Quaternary Geochronology最新文献

{"title":"Timing of fluvial sedimentation in the Baiyangdian catchment, North China Plain, since the late Pleistocene by multiple luminescence dating approaches","authors":"Yan Li ,&nbsp;Xiao Sun ,&nbsp;Yuhan Liu ,&nbsp;Yandong Pei","doi":"10.1016/j.quageo.2024.101589","DOIUrl":"10.1016/j.quageo.2024.101589","url":null,"abstract":"<div><p>The North China Plain is one of the key pathways to the ‘source-to-sink’ sedimentary system in East Asia and an important area of human occupation. It has also experienced a large amount of deposition of thick fluvial sediments. Thus, chronostratigraphy research in the North China Plain since the Late Pleistocene is critical to understanding the sedimentary processes and glacial–interglacial climate changes occurring since the Late Pleistocene. In this study, 14 fine-grained (FG) luminescence samples collected from a sedimentary core (GB210) drilled from the Baiyangdian catchment in the North China Plain, were employed for quartz optically stimulated luminescence (OSL), and polymineral post infrared (IR) IRSL (pIRIR₁₅₀ and pIRIR₂₉₀) dating. The luminescence ages were compared to evaluate the reliability and to establish a luminescence chronology of the core sediments. The results showed that the anomalous fading of the polymineral pIRIR₁₅₀ signal is small. The fading corrected pIRIR₁₅₀ ages agree with the FG quartz OSL ages. The FG quartz OSL age corresponding to early Marine Isotope Stage (MIS) 4 may be slightly underestimated due to signal saturation. However, the pIRIR₂₉₀ signal yielded overestimated ages. The chronology based on the fading corrected pIRIR₁₅₀ ages suggests that the deposition of the studied sediments began in MIS 5. Variations in the sedimentation rate correspond to summer climate changes, while the grain size indicates winter climate changes.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101589"},"PeriodicalIF":1.7,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141566611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Single grain pIRIR dating of glacigenic deposits in the Yuzhu Peak area of Kunlun Mountains of Tibetan Plateau revealed the glaciations during Holocene period","authors":"Jilei Yang ,&nbsp;Yixuan Wang ,&nbsp;Guoqiang Li ,&nbsp;Xiaoyan Wang ,&nbsp;Tao Lu ,&nbsp;Weiping Ding ,&nbsp;Xianjiao Ou ,&nbsp;Donglin Gao","doi":"10.1016/j.quageo.2024.101586","DOIUrl":"10.1016/j.quageo.2024.101586","url":null,"abstract":"<div><p>The variations of glaciers in the Kunlun Mountains of the northern Tibetan Plateau are influenced by the complex interaction of the East Asia summer monsoon (EASM), Indian summer monsoon (ISM) and Westerlies, as well as human activity during the Holocene period. Consequently there is ongoing debates regarding the evolution of glaciers and the factors driving their changes. The reconstruction of glacial evolutions in these regions has been hindered by insufficient chronological data for moraines and other glacial landforms. In this study, glacial sediment samples were collected from five moraine sequences located on the southern and northern slopes of the Yuzhu Peak in the Kunlun Mountains. These poorly bleached moraine samples were dated using the single-grain quartz optically stimulated luminescence (OSL) and K-feldspar post-infrared infrared stimulated luminescence (pIRIR) dating methods. The luminescence characteristics analysis of quartz grains shows that single grain quartz OSL dating cannot be used to date Holocene moraine samples due to the low brightness of quartz OSL signals. Various tests were conducted to assess the reliability of K-feldspar pIR₅₀IR₁₇₀ dating, including anomalous fading tests, dose recovery, and residual dose tests. The K-feldspar pIR₅₀IR₁₇₀ ages, determined using the Minimum Age Model (MAM), indicate that during the early Holocene, glaciations have expanded by ∼800 m in length at ∼ 8 ka, and during the end of the Neoglacial period, they extended by ∼200 m in length at ∼ 1 ka. The strengthened ISM precipitation and northward movement of ISM boundary likely contributed to the glacial expansion in the early Holocene. During the end of the Neoglacial period, the increase in westerlies precipitation and cold events may have played a role in the advancement of glaciers.