Dja Gr

Named after the Dja river in the Sembé-Ouesso Basin CAR, RC. The Dja Group (Alvarez 1995) records the evolution of multiple graben-like basins in the northeastern RC, the southeastern Cameroon and the southwestern CAR (Poidevin, 1985).

Synonym:

Reference: Chochine 1950; Sonet 1958; Gre`s and Legras 1967; Jaunatre 1969; Censier 1989; Alvarez, 1995; Poidevin, 1985; Poidevin and Pin 1986; Vicat et al. 1997

[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, 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]

Consists of tillite, sandstones, carbonates. The Dja Group is divided into two series: (i) the Lower Dja series (Lower Dja Gr), presumably of Paleoproterozoic (Poidevin and Pin 1986; Censier 1989; Vicat et al. 1997) or Tonian ages (Tonian is used here); and (ii) the Upper Dja series, presumably of Ediacaran age (Alvarez 1995; Vicat et al. 1997; Poidevin 2007).

Assumed to span the Tonian, through both glacials of the Cryogenian (with the 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).

Records the evolution of multiple graben-like basins