Mero Yannah^{1, 2,}, Juliana Amboh Tifang², Eric Martial Fozing¹, Yaya Fodoué³, Armand Dongmo Kagou¹, Samuel Ndonyui Ayonghe⁴

Somie-Ntem area within the Tikar plain form part of the Western Cameroon Domain (WCD) that belong to the Central African Pan-African Fold Belt (CAPFB). Petrography and whole rock geochemistry characterize the granitoids of this area into granites (Gr), granodiorites (GD) and tonalite (Tn) forming group I granitoids. These rocks displaying high-calc-alkaline to shoshonite affinity and strongly metaluminous I-type. They also show strong enrichment in Ba-Sr and no pronounced Euanomaly, belongs to syn-to post collisional tectonic setting. Group II rocks consist of AGr show strange characteristics with high K-calc-alkaline affinity, metaluminous and peraluminous of I-type, and also very poor in Ba-Sr, strong negative Eu anomaly typical of post orogenic. Both groups depleted in Nb, Th, Ti with Pb and Dy enrichment. However, the Al2O3/TiO2vs TiO2Harker plot show that the group I granitoids originated from a common melt and got differentiated through fractional crystallization during syn-to-post tectonic regime at subduction environment induced by a crustal thickening tectonic regime. Group II granitoids are post orogenic, emplaced following tectonic extension at subduction leading to the injection of strongly evolved magma from partial melting of new material at the lower crust.

granitoids, petrography, geochemistry, somie-ntem, tikar plain, pan-african, cameroon