Quaternary Geochronology最新文献

{"title":"Geochemical analysis of extremely fine-grained cryptotephra: New developments and recommended practices","authors":"Helen M. Innes,&nbsp;William Hutchison,&nbsp;Andrea Burke","doi":"10.1016/j.quageo.2024.101553","DOIUrl":"10.1016/j.quageo.2024.101553","url":null,"abstract":"<div><p>Tephrochronology is a powerful tool used to synchronise and date stratigraphic records by accurate and precise geochemical analysis of deposited volcanic glass shards. However, in many distal stratigraphic records (e.g., polar ice cores) tephra shards are often extremely fine-grained (&lt;10 μm). Geochemical characterisation of these shards is challenging because conventional preparation and analytical techniques require highly polished glass areas &gt;5 μm for electron probe microanalysis (EPMA) to ensure high analytical totals and minimise alkali element loss. Recent method developments have put forward alternative approaches to accurately measure major oxides of small shards: a smaller 3 μm diameter beam, overlapping large (20 μm) beam areas onto supporting epoxy resin, and using scanning electron microscopy with energy dispersive spectrometry (SEM-EDS). However, there has been no direct intercomparison of these alternative techniques, which to date have only been tested on a limited range of glass compositions and tephras that are much larger than the extremely fine-grained material found in distal archives. These issues complicate decision making about the best analytical approach to take when faced with small shards. Here, we provide a new workflow protocol for the analysis of &lt;10 μm tephra by determining the accuracy and precision of alternative SEM-EPMA methods. By analysing a variety of glass standards including those prepared to replicate fine-grained ice-core cryptotephras, we show that a 3 μm EPMA beam is suitable for use on all glass compositions provided the beam current is reduced to 1 nA. When glass areas are too small for a 3 μm beam we show that overlapping this small beam onto epoxy resin is preferable to SEM-EDS analysis. We also provide evidence confirming that using 3–0.2 μm polishes for &lt;5 min increases analytical precision of the most abundant major oxides by up to three times, whilst, crucially, preserving the smallest shards in a sample. By directly applying these alternative methods to ice-core cryptotephra, we demonstrate the data are of suitable accuracy and precision to make robust geochemical correlations. This workflow can be applied to future tephrochronology studies, significantly increasing the quality and quantity of data that are obtained from cryptotephra horizons in distal records.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101553"},"PeriodicalIF":1.7,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1871101424000578/pdfft?md5=3e6536ad8c7a07eb566dae6a3bee163b&pid=1-s2.0-S1871101424000578-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141391912","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":"Multi-method geochronological approach to reconstruct post-1800 floodplain sedimentation in the upper Rhine plain, France","authors":"Cassandra Euzen ,&nbsp;François Chabaux ,&nbsp;Gilles Rixhon ,&nbsp;Frank Preusser ,&nbsp;Frédérique Eyrolle ,&nbsp;Valentin Chardon ,&nbsp;Anja M. Zander ,&nbsp;Dominique Badariotti ,&nbsp;Laurent Schmitt","doi":"10.1016/j.quageo.2024.101561","DOIUrl":"10.1016/j.quageo.2024.101561","url":null,"abstract":"<div><p>The precise dating of sedimentary archives covering the last 200 years in floodplains massively impacted by human activities is a major challenge. A combination of geochronological approaches is necessary to accurately date post-1800 sedimentary deposits. Here, we use a combination of a wide range of methods to unravel floodplain sedimentary dynamics, through the example of the Upper Rhine which is a highly regulated river. This comprises short--lived radionuclides (¹³⁷Cs, ²¹⁰Pb_xs) and Infrared Stimulated Luminescence (IRSL) single-grain dating. Luminescence profiling methods (IRSL screening, portable luminescence reader) were also used to further characterise sedimentation dynamics. These were combined with a hydrogeomorphological approach based on historical planimetric and hydrological data, the knowledge of engineering works as well as the morpho-sedimentary adjustments they induced. Our study demonstrates the value of historic maps as well as historical hydrological data, which provide precise time markers for dating the sedimentary archive under study. We illustrate different assumptions, validity domains and limitations inherent to each method, especially the complexity of ¹³⁷Cs to date floodplain sediments and the potential of luminescence methods for dating and estimating sedimentation continuity. We finally show the advantage of combining geochronological approaches in the construction of robust age models for young floodplain sedimentary archives in highly anthropized fluvial environments.