苗儿山矿田中段红桥地区断裂构造特征及对铀矿找矿的指示意义OA

The Miao'ershan ore field in Guangxi is one of the important granite-type uranium deposits in South China,where ore bodies are strictly controlled by fault zones.Systematic field geological surveys were carried out in the Hongqiao area.By analyzing the development characteristics of faults across various tectonic stages and conducting a statistical analysis of joints from the Himalayan period,we can reconstruct the paleostress field corresponding to that period,and the fracture characteristics of each tectonic stage as well as their metallogenic effects were summarized.The results indicate that during the Caledonian orogeny,the area was controlled by southeast-northwest compressional stress,leading to the formation of the northeast-trending Miao'ershan composite intrusion.During the Indosinian orogeny,the regional stress field shifted to a near-north-south orientation.With continuous fault activity and crustal uplift,the rock deformation mechanism transitioned from ductile to brittle.During the Yanshanian stage,the regional stress field switched from a compressional tectonic regime to an extensional one.Uranium-bearing hydrothermal fluids migrated toward the intersections of multiorientation faults,precipitated and concentrated at these structural sites,and ultimately formed uranium ore bodies.In terms of mineralization characteristics,large-scale primary fault zones generally fail to form ore deposits,moderately sized secondary faults are the primary ore-hosting zones.Granitic uranium deposits in this study area are mainly controlled by third-and fourth-order fault structures.In addition,late-stage hydrothermal alteration exerts a prominent control on ore body thickness,and intense hydrothermal alteration can significantly increase ore body thickness.A comprehensive analysis indicates that structural domains characterized by intersecting multi-orientation faults,superimposed emplacement of orebearing hydrothermal veins and intense hydrothermal alteration possess excellent prospecting potential,this area can be designated as a priority for future exploration efforts.