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101586"},"PeriodicalIF":1.7,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141566610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High resolution luminescence and radiocarbon dating of Holocene Aeolian silt (loess) in west Greenland","authors":"D. Sechi ,&nbsp;T. Stevens ,&nbsp;P. Hällberg ,&nbsp;R.H. Smittenberg ,&nbsp;M. Molnár ,&nbsp;G.T. Kertész ,&nbsp;J.P. Buylaert ,&nbsp;R. Schneider ,&nbsp;C. Edward ,&nbsp;Keld Romer Rasmussen ,&nbsp;Niels Aage Tvis Knudsen ,&nbsp;S. Andreucci ,&nbsp;V. Pascucci","doi":"10.1016/j.quageo.2024.101579","DOIUrl":"10.1016/j.quageo.2024.101579","url":null,"abstract":"<div><p>Loess–palaeosol sequences serve as valuable archives of changes in climate and atmospheric mineral dust deposition. However, little work has been conducted on Holocene loess in the Arctic, despite the sensitivity of this region to climate changes. Aeolian silt/loess profiles in the ice-free region of western Greenland near Kangerlussuaq were sampled to develop a robust age framework using both luminescence and bulk organic matter radiocarbon dating. Radiocarbon ages generally show consistent age increases with depth but are likely offset to younger ages due to sediment mixing in the upper 10–20 cm of the profiles. Quartz OSL signals exhibit insensitivity, while low-temperature infrared stimulated luminescence performed at 50 °C (IR₅₀) and the post-IR IRSL at 180 °C (pIRIR₁₈₀) signals of polymineral fine grain revealed a consistent natural inherited dose of approximately 5 Gy for pIRIR₁₈₀ and an unbleachable residual of around 2 Gy for IR₅₀, with substantial fading rates in the latter. This led to a notable age overestimation when compared with bulk organic matter radiocarbon ages. To develop an appropriate dating approach, we evaluated the differential bleaching rates of feldspar IR₅₀ and pIRIR₁₈₀ signals, and corrected for modern inherited doses. Radiocarbon ages measured on the bulk organic carbon oxidised at 400 °C (LT ¹⁴C) increased very consistently with depth, allowing calculation of accumulation rates. The presence of the atmospheric radiocarbon bomb signal at depth indicated down-mixing of surface material into the profile, which caused negative (younger) age offsets. The offset-corrected radiocarbon-based age-depth model could be compared to the luminescence results.</p><p>We show that a combination of LT ¹⁴C with polymineral pIRIR₁₈₀ dating allows the development of age models for these deposits. This multi-chronological approach reveals that loess accumulation in the region was initiated around 4 ka, probably consisting of two main phases of loess accumulation at 4–3 ka and &lt;1 ka. The initial phase matches the proposed onset of aeolian sand activity in the wider region, but post-dates local ice retreat by c. 3 kyr. The more recent phase of accumulation also matches the timing of increased sand accumulation in the region and likely coincides with Neoglacial to Little Ice Age ice advances, or even enhanced dust activity in the last decades.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"84 ","pages":"Article 101579"},"PeriodicalIF":1.7,"publicationDate":"2024-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141937884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extending the ESR and OSL dating comparison on coastal dune deposits from the Wilderness-Knysna area (South Africa)","authors":"E. Ben Arous ,&nbsp;M.D. Bateman ,&nbsp;M. Duval","doi":"10.1016/j.quageo.2024.101580","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101580","url":null,"abstract":"<div><p>Our work follows up on the initial methodological ESR dating study by Ben Arous et al. (2022) on several quartz samples from the Plio-Pleistocene to Holocene aeolian coastal dune deposits of the Wilderness-Knysna area (South Africa) that were previously dated by optically stimulated luminescence (OSL). Here, we extend this first ESR-OSL comparison with five additional optically-bleached quartz samples. We used the Multiple Aliquot Additive Dose (MAAD) method to specifically (i) evaluate the influence of the irradiation dose steps on the determination of low D_e values (&lt;100 Gy) and (ii) obtain finite ESR ages for older samples that sometimes show saturated OSL signals. Following the Multiple Centre ESR dating approach, the Aluminium (Al) and Titanium (Ti) signals (Ti–H and Ti–Li–H, the latter resulting from a mixture of Ti centres) were systematically measured in all samples, and resulting D_e values and age estimates were compared with the corresponding OSL data. Our results show that for young samples (&lt;50 ka) showing D_e values of a few tens of Grays (Gy), the use of smaller irradiation steps spaced by &lt; 100 Gy has a noticeable impact on the MAAD dose evaluation from the Ti centres, usually leading to D_e results closer to the expected values (for 2/3 samples). However, this also makes the ESR measurements somewhat more challenging, with higher experimental uncertainties, lower measurement repeatability and lower goodness-of-fit resulting from the relatively weak Ti ESR intensities, ultimately impacting the robustness of the ESR data collected. In this sense, our study illustrates the limitations of the ESR method to detect very low dose irradiation values &lt; 30 Gy with our experimental conditions (i.e., using MAAD procedure, a standard resonator and a measurement temperature of ∼90 K). On the contrary, it also highlights the greater potential of the Ti–H signal to date Late Pleistocene samples, confirming previous studies. Moreover, our results suggest that the transport and bleaching conditions of these aeolianite deposits may not be ideal for the reset of the radiation-induced Al and Ti ESR signals, which is consistent with the very few existing studies specifically focused on this type of samples, but contrasts with other previous dating applications centered on fluvial environments. Finally, we also provide additional chronological constraints to the Landward barrier complex and Coversands deposits, two of the oldest Plio-Quaternary formations in the Wilderness-Knysna area.