Geochemical stratigraphy, sedimentology, and Mo isotope systematics of the ca. 2.58–2.50Ga-old Transvaal Supergroup carbonate platform, South Africa

•Geochemical and sedimentological description of a Neoarchean carbonate platform.•Mo isotope analyses on carbonates and mudstones, deposited shortly before the GOE.•Preservation of some geochemical signatures, like Fe and Mn, in Malmani carbonates.•Carbonates with δ98Mo signatures heavier than crustal values indicate oxygenation.•Mo distribution of analyzed samples is influenced by early diagenetic processes.