Uneven surface moisture as a driver of dune formation on ephemeral lake beds under conditions similar to the present day: A model?based assessment from the Makgadikgadi Basin, northern Botswana

An association between salt pans or dry lake beds and distinctive crescentic lake-floor sand mounds (1–10 m high, tens to hundreds of metres wide) is commonplace in desert systems. In the Makgadikgadi Basin northern Botswana, a debate about formative processes these landforms has persisted despite numerous morphometric, sedimentary geochronological analyses, with mound variously inferred be aeolian dunes, subaqueous spring shoreline remnants. We propose new mechanism which draws on interaction uneven moisture distribution pan surface mobile sediments. use numerical model (ViSTA), couples vegetation transport dynamics, together optically stimulated luminescence (OSL) dating investigate feasibility this ‘sticky hypothesis’. find that under range modelled environmental conditions, can lead development stabilization dunes growing upwind from point initial deposition, corresponding chronological data gained OSL feature. On removal moisture, erode dissipate. These findings suggest could dependent differential drying competence sediment system across floor.