A 300-ky history of sand erosion in the Yamin Plain, Negev Desert, Israel

New cosmogenic isotope data shed light on erosion and deposition processes that have been operating in the Yamin Plain syncline, Negev Desert, Israel, since the middle Pleistocene. Patches of desert pavement scattered in the Yamin Plain include Miocene and Senonian chert pebbles and clasts. The Miocene pebbles are an integral part of the Hazeva Formation sand section and concentrate at the surface as the sand is exhumed. The rate and timing of sand removal are simulated using a simple numerical model. Results suggest that Miocene chert pebbles have accumulated at the surface since ∼350 ka as sand was exhumed at a rate of ∼18 mm ky^-1. The source for the Senonian chert clasts is most likely the adjacent slopes. The clasts in the desert pavement were probably transported to the plain by mass wasting from the slopes. Senonian chert clasts that were transported into the Yamin Plain ∼200 ka may record one such event. Cosmogenic isotope concentrations measured in sand from the main water divide of the Yamin Plain suggest that sand is being exhumed at an average rate of 17.6 ± 1.13 mm ky^-1. The measured isotope concentrations in sand transported by the channels that drain the Yamin Plain are similar to the concentrations in sand samples amalgamated from a depth range of 0-2 meters. This similarity suggests that the presently incising channels are transporting a homogeneous mix of sand from a depth range of 0-2 meters. Thus, the cosmogenic signal in the alluvial channels cannot be interpreted in terms of the average basin-wide erosion rate. Rather, this signal is an indication of the depth of present incision into the sand cover of the Yamin Plain.