Emplacement of the Zindeng phonolitic lava flow (West-Cameroon) in the Cameroon volcanic line: Constraints from the anisotropy of magnetic susceptibility (AMS)

• Published in: Journal of African earth sciences (1994) 2020-02, Vol.162, p.103728, Article 103728
• Main Authors: Njanko, T., Gountié Dedzo, M., Tamen, J., Bella Nke, E.B., Kadji Kouémo, O.S., Fozing, E.M., Piankeu Doumsab, G., Tchakounté, J.
• Format: Article
• Language: English
• Subjects: AMS; Cameroon; Lava flow; Mount Bambouto; Phonolite; Zindeng
• ISSN: 1464-343X; 1879-1956
• DOI: 10.1016/j.jafrearsci.2019.103728

The Zindeng phonolitic flow forms a NW-SE elongated body located on the SE flank of Mount Bambouto (West-Cameroon), along the Cameroon Volcanic Line. It covers basalt emplaced on top of the Dschang biotite megacrystic granite. The magnitude of the magnetic susceptibility (Km) in the phonolitic lava flow varies between 196 μSI and 15769 μSI, indicating a dominantly ferromagnetic sensus lato behavior (Km > 1000 μSI; 89% of the stations) due to the presence of pseudo-single to multi-domain magnetite grains as deduced from hysteresis data. The low values of the degree of magnetic anisotropy, the dominantly oblate shape of the AMS ellipsoids and the concordance between lava plane and magnetic foliation point to flow-related magnetic fabrics. The pattern of the magnetic foliations and lineations indicate that the SE part of the phonolite was emplaced as a dome, whereas the NW part corresponds to a flow domain sensus stricto. It is suggested that the viscous phonolitic magma rose from a feeding conduit below the southeastern part of the lava flow and propagated laterally towards the NW. •We investigated the Zindeng phonolitic lava flow (southeastern flank, Mount Bambouto) fabric through AMS measurements.•The AMS parameters, magnetic foliation and lineation indicate magnetite–dominated magnetic fabric, that is flow-related.•A model of magma feeding from a source at depth followed by lateral flow is proposed for the Zindeng phonolite.