Fluid Characteristics And Quartz Infrared Spectra Of Yongxin Gold Mine In Heilongjiang Province

Yongxin gold deposit is located in the northeastern contact between the xingan block and the songnen block in the eastern part of the Xing-Meng orogenic belt and in determine the genetic type of the deposit,and the gold-bearing characteristics of the the cretaceous volcanic basin edge,the ore body occur in breccia bodies in the unconformity contact zone between syenite and mylonite.Based on the project of"study on mineralization rules and prospecting prediction in the Nenjiang-Heihe tectonic melange area in Heilongjiang province"?no.:201603?,in this paper,based on the summary and analysis of regional geological background,mining area and geological characteristics of ore deposit,ore body and ore geological characteristics system of yongxin gold mine,the metallogenic stage of Yongxin gold deposit is divided,fluid inclusion study,laser Raman probe test and hydrogen and oxygen isotope test further deposit are discussed by quartz infrared spectroscopy test.Achievements:1?The mineralization can be divided into four stages from early to late:pyrite-quartz???,quartz-pyrite???,quartz-polymetallic sulfide???and quartz-carbonate?IV?.The fluid inclusions in Yongxin gold mine are mainly aqueous fluid inclusion,and a small amount of fluid inclusions containing carbon dioxide appear in quartz-pyrite and quartz-polymetallic sulfide phases.2?Microscopical temperature measurement results show that,the homogenization temperature of aqueous fluid inclusion from early to late are 214³44?and 191²98?,120?³24?and 150²38?,and the peak of medium-term's homogenization temperature is concentrated in the 180²70?.The fluid salinity?%NaCleqv?of the deposit is low,ranging from 2.0%to 7.5%,and the density range is 0.60¹.00 g/cm³,with the process of mineralization from high temperature to low temperature,the fluid salinity shows a downtrend.The estimated range of metallogenic fluid pressure is 4²0MPa,and the fluid depth calculated according to hydrostatic pressure is 0.4²km.3?The He-Ar isotope characteristics of pyrite from Yongxin gold mine show that the range of⁴He_Mantleantle is 7.85%²2.77%,the H-O isotope characteristics of quartz indicate that the range of D value of the metallogenic fluid is-121.4‰^-113.9‰,and the range of 18O H2O is-8.1‰².7‰,,indicating that the characteristics of the ore-forming fluid are more similar to the mantle source region and are the mixture of magmatic water and atmospheric water,and with the progress of ore-forming,the degree of participation of atmospheric water is increasing.4?Combined with the metallogenic age and geological characteristics,Yongxin gold deposit is interpreted as a Epithermal gold deposit formed in early cretaceous.5?Through the quartz infrared spectroscopy test and analysis of the inclusion of yongxin gold mine,it is found that the relative optical density of H₂O and CO₂ is positively correlated with the content of gold,and the relative optical density of CO₂ is more correlated with the content of gold.When D₂/D₀<0.6,the minerality is poor.When D₂/D₀>0.65,the minerality is better.