Petrographic and Geochemical Characterization of Basalts in Bangangte Area (West Cameroon): Implications on Their Source

Abstract

The Bangangte area belongs to the Cameroon Volcanic Line. The volcanic rocks exposure in the area consist of fine microlitic porphiritic Basalts which still poorly surveyed. Petrographically, the studied rocks are made up of minerals like plagioclase, clinopyroxene, olivine phenocrysts and a lot of opaque minerals within a very fine grained matrice. The Bangangte basalts are quartz normative free and are olivine, Diopside, Hypersthene normative. Alkaline (Na 2 O + K 2 O) contents vary from 2.247% to 5.46%. These rocks are low-Mg basalts with the Mg# values vary from 42.86 to 45.95 which are characteristic of primitive mantle source. The studied rocks are alkali to transitional basalts with Nb/Y ratio>1.5. Chondrite normalized spider diagram pattern of REE shows uniform patterns with enrichment in LREE and a relative depletion in HREE. While MORB normalized spider diagram pattern of multi elements reveals a negative anomaly with K 2 O, with enrichement in LILE and depletion in HREE. The Eu anomalies are positive to nulle and are typical of alkali basalts. The Bangangté transitional alkali basalts were formed in intraplate setting of continental part of the CVL. They are the products of partial melting of about 13% of an asthenosphere made up of garnet peridotite. Geochemically, the studied basalts are similar to alkali basalts from Mount Bamenda.

Volcanology and geochemical study of the volcanic rocks of the Bafmeng area (Mount Oku, Cameroon Volcanic Line)

“…This implies a related upper mantle source from somewhere above the 670 km transition zone (Halliday et al, 1988(Halliday et al, , 1990Lee et al, 1994). However, some tholeiitic and transitional affinities have been described and discussed recently (Fosso et al, 2005;Kuepouo et al, 2006;Moundi et al, 2007;Ngounouno et al, 2001;Wotchoko et al, 2015).…”

Assessment of Hydraulic Parameters and Protection Zones of Catchment Aquifers for Water Supply Network in Ndé Division, West-Cameroon (Central Africa)

“…These pan-African rocks are partially covered by tertiary basalts that formed the eastern edge of the western Cameroon Highlands located in the NE trending southern continental segment of the CVL that stretches from the Annobon Island to Lake Chad [20]. These tertiary basalts occur as prismatic columnar lava flow at a mean altitude of 1400 m and dominantly consist of 3 -14 Ma alkaline and 36 -47 Ma transitional basalts [21] [22] [23] [24]. Both basalts are the product of the interaction between mantle upwelling and sublithospheric continental during a lithospheric extensional tectonic setting [22] [25].…”