Continental rifting reorganizes landscapes long before a fully developed rift basin emerges, through the interaction of fault growth, surface processes, and sediment distribution. The Okavango Rift Zone (ORZ) in southern Africa records this transitional stage, where localized faulting and subsidence have produced a prominent depocenter within the Kalahari Basin, while adjacent structural blocks preserve remnants of the pre-rift surface.
This study reconstructs the Pleistocene evolution of the ORZ by combining cosmogenic nuclide analysis, luminescence dating, sediment provenance, and geomorphic mapping across contrasting structural domains. This integrated approach establishes the timing of sediment formation, transport, and deposition in relation to rift development, allowing sedimentary responses to tectonic forcing to be resolved.
Results indicate that widespread eolian sand predates major incision into the rift and is preserved on elevated surfaces flanking the ORZ. In contrast, sediments within the subsiding rift record a later transition to incision-driven alluvial and systems, followed by lacustrine deposition as accommodation space increased and drainage was reorganized. These changes reflect a fundamental shift in sediment routing and depositional environments accompanying rift localization.
The established chronology links major landscape reorganization to regional tectonic adjustments during the middle Pleistocene (~ 1 Ma), demonstrating pronounced diachroneity between surface stability on structural highs and rapid sedimentary change within the rift. More broadly, this work shows that even in settings with mature fault systems, early to intermediate rifting stages can be expressed most clearly through sedimentological and geomorphic transitions rather than fault architecture alone. The ORZ thus provides important constraints on how tectonics, surface processes, and hydrology interact during the development of continental rifts.