Genetic Mineralogy And Ore-forming Fluid Study Of Xiaoyinchang Silver Deposit In Atong,HanXi Province

Xiaoyinchang silver polymetallic deposit located in Shan Xi Hunyuan County,in Mountain-Hengshan polymetallic metallogenic,this region is one of the main mining area,located at the base of the North China platformconstitute two things colliding continental blocks the region is formed,the so-calledcentral North China orogen.Here mineralization conditions are favorable.Theories and methods of mineralogy,on the basis of the previous geological characteristics,metallogenic background and geochemical characteristics of the deposit of the aboveresearch,studied mineralogy characteristics of ore-forming fluids and obtain main conclusions are as follows:Through measuring the shape of Mineralized quartz flow of the fluid inclusions,it is known that there are two hydrothermal mineralization period,the temperatures of the ore-forming fluid is baout 200℃and280℃,which is mid-temperature,high-temperature hydrothermal.The acerage salinity of ore-forming fluid which belongs to a kind of mid salinity fluid is about 13%,The density of the ore-forming fluid mainly ranges from 0.65~0.95 g g/cm3.Based on the elements combination characteristics,the analysis of the primary halo of the third vein shows that characteristics of the a Xial zonation and superposition is obvious,Cu+Ag+Pb+Zn as the near-ore hole elements combination;W+Co+Ni +Mo as the rear halo elements combination,the front halo elements combination appear to be no abnormal,the near-ore hole and the rear halo superimposed.The analysis showed that,the region’s mojor alteration minerals(relative oercentage greater than 5%)are muscovite(phengite),illite,dickite,are chlorite,epidote,calcite,dolomite,and a small amount of gypsum.According to the distribution and relatice content of the alteration minerals we think the alterative zone closing to ore body is phyllic alteration(alteration mineral assemblages;secondary muscovite+ illite,etc.);the alterative zong far away from the ore body is mudding(alteration mineral assemblages:dickite+ montmorillonite,etc.)...