Aeolian-Fluvial response to late-Pleistocene dunefield encroachments along the northwestern Negev dunefield margins (Israel)
- 1Geomorphology and Portable Luminescence Laboratory Leon Recanati Institute for Maritime Studies, University of Haifa, Mt. Carmel, Haifa, Israel
- 2Department of Geography and Environmental Studies, University of Haifa, Mount Carmel, Haifa, Israel
- 3Department of Geography and Environment, Bar Ilan University, Ramat-Gan, Israel
- 4Luminescence Laboratory, School of Resources and Environmental Sciences, Linyi University, Linyi, China
Aeolian-Fluvial (A-F) processes formed vast and flat landscapes during the late-Pleistocene along dunefield margins. A-F research examines the impacts of extrinsic processes of the aeolian and fluvial systems on one another, which formed these unique landscapes. However, the mechanisms and depositions of A-F processes are not fully understood. In this study, a 120 m wide and 7 m high, wadi bank exposure of an A-F sequence reveals the sedimentary units, where the northwestern Negev (Israel) dunefield desert margins interact with the Atadim fluvial system (64 km2). A chrono-stratigraphic analysis by laboratory measurements (Particle size distribution & Total of carbon), relative and absolute luminescence dating (POSL & OSL), radiocarbon and archeological dating, enabled conclusions regarding the depositional mechanisms and environment. Finally, DEM (~12.5 m pixel) and GPS-RTK (0.3 m resolution) were used to assess A-F depositional boundary.
The results demonstrate a unique perseverance of aeolian sand units covered by low-energy fluvial deposits. The sand and dune units illustrate several sand incursions into the fluvial system since the Last Glacial Maximum until the mid-Holocene. We observed low-energy fluvial deposits, which resulted from these sand incursions: (a) couplets deposited in an ever-emptying waterbody, impounded by a dune-dam. (b) massive fine-grained formation – deposition of suspended sediments in an impounded waterbody, near the damming-dune where the waterbody is the deepest. (c) Fining upwards with fine laminas deposits – embedded between couplet formations, deposited in a low-energy fluvial environment. The fine laminas indicate small tributaries income to the main low-energetic flow.
We demonstrate that in A-F sequences, not only are the aeolian sand units preserved but also they act as palaeo-fluvial archives. The section reflects that late-Pleistocene dune-damming build-up resulted in a lagged fluvial response enabled by a climatic change during the early-Holocene. The combination of stabilized dune-dams within the fluvial systems and high discharge flows with large available sediment supply resulted in vast aggregation of A-F sediments, forming the alluvial plain.
How to cite: Robins, L., Roskin, J., Yu, L., and Greenbaum, N.: Aeolian-Fluvial response to late-Pleistocene dunefield encroachments along the northwestern Negev dunefield margins (Israel), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-13303, https://doi.org/10.5194/egusphere-egu22-13303, 2022.
