Quaternary Science Reviews最新文献

{"title":"Vegetation change and grazing activities since the middle Holocene in the Zoige Basin, eastern Tibetan Plateau, China","authors":"Yuanqi Pan ,&nbsp;Xiaochun Zha,&nbsp;Chunchang Huang,&nbsp;Jiangli Pang,&nbsp;Yali Zhou,&nbsp;Na Wang,&nbsp;Yuxin Zhao","doi":"10.1016/j.quascirev.2025.109330","DOIUrl":"10.1016/j.quascirev.2025.109330","url":null,"abstract":"<div><div>Large herbivores of grazing activities are the most important production factor to maintain the permanent settlement of human beings in the high-altitude area of the Tibetan Plateau, China, and their population changes are the products of the interaction between climate change and human activities since the Holocene. Using pollen and fungal spore fossil records from a profile since mid-Holocene in the Zoige Basin, the history and controlling factors of vegetation change and grazing activities were revealed. The results showed that the history of vegetation change and grazing activities in the Zoige Basin could be divided into three stages: (ⅰ) During the period of 8.5–5.8 ka, alpine meadow dominated by Cyperaceae developed in the Zoige Basin with the highest tree pollen content and the best hydrothermal conditions. The low concentration of coprophilous fungal spore at this stage was probably related to wild herbivores. (ⅱ) During the period of 5.8–3.6 ka, the alpine meadow dominated by Cyperaceae developed further, the tree pollen content decreased slightly, and the climate began to change to drought, but the overall climate was still warm and humid. At this stage, coprophilous fungal spores occurred continuously and their concentration gradually increased, suggesting that there were human activities in the basin and grazing activities began at about 5.8ka. (ⅲ) During about 3.6–0 ka, the vegetation type changed to the desert steppe dominated by Chenopodiaceae and Asteraceae, and after 0.5 ka, the alpine meadow redeveloped. The pollen content of trees decreased significantly, and the climate was mainly cool and dry. Grazing activities, as represented by the concentration of coprophilous fungi spores, began to increase gradually after about 3.6 ka. There was a reverse correlation between grazing activities and the dry and cool climate in this stage. The dry and cool climate was one of the key factors to promote the development of grazing in the Zoige Basin. The research results further complement the evolution of human activities and environmental background in the eastern Tibetan Plateau, and have certain reference significance for understanding the impact of climate change on human survival strategies in the plateau environment.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"357 ","pages":"Article 109330"},"PeriodicalIF":3.2,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143759958","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":"Hydrological changes in the East Asian monsoon region around 4.2 ka precisely reconstructed from multi-proxy stalagmites","authors":"Chao-Jun Chen ,&nbsp;Yao Wu ,&nbsp;Jun-Yun Li ,&nbsp;Hai-Wei Zhang ,&nbsp;Hai Cheng ,&nbsp;Chuan-Chou Shen ,&nbsp;You-Feng Ning ,&nbsp;Dao-Xian Yuan ,&nbsp;R. Lawrence Edwards ,&nbsp;Jian Zhang ,&nbsp;Ting-Yong Li","doi":"10.1016/j.quascirev.2025.109321","DOIUrl":"10.1016/j.quascirev.2025.109321","url":null,"abstract":"<div><div>The 4.2 ka event was considered a climatic event that influenced ancient cultural transitions during the Middle-Late Holocene. However, whether this was a global climate event, remains controversial. Although some studies have discussed the changes in the Asian summer monsoon during the 4.2 ka event, the climate change patterns in the Yangtze River Basin (YRB) during this period remain unclear. In this study, we utilized multi-proxy (δ¹⁸O, δ¹³C, and Mg/Ca) records from stalagmite YK1306 to reconstruct the climatic changes in the YRB during 3000∼5000 yr BP. Based on comparative analysis of the high-resolution stalagmite records and other geological proxies within this region, the increased precipitation in the YRB during 4300∼4000 yr BP led to frequent flooding disasters, while double droughts occurred during 4000∼3700 yr BP and 4500∼4300 yr BP. Although there are differences in the characteristics of the 4.2 ka event recorded by speleothems across the Asian summer monsoon region, the 4.2 ka event indicated in the δ¹⁸O and δ¹³C records from speleothems in the YRB is inconsistent with the previously defined 4.2 ka event. The transition of El Niño-Southern Oscillation (ENSO) events resulted in the occurrence of flooding and droughts in the YRB during 4500∼3700 yr BP. This study not only provides new evidence of the hydrological changes in the YRB, but also helps evaluate the impact of climate change on civilizations in the YRB in the Late Neolithic.