Geological Geochemical Characteristics And Regional Prospective Evaluation Of The Yangjiazhai Gold And Polymetallic Mining Area In Luchun County,yunnan Province

Yangjiazhai metallogenic ore district is located in the southern Ailaoshan metallogenic belt.Complex structures and multi-period of magmatic rocks make it a favourable metallogenic zone.In this paper,the mineralization mechanism and metallogenic regularity are discussed in combination with the characteristics of soil geochemical characteristics and the geochemical characteristics of volcanic rocks.Combined with the geological metallogenic information,the geophysics and the geochemistry anomaly,remote sensing interpretation,the metallogenic prospect of the mining area is systematically evaluated and the mineralization prospects area is delineated.The lower Permian Gaojingchao group is the main exposed strata in Yangjiazhai mining area.The main ore bearing rocks are andesite and andesitic tuff,quartz porphyry.Geochemical data show the volcanic rocks has the geochemical characteristics of depleted mantle and the later magma crystallization residual magma,with the subduction related geochemical characteristics,a certain degree of crustal contamination occurred during the magmatic evolution.The volcanic rocks has the characteristics of synsubduction-type island arc volcanic rocks,may be formed in the geodynamic background of the ancient Ailaoshan oceanic crust westward subduction into the Lanping-Simao block during the Early Permian.The subducted oceanic slab subducted to the depths formed the magma by partial melting,this magma rised into the mantle wedge and partially melted with the mantle formed andesite magma.During the andesite magma ascent,large amounts of metallogenetic elements were released,have been hybridized subsequently by crustal material and overflow surface enrichment and mineralization.The soil element geochemical anomaly show the abnormal area has obvious concentration,continuous distribution of high value point,obvious three stage zoning.The anomaly is a well composit anomaly with association of Au-As-Sb-Ag-Mo-Hg and Cu-Pb-Zn.Through the analysis of primary halos of rock samples from Gaojingchao Group show the geochemical characteristics of the front halo and near ore halo of the ductile shear zone type of gold deposit,with the middle and deep prospecting potential.Based on analogy similar deposits and soil geochemical information,the authors present a ductile shear zone type gold and polymetallic ore prospecting model in this area.The use of geostatistical methods for geological metallogenic information,geophysics anomaly,geochemistry anomaly,remote sensing interpretation of scientific information,the geological,geophysical,geochemical and remote sensing information show that the information is well integrated with each other.Three metallogenic regions are delineated.The anomalous long axis direction is northwestward,which is consistent with the ore-controlling structure in the area,indicating that the area is obviously controlled by regional structure.The anomalous areas are mainly distributed in andesite,the lower Permian Gaojingchao group and Baliu group,indicating that the area is controlled by magmatic rocks and strata.The strata,tectonics and magmatic rocks are the main ore controlling factors in this area.This recognition is of great significance to the future prospecting work.