Quaternary Geochronology最新文献

{"title":"Dating the middle and late Quaternary Caspian Sea-level fluctuations: First luminescence data from the coast of Turkmenistan","authors":"R. Kurbanov ,&nbsp;A. Murray ,&nbsp;T. Yanina ,&nbsp;J.-P. Buylaert","doi":"10.1016/j.quageo.2024.101599","DOIUrl":"10.1016/j.quageo.2024.101599","url":null,"abstract":"<div><p>The Caspian region provides the basis of the stratigraphy and palaeogeography of the Pleistocene of Central Eurasia, and has been actively studied for more than 200 years. Many issues concerning the palaeogeographic history of the various basins of Caspian Quaternary remain unsolved, but the main problem centres on uncertainties in the chronology. Previous chronological studies have focused on a detailed description of the sedimentation history in the Lower Volga and Eastern Caucasus, ignoring a number of unique sites on the eastern Caspian coast, mainly due to inaccessibility. We obtained access to one of the most complete sections, western Cheleken, located on the Caspian coast of Turkmenistan. Within this sandy and generally lowland coast, the western part of the Cheleken peninsula forms a 10 km wide cliff opening a unique series of Middle Pleistocene - Holocene sediments which record in detail the history of Caspian transgressions and regressions. Stratigraphical, geomorphological and palaeontological studies of the section were supplemented with luminescence and radiocarbon dating. Analysis of Caspian molluscs and luminescence ages allowed the reconstruction of the sedimentary history of this region during one of the most important events of the Caspian Basin: the Early and Late Khazarian, Khvalynian and Novocaspian transgression/regression series. Luminescence dating of quartz and feldspar provided 12 OSL, IR₅₀ and pIRIR₂₉₀ ages, comparison of which showed that quartz grains were sufficiently bleached before deposition. Our chronology provides, for the first time, a deeper understanding of the sedimentation and environmental history in this region and the entire Caspian Sea. The Early Khazarian transgression occurred here at ∼220–200 ka (MIS 7). The Late Khazarian stage recorded in shallow-marine clays had relatively stable level ∼150–130 ka ago. In the second half of MIS 5 sea-level decreased and sedimentation was controlled by a large river, most probably the palaeo-Amu-Daria. The Early Khvalynian stage started at ∼27 ka and continued presumably until ∼14 ka.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101599"},"PeriodicalIF":1.7,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141639078","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":"From ice-dammed lake to aeolian dunes in the Store Mosse area, SW Sweden","authors":"Helena Alexanderson ,&nbsp;E. Martin Lund ,&nbsp;Tim Bjermo","doi":"10.1016/j.quageo.2024.101591","DOIUrl":"10.1016/j.quageo.2024.101591","url":null,"abstract":"<div><p>Wind is a significant geomorphological agent in formerly glaciated areas and aeolian deposits surround and stretch across the Store Mosse (<em>Great Bog</em>) bog complex in southwestern Sweden. Both peat and aeolian sand are underlain by lacustrine sediment and the deposits record the area's transition from an initially ice-dammed lake to Ancient Lake Bolmen, which gradually drained, exposing sediments to wind erosion and allowing peat to start forming in basins.</p><p>Here, we present 25 luminescence ages from lacustrine, fluvial and aeolian deposits that range from the time of deglaciation (∼14.5 ka) to the late Holocene (∼3 ka). Most of the waterlain sediments are dated to 11.5–11 ka while the bulk of the dunes formed 10–6.5 ka ago, possibly during two phases in the early and early-middle Holocene, respectively. The parabolic shape of some dunes indicates aeolian deposition or reworking in a partially vegetated environment, and contemporary dune and peat formation suggest a mosaic landscape in the early Holocene. Younger sand drift events and re-activation of some dunes are corroborated by windblown dust events in mid-late Holocene and are likely related to regional storm periods. The results add to the growing understanding of aeolian activity in formerly glaciated landscapes and illustrate a complex interaction of lacustrine, fluvial and aeolian processes.</p><p>The optically stimulated luminescence (OSL) dating was done on 180–250 μm quartz grains, which showed relatively dim luminescence signals dominated by a fast component. Several ages have relatively low precision which could be due to sediment mixing, either by bioturbation or by sampling across a significant layer thickness with an auger.