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"357 ","pages":"Article 109321"},"PeriodicalIF":3.2,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747480","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":"Central South Pacific bottom water response to thermohaline circulation crisis during the Middle Pleistocene Transition","authors":"N. Mahanta,&nbsp;Sunil K. Das,&nbsp;Raj K. Singh","doi":"10.1016/j.quascirev.2025.109344","DOIUrl":"10.1016/j.quascirev.2025.109344","url":null,"abstract":"<div><div>Mid-Pleistocene Transition (MPT) is still enigmatic in paleoclimatology, and the major disruption of the ocean thermohaline circulation (THC) system, which is known as the THC crisis during the MPT from ∼950 to 860 thousand years ago, is even more puzzling. Hence, benthic foraminifera and Iceberg rafted debris (IRD) of the Central South Pacific (CSP), International Ocean Discovery Program Site U1540 are examined, and compared with existing Nd isotope records (ε_Nd) from the South and North Atlantic, and δ¹³C of South Atlantic and Equatorial Pacific to evaluate the properties and influence of CSP bottom water during THC crisis in comparison to pre and post-THC crisis. Our data suggests variability in CSP bottom water conditions from oxic to suboxic throughout the MPT. During the pre-THC crisis (MIS 38-26), bottom water was suboxic with low bottom water current strength, which continued up to the Marine Isotopic Stage (MIS) 25, except for MIS 31. Evidence of a strong bottom water current with a high oxic species population and low IRD is found at MIS 31. During the THC crisis, between MIS 25 and 23, a sharp decline in the coarse sediment fraction (&gt;63 μm), oxic species and <em>Globocassidulina subglobosa</em> population is observed, which suggests sluggish bottom water at the CSP. However, during MIS 22, bottom water was relatively strong, marked by an increase in <em>G. subglobosa</em> and <em>Nuttallides umbonifera</em> and oxic species abundances. This suggests stronger southern source bottom water, which may reach up to the North Atlantic due to reduced northern sourced bottom water mass and is consistent with the interpretation of observed ɛ_Nd value. After the THC crisis, bottom water became better oxygenated, especially during the interglacials with high bottom water current strength, which continued post-MPT period. Bottom water current strength nearly follows the ACC strength during the MPT except for MIS 22.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"357 ","pages":"Article 109344"},"PeriodicalIF":3.2,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747128","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":"Thin on the mountainous landscape: The Late Pleistocene zooarchaeology of the southern Caucasus, Zagros, and Alborz","authors":"Reuven Yeshurun","doi":"10.1016/j.quascirev.2025.109325","DOIUrl":"10.1016/j.quascirev.2025.109325","url":null,"abstract":"<div><div>Only a handful of examples speak for Middle and Upper Paleolithic adaptations to mid-latitude highlands. Mountainous southwest Asia, consisting of the southern Caucasus (including the Armenian Plateau) and the Zagros and Alborz ranges, is arguably the richest, featuring numerous Late Pleistocene (ca. 130–12 ka) archaeological records. The region's long zooarchaeological research history and especially the data gathered during the last two decades are now sufficient to support a study of Neanderthal and modern human subsistence and mobility patterns. In this paper, I present a synthesis of the available zooarchaeological data from the southern Caucasus and the Zagros/Alborz. Using abundance indices of animal groups and taphonomic variables, I test the null hypothesis that humans hunted the available game proportionally to its abundance on the landscape. To this end, the natural abundance baselines were extrapolated from bioclimatic variables and nonhuman-generated Pleistocene faunas. Taphonomic and taxonomic patterns that pertain to site-occupation intensity were evaluated against a pertinent external reference, the well-studied zooarchaeological record of the southern Levant, representing a warmer and more habitable region.</div><div>The null hypothesis was only partially confirmed, enabling the identification of prey choice patterns, hunting specialization, and diversification. While acknowledging the region's archaeological variability, the study showed that the Middle and Upper Paleolithic habitations in the southern Caucasus and Zagros/Alborz were primarily ephemeral, attesting to low site habitation intensity and little, if any, population growth. It seems that all groups inhabiting the region could afford to practice highly selective game procurement strategies, exploiting vast territories and occupying many short-term camps, some strategically positioned to intercept migrating game. Both Middle and Upper Paleolithic populations consisted of small and highly mobile groups that sporadically inhabited the rugged landscape; they lived under harsh climatic conditions well under the environmental carrying capacity. This scenario contributes to viewing mountainous southwest Asia as a geographic cul-de-sac during the Pleistocene; it demonstrates that regardless of their biological and cultural backgrounds, human groups adopted similar behaviors in accordance with the regions' natural conditions.