Study On Metallogenic Geological And Geochemical Characteristics Of Hatu Gold Deposit In Xinjiang

The Hatu gold belt in the western Junggar area of Xinjiang is an important part of the Central Asian orogenic belt.The Hattu gold deposit is located in the narrow zone between the Hatu fault and the Anqi fault in the western margin of the Junggar basin.The mining area occurs in the strata of the Lower Carboniferous Xibeikulas formation,the Baogutu formation and Tailegula the formation.The deposit is controlled by the Anqi fault and the associated secondary faults,and mainly produces two kinds of gold orebodies:altered rock type and quartz vein type.Through the study of the geological characteristics,geochemical characteristics,fluid inclusions and metallogenic sources of the Hatu gold deposit,this paper provides a basis for an in-depth understanding of the genesis of the Hatu gold deposit and the metallogenic mechanism of the Hatu gold belt.At present,the following knowledge has been obtained:?1?According to the mineral symbiosis relationship and vein intercalation relationship,the formation of Hutu gold deposit can be divided into the early stage of albite-quartz assemblage,the middle stage of sulfide-natural gold-quartz assemblage and the late stage of carbonate-quartz assemblage.?2?The study of quartz vein fluid inclusions shows that there are three types of fluid inclusions in the ore body,which are type?:liquid-rich two phase inclusions?L+V?;type?:vapor-rich two phases inclusions?L+V?;type?:CO₂ three phases inclusions.The type I,type II and type III inclusions are developed in the early stage.The homogenization temperature is 293-379?,and the fluid salinity is 1%-5.7%NaCl_eqv.The type I,type II and type III inclusions are developed in the middle stage.The homogenization temperature is 213-291?and the fluid salinity is 0.5%-5.9%NaCl_eqv.In the late stage,only type I inclusions were developed.The homogenization temperature was 148-216?,and the fluid salinity ranged from 1.4%-4%NaCl_eqv.Based on the pressure and depth calculation,the metallogenic pressure is 47 to 97MPa and the corresponding depth is 4.8 to 9.4 km.The gas and liquid phase composition analysis of fluid inclusions shows that the ore-forming fluid belongs to NaCl-H₂O±CO₂±CH₄±N₂ system.?3?The?¹⁸O_V-SMOW value of quartz is 20.4‰-21‰.The calculated?¹⁸O_H2O value of balance water is 8.6‰-14.7‰.,and the?¹⁸D_H2O of the quartz inclusions is-77.2‰to-64.5‰.In the carbon and oxygen isotopic composition of calcite,the value of?¹³C_PDB is-11.4‰^-9.2‰,and the value of?¹⁸O_SMOW is+8.5‰⁺17.4‰.The sulfur isotope composition of sulfides was-2.9‰⁺0.8‰,concentrated in the range of0±3‰.The ore-forming fluid is low salinity and low density NaCl-CO₂-H₂O system mainly affected by magmatic activity with metamorphic water and meteoric water as the main body.the sulfur of ore-forming material comes from magmatic fluid or ore-bearing country rock.?4?The source of ore-bearing hydrothermal solution and the heat source needed for the migration and enrichment of ore-forming elements have nothing to do with the granite body exposed in the gold belt and may be related to the continental volcanic activity of the Kalagang formation in the early Permian.?5?The fluid inclusions,isotopic physical and chemical properties and ore-controlling structures were verified,the Hutu gold deposit is an orogenic type medium low temperature hydrothermal gold deposit.