Upper Dja Fm

Period:

Cryogenian, Ediacaran

Age Interval:

Cryogenian, Ediacaran

Province:
Northern Congo Margin

Type Locality and Naming

Named after the Dja river in the Sembé-Ouesso Basin CAR, Northeastern RC, the southeastern Cameroon and the southwestern CAR. Upper unit of the Dja Gr.

Synonym: Upper Dja Series. The Upper Dja series was formerly named the Mintom Formation (Alvarez 1995)

Reference: Alvarez 1995; Caron et al., 2010; Poidevin, 1985

[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: 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 (see text).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

Carbonate rocks. The Upper Dja series (then named Mintom Fm) was formerly subdivided into four members; i.e. Kol (diamictites), Me´tou, Momibole´ and Atog Adjap; on the basis of field, sedimentological and geochemical evidences, by Caron et al. (2010).

Lithology Pattern:

Limestone

Relationships and Distribution

Lower contact

The basal Kol tillite unit is indicated as being unconformably onto the Bandjia tillite unit of the uppermost Lower Dja Fm.

Upper contact

None given. Terminated by the Pan-African orogeny?

Regional extent

Sembé-Ouesso Basin CAR, RC. Extends in multiple graben-like basins in the northeastern RC, the southeastern Cameroon and the southwestern CAR (Poidevin, 1985)

GeoJSON

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Fossils

Age

Assumed to span the Marinoan glacial of the Cryogenian (with the underlying interglacial absent and being the boundary between the Upper and Lower Dja series), and into the early Ediacaran until the Pan-African orogeny at ca. 590 Ma (45% up in the Ediacaran).

Age Span:

Beginning stage:

Cryogenian

Fraction up in beginning stage:

0.9

Beginning date (Ma):

643.50

Ending stage:

Ediacaran

Fraction up in the ending stage:

0.45

Ending date (Ma):

591.71

Depositional setting

Evolution of multiple graben-like basins in the northeastern RC, the Southeastern Cameroon and the southwestern CAR

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