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"83 ","pages":"Article 101561"},"PeriodicalIF":1.7,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141415482","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":"U-series in situ dating of secondary carbonates associated with rock paintings using LA-MC-ICPMS","authors":"Yanuo Jiao ,&nbsp;Yue Liu ,&nbsp;Zeji Lu ,&nbsp;Rainer Grün ,&nbsp;Qingfeng Shao","doi":"10.1016/j.quageo.2024.101552","DOIUrl":"10.1016/j.quageo.2024.101552","url":null,"abstract":"<div><p>Rock art is found in many different regions of the world, with ages dated from late Palaeolithic period to the present. However, determining the precise ages for such artworks with direct chronological methods is challenging. U-series dating of secondary carbonates can constrain the age of rock art if these carbonates stratigraphically connected to the art. Hitherto, U-series isotope-dilution analyses with multi-collector inductively-coupled plasma mass spectrometry (ID-MC-ICPMS) has been increasingly used for rock art dating. This approach can achieve U–Th isotope-ratio quantification at the per-mille or submille level, but requires chemical pretreatment using isotope spikes and results in a relatively low sampling resolution. While <em>in situ</em> U-series dating using laser ablation-MC-ICPMS (LA-MC-ICPMS) is significantly less precise than ID-MC-ICPMS analysis, it allows to collect spatially resolved data sequences on very thin samples (&lt;1 mm). This is important for identification of open systems and the chronological integrity of the analyses. Therefore, we developed a new method for high spatial resolution U-series <em>in situ</em> analysis. A piece of homogeneous stalagmite was selected as an in-house standard (RM-C1) for U-series <em>in situ</em> dating analysis. RM-C1 contains high U (17.3 ± 1.0 μg/g) and low Th concentrations (&lt;5 ng/g). The ²³⁴U/²³⁸U and ²³⁰Th/²³⁸U activity ratios of 1.0116 ± 0.0006 and 0.9525 ± 0.0013, respectively, corresponding to a U-series age of 303.5 ± 1.5 ka, were determined by the ID-MC-ICPMS analyses (n = 10). Using the RM-C1 standard, we were able to date the Dansgaard–Oeschger (D/O) 19 event (with an expected age of 68.9 to 70.3 ka) in a stalagmite to a range from 68.0 ± 2.0 to 71.2 ± 2.5 ka, with an average age of 69.6 ± 1.5 ka (n = 15). This demonstrates the accuracy and reproducibility of our dating protocol. Subsequently, we conducted U-series <em>in situ</em> dating of secondary carbonates associated with rock paintings with two samples from the Cangyuan shelter (CY2-4 and CY2-7) and two samples from the Wanrendong Cave (SL3-A and SL5-A) in Yunnan Province, southwestern China. These samples had high U-concentration (&gt;4 μg/g) and negligible environmental Th. The carbonate layers immediately overlying the pigments of CY2-4 and CY2-7 were dated to 3.7 ± 0.3 and 3.2 ± 0.2 ka, respectively, suggesting that the Canyuan rock paintings belongs to a late Neolithic culture of this area. The pigment layer sandwiched in the sample SL3-A was bracketed to between 8.7 ± 0.3 and 10.1 ± 0.3 ka and in SL5-A to between 10.4 ± 0.3 and 10.8 ± 0.4 ka, implying that the Wanrendong rock paintings probably were created by a hunting-gathering population during the early Holocene.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"82 ","pages":"Article 101552"},"PeriodicalIF":2.7,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141190716","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":"Luminescence dating of glacially sourced deposits from northern Switzerland: Comparing multigrain aliquots and single grains of quartz and feldspar","authors":"Daniela Mueller ,&nbsp;Lukas Gegg ,&nbsp;Alexander Fülling ,&nbsp;Marius W. Buechi ,&nbsp;Gaudenz Deplazes ,&nbsp;Frank Preusser","doi":"10.1016/j.quageo.2024.101551","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101551","url":null,"abstract":"<div><p>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.