Study On The Fluid Inclusions And Genesis Of The Dongyaozhuang Glod Deposit In Wutai County,Shanxi Province

Dongyaozhuang gold deposit is a typical greenstone type of greenstone gold deposits in Wutaishan area,occurs in the Wutaishan granite-greenstone belt in the north-central part of the North China craton.The deposit is located at the western end of the Taihuai-Lijiazhuang composite syncline of the"Zhi"type structure in Wutaishan.The regional strata are NE-SW trending.Ore bodies occur mainly in sericite albite schist of Hongmen Formation of Wutai Group.There are three orebodies in the mining area,which correspond to three ore-bearing belts respectively.Among them,the No.1orebody is the largest one with the highest degree of work and is the main orebody in the mining area.This paper relies on the project of"Regional Difference of Gold Mineralization in Eastern North China",uses the laser facies of the quartz deposits in the deposit,microscopic temperature measurement and calculation,using laser Raman spectroscopy and infrared spectroscopy of inclusions and pyrite Rb-Sr isotope dating.The methods of the ore-forming fluids,physical and chemical properties and genesis of the ore deposits in the Dongyaozhuang gold deposit were discussed.The following main insights were obtained:The main types of inclusions in Dongyaozhuang gold deposit are mainly Gas-liquid H₂O two-phase inclusions,H₂O-CO₂ three-phase inclusions,pure liquid and pure Gas inclusions.It is showed that the temperature ranges of H₂O-inclusions by measuring temperature is about 96.4⁴37.6℃,the average temperature is 184℃,mainly concentrates ranges between 120²20℃.The mainly mineralized temperature ranges between 120²20℃.The salinity of the ore-forming fluid ranges between 0.5¹3.9wt%NaCl,with an average of 4.9wt%NaCl,mainly concentrated in 2.0⁶.0wt%NaCl.The density of the ore-forming fluid ranges between 0.52¹.04g/cm³,with an average of 0.92g/cm³,mainly concentrates in the range of 0.85¹.0g/cm³.The Metallogenic pressure ranges between 34.3⁵1.2 Mpa,with an average of 48.07 Mpa.The metallogenic depth ranges between 1.27¹.90 km,with an average of 1.60 km.Hydrogen and oxygen isotope studies show that theδD_H2O value of water in inclusions varies between-77‰^-95.8‰,with an average value of-87.6‰.Theδ¹⁸O value in quartz ranges from 12.1‰¹3‰,with an average of 12.3‰.Theδ¹⁸O_H2O2O value of water in inclusions ranged from-1.4‰⁰.2‰with an average value of-0.2‰.Through the mapping of hydrogen and oxygen isotope test results,it can be seen that the data points measured in Dongyaozhuang gold deposit are concentrated in the mixing area of magmatic water metamorphic water and atmospheric precipitation,but there is a trend towards metamorphic water.According to the Rb-Sr isotope method of measuring the age values for 2443±Ma.Dongyaozhuang gold deposit is a tectonic-metamorphic hydrothermal gold deposit formed by bedding shear of basic bedrock.