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"357 ","pages":"Article 109325"},"PeriodicalIF":3.2,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715576","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":"Examining the relationship between temperature and δ18O of freshwater molluscan carbonate from modern and Pleistocene fluvial sediments from the British Isles","authors":"J.E. Sherriff ,&nbsp;I. Candy ,&nbsp;A.P. Palmer ,&nbsp;R.C. Preece ,&nbsp;D.C. Schreve ,&nbsp;T.S. White","doi":"10.1016/j.quascirev.2025.109332","DOIUrl":"10.1016/j.quascirev.2025.109332","url":null,"abstract":"<div><div>The δ¹⁸O of freshwater molluscan carbonate (δ¹⁸O_c) from fluvial sequences has the potential to be a key palaeoclimate archive, given the close association between δ¹⁸O_c values and temperature in temperate lowland freshwater systems. However, the scarcity of systematic modern and Pleistocene studies from these deposits has limited the use of molluscan carbonate δ¹⁸O_c as a proxy for climate change. Here we present a study of fluvial molluscan carbonate δ¹⁸O_c from modern river systems and Pleistocene fluvial sequences located in central and southeast Britain. We compare molluscan carbonate δ¹⁸O_c from four species of gastropod to independently-derived estimates of temperature from the same contexts. We demonstrate that the δ¹⁸O_c of modern shells from three sites in southeast Britain are consistent with formation under equilibrium conditions with modern water temperature and δ¹⁸O_w values, which are in turn controlled by prevailing air temperature. The relationship between the δ¹⁸O_c value and temperature is also observable in the data obtained from fossil shells from ten Pleistocene sequences. Despite uncertainties with the interpretation of both the δ¹⁸O_c and palaeotemperature data at several localities, and the paucity of mollusc shells from cold climate contexts, this study highlights the potential of using δ¹⁸O_c analysis to obtain palaeoclimatic records from long Pleistocene fluvial sequences in temperate regions.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"357 ","pages":"Article 109332"},"PeriodicalIF":3.2,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715575","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":"Not by chemistry alone: Tephrostratigraphy, correlation, and context at two Palaeolithic sites in the southern Caucasus and Armenian Highlands","authors":"D.S. Adler ,&nbsp;V.L. Cullen ,&nbsp;K.N. Wilkinson ,&nbsp;B. Gasparyan ,&nbsp;N. Tushabramishvili ,&nbsp;P. Griffith ,&nbsp;C. Mallol ,&nbsp;J.P. Gill ,&nbsp;T.Z. Kovach ,&nbsp;S. Blockley ,&nbsp;P. Glauberman ,&nbsp;V.C. Smith","doi":"10.1016/j.quascirev.2025.109292","DOIUrl":"10.1016/j.quascirev.2025.109292","url":null,"abstract":"<div><div>Understanding the timing of Late Pleistocene population expansions and interactions is hindered by myriad factors among which the imprecision of absolute dating is of particular concern. The identification and geochemical characterization of cryptically preserved volcanic ash layers (cryptotephra) in archaeological sites can alleviate this problem, and in the southern Caucasus and Armenian Highlands has allowed for the correlation of lithostratigraphic units at Palaeolithic sites in the two geographic regions. Compositionally distinct tephras (isochrons) allow specific stratigraphic layers to be linked temporally at the sites of Ortvale Klde (OK, Georgia) and Lusakert-1 (LKT-1, Armenia). The ∼30 ka V-18/Nemrut Formation tephra from the Nemrut volcano, eastern Türkiye is correlated with an Upper Palaeolithic layer at OK and a Late Middle Palaeolithic layer at LKT-1. This isochron suggests the long-term regional coexistence of technologically distinct populations, and the late survival of Late Middle Palaeolithic hominins. These results appear to capture a critical and until now elusive moment in hominin evolution, a period when two distinct tool-making groups, generally assumed to be <em>Homo sapiens</em> and Neanderthals, occupied the same region and likely interacted. However, careful comparison of results with site-specific sedimentological, taphonomic, archaeological, and chronometric data throw these correlations into question. Closer consideration of newly available glass geochemistry for Nemrut suggests further correlations: OK Layer 4c correlates to the V-30 tephra in Lake Van (∼42–37 ka); LKT-1 Lithostratigraphic Unit (LU) 4 correlates to both the ∼60 ka V-45/Çekmece and ∼62 ka V-51/Ahlat Pumice 6; and the younger LKT-1 LU 3 also correlates to the V-51, but with a different compositional range to those seen in the older LU 4. The only way to reconcile the range of compositions observed is that there are additional Nemrut eruptions that have similar glass chemistries to the deposits characterized, and that our current understanding of Nemrut's eruption stratigraphy is incomplete thus hampering our ability to resolve the age(s) of these distal tephra deposits with confidence. Therefore, while the analysis of cryptotephra holds great promise for understanding the timing of key evolutionary events, its application in the southern Caucasus and Armenian Highlands, and elsewhere, must be predicated on the careful consideration of site-specific contextual data rather than chemistry alone.