Pub Date : 2024-11-23DOI: 10.1016/j.quascirev.2024.109091
Shuai Ma , Shengqian Chen , Jianhui Chen , Jie Chen , Dianbin Cao , Elena Xoplaki , Jürg Luterbacher , Fahu Chen , Wei Huang
Asian drylands encompass Arid Central Asia (ACA) and West Asia (WA), where water vapor transport is consistently governed by the westerlies. Recent research has identified a dipole pattern in Holocene hydroclimate changes between the ACA and WA, challenging previous assumptions of uniform hydroclimate shifts across the westerlies-dominated mid-latitudes of the Northern Hemisphere. However, the mechanisms behind the dipole pattern remain largely unknown. Our findings demonstrate that PMIP4 models accurately reproduced the dipole pattern, attributing it mainly to contrasting spring precipitation changes. From the middle to late Holocene, strengthened westerlies led to increased precipitation in the ACA. In contrast, rising spring solar insolation intensified the subtropical high, leading to reduced water vapor and increased descending air movement in WA, which decreased precipitation in the region. Our study suggests that WA is a distinctive region within the westerlies-dominated mid-latitudes, where low-latitude processes led to inconsistent precipitation variations from the middle to late Holocene.
{"title":"The Holocene precipitation dipole pattern in the Asian drylands: Mechanisms and processes from PMIP4 simulations and paleo-proxy evidence","authors":"Shuai Ma , Shengqian Chen , Jianhui Chen , Jie Chen , Dianbin Cao , Elena Xoplaki , Jürg Luterbacher , Fahu Chen , Wei Huang","doi":"10.1016/j.quascirev.2024.109091","DOIUrl":"10.1016/j.quascirev.2024.109091","url":null,"abstract":"<div><div>Asian drylands encompass Arid Central Asia (ACA) and West Asia (WA), where water vapor transport is consistently governed by the westerlies. Recent research has identified a dipole pattern in Holocene hydroclimate changes between the ACA and WA, challenging previous assumptions of uniform hydroclimate shifts across the westerlies-dominated mid-latitudes of the Northern Hemisphere. However, the mechanisms behind the dipole pattern remain largely unknown. Our findings demonstrate that PMIP4 models accurately reproduced the dipole pattern, attributing it mainly to contrasting spring precipitation changes. From the middle to late Holocene, strengthened westerlies led to increased precipitation in the ACA. In contrast, rising spring solar insolation intensified the subtropical high, leading to reduced water vapor and increased descending air movement in WA, which decreased precipitation in the region. Our study suggests that WA is a distinctive region within the westerlies-dominated mid-latitudes, where low-latitude processes led to inconsistent precipitation variations from the middle to late Holocene.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"347 ","pages":"Article 109091"},"PeriodicalIF":3.2,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722385","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}
Pub Date : 2024-11-23DOI: 10.1016/j.quascirev.2024.109083
Hailey Sinon , Mark Abbott , Eitan Shelef , Brad Rosenheim , Devon Firesinger , Melissa Griffore , Matt Finkenbinder , Bruce Finney , Mary Edwards
<div><div>The stability of arctic permafrost and the carbon it contains are currently threatened by a rapidly warming climate. Burial Lake, situated in northwestern arctic Alaska, is underlain by continuous permafrost and has a uniquely rich set of paleoclimate proxy data that comprise a 40-ka record of climate and environmental change extending well into Marine Isotope Stage (MIS) 3. Here, we examine the relationship between erosion, subsurface hydrology, and primary productivity from the Burial Lake sediments to improve our understanding of the links between climate, hydrology, sediment transport, and carbon mobility. The record is developed with radiocarbon (<sup>14</sup>C) age-offsets from two independent methods used to date the lake sediments: 1) <sup>14</sup>C measurements on paired bulk sediment and plant macrofossils from the same stratigraphic layer of lake sediment and 2) ramped pyrolysis-oxidation (RPO) <sup>14</sup>C analysis that separates fractions of organic carbon (OC) from a single bulk sediment sample based on thermochemical differences through continuous heating. As lakes capture and archive OC transported from the watershed, changes in the amount and relative age of permafrost-derived OC mobilized during past climatic variations can be documented by examining how age-offsets change over time. The