Vein mineralization at the Damang Gold Mine, Ghana: controls on mineralization

Two distinct styles of Au mineralization occur at the Damang Gold Mine; Palaeoproterozoic sediments of the Tarkwaian Group host both. One style of mineralization is stratabound within quartz–lithic conglomerates of the Banket Series. The second style of mineralization is associated with an extensive low-displacement, fault–fracture mesh that formed in a compressional stress regime late in the deformational history and after the peak metamorphism. Regional deformation within the Tarkwaian involved initial NW–SE directed shortening (D1). A major NNE-trending F1 anticline hosts the Damang orebody. Broadly N–S shortening during D2 resulted in the formation of E–W-trending thrusts with small displacements. The D3 shortening direction was similar to that of D1. Steep D1 faults were reactivated and a new set of low angle thrusts and associated flat-lying extension veins were formed. The bulk of the mineralization observed at Damang is associated with the low displacement D3 fault fracture mesh. The presence of flat-lying extensional veins and the reactivation of some misoriented D1 structures is indicative of periodic episodes of supralithostatic fluid pressures, low differential stress and fault-valve behavior towards the end of the deformation history.