Journal of Quaternary Science最新文献

{"title":"Exploring soil erosion in the lake basins of Michoacán, Mexico: From sediment cores to conservation policies","authors":"Jahzeel Aguilera Lara,&nbsp;SARAH E. Metcalfe","doi":"10.1002/jqs.3676","DOIUrl":"https://doi.org/10.1002/jqs.3676","url":null,"abstract":"<p>Understanding soil erosion, its history and links to potential drivers such as land use (particularly agriculture and deforestation), different cultural perspectives and climate change are crucial for the development of effective management and conservation strategies. Here, we explore soil erosion in two lake basins, Pátzcuaro and Zirahuen, in the highlands of Michoacán, Mexico, weaving together scientific enquiry (including lake sediment studies and monitoring data) and cultural–historical perspectives based on documentary sources. Both lake basins are within the Trans Mexican Volcanic Belt, lying at &gt;2000 m a.s.l. Pátzcuaro is large, but shallow, while Zirahuen is smaller, but deep. Archaeological evidence for long-term human occupation is clearer for Pátzcuaro. Pátzcuaro is known for severe degradation of both the catchment and the lake, while Zirahuen has, until recently, been regarded as less disturbed. The relative impacts of pre-Hispanic and post-Hispanic practices have been the subject of debates across the disciplines and have impacted approaches to conservation, particularly attitudes to indigenous land use practices. Palaeoenvironmental records highlight human impact on these basins, often expressed as periods of accelerated erosion in response to forest clearance, over at least 3500 years. This shows that neither can be regarded as pristine and were not pristine at the time of the Conquest. As well as responding to varying intensities of land use, often linked to population change, erosion relates to climate, but is also affected by cultural and socio-economic contexts and discourses. Historical documents show that concerns about deforestation and erosion have influenced the development of forest conservation policies, in the context of government reforms, tensions between agricultural expansion and forest conservation, and the growth of scientific research in limnology. These policies have also been shaped by changing cultural discourses regarding indigenous land management practices. The value of taking an holistic approach to understanding erosion is emphasized.</p>","PeriodicalId":16929,"journal":{"name":"Journal of Quaternary Science","volume":"40 4","pages":"671-683"},"PeriodicalIF":1.9,"publicationDate":"2024-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jqs.3676","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Land use, hydroclimate and damming influence organic carbon sedimentation in a flood pulse wetland, Malaysia","authors":"Suzanne McGowan,&nbsp;Jack H. Lacey,&nbsp;Stefan Engels,&nbsp;John Boyle,&nbsp;Charlotte Briddon,&nbsp;Melanie J. Leng,&nbsp;Heather L. Moorhouse,&nbsp;Virginia Panizzo,&nbsp;Muhammad Shafiq","doi":"10.1002/jqs.3672","DOIUrl":"https://doi.org/10.1002/jqs.3672","url":null,"abstract":"&lt;p&gt;Water bodies located in floodplains and tropical forests are known to be important carbon stores, but many are subjected to intensive pressures from damming, land use and climate changes. Sedimentary records preserve long-term archives for understanding how such changes affect the quantity and quality of carbon stores. We analysed sediment cores from seven sites across a flood-pulse multi-basin wetland, Tasik Chini in Peninsular Malaysia (for percentage LOI&lt;sub&gt;550&lt;/sub&gt;, sediment density and spheroidal carbonaceous particles), and conducted more analyses on three &lt;sup&gt;210&lt;/sup&gt;Pb-dated cores (X-ray fluorescence of elements, grain size analysis, carbon isotopes, C/N ratios, carotenoid pigments) to gain an understanding of the drivers of organic carbon accumulation rates (OCARs) since 1860 \u0000&lt;span&gt;ce.&lt;/span&gt; The median OCAR of 85 g m&lt;sup&gt;−2&lt;/sup&gt; a&lt;sup&gt;−1&lt;/sup&gt; for the basin since 1945 \u0000&lt;span&gt;ce&lt;/span&gt; was higher than in other floodplain and temperate lakes and in line with other tropical forest lakes. However, we found evidence for different mechanisms of OC deposition across the basin. In ‘autochthonous mode’, the site with minimal local land disturbance had lowest OCARs and OC was derived mainly from autochthonous production, which rose slightly around 1940 \u0000&lt;span&gt;ce&lt;/span&gt; when regional land disturbance increased nutrient influx to the basin. The site with the most long-term and intensive land disturbance through forest removal (1940s) and then conversion to rubber and oil palm farming (1980s) functioned mainly in ‘allochthonous mode’; that is, increases in OCARs after 1940 \u0000&lt;span&gt;ce&lt;/span&gt; were driven by deposition of soil-derived OC. The highest OCARs were in the basin that was converted to oil palm after the 1980s and had increased