The Research Of Picrite Sill And Its Relationship With Metallogenesis In Kuangshanliangzi Iron Deposit,Yanyuan County,Sichuan Province

As a part of Panzhihua iron deposits,the Pingchuan iron deposit in Pingchuan County,Sichuan Province has high-level exploration and low-level research.The main understanding about the Pingchuan iron deposit genesis focus on the 80s in the 20th century and has a difference with the Panzhihua iron deposit genesis.It is still not clear whether there is a link between two kinds of iron deposit genesis.This paper focus on the Kuangshanliangzi iron deposit—the main part of the Pingchuan iron deposit in Pingchuan County,Sichuan Province.Combined with previous report about the Pingchuan iron deposit,field geological investigation,sample collection in the system,analysis and Testing,quantitative textural analysis method(including crystal size distribution analysis,spatial distribution pattern analysis,and crystal alignment factor analysis),the author make the main ideas as followed:(1)Through the study of No.4 sill in the Kuangshanliangzi iron deposit,the author divided the olivine phenocryst into four kinds with different cause of formation:phenocryst olivine(including individual phenocryst and aggregation phenocryst),matrix olivine,olivine wrapped up in the pyroxene,long colum olivine.These different genetic types of olivine phenocryst belong to the corresponding populations:antecryst,residual crystal,matrix crystal.It shows that the magnesium-rich picrite basalt is not the product formed by the solidification process of the primary magma and has a complicated formation history;(2)the magnesium-rich picrite basalt of the Kuangshanliangzi is not the product formed by the solidification process of the primitive picrite melt in the closed system without component loss and added,but by adding a certain amount of olivine crystals once or several times;(3)Combination of geochemistry and CSD,we know the No.4 picrite sill is likely to be fed by multiple pulses of magma.(4)ore-bearing fluid moves and rises through the No.4 picrite sill,separates from magma and forms iron ore body.