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"82 ","pages":"Article 101551"},"PeriodicalIF":2.7,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1871101424000554/pdfft?md5=1325ffe6c4a497ef07a91b38ebeed8a0&pid=1-s2.0-S1871101424000554-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141239653","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":"Direct dating of an ancient stone causeway at Karlslunde, Sjælland, Denmark: A combined approach using luminescence from the surfaces of granitic cobbles and coarse grains from disaggregated heated rocks","authors":"W.K. Thompson ,&nbsp;J. Christensen ,&nbsp;A.S. Murray ,&nbsp;M. Autzen","doi":"10.1016/j.quageo.2024.101549","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101549","url":null,"abstract":"<div><p>In 2017 part of an ancient stone causeway was uncovered at Karlslunde on the island of Sjælland, Denmark. With no artefacts found at the site, optically stimulated luminescence dating of coarse grains, grains derived from disaggregated rocks, and surficial rock chips obtained directly from granitic road cobbles were used to determine the time of construction. Some granitic road cobbles were visibly disaggregating at the time of excavation, and laboratory measurements revealed surprising strong fast component dominated quartz sensitivity from these samples. It was concluded that some of the rocks used in the causeway had been heated, presumably prior to incorporation in the structure. Dose recovery plateau experiments using sedimentary quartz and quartz grains recovered by gently disaggregating heated rocks suggested the use of a 220/180 °C preheat/cut-heat combination (DR ratio 0.999 ± 0.018; n = 40); this reduced the risk of thermal transfer in these young samples. IRSL signals were used for rocks that could not be disaggregated. The L/T burial profiles obtained from two unheated rocks (1 granite, 1 felsic gneiss) indicated they had been exposed for sufficient time for us to be confident of obtaining accurate IRSL ages. The post-IR IRSL₁₈₀ signals were also measured in these two cobbles; the bleaching front was shallow and the signal was only sufficiently reset to allow accurate determination of D_e on one rock. After subtracting a residual, the dose recovery ratio results for the unheated rocks post-IR IRSL₁₈₀ and IR₅₀ were 1.006 ± 0.012 (n = 10) and 0.937 ± 0.007 (n = 10), respectively. In total 8 ages were accepted; 4 coarse grained sediment quartz ages from an unexcavated part of the road surface, 2 fading corrected IR₅₀ ages from surface slices from non-disaggregated cobbles, and 2 quartz ages from disaggregated (apparently heated) cobbles. IRSL signals from the sedimentary and heated samples were used primarily to assess the degree of resetting of the quartz blue-stimulated OSL; both the post-IR IRSL and IR₅₀ signals significantly over-estimated the quartz age. However, the sedimentary quartz ages, the heated cobble quartz ages and the fading corrected IR₅₀ ages from the unheated road cobbles, are consistent and likely reflect a construction age of ∼2ka ago.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"82 ","pages":"Article 101549"},"PeriodicalIF":2.7,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1871101424000530/pdfft?md5=2b190eaf42d3a5c7fc7045f78125f031&pid=1-s2.0-S1871101424000530-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141084618","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 dating of cobbles buried in moraines from the source area of the Litang River (Konglongluo Valley), eastern Tibetan Plateau","authors":"Kunmei Yang ,&nbsp;Xianjiao Ou ,&nbsp;Yang Li ,&nbsp;Geraint Jenkins ,&nbsp;Pan Yao ,&nbsp;Daobin Tang ,&nbsp;Yantian Xu ,&nbsp;Jinming Xie ,&nbsp;Lanhua Zeng ,&nbsp;Xiangjun Liu","doi":"10.1016/j.quageo.2024.101547","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101547","url":null,"abstract":"<div><p>Moraine deposits are difficult to date using conventional luminescence techniques, especially such deposits without glaciofluvial sand lenses incorporated within the feature. Recently developed rock surface luminescence burial dating has shown the potential for constraining