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101580"},"PeriodicalIF":1.7,"publicationDate":"2024-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141583211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical dating of charcoal kiln remains from WWII: A test of accuracy","authors":"Nasrin Karimi Moayed ,&nbsp;Dimitri Vandenberghe ,&nbsp;Koen Deforce ,&nbsp;Eva Kaptijn ,&nbsp;Karsten Lambers ,&nbsp;Wouter Verschoof-van der Vaart ,&nbsp;Wim De Clercq ,&nbsp;Johan De Grave","doi":"10.1016/j.quageo.2024.101582","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101582","url":null,"abstract":"<div><p>The majority of relic charcoal kilns in Europe are more recent than 1650 CE and cannot be precisely dated using radiocarbon dating (¹⁴C). Quartz-based optically stimulated luminescence (OSL) dating of the sediments associated with the kiln remains has been suggested as a viable alternative. Owing to the lack of reliable and sufficiently precise independent age information, however, it remains to be established whether OSL dating can yield accurate ages for post-1650 CE features. This is explicitly investigated in this study by applying a commonly adopted quartz OSL methodology to three relic charcoal kilns which are known to have been constructed and operated between December 1941 and March/April 1942 CE.</p><p>We first document the quartz luminescence characteristics and show through procedural tests that the adopted single-aliquot regenerative dose procedure should be appropriate for equivalent dose determination. Four samples collected from the uppermost part of the charcoal-rich layers in the three features yield the youngest optical ages and are considered coeval. Their average age is 1928 ± 13 CE (95% probability), which matches the independent age reasonably well. The precision associated with the individual OSL ages ranges between 7 and 14% (1 sigma total uncertainty) and it might ideally be possible to establish relative chronologies with a higher time resolution. Finally, we briefly discuss our entire set of OSL ages in relation to future strategies for sampling charcoal kilns remains. In general, we conclude that OSL dating can be particularly advantageous to help resolving chronometric issues that pertain to post-1650 CE relic charcoal kilns.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101582"},"PeriodicalIF":1.7,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141606322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Testing the applicability of standardised growth curves for chemically heterogeneous single-grain feldspars from the Atacama Desert, Chile","authors":"Linda A.E. Maßon ,&nbsp;Svenja Riedesel ,&nbsp;Anja Zander ,&nbsp;Mariana Sontag-González ,&nbsp;Tony Reimann","doi":"10.1016/j.quageo.2024.101585","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101585","url":null,"abstract":"<div><p>The Atacama Desert is generally considered the driest non-polar desert on Earth and is therefore an ideal study area for exploring the water and biota free endmember of Earth's Critical Zone (ECZ). Single grain (SG) luminescence dating has successfully identified processes in the ECZ. However, SG luminescence dating of Atacama Desert feldspars is challenging and time consuming since only a small fraction of grains emits sufficient luminescence and their potassium (K) contents, needed for internal dose rate calculations, are highly variable. Here we present an adaption of the standardised growth curve (SGC) method adjusted to the conditions of Atacama Desert sediments and a correlation of single-grain geochemistry and luminescence properties.