Antecedent bedrock control on the sediment-starved continental shelf of south/central Namibia

A sediment-starved continental shelf off south/central Namibia reveals persistent antecedent bedrock control over Pleistocene stratigraphy and geomorphology. The study, using high-resolution geophysical tools and drill cores, shows that the inner shelf's metamorphic basement and Eocene sandstones, shaped by a late Oligocene subaerial unconformity (H1), have dictated sediment accumulation patterns for millions of years. H1 acted as a backstop, influencing erosion and sedimentation during transgressive/regressive cycles, with limited Quaternary deposits preserved in lee depressions behind bedrock ridges. Notably, dolomite precipitation occurred during stable sea-level conditions around 37,000 cal BP, while the absence of thick sand cover suggests long-term onshore diversion of sediment—likely supplying the Namib Sand Sea—even during lower sea levels.

Green, A. N., Senna, W., Cooper, J. A. G., Heeralal, T., & Labuschagne, H. (2024). Antecedent bedrock control on the sediment-starved continental shelf of south/central Namibia. Marine Geology, 469, 107242. https://doi.org/10.1016/j.margeo.2024.107242