A Late Pleistocene Wetland Setting in the Arid Jurf ed Darawish Region in Central Jordan

Abstract

Current conditions in the southern Levant are hyperarid, and local communities rely on fossil subsurface water resources. The timing of more favourable wetter periods and also their spatial characteristics are not yet well constrained. To improve our understanding of past climate and environmental conditions in the deserts of the southern Levant, sedimentary sections including artefact-bearing beds from Jurf ed Darawish on the Central Jordanian Plateau were investigated using sedimentological and micropalaeontological analyses and OSL dating. Grain-size analysis and structures of the clayey-silty sediments show that they mainly represent reworked loess deposits. The OSL ages suggest that these fine-grained sediments were accumulated during Marine Isotope Stages (MIS) 5-3. Recorded ostracod valves (mostly Potamocypris, Ilyocypris and Pseudocandona), remains of aquatic and terrestrial gastropod shells, and charophyte gyrogonites and stem encrustations indicate that an in-stream wetland existed at the location of Jurf ed Darawish during MIS 5-4 which was replaced by a vegetated alluvial plain in MIS 3. The prevailing aggradational setting was replaced by an erosional setting sometime after 30 ka. Abundant artefacts, distributed over a vertical range of up to 40 cm in a bed covered by a sedimentary sequence of 12-m thickness, provide evidence for the presence of humans in the region during a relatively long period from ca. 85 to 65 ka. The reconstruction of an in-stream wetland at Jurf ed Darawish, and the presence of humans at the site and in other desert regions of the Jordanian Plateau, the Wadi Arava/Araba, and the Negev and the Nefud deserts, show that the regional climate in the late MIS 5 and MIS 4 was significantly wetter than today and provided favourable conditions for humans in the Southern Levant and the northwestern Arabian Peninsula.

Human dispersals out of Africa via the Levant

“…This decision was based on an assumption that the wetlands were saturated for a substantial fraction of the burial age. The estimated water content was consistent with similar settings in Jordan wetlands [e.g., ( 18 , 32 )]. The final dose rate and assigned ages in the present study were calculated using the LDAC program ( 76 ) for feldspar single-grain pIR-IRSL and the website program of DARC ( 77 ) for quartz OSL and feldspar MET pIR-IRSL.…”

“…The chronology of Bir Tirfawi and Bir Sahara in the western desert of Egypt revealed the formation of paleolakes associated with Middle Stone Age tools during most of MIS 5 ( 52 ). In the Jordan desert, the chronology of paleolakes and paleowetlands was indicated at Qa'a Azraq (Qa'a means depression) ( 53 ), Jurf Ed Darawish ( 26 , 32 ), Lake Elji ( 54 ), Qa'a Jafr ( 27 , 55 ), and Qa'a Mudawwara ( 28 ), indicating water resources availability facilitating human arrivals in Arabia either during MIS 5 and/or MIS 3. Our data show an agreement with the timing of the Dead Sea precursors: the last interglacial Lake Samra and the last glacial lake highstands ( Fig.…”

“…( B ) Digital elevation model map of the Levant showing the location of the study areas (yellow stars) along the Jordan Rift Valley (Wadi Gharandal and Gregra) and in the Jordanian Plateau (Wadi Hasa), and the paleolakes and speleothem records in the region. Paleolakes are represented by green circles, namely: Qa'a Azraq ( 53 ), Jurf Ed Darawish ( 26 , 32 ), Lake Elji ( 54 ), Qa'a Jafr ( 27 , 55 ), and Qa'a Mudawwara ( 28 ). Speleothem records in the Levant include Soreq cave (green triangle) ( 44 , 46 ), and the blue squares show sites with human fossils including Skhul and Qafzeh caves ( 5 ).…”

“…More extensive field investigation and results of optically stimulated luminescence (OSL) dating recently suggest that these sediments were formed ca. 120 to 65 ka ( 18 , 32 ). The present study provides a systematic luminescence chronology using quartz OSL and feldspar post–infrared-infrared–stimulated luminescence (pIR-IRSL) for three paleo-water bodies in the Jordan desert: Wadi Hasa, west-central Jordan, Gregra, and Wadi Gharandal along the Jordan River Valley.…”