heterogeneous glacial till sediments. However, the wider applicability of the luminescence dating of cobbles obtained from moraine deposits needs to be tested. Thirty-one buried granite cobbles from different generations of terminal moraines of the last deglaciation moraine series in the source area of the Litang River, eastern Tibetan Plateau, were collected. Eight cosmogenic nuclide ¹⁰Be exposure ages were generated from eight boulders obtained from the ridges of two moraines, to provide an external age control. A post-IR₅₀ IRSL₂₂₅ single aliquot regenerative dose (SAR) protocol was applied to measure the luminescence signal from rock slices. The IRSL₅₀ L_n/T_n-depth profiles from 23 cobbles showing surface age plateaus (up to 12 mm), indicating that the material was well-bleached prior to deposition. The depth of the bleaching front is variable between individual cobbles from the same deposit. Three distinct methods were employed to observe and correct for any anomalous fading present. We observe age agreement from different cobbles collected from the same moraine deposits, illustrating the reproducibility at our selected locations. The luminescence ages of burial cobbles (15.5 ± 2.1 ka to 20.0 ± 1.6 ka) align with geomorphic relationships and ¹⁰Be exposure ages. Particularly, the age of cobbles from one of the moraines (20.0 ± 1.6 ka) is consistent with independent ¹⁰Be exposure ages (18.6 ± 1.2 ka) of boulders from the same moraine. This study demonstrates the applicability of the luminescence dating of moraine deposits, using cobbles, and provides deeper insights of the last deglaciation in the eastern Tibetan Plateau.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"82 ","pages":"Article 101547"},"PeriodicalIF":2.7,"publicationDate":"2024-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141094924","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":"Orbital global change drove fluvial aggradation and incision in Tibetan upper Mekong river: Chronological perspectives","authors":"Yinjun Zhou ,&nbsp;Junfeng Han ,&nbsp;Qinjing Shen ,&nbsp;Yantian Xu ,&nbsp;Yaling Tao ,&nbsp;Penghui Lin ,&nbsp;Yuansen Lai ,&nbsp;Yixuan Wang ,&nbsp;Zhongping Lai","doi":"10.1016/j.quageo.2024.101546","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101546","url":null,"abstract":"<div><p>The Tibetan Plateau (TP), often known as the “Asia Water Tower”, is the source region of several continental-scale rivers. However, due to the extremely difficult access and harsh living conditions in the interior plateau, fluvial processes in the headwaters of these large rivers and their connections to global climate changes remain unknown. In this study, the luminescence (using both quartz and K-feldspar) and AMS ¹⁴C dating techniques were employed to date the four terraces of the Zado Basin in order to elucidate the aggradation and incision history of the initial intermontane basin in the headwater of the Mekong River. One sample from the upper part of T4 terrace (which features a 12 m thick gravel layer, the base of which is unexposed) provides a K-feldspar pIR₅₀IR₂₂₅ age of 125 ± 10 ka, indicating that the initial deposition of this terrace could predate marine isotope stage (MIS) 5. Considering the margin of error, this age also suggests that the onset of incision on T4 terrace during the climate transition from MIS 6 (glacial) to early MIS 5 (interglacial). This incision likely occurred due to increased meltwater and precipitation, causing the Mekong carving into the bedrock for more than 50 m. Eight luminescence samples are collected from T3 terrace (26.5 m in thickness) with ages ranging from 83 ± 7.6 ka to 22.3 ± 1 0.2 ka, indicating T3 formation/aggradation from late MIS 5 to the Last Glacial Maximum (LGM), possibly owing to reduced precipitation and enhanced sediment supply from intensive glacial activities. At around 22 ka, the Mekong once again shifted towards incision, crafting the T3 terrace, situated roughly 28 m above the current floodplain. This incision event was recorded by two luminescence samples from a sandy lens located at the top of gravel layer of T3, with OSL ages of about 22 ka. Floodplain samples from T2 and T1, dated at 16 ka and 2.8 ka respectively, demonstrate that from the last deglaciation to the Holocene, the Mekong continued its downward incision. This erosion developed two cut and fill terraces at elevations of 22 m and 11 m above the present floodplain, likely due to increased precipitation and enhanced vegetation at that time. Overall, the glacial–interglacial climate changes were the most likely driving force behind fluvial processes in the upper Mekong basin since the Late Pleistocene, with aggradation occurring during the glacial period while incision in deglacial and interglacial periods, suggesting a close link between the fluvial geomorphic evolution and orbital-scale climate changes.