ABSTRACT
Ore-related structures at the Zn-Pb Mississippi Valley-type San Vicente deposit, Central Peru, display a systematic geometry with respect to bedding and a regional thrust, interpreted as Miocene in earlier studies. Sparry dolomite veins and breccia bodies have a constant NS direction, and are either perpendicular to bedding with dips −70° to the east, or parallel to bedding, dipping −25-30° westerly. Zebra structures display identical concordant and discordant relationships relative to bedding. The preferential orientation of the gangue structures is interpreted within a dextral shear zone model, where they are either controlled by tensile fractures formed during thrusting or by pre-existent anisotropies, such as bedding planes. It is concluded that the San Vicente deposit is coeval with the host thrust zone, and therefore Late Andean in age.
