The damming of fluvial systems by encroaching dunes (dune-damming), result in unique morphologies and stratigraphies, lead to dust emission hotspots and influence dunefield evolution. Four decades of research evolved on dune-damming at the eastern Sinai-Negev erg - the arid northwestern (NW) Negev dunefield (Israel), where today, wadis usually flood 1-2 times pre annum. Here I review the formation, timing, morphology, sedimentology, landscape response, relations with prehistoric man, palaeoclimate drivers and methodological approaches concerning dune-damming in the NW Negev.
Vegetated linear dune (VLD) incursions mainly during the LGM, Heinrich1 and Younger Dryas (YD), blocked dunefield-margin ephemeral fluvial systems (<1-700 km2). The resulting shallow impounded and usually seasonal waterbodies, when dry, generated playa-like flats comprised of 1-10 m thick sequences of massive loam & sedimentary couplets that often truncate aeolian or fluvial sand. Couplets, indicative of single, dune-dammed impoundment fluvial events, amount to <dozen per section, representing only several flood seasons, despite being within an OSL-dated sequence spanning several kyr. This discrepancy may imply that impoundments were successive for only several years. More likely, the sequences are incomplete, having gone through depo-erosional cycles. Regionally anomalic amounts of OSL/radiocarbon-dated upper Paleolithic to Chalcolithic lithic-dominated concentrations/hearths by dune-dammed waterbody sediments testify to an attractive punctuated and short-term, aquatic environment that attracted mammalian and fowl game.
Despite post-YD, VLD stabilization, dune-dammed waterbody sediments continued to accumulate until the early Holocene due to dune maintenance and gradual downstream fluvial propagation of dune-dams penetrating the dunefield. The resultant current landscape is a result of the erosion of remaining up-basin loess availability along transitional times of open fluvial domination, aeolian domination (dune-damming) and finally, partial and gradual dune-dam breaching and reopening of large and medium fluvial systems, leading to incision and playa abandonment.