Quaternary Science Reviews最新文献

{"title":"Climatic and tectonic controls on deposition in the Heidelberg Basin, Upper Rhine graben, Germany","authors":"Lukas Gegg ,&nbsp;Laura Jacob ,&nbsp;Olivier Moine ,&nbsp;Ellie Nelson ,&nbsp;Kirsty E.H. Penkman ,&nbsp;Fiona Schwahn ,&nbsp;Philipp Stojakowits ,&nbsp;Dustin White ,&nbsp;Ulrike Wielandt-Schuster ,&nbsp;Frank Preusser","doi":"10.1016/j.quascirev.2024.109018","DOIUrl":"10.1016/j.quascirev.2024.109018","url":null,"abstract":"<div><div>The Upper Rhine Graben in Central Europe, and notably its depocentre in the Heidelberg Basin, is an archive of complex and long-lasting deposition throughout the Quaternary. A new drill core, 136 m long, from the southern Heidelberg Basin is investigated by characterising sedimentary facies, sediment provenance, as well as analysing the pollen and mollusc content. The chronological framework is based on post-infrared infrared-stimulated luminescence dating, and complemented with amino acid geochronology. The sediment sequence consists of fluvial, colluvial, and palustrine deposits that represent at least the last ∼500 ka, interrupted by some, major and minor, hiatuses. In the lower part, fluvial gravel and colluvial diamicts of a lateral alluvial fan into the Upper Rhine Graben prevail. The central part of the succession consists of a large-scale fining upward cycle that contains increasing amounts of material from the Alps delivered by the Rhine river. This sequence terminates with palustrine fines with rich mollusc and pollen assemblages that allow for a detailed reconstruction of environmental conditions. The results of pIRIR dating place the palustrine deposits in marine isotope stage 11. However, the pollen profile shares similarities with the Mannheim Interglacial that has previously been assigned to the Cromerian, a correlation that is supported by the amino acid geochronology, which poses a chronostratigraphical problem. In the upper part, Alpine sediments are progressively replaced by a new alluvial fan from the graben margin with striking variations in grain size. Overall, the diverse succession is the result of an interplay of tectonic activity and climatic factors. While subsidence triggers the generation of accommodation space and river deflection, pulses of coarse sediment are probably related to periglacial weathering, mass wasting and short-scale transport during cold periods.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"345 ","pages":"Article 109018"},"PeriodicalIF":3.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Abrupt enhanced Pacific warm water intrusion into the Sea of Okhotsk since the early Holocene","authors":"Xuguang Feng ,&nbsp;Jianjun Zou ,&nbsp;Xuefa Shi ,&nbsp;Zhengquan Yao ,&nbsp;Zhi Dong ,&nbsp;Jiang Dong ,&nbsp;Yonghua Wu ,&nbsp;Ruxi Dou ,&nbsp;Hualong Jin ,&nbsp;Aimei Zhu ,&nbsp;Xiaojing Wang ,&nbsp;Qingchao Wang ,&nbsp;Lingfeng Luo ,&nbsp;Sergey A. Gorbarenko ,&nbsp;Yuriy P. Vasilenko ,&nbsp;Aleksandr A. Bosin","doi":"10.1016/j.quascirev.2024.109026","DOIUrl":"10.1016/j.quascirev.2024.109026","url":null,"abstract":"<div><div>As the main heat and water mass sources, the warm and saline Pacific waters have significant influence on sea ice and intermediate water circulation in the Sea of Okhotsk (SO). However, the long-term history of Pacific warm water intrusion into the SO remains unknown, impeding accurate predictions of its future changes. In this study, provenance proxies (clay mineral assemblages and trace element ratios (&lt;2 μm)) from surface sediments and Site LV87-55-1 were used to investigate the history of Pacific water intrusion into the SO over the past 20 kyr. Provenance analysis indicates that sediments in the central SO primarily originated from the Amur River before 11.7 ka, with a significant rise in sediment input from the Kamchatka Peninsula since that time. By integrating published data on sediment grain size, sea surface temperature (SST), and sea-ice diatoms, we observed that the enhanced inflow of Pacific warm water into the SO led to intensified counterclockwise surface currents and the retreat of sea ice since the early Holocene, which subsequently resulted in a noticeable shift in sediment sources in the central SO. Furthermore, based on modern observation and TraCE-21 model simulations, we deduce that the intensified Aleutian Low (AL) since the early Holocene stimulated the East Kamchatka Current (EKC) through increased Sverdrup transport caused by cyclonic wind patterns. This, in turn, facilitated greater intrusion of Pacific warm water into the SO. Overall, our findings suggest an increase in Pacific warm water intrusion into the SO under future global warming scenarios, potentially posing a significant threat to the marine environment of both the SO and the subarctic Pacific.