地质通报2025，Vol.44Issue(9)：1641-1661,21.DOI:10.12097/gbc.2024.04.041
胶东前垂柳金矿床中—基性脉岩锆石U-Pb年龄、地球化学特征及对成矿时代的约束
Zircon U-Pb dating and geochemical characteristics of intermediate-mafic dykes in the Qianchuiliu gold deposit,Jiaodong Peninsula:Implications for mineralization age
摘要
Abstract
[Objective]The Qianchuiliu gold deposit is a newly discovered large-scale altered rock-type gold deposit in the northeastern margin of the Jiaolai Basin.Post-mineralization intermediate-mafic dikes(lamprophyre,diabase,and diorite porphyry)are widely developed in the mining area.Their formation age,petrogenesis,and relationship with gold mineralization remain unclear.Studying these dikes can provide new evidence for understanding the coupling between regional tectonic-magmatic evolution and mineralization processes.[Methods]Intermediate-mafic dikes(lamprophyre,diabase,and diorite porphyry)cutting through mineralized alteration zones were collected from surface and subsurface in the mining area.Systematic petrographic,whole-rock geochemical,and zircon U-Pb geochronological studies were conducted to analyze their geochemical characteristics,magma source,and formation age.[Results]The dikes exhibit alkaline,high-K,and low-Ti characteristics,with enrichment in large-ion lithophile elements(Ba,Th,U)and light rare earth elements(LREE),and depletion in high-field-strength elements(Nb,Ta,Zr)and heavy rare earth elements(HREE).These geochemical features classify them as shoshonitic to high-K calc-alkaline series,indicating a subduction-related tectonic setting.Geochemical and isotopic compositions,combined with zircon U-Pb age spectra,reveal that the dikes were derived predominantly from an enriched mantle source,with incorporation of Paleoproterozoic to Triassic crustal materials from the North China Craton and Sulu orogenic belt during magma emplacement,resulting in varying degrees of crustal contamination.The youngest weighted mean zircon U-Pb age of 117.5±1.8 Ma from the three dike types represents their final crystallization age.Together with their crosscutting relationship with mineralized alteration zones,this constrains the main gold mineralization at Qianchuiliu to have terminated by the Early Cretaceous(≥117.5 Ma),consistent with the previously defined lower limit of mineralization age in this region.[Conclusions]The formation of the Qianchuiliu gold deposit is genetically associated with large-scale Yanshanian tectonic-magmatic activities in eastern North China.The emplacement of intermediate-mafic dikes(～117.5 Ma)marks the termination of regional gold mineralization,demonstrating significant contributions from crust-mantle interactions under the Pacific Plate subduction setting.These findings provide new geological evidence for understanding the tectonic-magmatic-mineralization coupling during the Yanshanian period in eastern China.关键词
锆石U-Pb年龄/地球化学/中—基性脉岩/前垂柳金矿/成矿时代/胶东Key words
zircon U-Pb geochronology/geochemistry/intermediate-mafic dykes/Qianchuiliu gold deposit/mineralization age/Jiaodong分类
天文与地球科学引用本文复制引用
韩小梦,段留安,王建田,王志军,王宏亮,张健康..胶东前垂柳金矿床中—基性脉岩锆石U-Pb年龄、地球化学特征及对成矿时代的约束[J].地质通报,2025,44(9):1641-1661,21.基金项目
国家重点研发计划项目课题《脉状金系统的综合找矿技术与增储示范》(编号:2022YFC2903605)和中国地质调查局项目《山东牟平辽上金矿资源调查评价》(编号:DD20243129) Supported by National Key R&D Program of China(No.2022YFC2903605)and China Geological Survey Project(No.DD20243129) （编号:2022YFC2903605）