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"82 ","pages":"Article 101546"},"PeriodicalIF":2.7,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141097778","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 formation record of modern Nitraria tangutorum nebkhas on the Ordos Plateau of northern China based on optically stimulated luminescence dating","authors":"Yue Du ,&nbsp;Ruijie Lu ,&nbsp;Luo Ma ,&nbsp;Xiaokang Liu ,&nbsp;Dongxue Chen ,&nbsp;Yingna Liu","doi":"10.1016/j.quageo.2024.101550","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101550","url":null,"abstract":"<div><p>Nebkhas, as special biologically mediated aeolian landforms, play an important role in indicating regional aeolian activities and aeolian environmental changes. The Ordos Plateau is located in arid and semiarid regions of northern China that have a wide distribution of <em>Nitraria tangutorum</em> nebkhas. There are few chronological records of nebkha formation, so the history of the formation and evolution of nebkhas in the plateau is still unclear. In addition, the optically stimulated luminescence (OSL) dating method, which has been widely used in the dating of Holocene aeolian sediments, has not yet been applied to the dating of nebkha sediments in the Ordos Plateau. In this study, OSL methods were used to discuss the formation age and relevant aeolian activities of <em>Nitraria tangutorum</em> nebkhas in the Ordos Plateau. The results demonstrated that (1) the coarse-grained quartz OSL signals of nebkha sediments were insensitive and thus were inapplicable by the single aliquot regenerative (SAR) protocol. (2) The luminescence characteristics of the K-feldspar fraction and internal checks of the post-infrared infrared-stimulated (pIRIR) dating indicated that the pIR₅₀IR₁₇₀ protocol with 200 °C of preheating was applicable for D_e determinations of nebkha sediments. (3) The residual doses of the pIRIR₁₇₀ signals ranging from 0.02 to 0.14 Gy should be considered when calculating D_e values. (4) Bayesian age-depth models were used for the <em>Nitraria tangutorum</em> nebkha sedimentary sequences. The formation of nebkhas occurred during a relatively dry climate period accompanied by strong aeolian activity. That ∼0.38 ka was the main growth period of <em>Nitraria tangutorum</em> nebkhas. This study is the first report of the formation age of nebkhas of more than one hundred years in the region.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"82 ","pages":"Article 101550"},"PeriodicalIF":2.7,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141090669","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":"Amino acid dating of pleistocene mammalian enamel from the river thames terrace sequence: A multi-taxon approach","authors":"M.R. Dickinson ,&nbsp;K. Scott ,&nbsp;N.F. Adams ,&nbsp;A.M. Lister ,&nbsp;K.E.H. Penkman","doi":"10.1016/j.quageo.2024.101543","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101543","url":null,"abstract":"<div><p>Amino acid geochronology can provide effective relative dating frameworks for the Pleistocene and has enabled correlation of terrestrial deposits to the global climatic fluctuations described by the marine oxygen isotope record. Using methods developed for the analysis of intra-crystalline amino acids in tooth enamel, we aimed to construct an enamel-based amino acid geochronology for the terrace deposits in the valley of the River Thames in southern Britain using different mammalian taxonomic groups: elephant, horse and bison. To achieve this, chiral amino acid analysis was applied to 58 elephantid, 21 horse and 15 bison teeth from 10 horizons in the Upper Thames Valley, three in the Lower Thames Valley and one from a Thames tributary in the Lea Valley. We evaluate differences in the rates of amino acid breakdown between the taxa and establish which