Lukuga Gr

Cenozoic

Mesozoic

Paleozoic

Neoproterozoic

Paleoproterozoic

Lukuga Gr

Period:

Carboniferous, Permian

Age Interval:

Mid Bashkirian– Late Gzhelian (for glacial), through Campanian? For post-glacial clastics

Province:
Northern Congo Margin, Southern Congo Margin

Type Locality and Naming

The Lukuga Group is exposed in the Walikale area (Sechse et al., 2011).

Synonym: Dwyka Gr (regional correlative) of Karoo Supergroup, Lukuga Fm

Reference: Daly et al., 1991; Cahen 1954; Catuneanu et al., 2005; Cambier, 1930; Fourmarier, 1914; Johnson et al., 2006; Sechseet al., 2011; Delpomdor et al., 2018

[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, 1974) and the 1: 4M map Geology 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. Dotted lines between Banalia, Alolo and 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. Northern margin of the Congo Shield. (A) Geological sketch map of the Lindi Basin (modified after Verbeek 1970; Poidevin 1985)]

[Fig 7. Stratigraphic logs of the Lindi Supergoup in the DRC (modified after Verbeek 1970). (C and D) Stratigraphic logs of the Lindi Supergoup in CAR (modified after Poidevin 1985). cc cap carbonates, SG Sturtian Glaciation, MG Marinoan Glaciation]

[Fig 8. Stratigraphic correlation between the Neoproterozoic sedimentary basins in Central Africa. Correlations based on Sr isotopic data, radiometric age constraints and revised lithological relationships]

Lithology and Thickness

Made up of diamictites and varval shales (Kadima et al., 2011). Its base displays typical diamictites and varval clay of the Gondwana glaciation, equivalent to the ‘Dwyka Conglomerates’ diamictites of the Karoo type locality in South Africa, attributed to the Late Carboniferous (~320Ma).

The remaining part of the Lukuga Formation is represented by post-glacial claystones and sandstones (Dekese sub-basin) and coal-bearing measures (Lukuga and Luena grabens), correlated to the Ecca Subgroup of South Africa (Daly et al., 1991; Catuneanu et al., 2005; Johnson et al., 2006). In the Sankuru-Mbuji-Mayi-Lomami-Lovoy Basin (southeast DRC), the Lukuga Gr is about 20m thick (fig. 2 of Delpomdor et al., 2018), and consists of glacial polymictic tillites associated with periglacial sandstones and argillites deposited in local depressions or paleo-glacial valleys. [Generalized “glacial till” pattern and only the glacial age-span used for the paleogeographic display of this Group, pending separation into glacial an post-glacial formation entries.]

Lithology Pattern:

Relationships and Distribution

Lower contact

Lies unconformably on the Banalia Gr, or the Aruwimi Gr in the Linde basin. Unconformably underlain by the Kabele/Kabenga Fm (Pan-African Orogeny - (fig. 2 of Delpomdor et al., 2018) in the Sankuru-Mbuji-Mayi-Lomami-Lovoy Basin (southeast DRC).

Upper contact

Overlain unconformably in Linda Basin by the Kisangani Gr after a major hiatus that spans the Permian through early Jurassic. Unconformably overlain by the Loia Gr in the Sankuru-Mbuji-Mayi-Lomami-Lovoy Basin (southeast DRC).

Regional extent

The Lukuga Formation is preserved in tectonic grabens related to the East African rift, in the Lukuga basin along the border of Lake Tanganyika (Fourmarier, 1914), in the Luena basin in the Upemba depression of Central Katanga (Cambier, 1930), in U- shaped glacial valleys on the eastern margin of the Congo Basin (Boutakoff, 1948) as well as in the Dekese sub-basin of the Congo Basin (Cahen et al., 1960). Also northeastern DRC (Lindi Basin) and southeastern DRC (Sankuru-Mbuji-Mayi-Lomami-Lovoy Basin)

GeoJSON

{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[21.89,3.94],[23.36,3.92],[26.92,2.7],[26.79,3.14],[27.5,2.84],[29.65,3.19],[29.99,2.33],[28.36,0.65],[27.4,0.7],[26.18,0.99],[25.01,1.58],[23.45,2.72],[21.87,3.41],[21.11,3.97],[21.89,3.94]]]]}}

Fossils

Pollen-spores of Nuskoisporites,Vertigisporites and Vittatina (Boulouard and Calandra 1963).

Age

Late Carboniferous (glacial episodes); Early and Middle Permian (post-glacial; with late Permian a hiatus?); [Generalized “glacial till” pattern and only the glacial age-span used for the paleogeographic display of this Group, pending separation into glacial an post-glacial formation entries.]

Age Span:

Beginning stage:

Bashkirian

Fraction up in beginning stage:

0.5

Beginning date (Ma):

319.28

Ending stage:

Gzhelian

Fraction up in the ending stage:

1.0

Ending date (Ma):

298.89

Depositional setting

mountain glaciers and glacial lakes (Kadima et al., 2011)

Depositional pattern:

Additional Information

Compiler:

Enam O. Obiosio, Solomon Joshua Avong and Henry Nasir Suleiman (2024) - Stratigraphic Lexicon compiled from the following books:

Geology and Resource Potential of the Congo Basin by Maarten J. de Wit, François Guillocheau and Michiel C.J. de Wit , Published Springer-Verlag Berlin Heidelberg 2015; DOI 10.1007/978-3-642-29482-2

Linol, B., de Wit, M.J., Guillocheau, F., Robin, C., Dauteuil, O., (2015). Multiphase Phanerozoic subsidence and uplift history recorded in the Congo Basin: A complex successor basin. In: M.J. de Wit et al. (eds.), Geology and Resource Potential of the Congo Basin, Regional Geology Reviews, DOI 10.1007/978-3-642-29482-2_11, # Springer-Verlag Berlin Heidelberg 2015

Kadima, E., Delvaux, D., Sebagenzi, S.N., Tack, L., Kabeyaz (2011). Structure and geological history of the Congo Basin: an integrated interpretation of gravity, magnetic and reflection seismic data Basin Research (2011) 23, 499–527, doi: 10.1111/j.1365-2117.2011.00500.x