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"356 ","pages":"Article 109292"},"PeriodicalIF":3.2,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706061","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":"Holocene hydroclimate and landscape changes as drivers of organic carbon cycling in a small northern Fennoscandian lake","authors":"Lilia E. Orozco ,&nbsp;Jan Weckström ,&nbsp;Mateusz Plociennik ,&nbsp;Annika K. Åberg ,&nbsp;J. Sakari Salonen ,&nbsp;Darren R. Gröcke ,&nbsp;Laura Arppe ,&nbsp;Maija Heikkilä","doi":"10.1016/j.quascirev.2025.109323","DOIUrl":"10.1016/j.quascirev.2025.109323","url":null,"abstract":"<div><div>Lakes and ponds play a critical role in the high-latitude carbon cycle. Rapid climate warming, cryosphere degradation and increasing rainfall are transforming catchments and land-water interactions, altering lake carbon cycling in unprecedented ways. Here, we present Holocene (past 10.5 ka) sediment records from a small northern Fennoscandian lake to elucidate linkages of past hydroclimate change and lake carbon cycling. Using elemental and stable isotope composition of organic matter (C%, N%, δ¹³C, δ¹⁵N), age control from 23 radiocarbon dates, and a ground-penetrating radar survey of lake sediment layers, we reconstructed organic matter burial and sources, aided with a Bayesian end-member mixing model based on measurements from modern terrestrial and aquatic vegetation and particulate organic matter. The hydroclimate and lake hydrological regime changes were interpreted from lake-water ẟ¹⁸O (ẟ¹⁸O_lw) reconstructed from subfossil chironomid (Chironomidae; non-biting midges) head capsules and ẟ¹⁸O and ẟ²H monitoring of local meteoric, lake and groundwaters. The ẟ¹⁸O_lw and carbon burial mirror the Holocene temperature pattern, increasing in the cooler early Holocene, at their maxima in the warm mid-Holocene, and decreasing during the late Holocene cooling. The lake was dominated by aquatic organic matter through the Holocene, with benthic sources more dominant in the early Holocene and planktic in the late Holocene. A slight increase in the terrestrial organic matter proportion occurred in the warm and dry mid-Holocene despite reduced hydrological connectivity, which is contrary to the hypothesis that wetter climate increases allochtonous C burial. The higher mid-Holocene ẟ¹⁸O_lw values were superimposed by lower values at ca. 6.5 cal ka BP, interpreted as increased winter precipitation contributing to snowmelt and isotopically light groundwater impacting ẟ¹⁸O_lw. This interval is coupled with highly siliceous sediment deposition indicating marked aquatic productivity, possibly linked with inputs of groundwater rich in silica and phosphorous. Our findings underscore the importance of hydrological connectivity on both burial and sourcing of C in high-latitude lakes, and suggest that in future wetter climate, high-latitude lakes may play more important role as processors than sinks of carbon.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"357 ","pages":"Article 109323"},"PeriodicalIF":3.2,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698091","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":"Holocene vegetation history of the Mississippi River Delta: A regional synthesis","authors":"Kam-Biu Liu ,&nbsp;Junghyung Ryu","doi":"10.1016/j.quascirev.2025.109318","DOIUrl":"10.1016/j.quascirev.2025.109318","url":null,"abstract":"<div><div>The modern Mississippi River Delta (MRD) contains extensive areas of wetlands with a distinct vegetational zonation determined by a north-to-south salinity gradient. This paper presents the first reconstruction of Holocene ecological history of the MRD based on a review and regional synthesis of new multi-proxy records from four wetland sites across these vegetation zones. During the past 6 ka, ecological development in the MRD was primarily driven by the geological processes of delta lobe switching, as the Mississippi River formed six delta lobes along the coast. The progradation of the St. Bernard delta lobe during 4.6-2.6 ka delivered abundant freshwater and sediments to the northern sites, rapidly changing the estuarine or marine-influenced interdistributary environment to a freshwater lake, swamp, or marsh. Freshwater wetlands were widespread in the MRD during 2.3-0.7 ka, before they were progressively transformed into the modern saline and intermediate marshes in the southern sites over the past 700 years due to relative sea level rise. The arrival of black mangroves and its proliferation during the past century marked the latest chapter in the Holocene ecological history of the MRD. The modern vegetation zones—as governed by the salinity gradient—are relatively young ecosystems, having developed at their present locations for only a few hundred years. Human activity has played an increasingly important role in affecting the ecosystem and environment during the past 3000 years.