Geochemical Characteristics and Genetic Indications of Trace Elements and H-O Isotopes in Quartz of Baidi Gold Deposit,Guizhou Province
The Baidi gold deposit of Guizhou Province is a typical gold-antimony co-occurrence medium deposit located in the middle of Youjiang Basin,with fine clastic rock as its host rock and controlled by the tectonic system of steep inclined fault-fold belt.In this paper,the contents of trace and rare earth elements and H-O isotope of quartz in different hydrothermal mineralization stages are tested and analyzed,and the source and evolution of ore-forming fluid are discussed.The results show that quartz from at each hydrothermal mineralization stage,Sb,As,Cd,Ge,W,Li are enriched,and Be,Nb,Zr,Hf are strongly depleted,the rare earth content and partition curves of quartz from different hydrothermal mineralization stages vary greatly,the rare earth content and partition curve from quartz in different stages are quite different.The first hydrothermal mineralization stage is more obvious to the right,LREE is enriched,Ce anomaly is not obvious,and Eu negative anomaly is weak.The rare earth partition curve from quartz in the second hydrothermal mineralization stage is gently to the right,and the Ce and Eu anomalies are not obvious.The rare earth partition curve from quartz in the third hydrothermal mineralization stage is"upconvex",with MREE enrichment,weak positive Ce anomaly and obvious positive Eu anomaly.The results show that the ore-forming fluid of Baidi gold deposit has obvious mixed origin,mainly composed of formation water and a small amount of deep magmatic fluid mixed with basement metamorphic water.The fluid environment in theⅠ stage is reductive and acidic.The Ⅱ stage fluid inherited the characteristics of the Ⅰ stage fluid,and the environment changed to oxidation,alkaline,so that Au and other elements precipitated,and REE and Y entered the Ⅲ stage fluid.In the Ⅲ stage,the fluid environment is oxidized and alkaline,resulting in the precipitation of Sb and the entry of surrounding rock Sr.From stage Ⅱ to stage Ⅲ,the changes of fluid environment and the reduction of metamorphic water in deep basement indicate that the hydrothermal mineralization process of Baidi gold deposit is multi-stage,and the participation of deep magmatic fluid and basement metamorphic water in the ore-forming fluid gradually decreases.
quartztrace elementsrare earth elementssource and evolution of ore-forming fluidgeochemical characteristicsBaidi gold deposit,Guizhou Province
万方数据
维普
