Quaternary Science Reviews最新文献

{"title":"High-resolution sedimentary record in the eastern Mediterranean shelf shows reduced Nile-derived mud after the Little Ice Age (1830 CE)","authors":"Yael Edelman-Furstenberg ,&nbsp;Navot Morag ,&nbsp;Henko C. de Stigter ,&nbsp;Onn Crouvi ,&nbsp;Nadya Teutsch ,&nbsp;Orit Hyams-Kaphzan","doi":"10.1016/j.quascirev.2025.109185","DOIUrl":"10.1016/j.quascirev.2025.109185","url":null,"abstract":"<div><div>Chemical, sedimentological and micropaleontological records were used to track recent climatic and ecological events recorded in eastern Mediterranean shelf sediments. By studying a high-resolution record of well-dated sediment from the Israeli shelf, natural and anthropogenic influence during the past 270 years were differentiated and pinpointed to major events.</div><div>The most prominent changes occurred in sediment source at the end of the Little Ice Age (LIA), in 1830–1840 CE. Coarse, quartzose sand comprised only 5% of the sediment during the LIA, and increased significantly after the LIA to levels of up to 15%. There was a further increase in the coarse, quartzose content to &gt;20% following the damming of the Nile River (Aswan High Dam, in 1964), continuing the earlier post-LIA increase.</div><div>The geochemical data suggests a shift in the composition of the finer-grained sediments at the end of the LIA. During the LIA, clay-rich sediments were found to have lower levels of K₂O and higher levels of Ni compared to sediments post-LIA. These likely indicate a change in the source of sediments to the eastern Mediterranean shelf, shifting from a dominance of Nile-derived sediments and Nile Delta soils during the LIA, to more Saharan-derived, fine-grained dust and coarse-grained quartzose sands in the post-LIA period. The prevalence of Nile-derived sediments during the LIA suggests wetter conditions in coastal East Africa during that time period, as opposed to post-LIA.</div><div>The foraminiferal data also indicate a shift at the end of the LIA, mainly in group composition and abundance. A major increase in miliolid shell-type abundances after the LIA, aligns with a transition to warmer temperatures post-LIA. An additional increase is detected in species richness and abundance after the damming of the Nile River. However, this is superimposed on the ongoing increase since the LIA termination.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"351 ","pages":"Article 109185"},"PeriodicalIF":3.2,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159947","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 sea-level history from the southern Bohai Sea coast, China: Far-field GIA processes and an associated mid-Holocene sea-level highstand","authors":"Lizhu Tian ,&nbsp;Bert L. Vermeersen ,&nbsp;Fu Wang ,&nbsp;Jianfen Li ,&nbsp;Hong Wang","doi":"10.1016/j.quascirev.2024.109166","DOIUrl":"10.1016/j.quascirev.2024.109166","url":null,"abstract":"<div><div>The Bohai Sea, located in the innermost part of the East Asian marginal seas, is of particular interest in the studies of relative sea level (RSL) and glacial isostatic adjustment (GIA) due to its apparent far-field position. This study analyzed six cores and one pre-existing archaeological site from the southern Bohai Sea coast, generating 11 sea-level index points (SLIPs) from supratidal, upper tidal, and mid-lower tidal flat sediments using foraminifera tests and sedimentary analysis. All SLIPs were corrected for possible self-compaction, long-term tectonic effect, and the lowering effect due to water extraction. This enabled a high-quality reconstruction of RSL changes over the age range of 9000–3000 cal a BP. The RSL rose rapidly from about −17.19 ± 1.32 m to 1.76 ± 1.32 m MSL between around 9000 and 7000 cal a BP. However, the RSL rise rates quickly decreased from around 8–10 mm/a before 8000 cal a BP to ∼4mm/a by 7000 cal a BP. After 7000 cal a BP, the RSL continued to rise, reaching its peak of 2.44 ± 1.34 m MSL around 6000 cal a BP followed by a gradual decline to the present height at 3000–4000 cal a BP, with a maximum falling rate of 1.2 mm/a around 5000 cal a BP. Comparisons of the reconstructed RSL in this study with those from other non-deltaic regions, including the inner Hangzhou Bay and the surrounding coasts of western Bohai Sea, as well as with