Search

This paper presents a protocol for safe quartz etching with hydrofluoric (HF) acid as part of sample preparation for luminescence dating. Concentrated HF is extremely hazardous and can cause severe burns and poisoning, even leading to death. Generally, in order to avoid exposure to light and bleaching, HF etching is performed in a dark laboratory under weak orange-red light in wide-open beakers. Handling HF in open beakers in the dark could result in unfortunate accidents due to unintentional spillage. The presented protocol avoids these two main safety issues - working with open beakers and under poor lighting. The samples are etched inside black opaque bottles with narrow openings so that the procedure can be safely performed in comfortable light levels. To validate the harmlessness of the laboratory environmental light, bleaching experiments of quartz were conducted under the same conditions as the protocol. These showed that no bleaching occurred during this procedure. [ABSTRACT FROM AUTHOR]

Marine Isotopic Stage 5 is associated with wetter climatic conditions in the Saharo-Arabian deserts. This stage also corresponds to the establishment of Middle Paleolithic hominins and their associated material culture in two geographical provinces in southwest Asia—the Eastern Mediterranean woodland and the Arabian Peninsula desert. The lithic industry of the Eastern Mediterranean is characterized by the centripetal Levallois method, whereas the Nubian Levallois method characterizes the populations of the Arabian desert. The Negev Desert, situated between these regions is a key area to comprehend population movement in correlation to climatic zones. This investigation addresses the nature of the Middle Paleolithic settlement in the Negev Desert during MIS 5 by studying the site of Nahal Aqev. High resolution chronological results based on luminescence dating and cryptotephra show the site was occupied from MIS 5e to MIS 5d. The lithic industries at Nahal Aqev are dominated by centripetal Levallois core method. These data demonstrate that Nahal Aqev is much closer in its cultural attributes to the Eastern Mediterranean Middle Paleolithic than to the Arabian Desert entity. We conclude that Nahal Aqev represents an expansion of Middle Paleolithic groups from the Mediterranean woodland into the desert, triggered by better climatic conditions. These groups possibly interacted with hominin groups bearing the Nubian core tradition from the vast region of Arabia. [ABSTRACT FROM AUTHOR]

Optically stimulated luminescence (OSL) of quartz is an established technique for dating late Pleistocene to late Holocene sediments. Unfortunately, this method is often limited to up to 100 ka (thousands of years). Recent developments in new extended-range luminescence techniques show great potential for dating older sediments of middle and even early Pleistocene age. These methods include thermally transferred OSL (TT-OSL) and violet stimulated luminescence (VSL) for quartz and post-infrared infrared stimulated luminescence (pIRIR) for feldspar. Here we investigate the luminescence behaviour of the TT-OSL, VSL, and pIRIR signals of quartz and feldspar minerals of aeolian sediments of Nilotic origin from the eastern Mediterranean. We sampled a 15m thick sequence (Kerem Shalom) comprising sandy calcic palaeosols, which is part of a sand sheet that covers an extensive region in south-western Israel. Dose recovery and bleaching experiments under natural conditions indicated that the pIRIR250 signal is the most suitable for dating the Nilotic feldspar. Luminescence intensity profiles revealed natural saturation of the three signals at the same depth of ~6 m, indicating that ages of samples below that depth are minimum ages. Using TT-OSL and pIRIR250, a minimum age of 715 ka for the base of the section was obtained, suggesting aeolian sand accumulation along the eastern Mediterranean coastal plain already since the early Pleistocene. Our results indicate that both TT-OSL and pIRIR250 can accurately date aeolian sediments of Nilotic origin up to 200 ka and that minimum ages can be provided for older samples up to the early Pleistocene. [ABSTRACT FROM AUTHOR]

This paper provides an in-depth review of evidence for the presence of twelve waterbodies spanning the Late Pliocene through Late Pleistocene in southern Israel and southern Jordan. A comprehensive description of these waterbodies is presented, combined with new field, paleontological and numerical age data, along with a discussion of their implications for paleohydrology and paleoclimate. The region is currently hyper-arid and there are no permanent rivers, wetlands or lakes in the area. Nevertheless, during the time-frame examined, continuous layers of limestones and mudstones were deposited in wetlands and shallow lakes. According to their location, the waterbodies were classified into either resulting from local tectonic depressions or in wide natural depressions at base levels. Following the types of sediments and fauna associated with these waterbodies, it is suggested that four wetter periods occurred: Late Pliocene/Early Pleistocene, Middle Pleistocene, Middle Late Pleistocene and terminal Late Pleistocene. This resulted in the deposition of limestone, chalk, travertine, calcrete, mudstone, marl, clay, silt and sandstone. For several waterbodies, vertical and lateral transitions between white limestone and fine clastic sediments rich in carbonate, indicate changes in depositional conditions from a shallow lake to a wetland, both associated with wetter hydrological settings compared to current climatic conditions. [ABSTRACT FROM AUTHOR]