Salt as a fluid driver, and basement as a metal source, for stratiformsediment-hosted copper deposits

Abstract

The source of copper for stratiform sediment-hosted copper deposits is considered to be redbed clastics situated stratigraphically below the deposits. However, for one of the principal copper provinces in the world, the Zambian Copperbelt, there is insufficient thickness of redbeds to constitute a viable source. Numerical modeling demonstrates that high-salinity sedimentary brines, generated beneath a halite seal, will develop convective hydrothermal plumes that penetrate through the redbeds, deep into the crystalline basement, despite its low permeability and regardless of the availability of cross-stratal conduits. This greatly expands the volume of the potential metal source for this style of ore deposit.