Author(s)

Abdoulaye Ndiaye, Papa Malick Ngom^*

Department of Geology, Faculty of Sciences and Technology, Cheikh Anta Diop University, Dakar, Senegal.

The Cenozoic alkaline volcanism of the Senegalo-Mauritania sedimentary basin presents an episodic long-lasting volcanic activity from the Eocene-Oligocene boundary up to the Quaternary. Two volcanic episodes are usually distinguished on stratigraphical grounds: a Miocene one and a Quaternary one separated by a period of quiescence of several million years corresponding to the main phase of lateritic weathering. The Tertiary lavas are highly silica-undersaturated alkaline rocks ranging from nephelinites to basanites. They contain nepheline and fassaite-type clinopyroxene in their mineralogy. The Quaternary lavas are more evolved with Hy-normative in comparison to the Tertiary ones; they are composed of basanites and medium to coarser-grained dolerites. The distribution of the REE and other incompatible elements are typical of alkaline lavas with generally strong LREE enrichment without significant Eu anomaly. The Cenozoic Cap-Vert lavas have OIB (oceanic islands basalts)-affinities as shown by their relatively radiogenic Nd and unradiogenic Sr characters closed to the HIMU-OIB. This suggests a HIMU-type end member in the magma sources which is fairly comparable to those erupted in the Canaries and Cape Verde archipelagoes during the same period.

Cenozoic, Alkaline Volcanism, Oceanic Islands Basalts, Cap-Vert Peninsula, Senegalo-Mauritania Basin

Ndiaye, A. and Ngom, P. (2014) The Geodynamic Context of the Cenozoic Volcanism of the Cap-Vert Peninsula (Senegal). International Journal of Geosciences, 5, 1521-1539. doi: 10.4236/ijg.2014.512124.