iron mining activity in the 2000s; because this site was located distal from the flood pulse and became increasingly hydrologically disconnected after a low rainfall period in the 1970s, the lake responded strongly in ‘autochthonous mode’, through encroachment of fringing swamp, the spread of benthic algae and macrophytes, and efficient sediment retention. Weir installation in 1995 \u0000&lt;span&gt;ce&lt;/span&gt; raised water levels and increased lentic conditions, promoting autochthonous OC production and sedimentation across all basins. The long-term fate of this more recently deposited OC remains uncertain because it is more labile. Overall Tasik Chini has responded strongly to land use changes since at least the 1940s, earlier than anticipated in this region of Southeast Asia, and the sedimentary proxies indicate large changes in the ecosystem function and capacity for C storage over the past ca. 80 years. Most of these shifts have increased OC accumulation by strengthening autochthonous production or allochthonous OC fluxes, but the implications for other aspects of the C cycle, including catchment soil C loss and greenhouse gas production, need to be accounted for when evaluating the overall impacts of land and hydrolog","PeriodicalId":16929,"journal":{"name":"Journal of Quaternary Science","volume":"40 4","pages":"657-670"},"PeriodicalIF":1.9,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jqs.3672","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Lower Palaeolithic small flake prehension: Use-wear and residue analyses reveal hominin grasping potential at late Acheulean sites in Israel and Italy","authors":"Flavia Marinelli,&nbsp;Stella Nunziante-Cesaro,&nbsp;Ran Barkai,&nbsp;Cristina Lemorini","doi":"10.1002/jqs.3683","DOIUrl":"https://doi.org/10.1002/jqs.3683","url":null,"abstract":"<p>There is currently substantial debate over the use of prehension or hafting of tools by hominins. Many studies have been carried out to understand the prehension and hafting of hominin tools through experiments and through study of the anatomy and muscle system of both non-human primates and humans. This paper discusses the results of the analyses of macro-traces and micro-residues of prehension found on small flakes from the late Acheulean sites of Revadim (Israel), Jaljulia (Israel) and Fontana Ranuccio (Italy). Small flakes are ubiquitous in many Late Lower Palaeolithic sites where they were used for various activities, including butchering. Their reduced size leads us to consider how they were handled and if solutions including hafting techniques were adopted. In this paper, the experimental protocol adopted, and the results obtained from macro-traces and micro-residues allowed us to develop hypotheses regarding free-hand gripping of the small flakes by hominins at Revadim, Jaljulia and Fontana Ranuccio and the role that strength and pressure played in ensuring a good grip to enable the optimal use of these tools.</p>","PeriodicalId":16929,"journal":{"name":"Journal of Quaternary Science","volume":"40 2","pages":"332-354"},"PeriodicalIF":1.9,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jqs.3683","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143370060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Comparative study of paleoflood slackwater deposits in the Yarlung Zangbo and Hanjiang Rivers, China","authors":"Shuaihu Wu,&nbsp;Xudong Fu,&nbsp;Jiangli Pang,&nbsp;Chunchang Huang","doi":"10.1002/jqs.3679","DOIUrl":"https://doi.org/10.1002/jqs.3679","url":null,"abstract":"<div>\u0000 \u0000 <p>Paleoflood slackwater deposits have recently been investigated in small to moderately sized rivers. However, our understanding of the characteristics of paleoflood slackwater deposits in large rivers remains limited, which poses a notable obstacle to accurately predicting the magnitude, frequency and force of extraordinary floods. To address this research gap, this study compares the characteristics of paleoflood slackwater deposits in the middle Yarlung Zangbo River (YZR) and the upper Hanjiang River in China. Paleoflood slackwater deposits and aeolian deposits (e.g. loess, paleosol S₀ and aeolian sand) were investigated and sampled from these locations. For the paleoflood slackwater deposits and aeolian deposits, sedimentology (e.g. grain size distribution, magnetic susceptibility and geochemical elements) was analyzed in the laboratory. The macroscopic features of the paleoflood slackwater deposits in the middle YZR valley are very similar to those of the upper Hanjiang River valley. The paleoflood slackwater deposits were dominated by sand and silt in the middle YZR and by silt and sand in the upper Hanjiang River; this implied that the paleoflood slackwater deposits were suspended sediments of floodwater from different source regions. Compared with the paleoflood slackwater deposits in the upper Hanjiang River and other large rivers in China (e.g. the Yellow and Yangtze Rivers), the