Abstract
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.
Highlights
The West African Atlantic margin is spotted by three main alkaline volcanic provinces: the Canary Archipelago, How to cite this paper: Ndiaye, A. and Ngom, P.M. (2014) The Geodynamic Context of the Cenozoic Volcanism of the Cap-Vert Peninsula (Senegal)
The Cap-Vert peninsula is located at the westernmost part of the Senegalo-Mauritania basin about 1000 km at the east of the Cape Verde Archipelago
It is subsequent to the opening of the Central Atlantic Ocean during the Lias, and related to the sub-meridional faults and the occurrence of E-W significant transverse fractures corresponding to the extension of oceanic transform faults on the continent
Summary
The West African Atlantic margin is spotted by three main alkaline volcanic provinces: the Canary Archipelago, How to cite this paper: Ndiaye, A. and Ngom, P.M. (2014) The Geodynamic Context of the Cenozoic Volcanism of the Cap-Vert Peninsula (Senegal). The West African Atlantic margin is spotted by three main alkaline volcanic provinces: the Canary Archipelago, How to cite this paper: Ndiaye, A. and Ngom, P.M. (2014) The Geodynamic Context of the Cenozoic Volcanism of the Cap-Vert Peninsula (Senegal). M. Ngom the Cape Verde Archipelago and the Cap-Vert peninsula (Dakar, Senegal). The Cap-Vert peninsula is located at the westernmost part of the Senegalo-Mauritania basin about 1000 km at the east of the Cape Verde Archipelago. The volcanic province (Figure 1) which extends further east onshore, is marked by large positive gravity anomalies in the Cap-Vert peninsula (110 mgal) and the Cayar Dome (160 mgal) identified by geophysics offshore [1]. Reference [2] was the first to suggest two eruptive rock series: one considered of Upper Cretaceous and the other of post-Meso-Nummulitic age. Reference [2] was the first to suggest two eruptive rock series: one considered of Upper Cretaceous and the other of post-Meso-Nummulitic age. [3] confirmed the existence of these two series, but suggested stratigraphical
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