The Geochemical Characteristic And The Ore-forming Material Source Of Yuerya Gold Mine In Hebei Province

This paper drew support from consulting a large number of literatures and combined with field geological data, based on petrology, mineral deposits,petrogeochemistry and so on,analysed the major elements’ characteristics,trace elements’characteristics, rare earth elements’characteristics, fluid inclusions’characteristics, hydrogen and oxygen isotope’s characteristics, Ore-forming geological body, diagenetic age and mineralized age of Yuerya Gold Deposit in Hebei Province systematacially,discussed the removing and depositing system of gold and the ore-forming material source.The complex massif of Yuerya Gold Deposit is granite.Including early white granite and late red granite.The two are intrusive relationships.Their chemical compositions are similar, and have the crust source characteristic.They formed from partial melting and had the same material source, in accord with the characteristic of A-type granite.The age of Yuerya granite is 161Ma,and the age of ore body is 167Ma.The forming time of ore body is later then the forming time of granite.The spatial distribution of ore body is controlled by the granite. The plumbum isotope characteristic shows that the granite and the ore body are accordant.Based on the comparison of granite’s and ore body’s chemical composition and elementary characteristic,we can estimate the granite and the ore body come from the same source.The granite is the Ore-forming geological body of the gold ores.Mineralized hydrothermal water of Yuerya Gold Deposit mainly originated from the magmatic water,and added a little of atmospheric rainfall.The component of mineralized hydrothermal water are mainly H2O and CO2.The metallogenic temperature is mesothermal.The metallogenic depth is about 6.5 kilometer.Based on the test result of quartz fluid inclusions’ laser-raman spectrum, salinity and density,we consider that Yuerya gold deposit is a mesothermal-hydrothermal-deposit.The sulfur isotope test result shows that the sulfur mainly comes from hypomagma.There are some crust source sulfur.It shows that the metallogenic material of Yuerya gold deposit comes from the deep of the earth.Resulted from the forming of fault depression in North China, the pressure on the top of the lithosphere decreased and magma upwelled. Mesozoic granite’s large-scale emplacement drove the deep metallogenic material moving upward with the magma.In the process of moving,the physical-chemical conditions of fluid changed,and the pressure of the surrounding rocks reduced.When reached one balance point,the gold in the magma deposited and separated out,and mineralized in the suited structure position.