GIA predictions by ICE6G, ANU, and region-specific ‘final model’ reveal: (1) a significant and long-term early-to-mid Holocene continental levering effect on the southern Bohai Sea coast; (2) a close fit with the region-specific ‘final model’, albeit with SLIPs that fall slightly below predictions from 9000 to 8000 cal a BP and form a distinct mid-Holocene highstand above model projections after 7000 cal a BP; (3) these data-model misfits may result, in the former case, from the GIA model's Holocene ice melting history not embedding accelerated sea-level rise events, and in the latter, from the presence of a relatively strong upper mantle at the southern Bohai Sea coast, rather than the extremely weak upper mantle assumed for the Bohai Sea region.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"351 ","pages":"Article 109166"},"PeriodicalIF":3.2,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159952","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":"Changes in distribution of the Iberian vegetation since the Last Glacial Maximum: A model-based approach","authors":"Manuel Casas-Gallego ,&nbsp;José María Postigo-Mijarra ,&nbsp;Rut Sánchez-de Dios ,&nbsp;Eduardo Barrón ,&nbsp;Angela A. Bruch ,&nbsp;Karen Hahn ,&nbsp;Helios Sainz-Ollero","doi":"10.1016/j.quascirev.2024.109162","DOIUrl":"10.1016/j.quascirev.2024.109162","url":null,"abstract":"<div><div>Understanding past potential vegetation distribution across different spatial and temporal scales is a fundamental goal in palaeobotany and the study of past human societies. Additionally, this understanding is crucial in various ecological fields, including vegetation management, conservation and restoration. Our knowledge of past vegetation history mainly relies on palaeobotanical records. However, these records sometimes cover only short time spans and/or lack sufficient chronological control. Moreover, there are still large areas with limited available records. To help address these gaps, this study employs ecological niche modelling fed with inputs from high-resolution present and past climatic data, along with data on soil and current potential landscapes, to simulate the dynamics and distribution of the main vegetation types in the Iberian Peninsula since the Last Glacial Maximum (22,000 years BP). The simulations show significant changes in the extent of each vegetation type through time. Overall, the known vegetation dynamics inferred from fossil botanical data for the Eurosiberian and Mediterranean regions are well reproduced and enhanced by our models, stressing the central role of climate in the distribution of vegetation of the Iberian Peninsula. General biogeographic trends that have been recognised in fossil records, such as the massive expansion of non-forested vegetation mainly consisting of steppes during the Last Glacial Maximum and the Lateglacial; the expansion of deciduous forests during the early and mid-Holocene; and the altitudinal shifts of the vegetation belts in the main mountain ranges, are reflected in our models with great level of detail. Various areas are suggested to have been prominent as refugia for thermophilous vegetation, including the northeast of the Iberian Peninsula and the Atlantic coast of northern Spain and Portugal. The simulations presented here also provide new insights into the postglacial pathways of various vegetation types and offer a historical explanation for the present-day relict presence of taxa that remained unexplained or unexpected until now. Multiple palaeobotanical records are presented to validate the biogeographic patterns indicated by the simulations.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"351 ","pages":"Article 109162"},"PeriodicalIF":3.2,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159949","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":"Climate-controlled distribution of erosion over the Himalaya in the late Quaternary: Evidence from Sr-Nd isotope variability in paleo-Yamuna channel sediments","authors":"Mohd Amir ,&nbsp;Debajyoti Paul ,&nbsp;Shouye Yang ,&nbsp;Yuan-Pin Chang","doi":"10.1016/j.quascirev.2024.109179","DOIUrl":"10.1016/j.quascirev.2024.109179","url":null,"abstract":"<div><div>Over the millennial timescales, climate controls erosion rates and erosional fluxes in the Himalaya. However, the