paleoflood slackwater deposits contained more coarse particles in the middle YZR; this result may be closely related to the particular hydrogeologic and geomorphic conditions (e.g. rich sandy sediment, high riverbed slope and narrow valley) in the southeastern Tibetan Plateau. Compared with the paleoflood slackwater deposits in the upper Hanjiang River, the paleoflood slackwater deposits presented considerably worse sorting in the middle YZR; this may be closely related to the short transport distance in the middle YZR. The magnetic susceptibility values of the paleoflood slackwater deposits were relatively higher in the middle YZR and the upper Hanjiang River, suggesting that these slackwater deposits with minimal pedogenesis may contain a relatively high ferromagnetic mineral content because of the formation process of slackwater deposits. The sediment provenance of the paleoflood slackwater deposits may be closely related to that of the loess in the middle YZR valley, which implies that the sediment provenance of deposits of different genetic types may be greatly affected by the particular hydrologic–climatic and geomorphic conditions in the southeastern Tibetan Plateau.</p>\u0000 </div>","PeriodicalId":16929,"journal":{"name":"Journal of Quaternary Science","volume":"40 2","pages":"267-278"},"PeriodicalIF":1.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143370058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate influence on Si abundance and Si isotopes in the Yimaguan loess–paleosol sequence","authors":"Baoliang Wang,&nbsp;Hui-Min Yu,&nbsp;Wenhan Cheng,&nbsp;Jianghu Lan,&nbsp;Fang Huang","doi":"10.1002/jqs.3684","DOIUrl":"https://doi.org/10.1002/jqs.3684","url":null,"abstract":"<div>\u0000 \u0000 <p>The SiO₂/Al₂O₃ and SiO₂/TiO₂ ratios of loess–paleosol sequences in the Chinese Loess Plateau have been proposed as indicators recording changes of the East Asian winter monsoon. However, interference from silicon (Si) leaching induced by chemical weathering raises concerns about their applications to paleoclimate reconstruction. Silicon isotopes can serve as an effective tool for monitoring Si leaching, as the release of Si can lead to a decrease in δ³⁰Si values of soils. Here we use Si isotopes to evaluate previously published SiO₂/Al₂O₃ and SiO₂/TiO₂ ratios in loess–paleosol sequences from the Yimaguan profile, Gansu Province, Northwest China, and examine the potential alteration caused by chemical weathering. The SiO₂/Al₂O₃ and SiO₂/TiO₂ ratios show opposite trends to that of the frequency-dependent magnetic susceptibility (χ_fd) and the chemical index of alteration (CIA). However, the whole profile exhibits limited Si isotopic variation, with δ³⁰Si values ranging from −0.28‰ to −0.16‰. The homogeneous Si isotopic signature indicates that Si is not significantly leached during pedogenesis. Therefore, the SiO₂/Al₂O₃ and SiO₂/TiO₂ ratios are not modified by Si leaching due to chemical weathering; instead, they are mainly affected by the grain size sorting effect, which is controlled by the change of winter monsoon intensity. This suggests that SiO₂/Al₂O₃ and SiO₂/TiO₂ can serve as reliable indicators of paleoclimate changes, with an increase in the ratios reflecting the strengthening of the East Asian winter monsoon. Based on our observation of the Yimaguan loess–paleosol samples and the global loess data previously published, we also constrained the average Si isotopic composition of the upper continental crust (UCC) to be −0.22 ± 0.06‰ (2 s.d.).</p>\u0000 </div>","PeriodicalId":16929,"journal":{"name":"Journal of Quaternary Science","volume":"40 2","pages":"279-286"},"PeriodicalIF":1.9,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143370059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distribution and palaeoenvironmental significance of mountain blockstreams in the southern hemisphere","authors":"Stefan Grab,&nbsp;Jasper Knight","doi":"10.1002/jqs.3678","DOIUrl":"https://doi.org/10.1002/jqs.3678","url":null,"abstract":"<p>Openwork mountain block deposits (blockfields, blockstreams) have received much research interest globally given their visual appeal as prominent cold-region landforms. However, studies have shown that these landforms in both glaciated and non-glaciated environments are probably of considerable age (pre-Quaternary), yet the environmental conditions of their formation (such as the presence of permafrost) and associated processes remain poorly understood. This paper focuses on consolidating and critically analysing current knowledge on mountain blockstreams found in the southern hemisphere. This is achieved by reviewing past published work on such landforms, from the Falkland Islands, Marion Island, southern Africa and southeastern Australia. By presenting a variety of previously proposed landscape evolutionary models, we demonstrate that southern hemisphere blockstreams are products of a range of weathering and material mobilization processes over long multiple warmer/wetter and colder/drier pre-Quaternary and Quaternary climatic cycles. Although most southern hemisphere mountain blockstreams have some association with periglacial processes, they are not exclusively periglacial in their developmental history. This can be tested through field geomorphic, sedimentary and ecological methods; the use of remote sensing; radiometric and relative-age dating; seismic and other subsurface methods; and modelling. However, many research questions remain unanswered, such as the potential role of permafrost in blockstream formation and dynamics, or their sensitivity to ongoing climate change.