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101591"},"PeriodicalIF":1.7,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1871101424000955/pdfft?md5=d583ed4008bd9b7ef5b8db7b7e4d49bd&pid=1-s2.0-S1871101424000955-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141630477","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":"Contribution of coupled ESR/U-series fossil dating to a Paleolithic-Neolithic transition site - Naminan, Southwest China","authors":"Manchen Huang ,&nbsp;Fei Han ,&nbsp;Feng Gao ,&nbsp;Ping Xiao","doi":"10.1016/j.quageo.2024.101594","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101594","url":null,"abstract":"<div><p>The coupled ESR and U-series (ESR/U-series) method has been increasingly utilized for dating fossil teeth from Early to Middle Pleistocene hominid sites. One significant advantage of this method is its ability to directly analyze fossil animal or human teeth. However, compared with other radiometric methods such as ¹⁴C charcoal dating, U-series carbonate dating, and OSL sediment dating, this dating method is rarely employed for Late Pleistocene or younger sites. In this study, we present an ESR/U-series dating investigation conducted at the Naminan site, a Paleolithic-Neolithic transition (P–N transition) site situated on the Sino-Myanmar border. The ESR/U-series analysis of eleven dental samples yields an age range of 18.1–13.2 ka for the fossils. These obtained ages are generally consistent with the ¹⁴C chronology of the site. When dealing with young fossil samples, it was observed that due to relatively low uranium concentration in dental tissues, internal dose rate plays a less significant role compared to external beta and gamma dose rates in the total dose rate of the fossil samples. Consequently, evaluating the dose rate of surrounding sediment becomes a primary source of uncertainty. Additionally, in this study we attempted to employ the standardized growth curve (SGC) and representative dose response curve method for determining Equivalent Dose (D_E), which was then compared with values obtained using additive dose method (ADM). Although the precision of D_E estimated by two methods are comparatively lower than that of ADM, it demonstrates the potential to efficiently determine a more rational D_max for irradiation, identify samples with stratigraphic disturbances, and analyze small or valuable fossil specimens.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101594"},"PeriodicalIF":1.7,"publicationDate":"2024-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141606323","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":"Multi-method luminescence dating of young aeolian dunes in the central Tibetan plateau","authors":"Shengli Yang ,&nbsp;Xiaojing Liu ,&nbsp;Jinbo Zan ,&nbsp;Pushuang Li ,&nbsp;Xuechao Xu ,&nbsp;Dongxue Li ,&nbsp;Qiong Li ,&nbsp;Li Liu ,&nbsp;Chen Wen ,&nbsp;Xiaomin Fang","doi":"10.1016/j.quageo.2024.101595","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101595","url":null,"abstract":"<div><p>The environment of the Tibetan Plateau (TP) is extremely sensitive to global climate change, and the frequent aeolian activity on the central TP generates large amounts of dust with the result that the region has a major impact on regional and global environmental change. The extensive aeolian dunes on the central TP provide a direct and valuable archive of aeolian activity; however, the age and sediment deposition processes of these dunes are still poorly understood. Optically stimulated luminescence (OSL) dating, an effective method for dating aeolian sediments, has been used sparingly in the region. In this study, we applied quartz single-aliquot regenerative-dose (SAR) OSL, K-feldspar post-infrared infrared-stimulated luminescence (pIRIR), and single-grain K-feldspar pIRIR methods to determine the ages of two well-preserved sand dunes in the Lunpola (LD) and Tuotuohe (TTH) river basins in the central TP. Our results showed that the quartz OSL signal of the TTH dune was dim, while the LD dune quartz exhibited a higher OSL sensitivity than that of the TTH dune. The high recuperation observed could be attributed to the low signal-to-noise ratio of the OSL signals. The K-feldspar signal was bright and the pIR₅₀IR₁₇₀ signal could be used to date young dune samples in the central TP, whereas it could be affected by the residual dose, or incomplete bleaching in the TTH profile, resulting in age overestimation. The single-grain K-feldspar protocol had a good potential for dating the young TP dunes. Multi-method luminescence dating is recommended for the cross-checking of young dune samples with low OSL sensitivity in the TP. Our luminescence dating reveals that aeolian dunes in the central TP formed approximately 385 to 330 a and persisted to the present, possibly in response to climate change since the late stage of Little Ice Age (1400−1850 CE).