Palaeoclimate Reconstruction of Southwestern Gabon using laminated Stalagmites

Abstract

Central Western Africa lacks suitable paleoclimate proxy records and Gabon is no exception. Two stalagmites collected in June 2023 from Grotte de Camp Malheur located in the Ngounie Province of SW Gabon were used to reconstruct palaeorainfall records for the region over the past two centuries. Layer counts conducted by eye are matched to ERA5 reanalysis data, in conjunction with uranium-thorium dates, to produce annual palaeorainfall records. XRF analyses conducted on a Geotek Multi Sensor Core Logger (MSCL-S) produced a full geochemistry profile for the two stalagmites ranging from magnesium to uranium. The equatorial location of Gabon makes it a prime location for recording fluctuations and long-term changes in atmospheric circulation patterns, including the Intertropical Convergence Zone. Spectral analysis was used to determine any influences from atmospheric patterns or solar forcing on the stalagmite palaeorainfall record. This study provides a proof-of-concept that Gabonese stalagmites accurately preserve palaeorainfall information, paving the way for future studies extending further back in time.