system with a high water-rock ratio to a relatively closed environment with a low water-rock ratio,and the ore-forming fluids gradually changed from relatively high oxygen fugacity and weak acidity in the early stage to a neutral hydrothermal fluid with low oxy-gen fugacity in the late stage.The garnet U-Pb geochronology result shows that skarn fluorite mineralization age of the Fengshan deposit is(161.5±3.3)Ma,which belongs to the Late Jurassic and is consistent with the age of the magmatic rocks((158.8±1.8)Ma)in the deposit within the limits of error.This study demonstrates that the Fengshan fluorite deposit is closely related to the magmatic-hydrothermal fluid caused by the tectonic transforma-tion during the Yanshanian.The skarn fluorite mineralization was formed by combined controls which include F-rich magmatic-hydrothermal fluid,carbonate rocks,and contact zone-interlayer fractures.关键词
石榴子石/U-Pb定年/LA-ICP-MS/凤山萤石矿床/福建漳平Key words
garnet/U-Pb dating/LA-ICP-MS/Fengshan fluorite deposit/Zhangping City in Fujian Province分类
地质学引用本文复制引用
陈素余,徐净,戴定贤,范育敏,郭新强..福建漳平凤山矽卡岩型萤石矿床石榴子石特征及其意义[J].矿床地质,2025,44(3):635-657,23.基金项目
本文得到福建省自然资源科技创新项目(编号:KY-060000-04-2023-004)和福建省教育厅中青年教师教育项目(编号:JAT210043)联合资助 （编号:KY-060000-04-2023-004）