role of climate, particularly the strength of the Indian summer monsoon (ISM) and Himalayan glacial cover, on the distribution of erosion over the Himalaya is poorly understood. This study presents detrital radiogenic Sr-Nd isotope compositions in two ∼48 m long cores representing sediment deposition in a paleo-Yamuna River channel, northwest India (Haryana), since marine isotope stage (MIS) 4. ⁸⁷Sr/⁸⁶Sr (0.7342–0.8066) and ε_Nd (−14.0 to −19.7) values exhibit significant down-core variabilities and reveal varying proportions of sediments derived from the Higher and Lesser Himalayan sources. The down-core profiles show higher ⁸⁷Sr/⁸⁶Sr and lower ε_Nd during MIS 4, mid-MIS 3, and last glacial maximum in MIS 2, which indicate reduced contribution of sediments from the Higher Himalaya during cold and arid periods typified by weaker ISM precipitation and increased glacial cover over the Himalaya. Further, the paleo-Yamuna record and a few available records on the Himalayan-derived sediments suggest that variations in local geology, topography, and location of the focused precipitation in a catchment could also influence erosion distribution.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"351 ","pages":"Article 109179"},"PeriodicalIF":3.2,"publicationDate":"2025-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159954","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":"Knysna Eastern Heads Cave 1 – Stratigraphy, chronology, and archaeological find density from MIS 3 to MIS 1 on the edge of the Palaeo-Agulhas Plain (south coast, South Africa)","authors":"Naomi E. Cleghorn ,&nbsp;Ximena Villagran ,&nbsp;Rosaria B.K. Saktura ,&nbsp;Zenobia Jacobs","doi":"10.1016/j.quascirev.2024.109180","DOIUrl":"10.1016/j.quascirev.2024.109180","url":null,"abstract":"<div><div>Knysna Eastern Heads Cave 1 (KEH-1), a south-facing archaeological site on the southern coast of South Africa preserves the first record directly relevant to the lives and environments of people living on the edge of the Palaeo-Agulhas Plain (PAP) from later Marine Isotope Stage (MIS) 3 after ∼45 thousand years ago (ka) and continuing throughout the Last Glacial Maximum (LGM, 26.5–19 ka). This stratified deposit dated from at least ∼45 ka until ∼15 ka (modelled ages), includes periods of intensive site use by human forager populations from ∼34 ka to ∼19 ka and during the Holocene. Here we present a synthesis of the stratigraphy, chronology, and archaeological find distribution, including estimates of relative find density over time. We show that forager populations exploited coastal resources during late MIS 3. This contrasts with a subsequent and prolonged period of intensive site use during the LGM when foragers shifted their focus more to terrestrial resources. KEH-1 bridges a critical chronological gap between key Middle Stone Age (MSA) and Later Stone Age (LSA) archaeological sites along the southern coast and provides the first evidence of an intensive and continuous record of occupation on the edge of the PAP near the end of the Pleistocene. This result provides the first archaeological record explicitly tested against a recently published dynamic model of the PAP ecosystem that predicts relatively high concentrations of human foragers on the plain during the LGM. Given the continuity of the KEH-1 archaeological record and its contemporaneity with multiple technological transitions known from archaeological sites across southern Africa, the site is important to interpretations of the MSA to LSA transition. Further, the temporal overlap between KEH-1 and the deep inland sequence at Boomplaas Cave, as well as the later MIS 2 deposits at nearby Nelson Bay Cave provides an important expansion of the Western Cape regional archaeological record.