The Characteristics And Geological Implications Of The Pyrite And Gold Of Katebasu Gold Deposit,Xinyuan,Xinjiang Province

Katebasu gold deposit is situated in a deformation band near the north Nalati fracture on the northern margin of the Middle Tianshan Mountains.Pyrites in deposit develop extensively and they are related to mineralized minerals.The paper mainly study pyrites and gold of Katebasu deposit and study mineral feature,component feature and their implications of pyrite and gold by geological record and inside work.The deposit metallogenic process can be divided into two mineralization stages: the hydrothermal mineralization stage and supergene oxidation stage.The hydrothermal mineralization period can be further divided into four metallogenic stage:(?)pyrite-quartz phase,(?)quartz-pyrite phase(?)pyrite-sericite-quartz phase,(?)natural gold-polymetallic sulfide phase.Veinlet,disseminated and massive pyrite are often associated with sericite,which replaced by chalcopyrite.And the gold,sphalerite and galena can be seen in natural gold-polymetallic sulfide phase.The microscopic identification,photometer test,sclerometer and electron microbeam analysis of these four hydrothermal mineralization stage showed that the goldbearing of grannular pyrite and collective pyrite is better than others,and low reflectivity and low reflected color have a certain positive correlation with gold content.In the same stage,it also could concluded that the low hardness have better goldbearing in pyrite.The chemical composition of pyrite in Katebasu deposit show characteristic of slightly deficient of Fe and S,meanwhile,deficient S is more obvious than deficient Fe,which show the deposit has hydrothermal genesis characteristic.The pyrite value of ?(Fe)/?(S+As)is ranging from 0.859 to 0.888,the average value is 0.871,this value suggest that the formation environment is located in middle-upper position.The Co/Ni value is ranging from 1.94 to 4.56,which shows the information of pyrite is relative with hydrothermal activity;Pb and Zn elements could be seen in the pyrite of main metallogenic stage,indicating that the Pb and Zn elements exist in pyrite in the form of solid solution or nano-sized particles.The content of Cu in pyrite has a positive correlation with gold content in pyrite,and the higher contents of Cu and Au in main metallogenic stage.The gold-bearing pyrites are rich in As,but the content of As and Au don't present a positive proportion,only have positive correlation in former hydrothermal stage,Which suggest that As doesn't only derive from the mineralized thermal fluid but also comes from As dispersed in the wall-rock,the soil and the underground water which are extracted by the mineralized thermal fluid.The different elevation pyroelectricity of pyrites in mining area are tested,the result show distribution of the type P pyrites reduced gradually and the type N pyrites increased gradually with the loss of the height,meanwhile,a sudden increase of type P pyrite implies the existence of ore bodies in the deep part,which confirmed by zk5512.The temperature range of pyrite formation in Katebasu gold deposit was calculated by the equation,the temperature of type N is ranging from 220? to 370?,and the temperature of type P pyrite is ranging from 110? to 353?.The data is casted into pyrite thermoelectric coefficient temperature chart indicated the formation temperature of pyrite is mainly concentrated in 170~360?,indicating that the deposit is a medium temperature deposit.The gold bearing minerals are mainly pyrite,chalcopyrite and quartz,invisible gold and visible gold are two kinds of types in occurrence state of gold.Visible gold formed as independent minerals or developed with chalcopyrite,and the main forms of visible Au are round granular,grain shape long column,irregular shape,dendritic,vein.The distribution feature of gold is divided into encapsulated gold,fissure gold and crystal fissure gold.The content of the gold show that the main type of gold conclude native gold,silver-bearing native gold and electrum,which indicated the gold deposit developed in a medium-high environment.And the element about Fe?Cu?Zn?Cd?Sb?Co?Ni?Bi also could be detected,the Fe element are common sho w the gold have relatively connection with Fe.The Bi is the stable element in the gold which contents is ranging from 0.28 to 0.51.The native gold minera l with very high fineness according EPMA analyses means the deposit have a min eralogenetic epoch with Mesozoic.