Research On The Structural Deformation Characteristics And Genesis Of Awanda Gold Deposit,Xinjiang

There are several world-class and giant gold deposits in the southern Tianshan orogenic belt of Central Asia,such as the Muruntau gold deposit,the Zarmitan gold deposit,and the Jilau gold deposit.In recent years,the Savayalton giant gold deposit and many small and medium gold deposits have been discovered,which shows good prospecting potential in the southern Tianshan of the Xinjiang Uygur Autonomous Region.The Awanda gold deposit is a medium gold deposit newly discovered in the southern Tianshan of Xinjiang.The ore body stores in the late Paleozoic schists.Due to the ductile shear zone which shows two-stage deformation,the schists turned out to mylonitization.The ore body is mainly layered.Arsenopyrite,pyrrhotite and pyrite are the main metal sulfides in ores,and the content of metal sulfides is about 5%.The ore is mainly disseminated structure and fine vein structure.Wall rock alterations are silicification,sericitization,carbonation and chlorite.Mineralization is divided into two stages,the first stage is the medium-temperature mineralization stage,which is the main stage of gold mineralization.Electron probe analysis shows that arsenopyrite,pyrrhotite,and pyrite are all gold-bearing minerals.But the highest ore grade occours in which has the most content of disseminated arsenopyrite.The age of 298±15 Ma,via the zircon U-Pb method of newly discovered granite in the Awanda gold deposit,indirectly defined the upper limit of the the wall rock's age.And the wall rock was limited from the Devonian to the C arboniferous(405 Ma to about 298 Ma).The wall rock schist,which probably origined from the mudsone or the sandstone,formed by the regional metamorphism of the southern Tianshan orogenic belt.According to the geological exploration of the mining area,microstructural studies and the optimization result of quartz crystallography,it was founded that the mine experienced three major deformation and metamorphisms,the first time was a south-to-north thrust,whcih corresponding to the northern edge of the Tarim plate collided with the middle Tianshan;the second time was a left-lateral strike-slip effect,forming the ductile shear zone and mylonites.The major mineralization occured at the end of the strike-slip effect;the third time was a right-lateral thrust effect.The mylonite fractured and later filled with hydrothermal mineralization in the fracture.According to the relationship between structural deformation and mineralization,the age of the wall rock and the granite which near ore body,it is inferred that the metallogenic age of the Awanda gold deposit should be the Early Permian.After comparing the features of the Awanda gold deposit with the orogenic gold deposits and the large or giant gold deposits in the southern Tianshan,it is considered that the geological background,tectonic settings,metallogenic age,metal minerals,wall rock alterations,and fluid inclusions are similar.The genetic type should be orogenic gold deposit.