Geochemical Characterization and Petrogenetic Implication of Recent Mafic Magmatism from Foumbot-Koutaba (West-Cameroon) and Their Potential as Sustainable Natural Resources

Abstract

The Foumbot-Koutaba area which is part of the Noun plain, a component of Cameroon Volcanic Line (Central Africa) has experienced recent magmatism from 65 Ma up to date. Field and petrographic studies show that the recent mafic magmatic rocks of the area consist of basalts, dolerites and huge pyroclastics deposits. The rocks present doleritic (dolerites), porphyritic microlitics, aphyric (basalts) and vesicular (pyroclastics) textures. Geochemical studies show that the mafic rocks studied have high contents of FeOt (08.22–12.55% by weight) and V (130.83–255.19 ppm), low in SiO2 (47.15–54.57%), medium to high in MgO (5.33–12.58%) and Mg # (58–66) and the compatible element contents (Cr = 31.70–352.11 ppm, Co = 41.24–135.74 ppm and Ni = 48.01–148.89 ppm) which indicate that the magma parent of these mafic rocks would be of mantle origin and would have undergone a very low rate of contamination during their ascent. All samples have high Ba (185–1990 ppm) and Sr (350–708 ppm), higher than average values in the crust (Ba = 259–628 ppm and Sr = 282–348 ppm) which justifies the hypothesis of a very low contamination rate. The basalts were controlled by fractionation of olivine and apatite, while the dolerites would be the products of the accumulation of plagioclase. The pyroclastics of the study area are pozzolans low carbon cement materials. They are used artisanally for mortars to make construction blocks with pozzolan cement and water mixtures. Moreover, dolerite shows nice plagioclase laths, beautifying the rocks for tiles manufacture. The value of denstity (2.7) and water absorption (0.4%) are good for low carbon dimension stones production to replace tiles made of clay that pollute the environment through pyroprocess during their manufacture. Also, the huge outcrops of basalts are good resources for gravel and sand production. All these recent mafic materials are good resources for sustainability.