1 Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site. Journal of African Earth Sciences February 2015, Volume 102, Pages 218-232 http://dx.doi.org/10.1016/j.jafrearsci.2014.10.011 http://archimer.ifremer.fr/doc/00221/33255/ © 2014 Elsevier Ltd. All rights reserved. Archimer http://archimer.ifremer.fr Age, geochemical characteristics and petrogenesis of Cenozoic intraplate alkaline volcanic rocks in the Bafang region, West Cameroon Tchuimegnie Ngongang Nicaise Blaise 1 , Kamgang Pierre 1 , Chazot Gilles 2, 3, * , Agranier Arnaud 2, 3 , Bellon Hervé 2 , Nonnotte Philippe 2 1 Département des Sciences de la Terre, Faculté des Sciences, Université de Yaoundé I, B.P. 812, Yaoundé, Cameroun 2 Université de Brest (UBO), UMR 6538, Domaines Océaniques, Institut Universitaire Européen de la Mer, place Copernic, 29280 Plouzané, France Corresponding author : Gilles Chazot, email address : Gilles.Chazot@univ-brest.fr Abstract : The origin of the volcanism in the Cameroon Volcanic Line and the nature of its mantle sources are still highly controversial. We present major and trace element compositions as well as Sr-Nd-Pb-Hf isotopic results on mafic and intermediate lavas from the Bafang area in the central part of the Cameroon Volcanic Line. The lavas range from basanites and basalts to hawaiites and mugearites with an alkaline affinity and were emplaced between 10 and 6 Ma ago. The evolution from basalts and basanites to more differentiated rocks involved fractionation of olivine, clinopyroxene and Fe-Ti oxides, but the isotopic compositions show that crustal contamination processes affected some magmas during their ascent in the crust. Basalts and basanites originated from a garnet-bearing mantle source and their differences are mostly due to variable degrees of partial melting. The isotopic composition of the uncontaminated samples imply the participation of three distinct mantle components, the depleted MORB mantle (not dominant), an enriched component and a Pb radiogenic component similar to the source of the Mount Cameroon. Combined with previously published isotopic data from the Cameroon Volcanic Line, our new results indicate that the source of the volcanism mostly reside in the lithospheric mantle and is different from what can be expected from the melting of a mantle accreted from or modified during the emplacement of the St Helena mantle plume.