The stabilized northwestern (NW) Negev vegetated linear dunes (VLD) of Israel extend over 1300 km2 and form the eastern end of the Northern Sinai - NW Negev Erg. This study aimed at identifying primary and subsequent dune incursions and episodes of dune elongation by investigating dune geomorphology, stratigraphy and optically stimulated luminescence (OSL) dating. Thirty-five dune and interdune exposed and drilled section were studied and sampled for sedimentological analyses and OSL dating, enabling spatial and temporal elucidation of the NW Negev dunefield evolution.In a global perspective the NW Negev dunefield is relatively young. Though sporadic sand deposition has occurred during the past 100 ka, dunes began to accumulate over large portions of the dunefield area only at ~23 ka. Three main chronostratigraphic units, corresponding to three (OSL) age clusters, were found throughout most of the dunefield, indicating three main dune mobilizations: late to post last glacial maximum (LGM) at 18-11.5 ka, late Holocene (2-0.8 ka), and modern (150-8 years). The post-LGM phase is the most extensive and it defined the current dunefield boundaries. It involved several episodes of dune incursions and damming of drainage systems. Dune advancement often occurred in rapid pulses and the orientation of VLD long axes indicates similar long-term wind directions. The late Holocene episode included partial incursion of new sand, reworking of Late Pleistocene dunes as well as limited redeposition. The modern sand movement only reactivated older dunes and did not lengthen VLDs.This aeolian record fits well with other regional aeolian sections. We suggest that sand supply and storage in Sinai was initiated by the Late Pleistocene exposure of the Nile Delta sands. Late Pleistocene winds, substantially stronger than those usually prevailing since the onset of the Holocene, are suggested to have transported the dune sands across Sinai and into the northwestern Negev.Our results demonstrate the sensitivity of vegetated linear dunes located along the (northern) fringe of the sub-tropical desert belt to climate change (i.e. wind) and sediment supply.
Bibliographical noteFunding Information:
Dan Muhs is warmly thanked for mineralogical data, fruitful discussions in the field and office, constructive advice and remarks that upgraded the article. We thank Ezra Zilberman (Geological Survey of Israel), Nigel Goring-Morris (Hebrew University in Jerusalem) and Rami Ben-David for fruitful discussions in the office and field. Omri Barzilai from the Israel Antiquities Authority is thanked for cooperation in sampling at the Nahal Sekher excavations. Nati Bergman is thanked for keenly reviewing the article. We thank Rimon Wenkart for digitizing the Erg and Rony Bluestein-Livnon for the regional map. Ofer Rozenstein and Danny Zamler supplied great field assistance and innovative suggestions. Zvi Dolgin undertook sample preparation and Dina Shtuber and Olga Yoffe carried out the chemical analyzes. The research was supported by the United States-Israel Bi-National Science Foundation (BSF) in Jerusalem and by the Earth Science Research Administration of the Israel Ministry of Natural Infrastructures in Jerusalem. We would like to thank two anonymous reviewers for their insightful comments.
- Late pleistocene
- Vegetated linear dune