Provenance, paleoclimate and diagenetic signatures of sandstones in the Mamfe Basin (West Africa)

Petrography, heavy mineral and trace element geochemistry have been used to unravel the tectonic setting, source area lithology, diagenesis and paleoclimate conditions of the Mamfe sandstones. Quartz exists as monocrystalline (79%), and polycrystalline grains (21%). Orthoclase and microcline are the most dominant feldspars in the rocks. Heavy minerals such as zircon, tourmaline, kyanite, augite, garnets, hornblende, epidotes, diopside, muscovites, biotites, and opaque minerals were disclosed by the samples after bromoform separation. These sandstones are mineralogically and texturally immature and have been classified as arkose on the basis of the QFR diagram. QtFL plot indicates derivation mainly from a transitional continental region of continental block provenance with trace elements geochemical data pointing to a felsic source. The felsic sources are related to the Precambrian granitic/gneissic rocks which formed the basement and margins of the basin. The bivariant log-log Qt/F+R and Qp/F+R plot and the nature of quartz grains of the studied sandstone specimens indicate a semi-humid climatic condition prevailed at the time of deposition in a fluvial environment. The sandstones display deformation of mica, cementation, replacement, and albitization with some having an imprinted reddish brown color indicating a redoxmorphic, locomorphic and phyllomorphic diagenetic stages associated to early, burial and uplift diagenetic processes.