Residual colluvio-aeolian aprons in the Negev highlands (Israel) as palaeo-climatic indicator

Slope features, treated previously mainly pedogenetically and described as alluvial terraces or as a catenary compound of stony loessial Sierozem, are shown to be remains of former colluvial-loessial aprons. The loess was deposited in the central Negev during the uppermost Pleistocene by dust-laden rainstorms which triggered debris flows under conditions twice as humid as today. During the Holocene the aprons were selectively eroded by slope-runoff, resulting in a wide exposure of the basal slope, truncation of the wadi fill and the final formation of the present-day patchy slope morphology. The dust-laden rainy regime fits the last, more humid period, i.e. 70,000-10,000 yr B.P.