Palaeoclimatic Reconstruction Using Lacustrine Sediment Records from Lake Geriyo, Adamawa State

Lake Geriyo, a small crater lake in Adamawa State, North East Nigeria, contains laminated lacustrine sediments with the potential to record high-resolution palaeoclimatic signals spanning the Holocene, providing rare terrestrial climate archives from the northern Nigerian savanna zone. This study undertakes preliminary palaeoclimatic reconstruction using a short sediment core retrieved from the deepest point of Lake Geriyo, analysing sedimentological, geochemical, and biological proxies preserved in the sequence. Core lithology was described and photographed at sub-centimetre resolution, followed by grain size analysis and loss-on-ignition to characterise organic carbon and carbonate content variations through the sequence. Radiocarbon dating of organic-rich intervals was performed to establish a chronological framework. Diatom assemblage analysis was conducted at selected intervals to infer changes in lake water chemistry and salinity associated with moisture balance shifts. Magnetic susceptibility profiling provided an independent proxy for aeolian mineral input during dry episodes. Results are interpreted against published regional palaeoclimate syntheses for the West African monsoon zone. The study aims to demonstrate the utility of this underutilised archive and lay the groundwork for a longer-duration study incorporating a deeper core. Findings are shared with the Adamawa State Environmental Protection Agency and contribute to Nigerian participation in regional palaeoclimate networks. Keywords: palaeoclimate, lacustrine sediments, Lake Geriyo, Holocene, diatoms.