</p><p>To evaluate if SGCs are suitable for our study site and to determine the influence of the K-content on our luminescence age calculations, we used a set of five samples from the Atacama Desert and five chemically and structurally different feldspar sediment extracts from various geological origins worldwide. We performed a dose recovery test (DRT) using a post-infrared infrared stimulated luminescence (pIRIR) protocol and measured nine major element concentrations, including K, on a single grain level using a scanning electron microscope (SEM) with energy-dispersive X-ray spectroscopy (EDX). The DRT dataset was then used to test the application of SGCs. The accuracy of Atacama feldspar pIRIR measurements fitted onto SGCs frequently suffers from odd values in single measurement cycles, since the SGC approach developed for SG feldspar luminescence (Li et al., 2015b) uses one L_x/T_x measurement to project the L_n/T_n values onto a SGC. We investigate the influence of calculating a synthetic regenerative signal (sR) for SGC fitting, to reduce the effect of those odd values on individual grain measurements. Furthermore, we reduced the regenerative cycles used for our sR approach, to test if shorter protocols would result in equivalent dose (D_e) estimates in agreement with longer protocols. We then calculated Spearman rank correlations between the results obtained with our modified SGC and the SAR protocol, luminescence signal intensities, and the geochemical dataset.</p><p>Finally, we present a new method of fitting data onto a SGC which significantly decreases measurement time, without risking the inclusion of outliers. We furthermore show that the luminescence signal intensities, the D_e values and their dose recovery ratios obtained with our SGC method and a SAR protocol, are independent of the sample geochemistry.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101585"},"PeriodicalIF":1.7,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S187110142400089X/pdfft?md5=bf9b8612fdb16da46f987dd54510b9ed&pid=1-s2.0-S187110142400089X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141583210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variance in pIRIR signal bleaching for single grains of feldspar","authors":"Jungyu Choi,&nbsp;Elizabeth Chamberlain,&nbsp;Jakob Wallinga","doi":"10.1016/j.quageo.2024.101577","DOIUrl":"10.1016/j.quageo.2024.101577","url":null,"abstract":"<div><p>Evaluating remnant doses is crucial for luminescence dating of late Holocene sedimentary deposits, especially when slow-bleaching feldspar pIRIR signals are employed. Previous research demonstrated that the bleaching capacity varies between individual grains, but only a few attempts have been made to quantify this. In this research, we evaluate variance in bleachability at a single-grain level for a low-temperature pIRIR signal from K-rich feldspar extract. The research is conducted through experimental exposure to natural sunlight of two natural samples. The degree of zeroing is monitored over exposure times up to 100 min and related to the recuperation values obtained on the same grains from the standard pIRIR sequence. We find a positive correlation between recuperation doses of grains and their residual doses, which suggests that recuperation provides a proxy for grain bleachability. In addition, we combine our dataset of bleachability with information on the difference between IRSL₅₀ and pIRIR₁₇₅ equivalent doses determined on the same grain (D_e ratio), which allows us to identify grains for which light exposure was too limited to reset both signals. The results demonstrate that prior inheritance, light exposure, and grain bleachability all may impact the residual dose of grains, resulting in overdispersion in equivalent dose distributions. Combining the assessment of bleachability with the information on the D_e ratio can support the identification of best-bleached grains in a natural sample. Finally, the different bleachability of individual grains demonstrates that it may not be advisable to subtract the mean residual dose from paleodoses obtained with a minimum age model and for Holocene-aged deposits.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101577"},"PeriodicalIF":1.7,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1871101424000815/pdfft?md5=0d72e0cb509be2bd22390f4a7b8dbeee&pid=1-s2.0-S1871101424000815-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141566613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility of rock surface luminescence dating technique for measuring the burial ages of unheated flints","authors":"L. Ageby ,&nbsp;S. Jakathamani ,&nbsp;A.S. Murray ,&nbsp;M. Jain ,&nbsp;E.F. Rades","doi":"10.1016/j.quageo.2024.101566","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101566","url":null,"abstract":"<div><p>While flint and similar materials are some of the most often preserved finds from the pre-historic archaeological records, trapped charge techniques can currently only be used on heated flint pieces. Here, we investigate if rock surface luminescence dating using the light-sensitive OSL signal is applicable to unheated flint nodules and cobbles by measuring OSL signal-depth profiles in flint samples collected from eastern Zealand and Møn, Denmark. We demonstrate that a detectable, natural OSL signal is present in the centre in eight out of the nine investigated flint samples. Additionally, the OSL signal had been bleached to various depths at the flint surfaces, which were exposed to daylight at the time of sampling. The field-saturated OSL is 50% or lower compared to the laboratory OSL after a 6 kGy dose was administered to field-saturated flint slices; this discrepancy could be related to signal loss occurring over geological time scales, but the exact nature of the mechanism of signal loss remains unclear. The presence of a natural OSL signal that bleaches into the flint when exposed to daylight suggests that rock surface dating of unheated flints is feasible, and the method should be further tested on known-age samples.