Short residence time and fast transport of fine detritus in the Judean Desert: Clues from 7 Be in settled dust

The cosmogenic isotope 7 Be (t 1/2 = 53.3d) was measured in sediments collected from dust traps deployed in the Judean Desert which is part of the Dead Sea drainage basin. The results show that (a) the 7 Be dry deposition flux in the Dead Sea region is 2.0 ± 0.6 × 10 4 atoms cm −2 y −1 during summer and winter and 5.3 ± 0.7 × 10 4 atoms cm −2 y −1 during fall; (b) the residence time of dust in the Dead Sea drainage basin is less than one year; (c) the recycled component of the cosmogenic isotope 10 Be (t 1/2 = 1.39 10 6 y) in Judean desert dust is potentially small; and (d) the 7 Be inventory (atoms cm −2 ) in dust settled in the drainage basin did not reach steady state between consecutive rare events of desert winter floods suggesting a short transport rate of fine detritus material from the marginal terraces into the Dead Sea. Provided 10 Be behaves similarly (as implied by the common geochemistry and cosmogenic origin of 7 Be and 10 Be), we suggest 10 Be in Lake Lisan (Pleistocene Dead Sea) detrital sediments as a potential proxy for paleo‐flood frequency and dust transport.