Porphyry-skarn deposits are genetically associated with multistage intrusive complexes.However,their ore fertility varies markedly,as exemplified by the coexistence of mineralized and barren intrusions within a single...Porphyry-skarn deposits are genetically associated with multistage intrusive complexes.However,their ore fertility varies markedly,as exemplified by the coexistence of mineralized and barren intrusions within a single pluton.The factors controlling this disparity,particularly whether high oxygen fugacity(fO_(2))and volatile-rich magmas are essential,remain poorly constrained.This study investigates the Fengyan Zn-Pb-Mo deposit in the central Fujian region by comparing geochronological and geochemical features of ore-associated granite porphyry and barren monzogranite.SIMS zircon U-Pb dating reveals the mineralized intrusion crystallized at 142.5±1.6 Ma,significantly later than the barren monzogranite(150.3±1.3 Ma).The ore-associated porphyry exhibits higher magma temperatures and sulfur contents,yet lower fO_(2)and water content relative to the barren monzogranite.Hf-O isotopes reveal greater mantle input in the ore-related granite porphyry(ε_(Hf)(t)=-11.5 to-7.5;δ^(18)O=6.50‰to 7.11‰)than in the ore-barren monzogranite(ε_(Hf)(t)=-16.0 to-9.5;δ^(18)O=6.81‰to 8.00‰).Furthermore,elevated fO_(2)and volatile-rich conditions are not prerequisites for Zn-Pb-Mo mineralization,implying other factors are key.The barren rock formed during low-angle subduction of the Paleo-Pacific plate,whereas the mineralized porphyry originated during slab rollback and lithospheric extension.This study highlights that medium-low fO_(2)(meanΔFMQ+0.39 in granite porphyry vs.+1.80 in monzogranite),volatile-poor magmatic systems in extensional settings can form significant mineralization,offering new insights for exploration in central Fujian and analogous regions.展开更多
基金jointly funded by Innovation Youth Project of Natural Science Foundation of Fujian Province(No.2024J08144)the Open Fund Project of the Key Laboratory of Ionic Rare Earth Resources and Environment,Ministry of Natural Resources(Grant no.2022IRERE101)+2 种基金the National Natural Science Foundation of China(No.41820104010)Basic Scientific Research Fund of Chinese Academy of Geological Sciences(No.JYYWF20180601)China Scholarship Council(CSC,201908110163)。
文摘Porphyry-skarn deposits are genetically associated with multistage intrusive complexes.However,their ore fertility varies markedly,as exemplified by the coexistence of mineralized and barren intrusions within a single pluton.The factors controlling this disparity,particularly whether high oxygen fugacity(fO_(2))and volatile-rich magmas are essential,remain poorly constrained.This study investigates the Fengyan Zn-Pb-Mo deposit in the central Fujian region by comparing geochronological and geochemical features of ore-associated granite porphyry and barren monzogranite.SIMS zircon U-Pb dating reveals the mineralized intrusion crystallized at 142.5±1.6 Ma,significantly later than the barren monzogranite(150.3±1.3 Ma).The ore-associated porphyry exhibits higher magma temperatures and sulfur contents,yet lower fO_(2)and water content relative to the barren monzogranite.Hf-O isotopes reveal greater mantle input in the ore-related granite porphyry(ε_(Hf)(t)=-11.5 to-7.5;δ^(18)O=6.50‰to 7.11‰)than in the ore-barren monzogranite(ε_(Hf)(t)=-16.0 to-9.5;δ^(18)O=6.81‰to 8.00‰).Furthermore,elevated fO_(2)and volatile-rich conditions are not prerequisites for Zn-Pb-Mo mineralization,implying other factors are key.The barren rock formed during low-angle subduction of the Paleo-Pacific plate,whereas the mineralized porphyry originated during slab rollback and lithospheric extension.This study highlights that medium-low fO_(2)(meanΔFMQ+0.39 in granite porphyry vs.+1.80 in monzogranite),volatile-poor magmatic systems in extensional settings can form significant mineralization,offering new insights for exploration in central Fujian and analogous regions.
