Not much to show for it: Late Pleistocene dynamics of migrating megadunes in the Rub’ al-Khali, Saudi Arabia, indicate minimal preservation of their deposits

Abstract Luminescence dating of interdune sabkha sediments and cross strata deposited on the lee face of a 160-m-high mega-crescentic dune in the eastern Rub’ al-Khali sand sea provides information on dune dynamics and preservation potential. Optically stimulated luminescence ages show that the rates of dune accumulation varied during the latest Pleistocene and Holocene. Sedimentary structures indicate that megadune migration was the result of strong northwesterly “Shamal” winds. During the same interval of the late Pleistocene and early Holocene, linear dunes in the northeastern United Arab Emirates were also accumulating rapidly, indicating that the period 16–9 ka was characterized by regionally widespread dune formation and/or reworking. The dune has subsequently migrated to the SSE almost 900 m since the early Holocene, at an average rate of 77 m/k.y., indicating persistence of the Shamal wind system for at least 20 k.y. Rates of megadune migration and wet sabkha accumulation reveal that, despite their very large size, less than 1% of the megadune would be preserved in a sedimentary record.