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"345 ","pages":"Article 109026"},"PeriodicalIF":3.2,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142539657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 review of paleofloods in the middle-lower reaches of the Yangtze River during the Holocene: Processes, causes and effects","authors":"Zhaoxin Zhang ,&nbsp;Zhiping Zhang ,&nbsp;Jiahao Xu ,&nbsp;Junwei Chen ,&nbsp;Zhongwei Shen ,&nbsp;Xin Jia ,&nbsp;Fahu Chen","doi":"10.1016/j.quascirev.2024.109019","DOIUrl":"10.1016/j.quascirev.2024.109019","url":null,"abstract":"<div><div>The understanding of the flooding processes in the entire basin of the middle-lower reaches of the Yangtze River (MLRYR) during the Holocene remains elusive. This is primarily attributed to the constraints posed by site-scale data characterized by limited spatiotemporal resolutions, compounded by conflicting results of the reconstructed Holocene paleoflood records in some of the previous studies. In this study, by synthesizing 114 paleoflood data with robust evidence of flood occurrence (including timing and location of flood occurrence), we comprehensively reconstructed the first continuous Holocene paleoflood record that cover the entire basin of the MLRYR. The results show that at the onset of the Holocene, flood frequency peaked notably in the middle reaches of the Yangtze River (MRYR), with no corresponding peak observed in the lower reaches of the Yangtze River (LRYR). However, in both the MRYR and LRYR, a significant flood frequency peak emerged around 8.0 ± 0.5 ka BP, and scarce flood occurrences appeared approximately 7.5–5.0 ka BP. This scarcity shifted abruptly to a surge in flood frequency from 5.0–4.0 ka BP. Following this, the MRYR witnessed three successive peaks in flood frequency, occurring at approximately 3.0 ka BP, 1.8 ka BP, and 1.0 ka BP, respectively. In contrast, flood events in the LRYR were infrequent during the 3.0–2.0 ka BP period, followed by a surge in frequency from 2.0 ka BP onwards. We further explored the driving mechanisms of paleofloods in the MLRYR and found that floods were more likely to occur during periods of weakened EASM, characterized by wet and unstable climate conditions in the MLRYR. Marine erosion may be also a key factor in the lack of geological evidence for palaeofloods during the early Holocene. Additionally, variations in the ISM and human activities during the late Holocene have significantly influenced the occurrence of floods in the MLRYR. By comparing the paleoflood frequency with the spatial distribution and number of archaeological sites in the MLRYR, respectively, we propose that the period of flood scarcity during the middle Holocene may have facilitated the development of rice agriculture and the prosperity of ancient settlements. In contrast, during flood-prone period, ancient societies adapted and coped with floods by migrating to higher terrain during the early Holocene and implementing simple hydraulic engineering techniques during the late Holocene.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"345 ","pages":"Article 109019"},"PeriodicalIF":3.2,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of active channels in sediment transport to the Bengal Fan and their implications for climate and sediment source changes since 16 ka","authors":"Md Hafijur Rahaman Khan ,&nbsp;Jianguo Liu ,&nbsp;Yun Huang ,&nbsp;Zhong Chen ,&nbsp;Ananna Rahman","doi":"10.1016/j.quascirev.2024.109024","DOIUrl":"10.1016/j.quascirev.2024.109024","url":null,"abstract":"<div><div>The Bay of Bengal (BoB) is crucial in understanding sediment dynamics in the Indian Ocean. Analysis of sediment cores from the western BoB, focusing on the Middle and Lower Bengal Fan since 16,000 years ago, reveals rapid deposition within the submarine canyon. This deposition was driven by the Ganges-Brahmaputra (G-B) river system during lower sea levels, leading to the formation of turbidity currents. Increased glacial activity during cold phases enhanced physical weathering in the Himalayan highlands, affecting sediment transport to the BoB until the early Holocene. Following the early Holocene, the lower fan displayed a mixture of sources, while the deeper fan predominantly reflected Indian sources throughout the Holocene. Sediment contributions from the Indian subcontinental commenced after 9,100 years ago, becoming dominant since 7,000 years ago, particularly in arid-semiarid conditions in the middle to lower fan, primarily driven by monsoonal water currents. Cores located near active channels exhibited consistent sourcing patterns influenced by regional factors such as river systems and active channels since the mid-Holocene. Sediments with coarser-grain, higher smectite content, and primarily sourced from Indian rivers indicated an intensification of monsoonal currents since 9,100 years ago. Fluctuations in smectite/(illite + chlorite) ratios were correlated with changes in summer monsoon rainfall, impacting