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

The cosmogenic isotope Be-7 (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 Be-7 dry deposition flux in the Dead Sea region is 2.0 +/- 0.6 x 10(4) atoms cm(-2) y(-1) during summer and winter and 5.3 +/- 0.7 x 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 Be-10 (t(1/2) = 1.39 10(6)y) in Judean desert dust is potentially small; and (d) the Be-7 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 Be-10 behaves similarly (as implied by the common geochemistry and cosmogenic origin of Be-7 and Be-10), we suggest Be-10 in Lake Lisan (Pleistocene Dead Sea) detrital sediments as a potential proxy for paleo-flood frequency and dust transport. Citation: Belmaker, R., B. Lazar, M. Stein, and J. Beer (2011), Short residence time and fast transport of fine detritus in the Judean Desert: Clues from Be-7 in settled dust, Geophys. Res. Lett., 38, L16714, doi:10.1029/2011GL048672.