Petrology and geochemistry of the Tchabal Mbabo volcano in Cameroon volcanic line (Cameroon, Central Africa): An intra-continental alkaline volcanism

Fagny, Aminatou M.; Nkouandou, Oumarou Faarouk; Bardintzeff, Jacques Marie; Guillou, Hervé; Iancu, Ovidiu Gabriel; Ndassa, Z. N.Njankouo; Temdjim, Robert

doi:10.1016/j.jafrearsci.2020.103832

Cited by 5 publications

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“…This area was the site of significant Mid-Pliocene volcanic activity(Gouhier et al, 1974;Oustriere, 1984;Deruelle et al, 1987;Nkouandou et al, 2008). Volcanic eruptions have created high massifs such as Tchabal Nganha(Nono et al, 1994), Tchabal Djinga(Ménard et al, 1998) and Tchabal Mbabo(Fagny et al, 2020). Effusive flows of alkaline basalts have contributed to the formation of uneven relief on the plateau to the north and the east of Ngaoundere town(Nkouandou et al, 2010).…”

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Magmatism of the Beka Volcanic Massifs (Cameroon Volcanic Line, West-Central Africa): New Petrographical and Mineralogical Data

Dili-Rake¹,

Abdoulaye²,

Tchop³

et al. 2022

GEP

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The Beka volcanic massifs are located northeast of Ngaoundere region, within the Adamawa plateau. It consists mainly of basanites, trachytes and phonolites. The petrographic study shows that all the basanite lavas have porphyritic microlitic textures with a more pronounced magmatic fluidity than the felsic lavas displaying trachytic textures. The lavas are composed of phenocrysts, microlites and microphenocrysts of olivine, clinopyroxene, plagioclase and iron-titanium oxides for the basanites and of greenish clinopyroxene, alkali feldspar, and titanomagnetite for the felsic lavas. Chemical microprobe analysis indicates that the olivine crystals are magnesian (Fo 73-78 ). Clinopyroxene crystals have a composition of diopside (Wo 47-) in the basaltic lavas and diopside near the hedenbergite pole in the trachytes phonoliths and titanomagnetite (TiO 2 : 21.13% -22.36% and FeO: 68% -68%). Chemical analyses on whole rocks show that all the lavas belong to the same series and the felsic lavas come from the differentiation of basanite lavas by fractional crystallization of the minerals therein. The basanites originate from a low rate of partial melting of an OIB-type mantle. Contamination and mixing processes are suspected. Lavas of similar composition are found in other volcanic centres of the Adamawa plateau and the continental and oceanic sectors of the Cameroon Volcanic Line, in particular the Kapsiki plateau, Mounts Cameroon and Bamenda.

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confidence: 99%