Cenozoic

Mesozoic

Paleozoic

Neoproterozoic

Paleoproterozoic

Inzia Formation

Inzia Fm

Period:

Cretaceous

Age Interval:

Turonian-Santonian

Province:
Northern Congo Margin, Central Congo region

Type Locality and Naming

Lower formation in the Kwango Gr

Synonym: Inzia Gr

Reference: Linol et al., 2015

[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

Inzia Fm comprises 50–110 m thick red sandstones intercalated with red–brown mudstones. At Tshikapa, in the Kasai region of southern DRC, its basal conglomerates are diamondiferous (Cahen 1951).

Lithology Pattern:

Relationships and Distribution

Lower contact

Lies conformably on the Bokungu Gr (Lindi and eastern margin of Congo Shield, and Cuvette Centrale region), or Lola Fm of Lualaba Gr (Kwango region)

Upper contact

Overlain by the Nsele Fm

Regional extent

Located in the southeastern, and also northeastern DRC (Lindi Basin)

GeoJSON

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Fossils

pollen (Boulouard & Calandara,1963), Fish (e.g., Rhipis moorseli, Decertids and Diplomystus; Saint Seine 1953; Casier 1965), and freshwater phyllopods (Bairdestheria kitariensis, Pseudoestheria lepersonnei and Estheria lerichei; Marliere 1950; Defretin-Lefranc 1967) and ostracods (Afrocythere? 536, Cypridea kitariensis, Darwinula kwangoensis, Ilyocypris compressa, I. luzubiensis, Metacypris K3099, Dolerocypris kinkoensis and Paracypria makawaensis; Grekoff 1960; Colin 1994). “One bed contains a fish fauna largely marine in origin and of Cenomanian–Turonian age (de Saint-Seine, 1953). This age was corroborated by later studies (Casier, 1961).” (Giresse, 2005)

Age

Turonian-Santonian (Linol et al., 2015, Fig. 11.4), assuming this is lower part of his “upper” Kwango Gr and overlies the Bokungu Gr.

Age Span:

Beginning stage:

Turonian

Fraction up in beginning stage:

0.0

Beginning date (Ma):

93.90

Ending stage:

Campanian

Fraction up in the ending stage:

0.0

Ending date (Ma):

83.65

Depositional setting

Lacustrine, fluviatile, to Aeolian depositional environment

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

Giresse, P. (2005). Mesozoic-Cenozoic history of the Congo Basin. Jour. African Earth Sciences, 43: 301-315. doi:10.1016/j.jafrearsci.2005.07.009

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