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Quaternary environments on the Arabian Peninsula shifted between pronounced arid conditions and phases of increased rainfall, which had a profound impact on Earth surface processes. However, while aeolian sediment dynamics are reasonably well understood, there is a lack of knowledge with regard to variability in the fluvial systems. Presented here are the findings from several locations within wadi drainage systems to the west of the Hajar Mountains (United Arab Emirates). The performance of optically stimulated luminescence dating using a customized standardized growth curve approach is investigated, showing that this approach allows reliable determination of ages by reducing the machine time required. Three main periods of fluvial activity occurred at 160–135, 43–34, and ca. 20 ka. Additional ages fall into the latest Pleistocene and Late Holocene. None of the ages coincides with major wet periods in SE Arabia that have been identified in stalagmites and by the deposition of lake sediments. It is shown that fluvial activity was partly contemporaneous (within the given time resolution) with phases of aeolian deposition and was almost continuous, but likely sporadic, during the Middle to Late Pleistocene. This highlights the need for regionally defined paleoenvironmental records to fully understand the response of dryland systems to long-term climatic change. [ABSTRACT FROM AUTHOR]

A complex picture of the Pleistocene glaciation history of northern Switzerland has been identified over the last three decades. To gain further insights into the long-term landscape evolution, numerical dating is required. In the absence of alternative dating techniques, luminescence dating is the key method for establishing chronological constraints of past glaciations. However, this is presented with complex challenges, especially in regard to the resetting of the luminescence signal prior to deposition, the components contributing to the signal as well as the signal intensity and stability. In this study, the luminescence properties of glacially sourced deposits from northern Switzerland are assessed using single aliquot (SA) and single grain (SG) measurements of feldspar (F) and quartz (Q). While no obvious connection between bleaching and distal or proximal deposition in relation to the proposed ice margin is observed, most samples seem to reveal a partially bleached signature in F SG D e measurements. This appears to be masked in the respective F SA measurements even though only few grains emit luminescence signals. In addition, comparisons between fading corrected infrared stimulated luminescence (IR) and post-infrared infrared stimulated luminescence (pIR) D e values appear to be unreliable indicators of bleaching, even though these signals bleach at different rates. Hence, it is recommended to conduct both IR and pIR investigations in combination with Q measurements on a SG level. The dating potential of the investigated deposits remains rather limited, yet, in the sedimentologic context the presented results reveal that several glacial advances occurred prior to the Last Interglacial in the study area. • Absolute minimum age constrains for glacially sourced deposits from northern Switzerland were derived. • Quartz signals were investigated using single grains and multigrain aliquots. • Measurements of small aliquots apparently mask partial bleaching of feldspar luminescence signals. • Agreement between fading corrected IR and pIR signals no indicator for sufficient bleaching. • No obvious connection between bleaching and distance to the proposed ice margin was observed. [ABSTRACT FROM AUTHOR]

Rock surface dating, a relatively new approach within luminescence dating, determines when a rock surface was last exposed to sunlight by measuring the amount of latent OSL signal accumulated after burial. However, the potential and applicability of rock surface dating in glaciofluvial settings of the Alps has seen very limited application so far (Rades et al., 2018). Therefore, different luminescence methods including rock surface dating have been applied in a unique setting at the Hartheim gravel pit in the southern Upper Rhine Graben to establish a chronological frame for distal glaciofluvial deposits. First, a detailed field study was conducted in order to gather a comprehensive understanding of the different sediment types present. Fine grain sand, cobbles, pebbles and matrix sediments embedded within large clasts were collected and analyzed using a combination of OSL and IRSL dating. Conventional OSL dating of fine sand quartz is considered as robust age control compared to the other sediment types. A substantial amount of luminescence measurement has been done on the sand lens and gravel matrix sediment collected from Hartheim. OSL ages range around from ca. 19 ka to 32 ka for the different sediment types. Feldspar IRSL has been measured using a MET-pIRIR protocol to avoid problems with fading. Furthermore, a detailed dosimetry study was conducted to measure the varying levels of radionuclide concentration within materials of different grain size, in order to obtain accurate depositional ages. Overall, the purpose of this research contributes to our existing knowledge in the field of luminescence dating by showing the potential and versatility of different luminescence methods in different sediment types and environments that provide an ideal framework for future studies in similar contexts. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of the present work is to examine the effect of heating (up to 500°C) on the shape of a growth curve for optically stimulated luminescence (OSL) of quartz extracted from Chinese loess. For OSL of natural quartz grains, the growth curve constructed using a single aliquot regenerative-dose (SAR) protocol has a linear growth part in the high dose range of , which may allow the determination of a to and also implies that the OSL has contribution from more than a single trap/luminescence combination centre. When quartz grains are heated to a temperature of , the shape of a growth curve will change, and the saturation level of a growth curve is decreasing systematically. The significant difference in the growth curve shape before and after heating to might be used as an indicator to detect the thermal history, i.e. whether the quartz grains had undergone a heating event of before deposition. This has potential application for archaeological samples. The effect of heating on OSL sensitivity is also examined. [Copyright &y& Elsevier]

Abstract: Recent publications revealed different opinions regarding the existence of a common growth curve (CGC) for OSL of quartz. In the current study, 18 loess samples were collected from four continents (Asia, America, Africa, and Europe) in order to further examine this issue. Except the three samples from Chile in South America, 15 samples display similar dose–response curves up to a regeneration dose of 200 Gy using the SAR protocol, suggesting the existence of a global CGC for loess from different continents. For samples with equivalent doses ( from to , the s determined by the CGC are in good agreement with the s by the SAR protocol. The Chilean samples posses a growth curve that differs from the CGC, showing much lower saturation doses. We suggest that it may be due to contamination with heavy minerals. [Copyright &y& Elsevier]