Burial Lake sediment revealed higher age-offsets during the cold Last Glacial Maximum (LGM; ∼29-17 ka) than the comparatively warmer post-glacial (∼17 ka-present) and the MIS 3 interstadial (∼40-29 ka) periods. The relatively warm, wet climate of the post-glacial period promoted both terrestrial and aquatic productivity, resulting in increased OC deposition, and it likely favored transport via subsurface flow of dissolved OC (DOC) sourced from soils. This resulted in a greater flux of contemporary OC relative to ancient OC into the lake sediment, lowering the average age offset to ∼2 ka. In contrast, the low-productivity conditions of the LGM resulted in slow soil accumulation rates, leaving ancient OC in a shallower position in the soil profile and allowing it to be easily eroded in the form of particulate OC (POC). Although the amount of total OC deposited in the lakebed during the LGM is small relative to post-glacial deposition, the majority is ancient, which leads to a relatively high average age offset of ∼9 ka. Finally, climate and environmental conditions of the MIS 3 interstadial were intermediate between those of the post-glacial and the LGM. As with post-glacial sediments, a relatively large amount of OC is present; however, the vast majority of it is ancient (more similar to the LGM), and it produces an average age offset of ∼6 ka. The Burial Lake radiocarbon record demonstrates the complexities of the thaw and mobilization of permafrost OC in arctic Alaska, including the balance between production, transport, deposition, remobilization, and preservation. This record highlights the importance of considering factors that b
{"title":"Radiocarbon age-offset measurements reveal shifts in the transport mechanism and age of permafrost-derived organic carbon from Burial Lake, arctic Alaska from MIS 3 to present","authors":"Hailey Sinon , Mark Abbott , Eitan Shelef , Brad Rosenheim , Devon Firesinger , Melissa Griffore , Matt Finkenbinder , Bruce Finney , Mary Edwards","doi":"10.1016/j.quascirev.2024.109083","DOIUrl":"10.1016/j.quascirev.2024.109083","url":null,"abstract":"<div><div>The stability of arctic permafrost and the carbon it contains are currently threatened by a rapidly warming climate. Burial Lake, situated in northwestern arctic Alaska, is underlain by continuous permafrost and has a uniquely rich set of paleoclimate proxy data that comprise a 40-ka record of climate and environmental change extending well into Marine Isotope Stage (MIS) 3. Here, we examine the relationship between erosion, subsurface hydrology, and primary productivity from the Burial Lake sediments to improve our understanding of the links between climate, hydrology, sediment transport, and carbon mobility. The record is developed with radiocarbon (<sup>14</sup>C) age-offsets from two independent methods used to date the lake sediments: 1) <sup>14</sup>C measurements on paired bulk sediment and plant macrofossils from the same stratigraphic layer of lake sediment and 2) ramped pyrolysis-oxidation (RPO) <sup>14</sup>C analysis that separates fractions of organic carbon (OC) from a single bulk sediment sample based on thermochemical differences through continuous heating. As lakes capture and archive OC transported from the watershed, changes in the amount and relative age of permafrost-derived OC mobilized during past climatic variations can be documented by examining how age-offsets change over time. The Burial Lake sediment revealed higher age-offsets during the cold Last Glacial Maximum (LGM; ∼29-17 ka) than the comparatively warmer post-glacial (∼17 ka-present) and the MIS 3 interstadial (∼40-29 ka) periods. The relatively warm, wet climate of the post-glacial period promoted both terrestrial and aquatic productivity, resulting in increased OC deposition, and it likely favored transport via subsurface flow of dissolved OC (DOC) sourced from soils. This resulted in a greater flux of contemporary OC relative to ancient OC into the lake sediment, lowering the average age offset to ∼2 ka. In contrast, the low-productivity conditions of the LGM resulted in slow soil accumulation rates, leaving ancient OC in a shallower position in the soil profile and allowing it to be easily eroded in the form of particulate OC (POC). Although the amount of total OC deposited in the lakebed during the LGM is small relative to post-glacial deposition, the majority is ancient, which leads to a relatively high average age offset of ∼9 ka. Finally, climate and environmental conditions of the MIS 3 interstadial were intermediate between