species are similar enough to enable comparison for relative dating purposes. The relative dating of the river terrace deposits is in good agreement with the terrace stratigraphy, biostratigraphy, and other independent estimates of age for all three taxonomic groups. These frameworks demonstrate the potential of enamel-based amino acid geochronologies for relative dating of Middle–Late Pleistocene deposits in the UK, and establish an aminostratigraphic framework from which the dating of other tooth material can be refined. Enamel offers an opportunity to evaluate the age of sites where shell material is absent or poorly preserved. It can also, crucially, provide direct relative dating of mammalian fossils, which are often the focus of study in terms of their evolution, distributional changes or extinction. Direct dating negates the risk that the mammal fossils themselves might be reworked, or of different ages to shell, sediments or other dated material in the same deposits; it also enables archived samples with insecure provenance (e.g. from early 17th-19th century collections) to be directly dated.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"82 ","pages":"Article 101543"},"PeriodicalIF":2.7,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1871101424000475/pdfft?md5=f58ea1c2b545abfa9fc16637bbfab9db&pid=1-s2.0-S1871101424000475-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141090668","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":"Investigations on single and multi-grain optically stimulated luminescence (OSL) sensitivity and electron spin resonance (ESR) signals in quartz derived from sandstones: Insights on provenance of quartz in ancient depositional systems","authors":"Aditi K. Dave ,&nbsp;Daniela Constantin ,&nbsp;Relu D. Roban ,&nbsp;Mihai N. Ducea ,&nbsp;Cristian Panaiotu ,&nbsp;Alida Timar-Gabor","doi":"10.1016/j.quageo.2024.101548","DOIUrl":"https://doi.org/10.1016/j.quageo.2024.101548","url":null,"abstract":"<div><p>Trapped charge techniques of luminescence and electron spin resonance (ESR) are classic tools for dating Quaternary deposits. Over the past decade, these techniques have been routinely applied to investigate provenance and/or the sedimentary history of quartz grains based on their different luminescence and ESR characteristics. Of these, optically stimulated luminescence (OSL) sensitivity is one of the most widely investigated parameter for luminescence-based provenance approach. A majority of studies on this parameter are based on evaluation of multi-grain quartz OSL sensitivity of the samples. This is particularly concerning because single-grain quartz luminescence studies have shown that the luminescence signal of a multi-grain aliquot is contributed by less than ∼1–10% of the total grains. Since the sole criteria for discrimination of sources based on luminescence sensitivity relies on its intensity, therefore the results based on multi-grain analysis will most likely be skewed depending on the ‘proportion’ and ‘brightness’ of a few grains. This demands a need to evaluate the potential of single-grain quartz OSL sensitivity in provenance studies. In this study, we investigate single and multi-grain quartz OSL sensitivity from compositionally different sandstones with well-characterised sources based on U–Pb zircon ages. We further complement this analysis with characterisation of ESR centres commonly used in quartz provenance, namely E′₁ and [AlO₄]⁰ centres. Our study shows that single-grain quartz OSL sensitivity can help distinguish between sediments that have a predominant input from a single source as compared to those with contribution from multiple sources, which otherwise cannot be inferred from multi-grain studies. Moreover, our results on characterisation of quartz-based ESR intensity of E′₁ and saturated [AlO₄]⁰ centres successfully differentiates between sandstones and further complements the luminescence-based characterisation.</p></div>","PeriodicalId":54516,"journal":{"name":"Quaternary Geochronology","volume":"82 ","pages":"Article 101548"},"PeriodicalIF":2.7,"publicationDate":"2024-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1871101424000529/pdfft?md5=a9fa2253ce41097997626715a74ab80a&pid=1-s2.0-S1871101424000529-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141084063","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}