Basin Fluid Mineralization during Multistage Evolution of the Lanping Sedimentary Basin,Southwestern China

The Lanping sedimentary basin has experienced a five-stage evolution since the late Paleozoic:ocean-continent transformation(late Paleozoic to early mid-Triassic);intracontinental rift basin(late mid-Triassic to early Jurassic);down-warped basin(middle to late Jurassic);foreland basin(Cretaceous);and strike-slip basin(Cenozoic).Three major genetic types of Ag-Cu polymetallic ore deposits,including the reworked hydrothermal sedimentary,sedimentary-hydrothermally reworked and hydrothermal vein types,are considered to be the products of basin fluid activity at specific sedimentary-tectonic evolutionary stages.Tectonic differences of the different evolutionary stages resulted in considerable discrepancy in the mechanisms of formation-transportation,migration direction and emplacement processes of the basin fluids,thus causing differences in mineralization styles as well as in genetic types of ore deposit.