Cedric Roth Happi Djofna^1,, Merlain Houketchang Bouyo², Daouda Dawai³, Rigobert Tchameni¹, Landry Kouedjou⁴, Martial Periclex Tchunte Fosso¹, Hervé Brice Fotso Kengne¹

This article presents original geological and geochemical data on more or less deformed granitoids rocks of the Pitoa region in Domain North Cameroon. The Pitoa granitoids consist of leucocratic, gray and pink colored, fine to medium grained granites as well as quartz monzonite, containing numerous enclaves of mafic rocks, intruded in gneiss and amphibolite and cut by dykes of pegmatite, aplite and dolerite. They present porphyritic, inequigranular, granophyric and microgranophyric textures consisting essentially of quartz, K-feldspar, plagioclase, biotite and the accessory minerals are zircon, apatite, titanite and opaque minerals. The Plutonic rocks of Pitoa show the characteristics of the shoshonitic and calc-alkaline series with high-K content. They are magnesian to ferrous, luminous to slightly hyper-luminous metallic and exhibit the characteristics of type 1 granitoids. REE data and normalized chondritic plots show variable enrichment of all rocks in LREE compared to HREE with a negative europium anomaly (Eu/Eu*= 0.19 – 0.8), except for the pink granite sample DS15 which shows a positive Eu anomaly (14.6). They are distinctively depleted in Th, Nb, Ba, Sr, Ti and Ta. The data indicate that this assemblage of granitic rock did not result from the simple differentiation of a common parental magma, but show that the plutonic rocks of Pitoa arose from different crustal protoliths. Trace element and major composition are consistent with the magmatism which may have involved reworking of a composite protolith of metagrey-wackes in the upper crust and amphibolitised high -K calc-alkaline basaltic andesites in the northern domain of the Orogenic belt from Central Africa. These granitoids were set up in a tectonic context of continental subduction collision. They are emplaced in the active continental margin and fractional crystallization (FC) is a major process that controls magmatic differentiation.

petrography, geochemistry, north cameroon domain, pan-african granitoids, geodynamics