erosion and sediment dynamics. Active channels played a crucial role in transporting Himalayan sediments via the G-B river system to the deep ocean during periods of low sea levels, but their influence has diminished with rising sea levels. Therefore, the proximity of sediments to active channels denotes the dominance of Himalayan sources; however, sediment from the lower fan transitioned to Indian sources since 9,100 years ago, influenced by the combined effects of monsoonal currents, active channels, and underwater currents shaping sediment transport dynamics. During the Holocene Climatic Optimum (HCO), intensified summer monsoons led to increased sediment contributions from Indian sources, driven by water currents during the winter monsoon, with notable impacts after 7,000 years ago. This study highlights the complexity of sedimentary processes and provides insights into past environmental conditions, contributing to our comprehension of sediment deposition patterns in the northeastern Indian Ocean.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"345 ","pages":"Article 109024"},"PeriodicalIF":3.2,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the origin of Holocene sea-level transgressions in formerly glaciated regions","authors":"Samuel J. Chester ,&nbsp;Jacqueline Austermann ,&nbsp;William J. D’Andrea ,&nbsp;Andrew J. Lloyd ,&nbsp;Roger C. Creel","doi":"10.1016/j.quascirev.2024.108986","DOIUrl":"10.1016/j.quascirev.2024.108986","url":null,"abstract":"<div><div>Over glacial cycles, the growing and shrinking of ice sheets has caused relative sea level (RSL) to differ from global mean sea level (GMSL) due to glacial isostatic adjustment (GIA), which depends on the viscoelastic properties of the solid Earth. During the last termination and through the Holocene, GIA-related isostatic uplift caused RSL to fall in regions formerly covered by ice sheets. Surrounding these uplifting regions is a narrow band of land where postglacial RSL fall was interrupted during the Holocene by a period of sea-level rise (i.e., a transgression) that culminated in a high stand before sea-level fall resumed. Holocene transgressions and high stands have been well documented in many locations including Norway, the Canadian Atlantic coast, the Canadian Pacific coast, Svalbard, the Baltic Sea, and the British Isles. A leading hypothesis poses that transgression occurred when GMSL rise outpaced isostatic rebound. We investigate the origins of these Holocene transgressions using GIA modeling and test the alternative hypothesis that they are predominantly the result of solid Earth deformation. Our results highlight a unique pattern of solid Earth deformation in which the region of subsidence (peripheral bulge) surrounding the ice sheet migrates first towards and then away from the melted ice mass. We show how this effect, which we term ‘reverse migration’, is the direct result of the contrast in viscosity between the upper and lower mantle. We compare our GIA model predictions of RSL change to two datasets: (1) RSL data from the last glacial maximum to present and (2) specific constraints on the transgression magnitude in Norway and Eastern Canada. Both datasets better fit RSL predicted by GIA models that include a mantle with a substantial (order of magnitude) increase in viscosity with depth over GIA predictions that do not include a contrast in mantle viscosity. We argue that this is a useful constraint on the local viscosity structure. Further, this suggests that in contrast to the conventional view that Holocene transgressions record GMSL temporarily outpacing isostatic uplift, solid Earth deformation and specifically reverse migration played an important role in generating near-field Holocene transgressions.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"345 ","pages":"Article 108986"},"PeriodicalIF":3.2,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strong coupling between the East Asian summer monsoon and regional hydrological conditions as evidenced by multiproxy stalagmite records for the last deglaciation","authors":"Wenna Ding ,&nbsp;Jingyi Cao ,&nbsp;Jinguo Dong ,&nbsp;Jiaqi Cong ,&nbsp;Yijia Liang ,&nbsp;Wei Huang","doi":"10.1016/j.quascirev.2024.109023","DOIUrl":"10.1016/j.quascirev.2024.109023","url":null,"abstract":"<div><div>Millennial-to centennial-scale abrupt climate events during the last glacial‒interglacial transition have significant relevance to modern-day extreme climate changes, which are occurring more frequently in the context of global warming. However, the regional expression of humidity conditions during the last deglaciation and their possible forcing mechanism in northern China are controversial. Here, combined with published δ¹⁸O data, we report 35-year-resolved δ¹³C and 76-year-resolved Mg/Ca and Sr/Ca records from a stalagmite from 15.3 to 10.9 ka BP from Lianhua Cave, northern China. The LH4 