</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101595"},"PeriodicalIF":1.7,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141583209","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":"Unraveling the deposition and incision paces of alluvial fan-river system by using single grain K-feldspar luminescence dating","authors":"Kechang Li ,&nbsp;Jintang Qin ,&nbsp;Jie Chen ,&nbsp;Jinfeng Liu ,&nbsp;Yuan Yao","doi":"10.1016/j.quageo.2024.101587","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101587","url":null,"abstract":"<div><p>Alluvial river in the piedmont area deposits and incises cyclically, in response to both exogenetic and endogenetic forcing across a range of timescales. The paces of these processes unveil the mechanisms governing the evolution of alluvial fan-river system and affect the policy for river management. Numerical simulation suggests that the incision of alluvial river is much faster than the deposition process. However, the field observations are rare. Alluvial rivers entrench up to 300 m into the alluvial fans built pre-Holocene on the northern piedmont of Chinese Tianshan, which provide ideal sites to unveil the pace of alluvial fan-river evolution. Jingou River is one of these rivers, with four levels of terraces identified at the downstream area. These terrace deposits are characterized by a complex of upper very coarse gravels and cobble (VCGC) unit and lower medium and coarse gravels (MCG) unit. In this study, potassium-feldspar (K-feldspar) single grain pIR₁₁₀IR₁₇₀ luminescence dating procedure was employed to date the samples taken from sandy lens of both upper VCGC and lower MCG units, for which the depositional ages are supposed to be associated with the fan-building and river incision processes, respectively. The luminescence ages of the lower MCG unit suggests a gradual fan building phase between 16 ± 1.9 ka and 8.1 ± 0.9 ka, while the ages of the upper VCGC unit cluster around ∼5.2 ka rather than a monotonic decrease towards low level terraces. Several scenarios are discussed with respect to the attained age sequences to unravel the pace of deposition and incision of Jingou River, of which the asymmetric aggradation and incision is more preferred and echoes to the finding of previous numerical investigation.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101587"},"PeriodicalIF":1.7,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141606250","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":"A luminescence-derived cryptostratigraphy from the Lake Suigetsu sedimentary profile, Japan: 45,000–30,200 IntCal20 yr BP","authors":"Richard A. Staff ,&nbsp;David C.W. Sanderson ,&nbsp;Charlie L. Rex ,&nbsp;Alan Cresswell ,&nbsp;Masayuki Hyodo ,&nbsp;Ikuko Kitaba ,&nbsp;Michael H. Marshall ,&nbsp;Gordon Schlolaut ,&nbsp;Keitaro Yamada ,&nbsp;Yoshiaki Suzuki ,&nbsp;Vanessa Nowinski ,&nbsp;Ryuji Tada ,&nbsp;Takeshi Nakagawa","doi":"10.1016/j.quageo.2024.101588","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101588","url":null,"abstract":"<div><p>The luminescence characteristics of sediments are affected by a variety of environmental factors, reflecting both local and broader regional influences. If seeking to apply stimulated luminescence as a ‘pure’ dating technique, variability in these external variables needs to be controlled for, involving, <em>inter alia</em>, lengthy pretreatment procedures and complex dose rate corrections. However, in so doing, a lot of potentially valuable palaeoenvironmental information is lost.</p><p>Instead, in the present study, we explicitly analysed raw, non-pretreated sediment that preserves this wealth of contributory environmental influence. Using a SUERC portable luminescence (POSL) reader, we performed rapid profiling across a 14,800 year interval of the annually laminated (varved) Lake Suigetsu sedimentary profile, central Japan (i.e., 45,000 to 30,200 IntCal20 yr BP), producing 303 contiguous measurements with a mean sampling resolution of 49 years. To further inform our understanding of this dataset, additional follow-up laboratory dosing was performed to provide sensitivity estimates.</p><p>The ‘cryptostratigraphy’ (‘hidden stratigraphy’) revealed by our data includes the identification of a step-change in luminescence parameters circa 39,200 IntCal20 yr BP, which we attribute to a major earthquake that resulted in re-routing of inflow to the lake. Further variability in the derived luminescence signals is compared with supporting high resolution x-ray fluorescence (μXRF) data and palynological data from Lake Suigetsu. A correlation between the luminescence profile (both net infra-red-stimulated and net blue light-stimulated signals) and mean annual temperature is revealed, mediated through subtle differences in sediment characteristics under warmer or cooler climatic conditions.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101588"},"PeriodicalIF":1.7,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S187110142400092X/pdfft?md5=bb5c01ac7bc5d20fdfb5f3b6efccd976&pid=1-s2.0-S187110142400092X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141606251","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":"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}