143-22 Geochemical Signatures and Paleoecological Shifts on the Eastern Niger Delta Shelf: Emergence of Late Pleistocene Lowstand Dynamics and Holocene Marine Transgression

Abstract:

This research investigates the environmental transformation of the eastern offshore Niger Delta, Eastern Atlantic Ocean, through an integrated analysis of sedimentological, geochemical, and micropaleontological records obtained from three gravity cores (GC1–GC3). By combining lithofacies observations, granulometric profiles, Ti/Zr elemental ratios, and foraminiferal community assessments within an age-constrained framework, the study reconstructs a sequence of major paleoenvironmental transitions spanning the last ~18,000 years. The earliest core intervals indicate a prodeltaic and delta-front landscape, marked by coarse sediments, elevated Ti/Zr ratios, and abundant benthic foraminifera (notably Melonis spp., Uvigerina spp., and Ammonia sp.), pointing to dominant riverine input under low sea-level conditions. During the Holocene transistion, a pronounced shift is detected: Ti/Zr ratios decline, mud content increases, and planktonic foraminifera (such as Globigerinoides ruber and Globorotalia tumida) become more prominent, reflecting the landward movement of the shoreline and progressive marine flooding. The uppermost core layers are typified by fine-grained shelf deposits, reduced terrestrial influx, and a surge in planktonic foraminiferal abundance, indicative of a stable mid-Holocene highstand. Multivariate statistical techniques: Pearson correlation, principal component analysis, and hierarchical clustering corroborate the major role of post-glacial sea-level rise in shaping sediment dispersal patterns, depositional environments, and biological communities across the shelf. Collectively, these findings elucidate the evolution of coastal and marine systems in the Niger Delta region and enhance our understanding of how tropical Atlantic shelves responded to Late Quaternary climatic fluctuations.

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