ABSTRACT
The Mines Group orebodies in the fold-thrust region of the Katangan belt in the DRC (Neoproterozoic-Lower Palaeozoic) occur at two levels within allochthonous mineralised megablocks embedded in the northern foreland basin strata, the Fungurume Group. The lower orebody, with exceptionally rich Cu-Co mineralisation, is hosted mainly in reduced clastic rocks called the grey R.A.T. underlain by oxygenated red bed facies (the red R.A.T.). A set of constraining factors, which include a new tectonostratigraphic reconstruction, suggests that the grey R.A.T. orebody could be genetically related to two stages of thrusting within the northern foreland basin. At stage 1, metal-rich fluids expelled from red beds lead to precipitation of the metals in the grey R.A.T. overridden by a nappe with the Roan carbonate rocks, which already hosted the upper orebody. At this stage, the new orebody, and some of the underlying red beds, were diagenetically ‘welded’ to the base of the nappe. Stage 2 thrusting resulted in diagenetic modifications, fragmentation of the nappe and, often, recycling into a new sub-basin of the foreland region.
