Petrology of the meta-mafic rocks from the Lolodorf area, Nyong complex (Southwest Cameroon): implication for the origin and emplacement conditions

Abstract This study presents the new petrology and geochemistry data for comprehension of origin emplacement conditions Lolodorf mafic rocks whitin Nyong Complex. The meta-mafic consist fine-grained garnet (FGM) coarse-grained (CGM) presenting nearly similar mineral composition. They are made up quartz, plagioclase, orthopyroxene, clinopyroxene, amphibole, opaques, apatite rutile. also present recrystallization features such as quartz ribbons, corroded grain mineral, cuspate plagioclase boundary necklace garnets in matrix. These assemblages suggest that took place under granulite facies condition. have basaltic tholeiitic composition like magmas (SiO 2 FGM = 48.20–50.70 wt% SiO 2CGM 46.68–50.27 Mg 43.24–62.27 CGM 40.85–69.70) emplaced active continental margin context. low La/Th ratio observed high together with Hf content imply reworked plutonic recorded both grade partial melting metamorphism whereas only imprints. Thermobarometry results metamorphic peak occurred around amphibolite-granulite transition. pressure estimated at 2.7–14.89 kbar temperature interval between 672 952 °C while meta-mafics settled 1.5–16.09 631–909 °C. selected amphiboles display water (1.92–2.10 wt%) plot NNO + buffers indicating they crystallized oxidizing conditions. coupled previous geochronological may Mesoarchean been during Eburnean formed Eburnean.