PALYNOLOGY OF THE CARBONIFEROUS OF NORTHE RN NIGER AND THE SAHARAN PLATFORM - STRATIGRAPHIC AND PALEOGRAPHIC IMPLICATIONS

Palynological study of the Talak, Guezouman, Tchinezogue and the lower and middle Tarat Formations (northern Niger) produced rich and varied microfloras showing a close resemblance to those from the Visean-Namu rian described from further north on the Saharan Platform. The ages of the various formations have been determined. The diachron Talak Forma tion is of Visean age. In the south of the basin (borehole G52), the l owermost Namurian possibly is present at the top of the Talak Formatio n. In the Arlit area (Akouta, borehole G122), the age of the Guezouman Formation is latest Visean-Early Namurian. The Tchinezogue Formation, which lacks Aratrisporites saharaensis Loboziak, Clayton and Owens an d monosaccate pollen grains, belongs to the Early Namurian. It is not possible to date precisely the lower and middle unit of the Tarat Form ation. These two units, in which Lycospora is very rare, can be dated as Namurian (Lower Namurian excluded). The important gap separating th e lower-middle unit from the Upper Permian unit is confirmed. The Vise an microflora of the Tim Mersoi Basin, as well as that of the Saharan Platform, is clearly distinguished from the Laurasia microflora and al so from that of Gondwana (Australia). During the Visean-Namurian, the North African margin constituted a well-defined microfloristic provinc e.