Provenance Analysis of Cretaceous Sandstones in the Anambra Basin Using Detrital Zircon Geochronology

Understanding the provenance of Cretaceous sandstones in the Anambra Basin is critical for reconstructing palaeogeographic configurations, evaluating sediment routing systems, and interpreting potential hydrocarbon reservoir quality, yet detrital zircon geochronology data from this basin remain sparse compared with equivalent studies in other West African basins. This study determines the provenance of Late Cretaceous sandstone formations in the Anambra Basin using detrital zircon U-Pb geochronology. Sandstone samples were collected from the Ajali Formation and the Nkporo Formation at five outcrop localities distributed across the basin. Zircon grains were separated by standard heavy mineral processing and their U-Pb ages determined by laser ablation inductively coupled plasma mass spectrometry at a facilities laboratory. Age spectra were plotted as kernel density estimate plots and compared against potential source terrains including the West African Craton, Trans-Saharan orogenic belts, and Cameroon Line basement units using the Kolmogorov-Smirnov test and multidimensional scaling. The study tests the hypothesis that a significant proportion of Cretaceous sediment was sourced from the Oban Massif and northern basement highs, with a lesser Gondwana-recycled component. Implications of provenance interpretations for interpreting long-distance sediment transport pathways and basin palaeogeography during the Late Cretaceous are discussed in the context of evolving regional tectonic models. Keywords: provenance, detrital zircon, U-Pb geochronology, Anambra Basin, Cretaceous sandstones.