stalagmite δ¹⁸O record clearly records a weak monsoon event during the Younger Dryas (YD) from 12.8 to 11.6 ka BP and a strong monsoon event during the Bølling-Allerød (BA) from 14.6 to 12.8 ka BP. In addition, the δ¹³C and trace element ratio records, which represent local hydroclimatic changes, indicate wetter conditions during the BA and drier conditions during the YD, which appear to match well with the δ¹⁸O variations on the millennial timescale. A comparison of 28 records from 17 sites along the modern margin of the China summer monsoon revealed that the BA was characterized by wet conditions; inversely, the YD was characterized by dry conditions throughout northern China, which is obviously different from the consensus of the wet YD and the dry BA in northern northeastern China. The covariance in northern China suggests that the hydrological variation may be modulated by the advance and retreat of the large-scale East Asian summer monsoon (EASM) circulation. Further comparison revealed an anticorrelated relationship between millennial-scale precipitation changes in northern China and the middle‒lower reaches of the Yangtze River Valley during the last deglaciation. This correlation is analogous to the dipole precipitation mode at present, which is likely associated with the strength and position of the westerly jet and/or the western Pacific subtropical high, both of which play important roles in the spatial distribution of precipitation over eastern China.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"345 ","pages":"Article 109023"},"PeriodicalIF":3.2,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Retraction notice to “Delayed Western Gotland Basin (Baltic Sea) ventilation in response to the onset of a Mid-Holocene climate oscillation” [JQSR (2021) 107253]","authors":"Markus Czymzik ,&nbsp;Olaf Dellwig ,&nbsp;Raimund Muscheler ,&nbsp;Patricia Roeser ,&nbsp;Achim Brauer ,&nbsp;Jérôme Kaiser ,&nbsp;Marcus Christl ,&nbsp;Helge W. Arz","doi":"10.1016/j.quascirev.2024.109017","DOIUrl":"10.1016/j.quascirev.2024.109017","url":null,"abstract":"","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"345 ","pages":"Article 109017"},"PeriodicalIF":3.2,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Worldwide consequences of a mid-Holocene cold event in the Nordic Seas","authors":"Maciej M. Telesiński ,&nbsp;Wei Liu ,&nbsp;Xianglin Ren ,&nbsp;Marek Zajączkowski","doi":"10.1016/j.quascirev.2024.109002","DOIUrl":"10.1016/j.quascirev.2024.109002","url":null,"abstract":"<div><div>The present interglacial is a relatively warm and stable period, especially compared to the preceding glacial time. However, the Holocene has seen the emergence of several remarkable cold events, some with worldwide consequences. Leveraging marine records from the Nordic Seas, we provide the first detailed account of a cold event centered around 6.8 ka BP. Utilizing paleoceanographic proxies and advanced modeling, we unveil a distinct subsurface water cooling, associated with a stepwise increase in sea-ice cover in the eastern Fram Strait. Our findings emphasize the role of Greenland Sea deep convection onset and the subsequent westward shift in Atlantic Water flow, enabling sea-ice advection from the Barents Sea. The heightened sea-ice cover weakened Atlantic Water advection, perturbing thermohaline circulation in the eastern Nordic Seas. These perturbations propagated worldwide, affecting North Atlantic deep-water circulation, inducing widespread hemispheric cooling, shifting the Intertropical Convergence Zone southward, and weakening the East Asian monsoon. Incorporating results from the Transient simulations of Climate Evolution of the last 21,000 years (TraCE-21ka) supports and augments proxy-based paleoreconstructions, underscoring sea-ice dynamics and ocean circulation's critical influence. This study highlights the potential for localized cold events within ostensibly warm climatic intervals. It underscores the need to comprehend their mechanisms for precise climate predictions and informed policymaking toward a sustainable future.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"344 ","pages":"Article 109002"},"PeriodicalIF":3.2,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142530722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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":"Long-term Holocene warming trend in Southern China revealed by corrected pollen data","authors":"Qiuchi Wan ,&nbsp;Cong Chen ,&nbsp;Kunshan Bao ,&nbsp;Xiao Zhang ,&nbsp;Yongjie Tang ,&nbsp;Xin Zhong ,&nbsp;Zhuo Zheng ,&nbsp;Kangyou Huang","doi":"10.1016/j.quascirev.2024.109015","DOIUrl":"10.1016/j.quascirev.2024.109015","url":null,"abstract":"<div><div>Holocene temperature changes and their forcings serve as pivotal references for current and future warming trends. However, significant discrepancies exist between proxy reconstructions and