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"357 ","pages":"Article 109318"},"PeriodicalIF":3.2,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698090","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":"Evolution of Indian monsoon precipitation and vegetation dynamics in the Bay of Bengal region since the last glacial period","authors":"Ananna Rahman ,&nbsp;Chuanxiu Luo ,&nbsp;Md Hafijur Rahaman Khan ,&nbsp;Sui Wan ,&nbsp;Yiping Yang ,&nbsp;Haicheng Wei ,&nbsp;Rong Xiang ,&nbsp;Lanlan Zhang ,&nbsp;Jianguo Liu ,&nbsp;Xiang Su ,&nbsp;Yun Huang","doi":"10.1016/j.quascirev.2025.109314","DOIUrl":"10.1016/j.quascirev.2025.109314","url":null,"abstract":"<div><div>The Indian Summer Monsoon (ISM) is among the major global climate systems and influences one-quarter of the world's population. However, the long-term variability of ISM precipitation from the last glacial to the present remains a subject of major debate. One debate concerns the precipitation change driven by the ISM from Marine Isotope Stage (MIS) 2 to MIS 1, while another focuses on the varying degrees of monsoonal rainfall intensity across different warm periods (MIS 3 and MIS 1). In this study, we reconstruct high-resolution palynological records from two sediment cores (YDY10 and E87-32B) in the Bay of Bengal (BoB) to explore changes in regional vegetation and ISM precipitation since the last glacial period. The results show that the concentrations of terrigenous pollen-spore decrease with increasing offshore distance, primarily reflecting pollen-spore input and transportation from the Ganges-Brahmaputra (G-B) river basins. Significant shifts in evergreen broad-leaved pollen at ∼40.5 ka and ∼12 ka indicate notable changes in hydrodynamic forces and intense precipitation, reflecting strong ISM activity. Data from core E87-32B indicate that ISM precipitation during the early to middle Holocene (MIS 1) was higher than during MIS 3, likely influenced by summer solar insolation (SSI) on an orbital timescale. From the Last Glacial Maximum (LGM) to the middle Holocene in MIS 1, the region experienced a transformation from extensive herbaceous vegetation to tropical and subtropical broad-leaved forests, followed by millennial-scale fluctuations in ISM precipitation in both cores. In core YDY10, broad-leaved forest pollen shows three distinct low values corresponding to Heinrich 1 (H1), Younger Dryas (YD), and the 8.2 ka cold and dry events, respectively, consistent with variations in the weakened Atlantic meridional overturning circulation (AMOC). Meanwhile, in core E87-32B, the broad-leaved pollen percentage increase from the LGM to the early and middle Holocene, indicating stronger ISM precipitation and G-B river input. This suggests that the ISM variation in this period was driven by AMOC and other factors, such as river input. Overall, this study offers a comprehensive perspective on past climate and vegetation dynamics around the BoB region on orbital and millennial timescales and contributes to a better understanding of the controls on monsoonal rainfall under different boundary conditions.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"356 ","pages":"Article 109314"},"PeriodicalIF":3.2,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143697683","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":"New global lacustrine brGDGTs temperature calibrations based on machine learning","authors":"Zeyang Zhu,&nbsp;Jing Wu,&nbsp;Guoqiang Chu,&nbsp;Jiaqi Liu","doi":"10.1016/j.quascirev.2025.109319","DOIUrl":"10.1016/j.quascirev.2025.109319","url":null,"abstract":"<div><div>Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are ubiquitous bacterial membrane lipids that serve as a reliable proxy for paleotemperature reconstruction. The salinity and seasonal icing of lakes play a crucial role in brGDGT calibration, with calibrations varying between tropical, mid-high latitude, and freshwater versus non-freshwater lacustrine sediments, which complicates their universality. Furthermore, changes in a lake's salinity and seasonal icing during glacial and interglacial cycles can influence the accuracy of paleotemperature reconstructions across different time periods. In this study, we present improved global calibrations based on a comprehensive lacustrine brGDGT dataset consisting of 949 samples, utilizing methods such as linear regression for the fractional abundance of key brGDGTs and support vector machine regression with a linear kernel. The calibrations yield root mean square errors ranging from approximately 2.0 °C–2.6 °C for the test dataset, closely matching those obtained from the training dataset, indicating that the results are not overfitted. These calibrations show improved performance when applied to lake sediment sequences.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"357 ","pages":"Article 109319"},"PeriodicalIF":3.2,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143696652","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}