Neogene sedimentary processes forming the NAMIB sand sea

The Namib Sand Sea (NSS) originated from long-distance sediment transport fueled by high-latitude climate dynamics, with its formation intricately linked to the behavior of the Benguela Current. Research reveals that while sediment transport and climatic conditions have remained largely stable since the Early Miocene, the Benguela Current's behavior—shifting westward during less arid periods—serves as a key indicator of past climate variability. Analysis of Neogene formations (Oligocene to Pliocene) in the NSS, including detrital modes, heavy mineral assemblages, and cosmogenic-nuclide modeling, demonstrates that the modern NSS's sediment composition differs significantly from its past state. Notably, the Late Miocene Tsondab Sand Sea was primarily sourced by local rivers rather than the Orange River, challenging assumptions about its origin. Additionally, the last major aridification phase occurred approximately 2 million years ago, with northern sand deposits having a residence time of ~1.5 million years during northward transport.

Caracciolo, L., Stollhofen, H., Garzanti, E., Vainer, S., Limonta, M., Hatzenbühler, D., Liedel, S., Vermeesch, P., Joachimski, M., & Ben Dor, Y. (2025). Neogene sedimentary processes forming the NAMIB sand sea. Earth-Science Reviews, 271, 105247. https://doi.org/10.1016/j.earscirev.2025.105247