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"351 ","pages":"Article 109180"},"PeriodicalIF":3.2,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143159951","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":"Glacial geology of the Hudson Mountains, Amundsen Sea sector, West Antarctica","authors":"Joanne S. Johnson ,&nbsp;Keir A. Nichols ,&nbsp;Teal R. Riley ,&nbsp;Ryan A. Venturelli ,&nbsp;Dominic A. Hodgson ,&nbsp;Greg Balco ,&nbsp;Brenda Hall ,&nbsp;James A. Smith ,&nbsp;John Woodward","doi":"10.1016/j.quascirev.2024.109027","DOIUrl":"10.1016/j.quascirev.2024.109027","url":null,"abstract":"<div><div>The Hudson Mountains are situated in the eastern Amundsen Sea sector of the West Antarctic Ice Sheet, adjacent to Pine Island Glacier. They form a volcanic field of 17 stratovolcanoes and parasitic vents, preserved as nunataks. Two former tributaries of Pine Island Glacier (Larter and Lucchitta glaciers) flow through the mountains. Here we present a detailed study of the glacial geology of the area. We describe field observations and measurements of geomorphological features from 15 of the nunataks, meltwater ponds found on the surface of three nunataks and supraglacial features (ice dolines) from two sites near the present grounding line. Together these provide constraints on the past ice sheet extent, flow pathways and thermal regime, and enhance our understanding of the present hydrological regime – all of which are important as context for the observed modern ice sheet behaviour.</div><div>We find evidence suggesting that all nunataks in the Hudson Mountains were covered by ice during the Last Glacial Maximum (defined here as 26.5-19 ka; Clark et al., 2009) and have since deglaciated. Faceted and polished erratic cobbles and boulders of exotic lithologies (syenites, alkali granites, granites, granodiorites, tonalites and gabbros) are numerous and perched on nunatak surfaces. A marked difference between the dominant erratic lithologies on nunataks adjacent to Pine Island Glacier (granite) and Lucchitta Glacier (granodiorite-tonalite) indicates that the ice sheet was transporting clasts from at least two distinct upstream source regions. The similarity in degree of weathering suggests, however, that all the erratics were transported by one phase of (warm-based) glaciation; their presence on or close to the summits of all except one nunatak indicates that the ice sheet during that time was at least 700 m thicker than present. These results are consistent with ice sheet model simulations which suggest that all nunataks in the Hudson Mountains were completely submerged by the Last Glacial Maximum ice sheet.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"350 ","pages":"Article 109027"},"PeriodicalIF":3.2,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136571","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":"Environmental and provenance variations in borehole core CSH-01B from the western edge of the North Yellow Sea: Responses to tectonic movements since the late pliocene","authors":"Zhi-Xian Tian ,&nbsp;Yong Zhang ,&nbsp;Wei Xiong ,&nbsp;Bei-Bei Mi ,&nbsp;Zhong-Lei Wang ,&nbsp;Shi-Pu Bi ,&nbsp;Jing-Yi Cong ,&nbsp;Xi Mei","doi":"10.1016/j.quascirev.2024.109164","DOIUrl":"10.1016/j.quascirev.2024.109164","url":null,"abstract":"<div><div>To better understand the coupling between sedimentary and tectonic evolution in the East China continental margin, a 120.44-m-long borehole core designated CSH-01B was retrieved from the western margin of the North Yellow Sea. Paleomagnetic measurements revealed B/M, M/G and G/Gil boundaries at depths of 34.82 m, 86.58 m, and 119.98 m, respectively, yielding an extrapolated basal age of ∼3.6 Ma. Alongside systematic investigations encompassing lithofacies discrimination, microfossil examination, and provenance identification based on detrital zircon U‒Pb dating, the studied core was compared with extensively researched boreholes in the Yellow–Bohai Sea region. The sedimentary environment of the North Yellow Sea shifted since ∼2.0 Ma from long-term lacustrine sequences with episodic fluvial deposition, akin to those in the Bohai Sea, to alternating fluvial and marine facies, resembling those in the South Yellow Sea. Additionally, sediments derived from south of the Qianliyan Uplift emerged, in contrast to those primarily delivered by outflows from the Bohai Paleolake previously. Therefore, the Qianliyan Uplift dividing the Yellow Sea must have subsided and/or collapsed at ∼2.0 Ma. Concomitantly, the North and South Yellow Seas experienced subsidence and uplift, respectively, as indicated by their contrasting deposition rate trends. Quaternary marine transgressions began at ∼1.7 Ma were hindered from affecting the Bohai Sea by the Miaodao Uplift until its subsidence and/or fragmentation during the Jaramillo subchron, along with the central South Yellow Sea, establishing a low-lying topographic corridor. Additionally, the provenance analysis in this study contributes new insights into the long-debated evolutionary history of the Yellow River. The prototype of the modern Yellow River must have emerged no later than 2.4 Ma and experienced an interruption at approximately 1.4 Ma. With the commencement of the large-scale marine transgression at ∼0.8 Ma, the reintegrated Yellow River started to influence the East China continental margin widely and constantly.