How to resolve the controls on mesothermal vein systems in a goldfield characterized by sparse kinematic information and fault reactivation―a structural and graphical approach

摘要

Current mine exposures of auriferous veins in the Charters Towers Goldfield (CTGF) are characterized by a scarcity of kinematic indicators. Furthermore, the dip direction of exposed and historically mined orebodies largely coincides with the orientation of pre-existing discontinuities. Consequently, the reactivation of earlier structures during gold deposition is strongly indicated. Both factors complicate the structural analysis of the auriferous vein systems, as slip on earlier faults likely occurred before new rock failure and evolution of fault networks reflecting the stress field present at the time of gold deposition. Despite access to drillcore, open pits and underground workings, extracted data were limited to ten occurrences of wear groove striations and three reverse separations of dykes and a pegmatite cut by sulphide-bearing quartz veins. Because of the scarcity of kinematic information, the structural analysis focused on the geometry of veins and ore-shoots, also applying basic graphical and kinematic methods.