The Inter-cratonic Neoproterozoic Katangan basin of Central Africa: rift basin formation, orogenic inversion and potential fluid pathways

The tectono-stratigraphic development of continental basins is crictical to an understanding of continental tectonics and the formation of metal deposits. The Neoproterozoic, inter-cratonic Katangan copper basin of Central Africa records a tectono-stratigraphic evolution and the generation of potential metal transporting fluid pathways. Integration of lithospheric structure, quantitative basin analysis, sediment routing systems, and basin structure defines the tectono-stratigraphic model of the basin. The basin lies between the Congo and Kalahari cratons, on lithosphere distinctly thinner than the adjacent craton cores. Crustal scale fault zones parallel the craton margins and suggest lithospheric weaknesses influenced the basin shape. Basin subsidence analysis indicates two phases of rift-driven subsidence and increasing lithospheric extension from the basin boundary to a Central Rift Zone (CRZ). The CRZ also marks a sediment provenance boundary. Drill core and seismic reflection data show extensional, half graben geometries. Subsequent, Late Ediacaran and Cambrian orogenesis and basin closure and inversion occurred regionally and most intensively within the CRZ. The deformation resulted in crustal thickening, preserved as a ~50 km wide zone of garnet-amphibolite facies metamorphism. The CRZ is underlain by relatively thin, continental lithosphere, and is characterised by intense orogenic tectonics and inversion of the earlier formed rifts. The reactivated fault structures imply crustal weakening and define several tectonic domains that occur as fluid pathways for high volume fluid migration of metal bearing brines.