The Pan-African orogenic belt of southern Mauritanides and northern Rokelides (southern Senegal and Guinea, West Aftica): gravity evidence for a collisional suture

A new interpretation of the deep-part of Senegal-Mauritanian Basin in the Diourbel-Thies area by integrating seismic, magnetic, gravimetric and borehole data: Implication for petroleum exploration

“…Tertiary sediments are unconformable with the Upper Cretaceous and consist primarily of marine shales and carbonates (Ponsard et al, 1988;Chanut and Micholet, 1988;Ndiaye, 2012).…”

“…The syn-rift deposits in the Diourbel-Thies area have not been intersected by deep well drilling, but the syn-rift section of the southern and northern SMB consists principally of thick Triassic to Early Jurassic evaporites which have been defined from borehole data (Templeton, 1971;Lehner and De Ruiter, 1977;Le Pichon et al, 1977;Liger and Roussel, 1979;Liger, 1980;Ponsard et al, 1988) (figure 1a) and overlying inferred Triassic clastic rocks, which may include organic-rich lacustrine rocks. The syn-rift evaporite section in the Casamance sub-basin may be as much as 2,000 m thick consisting mostly of salt with an anhydrite cap;…”

The nature and location of the suture zone in the Rokelide orogen, Sierra Leone: Geochemical evidence

“…Earlier collision between the Kasila Group and this microcontinent/arc would then be followed by later Pan African collision between the Kasila-arc collage and West African Craton. , Ponsard et al (1988) and Lécorché et al (1989) devised similar tectonic models for evolution of the Mauritanides. According to their models, westward rifting of a continental fragment (Western Block Craton) from West Africa occurred around 700 Ma and was accompanied by emplacement of alkaline to tholeiitic basalts.…”

“…If the Kasila Terrane was a piece of the western West African Craton, it may have rifted away from the latter as part of the Western Block Craton at 700 Ma. Continental rifting was followed by opening of a small intervening ocean basin (Ponsard et al, 1988;Lécorché et al, 1989). The Terméssé and Guingan volcanic-sedimentary sequences were deposited along the margins of the separating West African and Western Block cratons, respectively (Ponsard et al, 1988).…”

“…Kennedy, 1965), a positive gravity anomaly with a paired negative anomaly (e.g. Ponsard et al, 1982Ponsard et al, , 1988, and deformed alkaline rocks and carbonatites (DARCs) (Burke et al, 2003a) that have all been described from one or more, in some cases from many, places along the border of the West African craton (Fig. 1).…”