</p>","PeriodicalId":16929,"journal":{"name":"Journal of Quaternary Science","volume":"40 3","pages":"537-557"},"PeriodicalIF":1.9,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jqs.3678","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143778193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Australian subtropical vegetation and wetland response to fire, climate and nutrient availability during the Holocene","authors":"Haidee Cadd,&nbsp;Michela Mariani,&nbsp;John Tibby,&nbsp;Jonathan Tyler,&nbsp;Cameron Barr,&nbsp;Melanie J. Leng,&nbsp;Patrick Moss,&nbsp;Richard Lewis,&nbsp;Tim Cohen,&nbsp;Sam Marx,&nbsp;Glenn B. McGregor,&nbsp;Jonathan C. Marshall,&nbsp;Lynda Petherick","doi":"10.1002/jqs.3681","DOIUrl":"https://doi.org/10.1002/jqs.3681","url":null,"abstract":"<div>\u0000 \u0000 <p>The iconic sand dune systems of Minjerribah (North Stradbroke Island), in southeastern Queensland, Australia, host numerous lakes and swamps containing organic-rich sediment deposits that record changes in climate, fire and surrounding vegetation. Palaeoenvironmental reconstructions from individual locations can provide insights into changes in the environment, but determining the regional extent of these changes is seldom possible from a single site. Multi-site compilations help elucidate the geographical nature of environmental changes and determine if they are driven by local or regional forces. Here, a synthesis of palynological records from six Minjerribah wetlands using a muti-tiered Monte Carlo empirical orthogonal function (EOF) analysis allows island-wide patterns of vegetation change to be identified. Coherent changes in vegetation were recorded, with first-order changes (EOF1) indicating a long-term shift in vegetation composition from closed forests towards woodland and heath vegetation. A compilation of macroscopic and microscopic charcoal from the same sites shares coherent patterns of change with a rainfall record from the island, suggesting that regional fire occurrence between 7000 and 2000 cal a <span>bp</span> was driven primarily by long-term variations in rainfall and its influence on biomass. Comparison with fire activity, rainfall, sedimentary carbon, nitrogen and dust records from Minjerribah suggests that regional vegetation changes occur primarily in response to long-term changes in nutrients and increasing rainfall variability. This analysis highlights the multi-millennial connection between vegetation composition, climate, nutrients and fire occurrence across the Holocene in subtropical environments.</p>\u0000 </div>","PeriodicalId":16929,"journal":{"name":"Journal of Quaternary Science","volume":"40 3","pages":"519-536"},"PeriodicalIF":1.9,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143778354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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-proxy analysis of early Holocene vegetation dynamics on the islands of proglacial Lake Ojibway (northeastern America)","authors":"Marianne F. S. Vogel,&nbsp;Sébastien Joannin,&nbsp;Mebarek Lamara,&nbsp;Hugo Asselin,&nbsp;Adam A. Ali,&nbsp;Sabrina Leclercq,&nbsp;Cécile Latapy,&nbsp;Franck Richard,&nbsp;Yves Bergeron","doi":"10.1002/jqs.3682","DOIUrl":"https://doi.org/10.1002/jqs.3682","url":null,"abstract":"<p>Following deglaciation, lowland sites in eastern Canada that were covered by proglacial Lake Ojibway recorded direct afforestation with boreal mixedwood taxa, without an initial tundra phase, contrary to sites that were never covered by this lake. Because former islands of proglacial Lake Ojibway were colonized by vegetation before lake drainage around 8200 cal a <span>bp</span>, we hypothesized that these paleo-islands went through a non-arboreal phase which eventually transitioned to boreal mixedwoods, hence providing a source of propagules for rapid and later colonization of the lowlands. We carried out a multi-proxy analysis combining pollen, macro-remains, sedimentary ancient DNA and charcoal to document vegetation composition and dynamics on two paleo-islands. Both study sites recorded progressive vegetation establishment starting with a tundra-like phase with only herbs and shrubs, followed by open forests dominated by either larch or pine, culminating with the establishment of the boreal mixedwoods about 300 years before the final drainage of proglacial Lake Ojibway. Fire regimes seem to have partially driven vegetation dynamics and diversity on the paleo-islands. Paleo-islands were sources of propagules, which helps explain how the former Lake Ojibway lowlands were directly colonized by boreal mixedwoods, without an initial tundra phase.