Multiple phases of North African humidity recorded in lacustrine sediments from the Fazzan Basin, Libyan Sahara

Geomorphological investigations in the catchment area of the Baydragiyn river along the southern slope of the Khangay and in the Valley of the Gobi Lakes in western Mongolia provide evidence for Late Quaternary glaciations and lake-level changes. Thermoluminescence (TL) and infrared optically stimulated luminescence (IRSL) dating of aeolian and colluvial sediments from the central Khangay place the sediments that overlie fluvial and glaciofluvial terraces in the Holocene. An age of 21 ka is determined for a sand deposit overlying the terrace that is related to the last glacial ice-margin. Lacustrine sediments from higher beach lines in the Valley of the Gobi Lakes provide evidence for a slightly more humid period around 1.5 ka, and a larger extent of the lakes in the Early Holocene at about 8.5 ka, as also reported from other parts of Central Asia. Remnants of lacustrine sediments buried by alluvial gravel, and indicating a huge palaeolake in the basin of the Orog Nuur, however, date to the early stage of the last glaciation around 70 ka. Copyright © 2001 John Wiley & Sons, Ltd.

Optically stimulated luminescence dating of coastal sediments from southwestern Korea

Glacial and vegetation history of the Polar Ural Mountains in northern Russia during the Last Ice Age, Marine Isotope Stages 5–2

Quaternary paleoenvironmental change on the Tibetan Plateau and adjacent areas (Western China and Western Mongolia)

Luminescence dating reveals late Quaternary evolution of the Pearl River Delta estuary (China) in response to global climate and sea-level changes

There are more than 1,000 lakes within the Tibetan Plateau (TP), all of which are sensitive to changes in regional climate and local hydrology. Lacustrine sediments within these lakes preserve a good record of these changes. However, determining their precise ages is difficult due to the complex nature of lake reservoir effects (LRE), which limit our understanding of paleoenvironmental changes. Focusing on an exposed 600 cm thick lacustrine sediment profile located in western Zhari Namco, we used a combination of both radiocarbon and optically stimulated luminescence (OSL) dating methods in order to evaluate the carbon reservoirs of bulk organic matter (BOM) and aquatic plant remnants (APR), and to explore the age differences between14C and OSL and their respective reliability. We demonstrated that (i) OSL ages were changed in stratigraphic order, and the OSL age just below the beach gravel layer was consistent with previously reported paleoshoreline ages; (ii)14C ages were divergent between BOM and grass leaves; (iii)14C ages of BOM were older than14C ages of APR; and (iv) all14C ages were older than OSL ages. This could be attributed to changing LRE in the past, causing the14C ages to appear unstable during the deposition period. Although the14C ages of terrestrial plant remnants (TPR) were not affected by LRE, an analyzed twig nonetheless returned a14C age older than its respective layer’s OSL age, suggesting it may have been preserved on land prior to transportation into the lake. Our study suggests that OSL ages are more reliable than14C ages with respect to Zhari Namco lacustrine sediments. We recommend caution when interpreting paleoenvironmental changes based on lacustrine sediment14C ages alone.

Late Pleistocene braided rivers of the Atlantic Coastal Plain, USA

Luminescence chronology of the loess record from the Tönchesberg section: A comparison of using quartz and feldspar as dosimeter to extend the age range beyond the Eemian

Underestimated single-aliquot quartz OSL ages of Late-Pleistocene sediments due to the dominance of medium component

Landscape evolution and geodynamic controls in the Gulf of Cadiz (Huelva coast, SW Spain) during the Late Quaternary

Luminescence dating technology has been used for chronological constraints on lacustrine sediments due to the ubiquitous materials (e.g., quartz and feldspar) as dosimeters, and a relatively long dating range, compared with the commonly used radiocarbon dating method. However, quartz dating on the Tibetan Plateau may suffer from dim and unstable luminescence signals. In the current study, we investigate a lake-related outcrop from the shore of Cuoe Lake on the central Tibetan Plateau. Both coarse-grained quartz and K-feldspar fractions were extracted, and OSL and post-IR IRSL signals were measured from these fractions, respectively. Combining the stratigraphy analysis and dating results, this study shows that: (1) quartz appears to be unsuitable for dating because of very dim natural signals and even anomalous fading (average <i>g</i>-value: 4.30 ± 2.51 %/decade). The suitability of the applied pIRIR protocol measured at 150°C (pIRIR<sub>150</sub>) for K-feldspar samples was confirmed by a set of luminescence tests; (2) compared with the luminescence-based chronology, the <sup>14</sup>C age of shells from the same sediment layer yielded older age by ∼7 ka, which is likely attributed to hard water reservoir effect in Cuoe Lake; (3) the lake level reached its peak and maintained high-stand during the early Holocene (∼9.4–7.1 ka). This study highlights the applicability of K-feldspar luminescence dating when the counterpart quartz OSL is insensitive and encounters anomalous fading.

Optically stimulated luminescence dating of young (<500 years old) sediments: Testing estimates of burial dose

OSL dating of flood sediments in the North China Plain

Fine-grained windblown deposits, known as loess, in which fossil soils (palaeosols) are preserved, serve as excellent records of past climate. However, paleoclimate reconstruction studies on loess-palaeosol sequences (LPS) in Southeastern Europe have primarily focused on climate changes during the last one or two glacial-interglacial cycles. Surprisingly, little attention has been given to the climate of the current interglacial, the Holocene. This oversight may be attributed to the prevailing notion that, based on ice core and marine isotope records, the Holocene is considered a climatically stable period. Additionally, the scarcity of LPS with well-preserved Holocene loess has contributed to this lack of attention until now. Three recently discovered loess-palaeosol sequences in the Eastern Carpathian and the Wallachian Basins present fully preserved loess covering MIS 1-MIS 2 offering the potential to unveil new and detailed information about Holocene climate. In this study, we present initial results from two of these LPS: Kisiljevo (44&amp;#176;44&amp;#8242;0'' N and 21&amp;#176;25&amp;#8242;0'' E) in the Carpathian Basin, and Velika Vrbica (44&amp;#176;35&amp;#8217;1.70&amp;#8217;&amp;#8217;N, 22&amp;#176;43&amp;#8217;15.97&amp;#8217;&amp;#8217;E) in the Wallachian Basin. For both sequences, detailed optically stimulated luminescence (OSL) chronologies using 63-90 &amp;#181;m quartz have been constructed. Age models based on the OSL ages were constructed using the r.bacon software (Blaauw &amp;amp; Christen, 2011), following which dust accumulation rates (MAR) for the last approximately 30,000 years were calculated. The initial results from Kisiljevo reveal a significant loess accumulation during the Holocene, amounting to approximately 120 cm. The highest MARs were observed between 10 and 12 ka (10,000-8,000 BC) with a mean value of 148 g m2 a-1. A similar trend is evident at the Velika Vrbica LPS, where the average calculated MARs during the early Holocene (8 &amp;#8211; 11.7 ka) were 189 g m2 a-1, showing a decreasing trend toward the later part of this period (3.1 &amp;#8211; 8 ka) with average values reaching 132.1 m2 a-1. Interestingly, at this site, the mean MARs during Marine Isotope Stage 1 (MIS) were higher than during the cold, stadial MIS 2, where the recorded values averaged 177 g m2 a-1. These initial results suggest that the Holocene dust dynamics in this region was more variable than what generally accepted models suggest.

Luminescence dating of a sedimentary sequence in the eastern North Yellow Sea