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Provedor de dados:  ArchiMer
País:  France
Título:  Age, geochemical characteristics and petrogenesis of Cenozoic intraplate alkaline volcanic rocks in the Bafang region, West Cameroon
Autores:  Ngongang, Nicaise Blaise Tchuimegnie
Kamgang, Pierre
Chazot, Gilles
Agranier, Arnaud
Bellon, Herve
Nonnotte, Philippe
Data:  2015-02
Ano:  2015
Palavras-chave:  Cameroon Volcanic Line
Mantle source
Resumo:  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.
Tipo:  Text
Idioma:  Inglês

Editor:  Pergamon-elsevier Science Ltd
Formato:  application/pdf
Fonte:  Journal Of African Earth Sciences (1464-343X) (Pergamon-elsevier Science Ltd), 2015-02 , Vol. 102 , P. 218-232
Direitos:  2014 Elsevier Ltd. All rights reserved.


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