Research On The Mineralogical Characteristics Of Metallic Mineral And Mineralization Of Longtougou Gold Deposit ,Shanyang, Shanxi Province

Longtougou gold deposit is located 13 km southeast of Shanyang County,Shaanxi Province,between the Shanyang-Fengzhen fault and the Zhenan-Banyan fault.The Xiajiadian gold-vanadium deposit and Wangjiaping gold deposit have been found in the region,and there are many copper,gold and silver anomalies,which have certain prospecting potential.Because Longtougou gold deposit was discovered late,predecessors only made a preliminary study on the characteristics of the deposit,but there are still some deficiencies in the study of the characteristics of metal minerals,the occurrence state of gold and the characteristics of gold-bearing minerals.In this study,by observing the field geological characteristics and ore samples characteristics of the Longtougou mining area,combined with microscopic characteristics research and electron microscope data analysis,the characteristics of metal minerals were identified,and the metallogenic stage was divided,the occurrence state of gold-bearing minerals was studied,and the metallogenic process of Longtougou gold deposit was preliminarily discussed.The results show that the main metal minerals in Longtougou gold deposit are pyrite,limonite,chalcopyrite,tetrahedrite,sphalerite,galena and gold-bearing minerals.According to the geological phenomena in the field,the petrographic characteristics of ores,the mineral symbiotic association,the types and compositions of metallic sulfides,the metallogenesis of Longtougou gold deposit can be divided into hydrothermal metallogenic stage and epigenetic weathering stage.The hydrothermal metallogenic stage can also be divided into three metallogenic stages: quartz-pyrite,quartz-gold-polymetallic sulfide and quartz-calcite-barite.The analysis of EPMA data shows that pyrite is generally characterized by sulfur deficiency.The average Co/Ni ratio in trace elements is greater than 1,indicating that the mineralization is related to magmatic hydrothermal solution.The Zn-Fe geothermometer and the Zn-Cd geothermometer of sphalerite indicate that the mineralization temperature is medium and low temperature.The high Ag content in galena indicates that the mineralization is closely related to magmatic hydrothermal solution.The wide distribution of tetrahedrite indicates that metallogenesis may be related to mesothermal hydrothermal solution.Most of the gold-bearing minerals occur between pyrite particles or wrapped in pyrite particles,while a few are distributed in pyrite fissures.Gold-bearing minerals in oxidized ores are closely related to limonite.Therefore,the main gold-bearing minerals are pyrite,limonite and beryllium copper.Gold fineness ranges from 825.0 to 975.0,with an average of 874.6.It is presumed that the gold metallogenic temperature range is medium temperature.The average temperature of the inclusions in the pre-mineralization period is 207 ?;the average temperature of the inclusions in the mid-mineralization period is 249 ?;the average temperature of the inclusions in the later stage of mineralization is 190 ?.The Longtougou gold deposit is judged to be a mesothermal magmatic hydrothermal gold deposit by comprehensive study.