Late Stenian–Tonian magmatic signatures and provenance of metasedimentary rocks from the Deng-Deng area, East Cameroon

The Deng-Deng metasedimentary rocks crop out in the central domain of the Central African Fold Belt (CAFB), Cameroon. Field investigations and petrography reveal garnet-biotite and calc-silicate gneisses, metamorphosed under amphibolite to granulite-facies conditions. Their Chemical Index of Alteration values range from 30.61 to 55.50, suggesting weak chemical weathering under dry and cold paleoclimatic conditions, while Index of Compositional Variability values (1.03–1.90) indicate immature sediments. Provenance indicators including high Zr/Sc ratios and element am ratios such as Th/Co and La/sc, suggest derivation from felsic source rocks and varying degrees of sedimentary reworking. Tectonic setting discrimination diagrams, based on major, trace, and REE elements, point to a continental arc depositional environment. The detrital zircon age spectrum highlights two main magmatic age peaks ca. 966 Ma and ca. 797 Ma, respectively, and a maximum depositional age of 673 ± 5 Ma. These new data provide evidence of late Stenian to Tonian (ca. 929–1024 Ma) magmatism in the CAFB and reworking during the Cryogenian–Ediacaran.