The Geochemistry And Morphology Of Titanite As Indicators For W?Fe?Au Mineralizations

Titanite?CaTiSiO₅?as an important REE-rich mineral,has been widely developed in various geological bodies,recorded abundant diagenesis and mineralization information.However,there is a lack of systematic research on the identification of different metallogenesis effects on the morphology and geochemistry of titanite.In this paper,by collecting and collating data on the occurrence,morphology,and chemical composition of titanite in different types of W,Fe,and Au deposits,the identification of titanite typomorphic characteristics on mineralization is studied.The Huashan and Wenyu plutons represent two typical Mesozoic magmatic intrusions in the Xiaoqinling gold deposit concentration area and were coeval with the Au mineralization,but the spatial relationship with the Au deposit is obviously different.By comparing the characteristics of major elements,trace elements and compositional zones of titanite in these plutons,the relationship between Au enrichment and granite diagenesis was discussed.Combining the measured 648EPMA data,60 LA-ICP-MS data and the collected data,it summarizes the identification of titanite components for different types of W,Fe,Au deposits and different ore body positions.Statistical research shows that the titanite F-?Al₂O₃+FeO_T?diagram can identify the distance from the ore body.The titanite in altered rocks and hornfels away from the ore body is relatively low in F and low?Al₂O₃+FeO_T?,and the titanite in the near ore body is relatively high in F and high?Al₂O₃+FeO_T?.In different mineralization types,the titanite LREE-MREE-HREE diagrams have obvious spatial differences in composition areas and have a certain distinguishing effect.The content of V⁵⁺,Ga³⁺and Fe³⁺in titanite is positively correlated with fO₂,which has a good identification effect on fO₂ in the environment of titanite formation.?Ce and?Eu are disturbed by many factors.As an index for comparing the relative fO₂ of the deposit,its regularity may be destroyed,so it needs to be used with caution.The Al content at the Ti-site is positively correlated with the pressure of the titanite formation environment.The titanite Fe/Al is a good indicator of the type of minerals and deposits.To a certain extent,it can distinguish the deposits of different origins of the same minerals,as well as distinguish and predict the minerals.Compared with the Huashan pluton's titanite,the Wenyu pluton's titanite has a higher?REE,Fe/Al,and lower Al₂O₃.LREE/HREE is almost twice that of the Huashan pluton's titanite.The differentiation of REE is more obvious,and the oscillating zone is more developed.The environmental turbulence when the Wenyu pluton was formed was relatively obvious,and the formation pressure was low.The different properties of the two plutons may be an important reason for the difference in the spatial distribution of the gold deposits in the Xiaoqinling area.The characteristics of the Wenyu pluton may be more conducive to the Au mineralization and the gold-forming potential is superior to the Huashan pluton.