La Formation glaciaire de la Mambéré (République Centrafricaine): Reconstitution paléogéographique et implications à l'échelle du Paléozoique africain

One, two or no record of late neoproterozoic glaciation in South-East Cameroon?

“…Note that ice-flow data collected from the Mintom Basin are compatible with the existing Hirnantian ice-flow directions and location of a geographic South Pole located in western Central Africa (Smith, 1997). Question marked black arrow: ice-flow direction from Censier and Lang (1992) for (?) Silurian or Carboniferous glacial strata in Central African Republic.…”

“…Published data on Palaeozoic glacial deposits in Central Africa are particularly scarce, and their attribution to a given glaciation faces the same difficulties as for the glacial features in the Mintom Basin, i.e., lack of microfossils and absence of reliable radiochronology. Censier and Lang (1992) reported on the occurrence of glacio-fluvial sediments in CAR, containing faceted clasts and flattened pebbles, to which they assigned a lower Silurian to Carboniferous age interval. They deduced the direction of ice flow towards the north after identification of the sediment source south of their study site.…”

“…This south-north direction contrasts markedly with our own measurements on the glacial striae in Cameroon. This may indicate that either: (1) the northward path envisaged by Censier and Lang (1992), which is based on sediment provenance but not on physical evidence of ice flow, is not correct; (2) the glacial features are correlated but point to regional differences in ice movements; and (3) the Mintom Basin and CAR records relate to distinct glaciations. We have no argument in favour or against either of these hypotheses, except that the ice flow towards the WSW measured in Cameroon is compatible with the directions of ice-sheet advance from Central Africa during the Hirnantian glaciation (Fig.…”

Paléoenvironnements et caractérisation des roches mères pétrolières des séries pré-salifères du bassin intérieur du Gabon

“…Lacustrine environments are characterized by the low diversity of fauna, by small-sized ostracods and remain of fresh-water fishes. The lacustrine facies of the Agoula series overlies a tillite deposits, related to the Permo-Carboniferous glacial event recognized elsewhere in the central and southern Africa [3]. The high concentration of organic matter from the 'Schistes' series is related to widespread extension of lakes during the rifting and the consecutive high sedimentation rate.…”

The Ordovician strata of the Ennedi Plateau, northeastern Chad (Erdi Basin)

“…It indicates Ordovician ice-divide areas positioned in southern Chad or even further to the south in Central Africa. Here, a glacial record of unknown age but displaying northward-oriented dispersal patterns is identified [Censier and Lang, 1992], which might correlate with the Chadian Ordovician record. A potential end-Ordovician record have also been inferred in Cameroon, where an undated iceflow pattern toward the WSW has been documented [Caron et al, 2011].…”