model simulations of Holocene temperature evolution. Pollen evidence, often central to these discrepancies, have been criticized for potentially reflecting human influence rather than pure temperature variations, complicating our understanding of Holocene temperature changes. Our study focuses on southern China, a region with pronounced discrepancies between models and proxies. We introduce and validate a novel methodology to isolate genuine temperature signals from pollen data. This approach employs an arboreal pollen-based temperature index and correct biases inherent in raw pollen data using the Regional Estimates of Vegetation Abundance from Large Sites (REVEALS) model. Applying this method, we present a new winter/annual temperature record for the past 10,000 years based on two fossil pollen data from the Luoxiao Mountains. Simultaneously, we reconstruct the historical impact of human activities in the region. Our temperature records reveal a sustained warming trend during the Holocene, closely matching model-simulated mean annual temperatures (R = 0.97), and temperature reconstructions based on branched glycerol dialkyl glycerol tetraethers from regional terrestrial and marine archives. In contrast, uncorrected pollen data indicate a cooling trend during the late Holocene, coinciding with significant human impact since approximately 3 ka BP. Our analysis and regional comparison with existing temperature records indicate that such contrasting temperature trends stem from a human-induced cooling bias, particularly pronounced in uncorrected pollen data. We infer that the early to middle Holocene warming was due to various factors, while late Holocene warming was predominantly driven by local annual insolation changes. Our findings challenge previously widely identified late-Holocene cooling trends based on uncorrected pollen data, demonstrating that the correction of pollen data can effectively mitigate human-induced cooling biases in temperature reconstructions. This study confirms the accuracy of climate models in simulating a Holocene warming trend, both temporally and spatially, at least in southern China.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"344 ","pages":"Article 109015"},"PeriodicalIF":3.2,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142531147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent sedimentology at the grounding zone of the Kamb Ice stream, West Antarctica and implications for ice shelf extent","authors":"Theo Calkin ,&nbsp;Gavin B. Dunbar ,&nbsp;Cliff Atkins ,&nbsp;Andrew Carter ,&nbsp;Jason J. Coenen ,&nbsp;Shaun Eaves ,&nbsp;Catherine E. Ginnane ,&nbsp;Nicholas R. Golledge ,&nbsp;David M. Harwood ,&nbsp;Huw J. Horgan ,&nbsp;Benjamin C. Hurwitz ,&nbsp;Christina Hulbe ,&nbsp;Justin D. Lawrence ,&nbsp;Richard Levy ,&nbsp;James W. Marschalek ,&nbsp;A.P. Martin ,&nbsp;Andrew D. Mullen ,&nbsp;Sarah Neuhaus ,&nbsp;Enrica Quartini ,&nbsp;Britney E. Schmidt ,&nbsp;Peter M. Washam","doi":"10.1016/j.quascirev.2024.108988","DOIUrl":"10.1016/j.quascirev.2024.108988","url":null,"abstract":"<div><div>Sediment accumulating beneath floating ice contains a record of ice dynamics in polar regions where <em>in situ</em> observations are rare. In 2019 a hole was melted through a 590m-thick region of the Ross Ice Shelf ∼5 km seawards of the Kamb Ice Stream (KIS) grounding line (82.7841°S, 155.2626°W) to access the seafloor. Imagery from a remotely operated vehicle (ROV, Icefin) shows ocean current-generated ripples likely formed by tidal flow parallel to the grounding line (GL). Observed current speeds &lt;0.15 m s⁻¹ suggest these bedforms may be relict. Larger, dm-scale, ‘furrows’ parallel to the former direction of KIS flow may relate to past grounding line processes. A 0.49 m-long gravity core collected from the seafloor contains weakly stratified diamicton. The sediment matrix comprises variable mixtures of reworked Tertiary biogenic silica, predominantly diatoms, and arkose material. Sediment ε_Nd values of ∼7 are consistent with derivation from the WAIS, as is the U-Pb age distribution and modelled late Holocene ice flows. Ramped pyrolysis ¹⁴C analysis shows all fractions are either &gt;30 ka or ¹⁴C dead. By contrast, ²¹⁰Pb-210 activity of &gt;30 Bq Kg⁻¹ indicates deposition within the last 120 years. The combination of features suggests rapid rainout deposition from melting of a sediment-laden basal debris layer as the GL retreated, followed by some reworking by ocean currents and little modern accumulation. Although Tertiary diatoms are abundant, unambiguously Late Quaternary forms are absent and we speculate on the implications for Ross Ice Shelf stability. [239 wds]</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"344 ","pages":"Article 108988"},"PeriodicalIF":3.2,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142530724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}