</p>","PeriodicalId":16929,"journal":{"name":"Journal of Quaternary Science","volume":"40 2","pages":"229-242"},"PeriodicalIF":1.9,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jqs.3682","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143370093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Insights into human–environment interactions in tropical Africa during the Late Holocene based on the sediment sequence from Saiwa Swamp, Kenya","authors":"Lawrence Morara Kiage","doi":"10.1002/jqs.3673","DOIUrl":"https://doi.org/10.1002/jqs.3673","url":null,"abstract":"<div>\u0000 \u0000 <p>The present landscapes that define the tropical African region have evolved through the intricate interplay of climate and human interventions across various spatial and temporal scales. The late Holocene period is a valuable window for investigating how the environment responded to human influence. This study examined paleoenvironmental changes in the African tropics over the past 3500 years using proxy data, encompassing pollen, fungal spores, loss-on-ignition and microscopic charcoal extracted from core SS4 collected from Saiwa Swamp in western Kenya. The results show that Afromontane forests, represented by <i>Podocarpus, Olea, Celtis</i> and <i>Juniperus</i>, persisted in the region for much of the late Holocene despite prevailing conditions that favored the expansion of open savanna-like vegetation and drought-adapted taxa. The charcoal record reveals continuous fire occurrences throughout the sequence, raising questions about human-induced fires and their potential role in shaping the landscape. The emergence of <i>Sordaria</i> fungal spores in the record between approximately 925 \u0000<span>bce</span> and 970 \u0000<span>ce</span> points to early human settlements engaging in livestock farming. Yet, these initial anthropogenic impacts did not trigger extensive forest clearing, hinting at a nuanced interplay between human activities and the environment during that era. The study emphasizes the importance of considering natural and human factors when interpreting environmental changes. It highlights the complex interplay of climatic, ecological and anthropogenic factors in shaping the landscape and vegetation dynamics over time.</p>\u0000 </div>","PeriodicalId":16929,"journal":{"name":"Journal of Quaternary Science","volume":"40 2","pages":"319-331"},"PeriodicalIF":1.9,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143370057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sub-centennial upper water column structure variability of the tropical Indian Ocean since the Last Glacial Maximum","authors":"Soni Rai,&nbsp;D. P. Singh,&nbsp;R. Saraswat,&nbsp;A. S. Maurya","doi":"10.1002/jqs.3680","DOIUrl":"https://doi.org/10.1002/jqs.3680","url":null,"abstract":"<div>\u0000 \u0000 <p>The upper water column (UWC) is involved in the worldwide distribution of heat and nutrients. However, global warming is expected to alter the UWC structure due to temperature- and precipitation-induced stratification. This impact of global warming is comparatively more pronounced in the Indian Ocean. Therefore, to understand the fate of the UWC structure in the future, it is important to comprehend its past variability in the Indian Ocean. To achieve this, we have reconstructed sub-centennial scale variations in the UWC structure of the tropical central Indian Ocean by using the isotopic composition (δ¹⁸O and δ¹³C) of surface-dwelling planktic foraminifera <i>Globigerinoides ruber</i> and subsurface-dwelling <i>Neogloboquadrina dutertrei</i>. The difference in the isotopic composition of the surface- and subsurface-dwelling species (Δδ¹⁸O_r-d and Δδ¹³C_r-d) was used to understand the UWC structure variability in the tropical central Indian Ocean. We report a deeper mixed layer and thermocline during the last glacial period, followed by a shoaling of the thermocline during the glacial–interglacial transition. The thermocline also deepened during intense boreal summer monsoon events such as in the Bølling–Allerød and early Holocene. Our findings suggest that the tropical Indian Ocean UWC is influenced primarily by the intensity of the monsoon winds. From the comparison of our record with those of the eastern and western Indian Ocean, it is evident that a similar climatic forcing governed the central and eastern regions during the last glacial–interglacial period.</p>\u0000 </div>","PeriodicalId":16929,"journal":{"name":"Journal of Quaternary Science","volume":"40 2","pages":"257-266"},"PeriodicalIF":1.9,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143370061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}