Author(s)

Emmanuel Nomo Negue^1,2*, Rigobert Tchameni², Olivier Vanderhaeghe^3,6, Pierre Barbey^4,5, Periclex Martial Fosso Tchunte², Jonas Didero Takodjou Wambo¹, Brice Yanick Lemdjou¹, Nicaise Alliance Saha Fouotsa²

¹Department of Earth Sciences, Faculty of Science, University of Yaoundé, Yaoundé, Cameroon.
²Department of Earth Sciences, Faculty of Science, University of Ngaoundéré, Ngaoundéré, Cameroon.
³CNRS, UMR7359, GeoResources, Vandoeuvre-lès-Nancy Cedex, France.
⁴CNRS, UMR7358, CRPG, Vandoeuvre-lès-Nancy Cedex, France.
⁵Université de Lorraine, Nancy, France.
⁶GET, Université Paul Sabatier, Toulouse, France.

In this article, we discussed about the petrography and geochemistry of magmatic rocks of the Mbip massif located SW of Tcholliré, in Central North Cameroon (Central African Fold Belt). Petrographic study shows that this massif is made of granodiorite, amphibole-biotite granite, and biotite granite which often contain enclave of mafic rocks (gabbro). Granodiorites and granites show porphyritic texture and consist dominantly of plagioclase and alkaline feldspar phenocrysts, quartz, biotite and often few amphibole. The gabbro enclaves are characterized by a granular porphyroid texture constituted of amphibole, plagioclase and olivine phenocrysts, all in a matrix of small crystals of plagioclase, olivine, amphibole, pyroxene and opaque minerals. All the analyzed rocks provide geochemical features of sublkaline serie and have nothing to do with the alkaline nature previously signaled in the former works. Granodiorites and granites are shoshonitic to calc-alkaline strongly potassic affinity consistent with emplacement in the continental collision setting. They present positive anomalies in Rb, Th, U; negative anomalies in Sr, P, Ti, Nb, Ta and some facies contain hydrated minerals such as amphibole. These characters are consistent with crustal and mantle contribution in their genesis. The mafic rocks (gabbro) have geochemical characteristics conferring a mantle origin, as confirmed by the high Mg# value (49.9). On the whole, the fractional crystallization of the magma formed by melting of crustal material and the magmatic mixing are the main petrogenetic process in the Mbip massif. Petrographic studies and geochemical data shows that the Mbip massif was emplaced in an active continental margin, into transitional regime from the end of maximum compression to the beginning of relaxation.

Central African Fold Belt, Granitic Rocks, Mafic Rocks, Transitional Regime, Active Margin.

Negue, E. , Tchameni, R. , Vanderhaeghe, O. , Barbey, P. , Tchunte, P. , Wambo, J. , Lemdjou, B. and Fouotsa, N. (2015) Petrography and Geochemistry of the Mbip Granitic Massif, SW Tcholliré (Central North Cameroon): Petrogenetic and Geodynamic Implication. International Journal of Geosciences, 6, 761-775. doi: 10.4236/ijg.2015.67062.