Analysis of Ore-controlling Structure and Prospecting of Tectonogeochemistry in Jinshan Au-Ag Mining Area,Guangxi

Through the field investigation and structural maping of the Jinshan Au-Ag mining area in Guangxi Province,the ore-controlling structural regularities have been summarized.On this basis,the prospecting study of geochemistry was carried out in the main ore-controlled fault zone.There are two deposit types in the mining area,one is altered rock type gold deposit which was hosted in the main ore-controlled fault zone,and the other is quartz vein type gold deposit which was hosted in the flank pinnate tension fracture.The different mineralization types were controlled by the different tectonic environment,and they can be a prospecting criteria for each other.The orebody was controlled by the tectonic interface.The mineralization have obviously sub-enrichment regularity because the ore-controlling fault opened heterogeneously in the mineralization period.The tectonic activities in mineralization period shows the hanging wall of the main fault oblique-slipped toward southeast,accordingly the orebody is SW-lateral trending and its depth is greater than extension.The middle of orebody is thicker than both sides,and the exploration line No.11 is the enrichment center of mineralization.The concentrations of metallogenic elements,Ag,Au,Cu,Pb,and Zn increased with increasing alteration.Factor analysis show the main metallogenic elements association is Ag,Au,Cu,Pb,and Zn,which can be used as indicator elements.The elements distribution patterns,combination analysis and fractal dimension statistics show that multistage silver and gold mineralization.The zoning sequence of tectono-geochemical primary halo is Au-Hg-As-Bi-Sn-Sb→Mn-V-Ag-Ni-Ti-Cr-Co-W→Mo-Pb-Zn-Cu from upper to down,which shows that the deposit is a shallow denudated deposit and may be superimposed by late-stage hydrothernal fluids.On the basis of the analysis of ore-forming structures,the magmatic activities,the characteristics of alteration zone and tectono-geochemical primary halo zoning,it can be proposed that the deep and periphery of the mining area have still better prospecting potential.The key zone of prospecting is in the southwest of the exploration line No.11.