Katanga Super Gr

Katanga Basin, Southern Congo margin DRC and Zambia. Lithostratigraphically, the Katanga Supergroup is divided, from oldest to youngest (Cailteux et al. 2007) into: (i) the Roan Group; (ii) the Nguba Group (formerly Lower Kundelungu); and (iii) the Kundelungu Group (formerly Lower Kundelungu). Wendorff (2000, 2005) proposed an alternative interpretation of the stratigraphy, with absence of the Lower Roan in the DRC (iv) Biano Subgroup (Master et al. 2005).

Synonym: Katanga Supergroup

References: Armstrong et al. 2005; Brock 1961; Barron et al. 2003; Cailteux 1983; Cailteux et al. 2003; Cailteux et al. 2007; Steven 2000; Lefebvre 1975; Liyungu et al. 2001; Key et al. 2001; Lefebvre 1973; Kabengele et al., 2003; Mendelsohn 1961; Master et al. 2005; Ramsay and Ridgeway 1977; Lefebvre and Patterson 1982 Wendorff 2000, 2005

[Fig 1. Simplified geological map of the Congo Basin, compiled from various published map. The stratigraphic units have been assembled into major sequences (Late Neoproterozoic, Paleozoic and Cenozoic)]

[Fig 2: Tectonic setting of the Neoproterozoic basins of present-day Central Africa, compiled from the 1: 2M geological map of the Zaire (Lepersonne, 1974a) and the 1: 4MmapGeology and Major Ore Deposits of Africa (Milesi et al., 2006)]

[Fig 3: Lithostratigraphic synthesis for the Neoproterozoic to Early Paleozoic period. Compiled after various authors (see text).Dotted lines between Banalia, Aloloand Galamboge formations: stratigraphic transition by recurrences]

[Fig 4: Lithostratigraphic columns for the Congo Basin established using data from the 4 wells in the central part of the basin and outcrops on its NE margin (Lindi-Ubangi and Kisangani-Kindu region), compared with the West-Congo and Katanga stratigraphy]

[Fig 5: Simplified geological map of Sub-Saharan Africa showing the Neoproterozoic basins on and around the Congo Shield (modified after De Waele et al. 2008). (LC) Lower Congo Basin, (Co) Comba Basin, (Sa) Sangha Basin, (Ny) Nyanga-Niari Basin, (An) Angola Basin, (SO) Semb-Ouesso Basin, (Ba) Ubangui Basin, (LiB) Likki-Bembe´ Basin, (Bk) Bakouma Basin, (Fou) Fouroumbala Basin, (Li) Lindi Basin, It Itombwe Basin, (Ma) Malagarazi-Bukoban Basin, (Mb) Sankuru-Mbuji-Mayi-Lomami-Lovoy Basin, (Lu) Luamba Group, (Kat) Katanga Basin, (RB) Ruwenzorian Belt, KaB) Karagwe-Ankole Belt, (RuB) Ruzisian Belt, (KiB) Kibaran Belt,(UB) Ubendian Belt, IB Irumide Belt]

[Fig 6: Southern margin of the Congo Shield. (A) Geological sketch map of the Katanga Basin (modified after Heijlen et al. 2008). (B) Synthetic stratigraphic log combined with C and Sr isotopic curves of the Katanga Supergroup in the DRC and Zambia (modified after d ‰13 Cailteux et al. 2005). Note the declines in C estimated at 6.7 in d 1 the Lower Roan Group, followed by intervals with strong 3C enrichments, attributed to the Bitter Spring negative excursion and a d1 second negative 3C shift at the top of the Mwashia Group, reported to the Sturtian glacial events (Bull et al. 2011)]

[Fig 7: Stratigraphic correlation between the Neoproterozoic sedimentary basins in Central Africa. Correlations based on Sr isotopic data, radiometric age constraints and revised lithological relationships]

Consists largely of tabular metasedimentary sequences that extend from the DRC into Zambia. In thrust-fold belt, Regional metamorphism grades from amphibolite prehnite-pumpellyite facies in the outer zones to lower greenschist facies toward the inner zones (Ramsay and Ridgeway 1977; Lefebvre and Patterson 1982).

The Roan Gr is subdivided into four subgroups (Cailteux et al. Subgroup’ 2007): (i) the ‘Roche Argilo-Talqueuse (R.A.T.; undeterminated thickness) reported stratigraphically to the 880 Ma Mindola Subgroup in Zambia (Armstrong et al. 2005); (ii) the > 400 m-thick carbonate Mines Subgroup correlated with the Kitwe Subgroup in Zambia; (iii) the >1,000 m-thick carbonate Dipeta Subgroup equivalent to the Kirilabombwe Subgroup in Zambia (Cailteux 1994; Cailteux and Kampunzu 1995); and (iv) the 600–800 m thick carbonate and siliciclastic 760 Ma Mwashya Sub group (formerly Upper Mwashya; Armstrong 2000; Liyungu et al. 2001; Key et al. 2001; Barron et al. 2003) including mafic volcaniclastic rocks (Lefebvre 1973; Cailteux 1983; Cailteux et al. 2003; Kabengele et al. 2003) coeval with the gabbroic bodies emplaced within rocks of the Dipeta Sub group (DRC) and Bancroft-Kanwangungu formations (Mendelsohn 1961; Lefebvre 1975; Cailteux et al. 2007). Cailteux et al. (2007) adopted a similar lithostratigraphic scheme for the Upper Katanga Supergroup, i.e. the Nguba and Kundelungu groups, between the DRC and Zambia. The Kundelungu Gr is further subdivided into (i) the Gombela Subgroup including the glacigenic diamictites of the ‘Petit Conglome´rat’ or Kyandamu Formation and the cap carbonates of the Lusele Formation; (ii) the carbonate, then siliciclastic Ngule Subgroup; and (iii) the siliciclastic ±573 Ma Biano Subgroup (Master et al. 2005); Now a separate Gr from the Katanga Supergroup. The Nguba Gr comprises a 2,000 m-thick shaly carbonate succession becoming siliciclastic at the top, and is subdivided into (i) the Muombe Subgroup including the diamictitic 765–735 Ma ‘Grand Conglome´rat’ or Mwale Formation (Key et al. 2001; Wendorff and Key 2009) correlated with the global Sturtian glacial event (Cailteux et al. 2007); and (ii) the carbonate and siliciclastic Bunkeya Subgroup.

These sequences are affected by the Pan-African or Lufilian north-directed folding and thrusting deformations (620–570 Ma; Kampunzu and Cailteux 1999), Since the Mesoproterozoic Eon, the CS region was subjected to intermittent episodes of extensional activity resulting in long-lived shallow cratonic basins, which were subsequently deformed by short-lived phases of compression during the Neoproterozoic (e.g. Fernandez-Alonso et al. 2012). The time-equivalent Roan and BII groups are interpreted as lacustrine or lagoonal systems (Cailteux et al. 2007; see also Delpomdor et al. 2014), while the Roan Group from Zambia appear to be marine. Inkisi Group and Biano Group are considered to be red-bedsequences of post-Pan African and pre-Karoo age (Tait et al. 2011; see also de Wit and Linol 2014).