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Thierry De Putter
Earth Sciences
Geodynamics and mineral resources
Geodynamics and mineral resources
Publication details
Cailteux, J. & De Putter, T. 2018. ‘The Neoproterozoic Katanga Supergroup (D.R. Congo): state-of-the-art and revisions of the lithostratigraphy, sedimentary basin and geodynamic evolution ’. Journal of African Earth Sciences, in press (corrected proofs). DOI: 10.1016/j.jafrearsci.2018.07.020. (PR).
Article in a scientific Journal / Article in a Journal
In the last 25 years, successive revisions were introduced in the lithostratigraphy of the Neoproterozoic Katanga
Supergroup, which hosts the Katanga Copperbelt (KCB, D.R.Congo). The evolving changes in nomenclature and
definitions of the formations and subgroup/group relationships, superposed with the different previous classifications,
are clarified and summarized in the present stage of knowledge. Moreover, revisions are proposed
based on lithologic and sedimentary considerations. The R.A.T. Subgroup, at the bottom of the succession, is renamed
“Musonoï” based to one of the two sites where this unit is best observed in drill cores. The R.A.T. Grises
are included in the Musonoï Subgroup as the topmost formation of this succession displaying similar sedimentary
conditions. The Dipeta Subgroup is re-named as the Fungurume Subgroup, and defined as containing five formations:
the R.G.S. (re-named “Kwatebala”) at the base, overlain by the alternating dolomite and siltstone beds
of the Dipeta and Tenke formations, and by two dominantly carbonate sequences at the top, the Mofya and
Kansuki formations. The Mofya Formation and the transition to the Kansuki Formation is still poorly documented.
The sedimentary, lithologic and recent geochronological data on diagenetic and metamorphic-hydrothermal
minerals clearly confirm that the Musonoï (former R.A.T.), Mines and Fungurume (former Dipeta)
subgroups are part of the Roan sedimentary pile as a typical Congo facies, and cannot be interpreted as a
Kundelungu-foreland deposition. Supported by a ∼765 Ma geochronological age of Kansuki lavas in northwestern
Zambia, the basal conglomeratic beds of the Kamoya Formation (bottom of the Mwashya Subgroup) are
interpreted as a diamictic deposition that corresponds to the Kaigas glacial event (∼770-735 Ma). The Mwale
and Kyandamu diamictites are considered as separate formations from the overlying Muombe and Gombela
subgroups at the base of the Nguba and Kundelungu groups, respectively. In addition to previous revision of the
Nguba Group, the “Dolomie Tigrée” cap-carbonate succeeding the Mwale Formation is introduced as a new
formation at the base of the Muombe Subgroup. Inversion from an extensional to a compressional orogenic
regime is marked by a group of metamorphic peaks at ∼595 Ma that probably correspond to the first D1 folding
deformation phase of the Lufilian orogeny at the end of the Gombela Subgroup deposition. The second D2 main
deformation phase between ∼550 and ∼530 Ma and the final collision is marked by hydrothermal-metamorphic
crystallisations or remobilisations associated with the paroxysms of this compressive period. Thrusting
and bending of the Lufilian arc probably occurred between these two main metamorphic events. The Mongwe
and Kiubo formations, that represent the upper part of the Kundelungu Group (or Ngule Subgroup), belong to the
folded Katangan and are interpreted as sediments filling northward-prograding foreland basins, north of the
thrusting. The sub-horizontal Sampwe Formation that was deposited at the final stage of the thrusting, probably
represents the only autochthonous Kundelungu rocks in the KCB. The overlying Biano tabular sediments are
interpreted as a group distinct from the Kundelungu Group, and is possibly of Cambrian age.