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"350 ","pages":"Article 109164"},"PeriodicalIF":3.2,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137031","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":"Molluscan isotope sclerochronology in marine palaeoclimatology: Taxa, technique and timespan issues","authors":"Andrew L.A. Johnson ,&nbsp;Bernd R. Schöne ,&nbsp;Sierra V. Petersen ,&nbsp;Niels J. de Winter ,&nbsp;Harry J. Dowsett ,&nbsp;Jean-François Cudennec ,&nbsp;Elizabeth M. Harper ,&nbsp;Ian Z. Winkelstern","doi":"10.1016/j.quascirev.2024.109068","DOIUrl":"10.1016/j.quascirev.2024.109068","url":null,"abstract":"<div><div>Study of the accretionary biomineralised hardparts of organisms (sclerochronology) can make a useful contribution to palaeoclimatology. Ontogenetic sequences of isotopic data (δ¹⁸O and Δ₄₇ values) from the shells of marine molluscs are a source of information on seasonal sea-surface temperatures that can be used for detailed and rigorous evaluation of the outputs of numerical climate models. In situations where there is significant seasonality, and where shell preservation is adequate, accurate information about winter and summer surface temperature can be obtained from shallow-water benthic forms (bivalves and gastropods), in particular the early ontogeny of fast-growing species. Accurate information about winter surface temperature can also be obtained from individuals that lived at mid-shelf depths (20–40 m), but summer seafloor values from these need upward adjustment to derive a plausible surface temperature if thermal stratification of the water column occurs in this season. Ontogenetic δ¹⁸O profiles from planktonic pteropod gastropods are a potential source of insight into seasonal surface temperatures in the ocean basins; these organisms merit investigation for provision of information to complement shelf data.</div><div>Temperature profiles constructed from shell δ¹⁸O require an estimate of the δ¹⁸O value of ambient seawater, which can be derived by back-calculation from the Δ₄₇-temperature supplied by the same shell material. Alternatively, through appropriate sampling and data processing, seasonal temperatures can be obtained directly from Δ₄₇ profiles. Climate parameters are defined in terms of the mean state over a period of 30 consecutive years, a statistic (e.g., for seasonal temperatures) which can be derived from the long isotopic temperature records obtainable from bivalve species that live for many tens or hundreds of years. Efforts should be made to acquire such records, especially averaged data from crossdated shells, to specify climate parameters for precise times in the past. Information for precise times would be of particular value for icehouse intervals like the late Cenozoic, characterised by high frequency (high amplitude) climate fluctuation. Short records from non-crossdated shells can nevertheless provide useful insights into climate, particularly if a large dataset is obtained, supplying a reliable picture of the mean state and range of variation in climate parameters over the interval represented by the shells.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"350 ","pages":"Article 109068"},"PeriodicalIF":3.2,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137054","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":"Dammed lake chronology in the middle Yarlung Tsangpo River: Tracing the origin of late Holocene megafloods","authors":"Anna Yang ,&nbsp;Weiming Liu ,&nbsp;Hao Wang ,&nbsp;Kaiheng Hu ,&nbsp;Xuemei Li ,&nbsp;Lu Cong ,&nbsp;Yanlian Zhou ,&nbsp;Zewen Yang","doi":"10.1016/j.quascirev.2024.109155","DOIUrl":"10.1016/j.quascirev.2024.109155","url":null,"abstract":"<div><div>Failure of natural dams on major rivers has caused some of