甘肃大店沟金矿床中脆硫锑铅矿的发现与成矿启示OA

The newly identified jamesonite in the Dadiangou gold deposit,Liangdang County,Gansu Prov-ince,is closely associated with stibnite,galena,pyrite,and quartz.Detailed mineralogical,electron probe microanalysis(EPMA)and X-Ray Powder Diffraction(XRPD)reveal that its chemical composition(average formula Fe1.02Pb4.51Sb5.92S14.00)and crystal structure(monoclinic system,a=1.5383 nm,b=1.8716 nm,c=0.3937 nm)are in good agreement with theoretical values.This study not only identifies the mineral itself but,more importantly,we use its specific occurrence and composition as key geochemical indicators.The formation of jamesonite clearly indicates the injection of magma-derived fluids with high sulfur fugacity and enriched in Pb and Sb during the late stage of gold mineralization.This discovery provides robust mineralogical evidence for the involvement of magmatic-hydrothermal processes in the formation of the deposit under the shallow,variable geological conditions,thereby deepening the understanding of the mineralization mechanisms in this region.