Varved sediments of Lake Yoa (Ounianga Kebir, Chad) reveal progressive drying of the Sahara during the last 6100 years

A 6100-year sediment record from Lake Yoa, part of the UNESCO World Heritage Site Lakes of Ounianga in Chad, reveals a progressive drying trend in the eastern Central Sahara. The study, utilizing high-resolution sedimentological and geochemical analyses, including X-ray fluorescence core scanning, demonstrates that decreasing monsoon rainfall combined with strong evaporation transformed the once hydrologically open and fresh lake into its current hypersaline state, which has persisted for about the last 1050 years. The data also indicate a gradual increase in aeolian input, supporting the notion of a progressive rather than abrupt transition from a humid to an arid Sahara during the Mid to Late Holocene.

Francus, P., von Suchodoletz, H., Dietze, M., Donner, R. V., Bouchard, F., Roy, A.-J., Fagot, M., Verschuren, D., & Kröpelin, S. (2013). Varved sediments of Lake Yoa (Ounianga Kebir, Chad) reveal progressive drying of the Sahara during the last 6100 years. Sedimentology, 60(4), 911–934. Portico. https://doi.org/10.1111/j.1365-3091.2012.01370.x