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Lithospheric Thickness, Rift and Inversion Tectonics: The Formation and Deformation of the Neoproterozoic Katangan Basin of Central Africa.
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  • Michael Christopher Daly,
  • Munshya Zimba,
  • Martin Purkiss,
  • Francis Chibesakunda
Michael Christopher Daly
Oxford University

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Munshya Zimba
First Quantum Minerals Ltd.
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Martin Purkiss
Oxford University
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Francis Chibesakunda
Geological Survey of Zambia
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Abstract

The tectono-stratigraphic development of continental basins is key to our understanding of the location and scale of metal deposits required by the energy transition. We examine the Neo-proterozoic Katangan copper basin of Central Africa to determine the link between lithosphere and crust and the generation of potential fluid pathways. Integration of lithospheric thickness, quantitative basin analysis and structure, defines a basin scale tectono-stratigraphic model for controls on potential fluid pathways. The basin developed along the thinned (140-170 km thick) margins of the Congo, Kalahari and Bangweulu cratons. Crustal scale fault zones define these margins and imply a mechanical weakness in the basin. Drill core and seismic data show extensional, half graben geometries. 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 maps out as a sediment provenance boundary. Subsequent Late Ediacaran and Cambrian orogenesis and rift-fault inversion occurred most intensively within the CRZ. Basin expulsion and thrust tectonics resulted in a narrow belt of crustal thickening defined today by a ~50 km wide zone of garnet amphibolite facies metamorphism. The spatial coincidence of early crustal extension, relatively thin lithosphere, and later intense basin inversion along the CRZ, indicates that pre-existing crustal structure and weakness was a key tectonic control. The reactivated structures define several tectonic domains, control basin architecture within the zones and occur as potential fluid pathways for high volume fluid migration for metal bearing brines.
23 Apr 2024Submitted to ESS Open Archive
26 Apr 2024Published in ESS Open Archive