| Dongzigou lead-zinc deposit is located in Xishui county of Guizhou province,and the tectonic position is located in the southern passive margin of the Yangtze block.The main outlying strata are sinian,Cambrian,ordovician,silurian,carboniferous,Permian,Triassic,Jurassic,cretaceous,etc.The total thickness is greater than 10km.Orebodies occur in Sinian Dengying Formation the group of the dolostone and its place in the mulberry field lead-zinc mine belt is about 4 km long,about 1 km wide,within the scope of 4.5 km~2,sporadic exposed lead-zinc mine points and lead barite veins;Research in wall rock alteration are mainly dolomitization,calcite and pyrite,time for silicide,barite,hotaru petrochemical,lead-zinc mine output and dolomitization,barite mineralization.The ore structure is dominated by breccia structure,followed by dense disseminated,sparse disseminated,fine vein,reticulate,submassive and clumpy structure;The structure of the ore consists of self-shaped and semi-automorphic granular structure,the structure of his shape,erosion,metasomatic structure,common edge structure,including structure and girdle structure.The main metallic minerals are sphalerite,galena,pyrite,lead,white lead,fibrous iron,pyrite,and a small amount of sulphide.The main gangue minerals are dolomite,barite,fluorite,calcite and a small amount of quartz.The mineralization period of this deposit is divided into hydrothermal phase and table life oxidation period according to the observation of the field geological phenomena and the mineral symbiosis under the microscope.The hydrothermal phase is divided into quartz-pyrite phase(I),pyrite-sphalerite-galena stage(II)and sphalerite-barite-bituminous stage(III).According to the ore fabric,the ore can be divided into breccia ore,disseminated ore,fine vein ore and dense lump ore,etc.According to the useful composition and oxidation degree of ore,it can be divided into zinc oxide ore,zinc oxide ore,mixed zinc ore and mixed lead and zinc ore.This study is based on the previous studies and uses a combination of macroscopic and microscopic methods to conduct a detailed study of the typical mineral characteristics of the Dongzigou lead-zinc deposit in order to provide some theoretical basis for ore deposit genesis.The main understanding is as follows:(1)By testing the microhardness and reflectivity of the sphalite deposit in dongziou deposit,it can be seen that it is close to the sedimentary deposit.(2)In the phase I to phase II,the crystal cell parameters gradually decreased,indicating that the Fe element content of sphalerite from stage I to stage II gradually decreased.(3)The chemical composition standard of sphalerite is high in Zn element and low in Fe content;The content of Mn and In elements is low,and the content of Ag,Cu,Ga and Ge is high,indicating that the sphalite is formed In the middle and low temperature environment,through lg(Ga/Zn)-lg(Ga/Ge)and ln Ga-ln In diagram,it indicates that it is similar to the sediment-controlled lead-zinc deposit.(4)The chemical composition Ag of galena is relatively low,and the ratio of Sb/Bi indicates that it belongs to the cause range of low temperature,and the lnbi-lnsb diagram indicates that it is similar to the sediment-type lead-zinc deposit.(5)The ratio of Co,S/Fe and Co/Ni in pyrite chemical composition indicates that pyrite is mainly formed in the medium temperature environment.In conclusion,the Dongzigou deposit belongs to the sediment-controlled lead-zinc deposit formed in low temperature environment. |
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