Petro-Geochemistry, Genesis and Economic Aspect of Syenitic and Mafic Rocks in Mindif Complex, Far North Cameroon, Central Africa

Abstract

Syenitic and mafic rocks in Mindif Complex (Far North of Cameroon) were surveyed and characterized to classify them, understand their formation history, and assess their economic interest. Syenitic bodies (hololeucocratic microsyenites; mesocratic aplitic quartz-syenite; leucocratic porphyritic quartz-biotite syenite, and leucocratic porphyritic biotite-syenite) are silica-oversaturated to silica-saturated, alkaline, and metaluminous. Hololeucocratic microsyenites are structural oriented rocks, cooled in shallow depth from low trace and REE dry residual alkaline melts. Mesocratic aplitic quartz-syenite also crystallized in shallow depth from a much Ba-rich less dry residual melt. Leucocratic porphyritic quartz-biotite and biotite syenitic stocks represent two different rock types cooled from hydrous-rich melts in deep seated environments. The Mindif syenites probably crystallized in crustal source magmas (with important alkali feldspar accumulation) from partial melting of pre-existing igneous protoliths. Medium to coarse-grained-peraluminous granite found at the edge of pink microsyenitic dykes (in contact with granite host), is probably a crystallized product from magmatic mixture between the intrusive syenitic melt and a melt from partial fusion of the granite host rock. Mafic igneous rocks in Mindif are peridotgabbro and gabbro with different characteristics. Peridotgabbro, alkaline, holomelanocratic, medium-grained and ultrabasic, is an REE and incompatible elements depleted rock crystallized in shallow depth from a more evolved mantle source magma with plagioclase accumulation. Tholeiitic gabbro, melanocratic, and also medium-grained, was

Mineralogy, Petrography and Geochemistry of the Ina Syenite (Linté, Central Cameroon) as a Source of Industrial Feldspars

“…In addition, the granite, monzonite and granodiorite of the Ina site can also be used as a source of feldspathic flux. These rocks, including syenite, can be exploited as dimension stones [4] [7] [8].…”

“…[3] [6][19] [21][22] [64][65], monzonite and quartz monzonite[19], granite[17] [19] and even gneiss[66]. The rock samples of Ina batholith, according the geochemical characterization and nomenclature from the TAS diagram[49], belong to the range of these igneous rocks used as feldspathic fluxes.Syenite, due to their specify, are among the most requested rocks as alternative source for feldspathic flux worldwide[4] [17][22] [67][68]. For this purpose, several characteristics criteria based on petrographic features, mineralogical and geochemical composition are analysed.…”