the most destructive freshwater floods on Earth and other planets. Previous studies have identified two Holocene outburst floods in the middle reaches of the Yarlung Tsangpo, along with upstream lacustrine deposits, termed Zangga dammed lake in this study, but it has not been possible to disentangle their causal relationship due to the lack of a robust chronology. The sedimentological similarity between lacustrine deposits of river blockage and aeolian loess formed from proximal materials in the heavily braided river, make it very challenging to re-establish the evolution of dammed lake. This study aims to clarify the origin of megafloods in the middle reach of the Yarlung Tsangpo River by establishing a chronology for Zangga dammed lake based on 12 robust optically stimulated luminescence (OSL) ages from well-defined lacustrine, loess and aeolian deposits. Our results provide hard evidence for repeated river blocking and dam failure events in the middle reach of the Yarlung Tsangpo River, which corresponds well with downstream two megaflood events. Continuous clay varve accumulation indicated that the Zangga dammed lake grew back during 7.5–4.6 ka and generally stable and has persisted at least 3 ka. It is speculated that Zangga dammed lake collapsed during the late Holocene altithermal period, leading to catastrophic outburst flood events in the Yarlung Tsangpo. The age of 7.5–4.6 ka for lake formation means a glacier/moraine mechanism of river blocking is unlikely, as their extent was much reduced, instead landslides were the major blocking agent. Our study provides crucial insights into the complex chronology of dammed-lake events in the middle reach of the Yarlung Tsangpo. Identification of lacustrine sediments, along with OSL dating, has allowed for a more accurate reconstruction of lake evolution. Understanding these dynamics is vital for assessing the potential risks associated with future dammed-lake collapses and their consequential megafloods.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"350 ","pages":"Article 109155"},"PeriodicalIF":3.2,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136568","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":"Orbital forcing on paleo-productivity in the northern South China sea during the late Pleistocene","authors":"Ye Xu ,&nbsp;Bao-Hua Li ,&nbsp;Qi Cui","doi":"10.1016/j.quascirev.2024.109170","DOIUrl":"10.1016/j.quascirev.2024.109170","url":null,"abstract":"<div><div>Unraveling marine productivity and its driving forces is crucial for understanding the ocean carbon cycle. In this study, we present data on the relative abundance of planktonic foraminifer <em>Globigerina bulloides</em>, the ratio of mixed-layer species to thermocline species, the thermal gradient of upper water column, δ¹⁸O_residual, TOC content, and TOC/TN ratio in the northern South China Sea over the past 350 kyr. These proxies provide insights into the variations and forces on marine paleo-productivity. Our results show distinct glacial-interglacial cyclicity superimposed with precession-driven variability in the paleo-productivity record. On a glacial-interglacial timescale, enhanced paleo-productivity coincided with increased terrestrial nutrient matter input during glacial sea-level lowstands and strong mixing of the upper water column caused by the intensified glacial East Asian winter monsoon. On a precession timescale, greater East Asian summer monsoon intensity, coupled with the relatively unstable upper water column due to increased surface water salinity during insolation maxima, promoted strong mixing of the upper water column, thereby enhancing paleo-productivity. Furthermore, paleo-productivity may be constrained by low insolation and a relatively stable upper water column during periods of intensified East Asian winter monsoon on a precession timescale. We propose that terrestrial nutrient matter input and upper water mixing caused by the East Asian monsoon play a crucial role in paleo-productivity changes in the northern SCS on glacial-interglacial and precession timescales, respectively.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"350 ","pages":"Article 109170"},"PeriodicalIF":3.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143137130","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}