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101566"},"PeriodicalIF":1.7,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1871101424000700/pdfft?md5=6e03f93bc81a34a261f4f27469999736&pid=1-s2.0-S1871101424000700-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141539949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Luminescence ages of sediments from the margin of the penultimate glaciation in the north-eastern East European plain","authors":"Anna Utkina ,&nbsp;Jeong-Heon Choi ,&nbsp;Andrew Murray ,&nbsp;Andrei Panin ,&nbsp;Nataliya Zaretskaya ,&nbsp;Redzhep Kurbanov ,&nbsp;Jan-Pieter Buylaert","doi":"10.1016/j.quageo.2024.101578","DOIUrl":"10.1016/j.quageo.2024.101578","url":null,"abstract":"<div><p>In this study we apply optically stimulated luminescence and infra-red stimulated luminescence to the sediments from the interfluve dividing three river basins: the Pechora, the Kama and the Severnaya Dvina, hoping to gather new age data on glaciofluvial sediment. We also studied the valley of the Berezovka, a medium-scale river cutting through this interfluve. We obtained a chronology from 17 quartz and 15 feldspar ages. Sedimentological analyses and luminescence dating show that most of the sediments examined here are water-transported (gully alluvium, slopewash deposits), and their ages mark a period of accumulation during MIS 2. Some of these sediments were reworked by aeolian processes; these took place over a time span consistent with such processes in other parts of the East European Plain (19-12 ka). The Berezovka river experienced incision before ∼22 ka and another erosion event with extremely high floods at 15–16 ka. Its terrace formed in MIS 5, constraining the minimum age of the valley. In the bottom part of the sections, much older, possible MIS 8, glaciofluvial sediments were found; the apparent absence of MIS 6 sediments may argue for moving the MIS 6 ice sheet limit further to the north of the study area.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101578"},"PeriodicalIF":1.7,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141577414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Holocene lake shrinkage on the northwestern Tibetan Plateau revealed by K-feldspar single-grain pIRIR dating of paleo-shorelines","authors":"Shuai Zhang ,&nbsp;Hui Zhao ,&nbsp;Leibin Wang ,&nbsp;Fahu Chen","doi":"10.1016/j.quageo.2024.101583","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101583","url":null,"abstract":"<div><p>As a vital component of the “Asian water tower”, lakes on the Tibetan Plateau (TP) significantly influence the regional ecosystems and economies and they are also an effective sentinel of climate change. However, the temporal and spatial patterns of lakes and the related hydroclimatic evolution on the northwestern TP (NWTP) remain unclear. We reconstructed the lake level variations of a non-glacier-fed lake, Longjue Co, on the NWTP, using optical dating of paleo-shorelines. The optically stimulated luminescence signals of quartz grains were unsuitable for dating due to high contributions of the medium component, and thus the post-infrared infrared stimulated luminescence signals (pIR₅₀IR₁₇₀, pIR₅₀IR₂₂₅) of K-feldspar single grains were used. Internal checks including dose recovery tests, residual dose tests, and anomalous fading tests showed that the pIR₅₀IR₁₇₀ signal was suitable for paleo-shoreline dating in Longjue Co. However, some of the samples were affected by the incomplete bleaching of pIRIR signals before deposition, and in this case the Minimum Age Model was used to constrain the ages. We also examined the dependence of the K-feldspar equivalent dose (D_e) on grain brightness and explored the possible mechanisms, and the brightest grains were then used for D_e calculations. The results show that Longjue Co reached its maximum Holocene level (+34 m) during the early Holocene (10.06 ± 1.39 ka), and then after ∼5 ka it commenced a shrinking trend, punctuated by two rapid lake level decreases. Reference to independent paleoclimate records suggests that the Holocene lake level variations of Longjue Co and the regional hydroclimate were mainly controlled by the Indian summer monsoon.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101583"},"PeriodicalIF":1.7,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141486898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}