those of the post-glacial and the LGM. As with post-glacial sediments, a relatively large amount of OC is present; however, the vast majority of it is ancient (more similar to the LGM), and it produces an average age offset of ∼6 ka. The Burial Lake radiocarbon record demonstrates the complexities of the thaw and mobilization of permafrost OC in arctic Alaska, including the balance between production, transport, deposition, remobilization, and preservation. This record highlights the importance of considering factors that b","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"347 ","pages":"Article 109083"},"PeriodicalIF":3.2,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721723","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}
Pub Date : 2024-11-23DOI: 10.1016/j.quascirev.2024.109094
Yukun Fan , Jibao Dong , Zhongyi Liu , Xue Zhao , Yanyun Wang , Xianghui Kong , Qi Liu , Weijian Zhou , Xiaolin Hou
The larger dispersion of pre-nuclear Iodine-129/Iodine-127 (129I/127I) in terrestrial sediments and the complexity of environmental factors made terrestrial 129I dating extremely difficult. Sorting and dissociating possible influences will hopefully lead to a pattern of change in the pre-nuclear 129I/127I and accordingly an initial value for terrestrial dating. Here, we present the iodine isotope records of two loess-paleosol sections from Chinese Loess Plateau. The coupled variations of the 129I fluxes and other paleomagnetic field records, with known paleomagnetic excursions being clearly matched, indicated the prominent modulation of cosmogenic 129I production rate by paleomagnetic field, while the variation of 127I concentrations again verified the climate control. Discrepancies in amplitudes of 129I fluxes and other paleomagnetic field records were supposed to be a result of possible climate impact and organic matter degradation. These findings add new information to our knowledge of iodine-isotope composition, and are instructive for future study methodology.
{"title":"Geomagnetic field modulation of cosmogenic 129I recorded in Chinese loess sequences","authors":"Yukun Fan , Jibao Dong , Zhongyi Liu , Xue Zhao , Yanyun Wang , Xianghui Kong , Qi Liu , Weijian Zhou , Xiaolin Hou","doi":"10.1016/j.quascirev.2024.109094","DOIUrl":"10.1016/j.quascirev.2024.109094","url":null,"abstract":"<div><div>The larger dispersion of pre-nuclear Iodine-129/Iodine-127 (<sup>129</sup>I/<sup>127</sup>I) in terrestrial sediments and the complexity of environmental factors made terrestrial <sup>129</sup>I dating extremely difficult. Sorting and dissociating possible influences will hopefully lead to a pattern of change in the pre-nuclear <sup>129</sup>I/<sup>127</sup>I and accordingly an initial value for terrestrial dating. Here, we present the iodine isotope records of two loess-paleosol sections from Chinese Loess Plateau. The coupled variations of the <sup>129</sup>I fluxes and other paleomagnetic field records, with known paleomagnetic excursions being clearly matched, indicated the prominent modulation of cosmogenic <sup>129</sup>I production rate by paleomagnetic field, while the variation of <sup>127</sup>I concentrations again verified the climate control. Discrepancies in amplitudes of <sup>129</sup>I fluxes and other paleomagnetic field records were supposed to be a result of possible climate impact and organic matter degradation. These findings add new information to our knowledge of iodine-isotope composition, and are instructive for future study methodology.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"347 ","pages":"Article 109094"},"PeriodicalIF":3.2,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721724","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}
Pub Date : 2024-11-22DOI: 10.1016/j.quascirev.2024.109092
Emma D. Henderson, Ann S. Ojeda, Richard S. Vachula
Spheroidal carbonaceous particles (SCPs) are preserved in geologic archives such as lake sediments, ice cores, or peatlands, and can provide chronology for cores. SCPs are only produced during the combustion of coal and fuel oil, so they are a reliable global marker of the onset of industrialization and can be used to track deposition from these sources. While the usage of SCPs as chronostratigraphic indicators in recent sediments is common, the enumerative method of quantifying their sedimentary concentrations has remained virtually unchanged, and assumes that one subsample is representative of the entire sediment sample. We test this assumption and explore its implications for the SCP chronological method of dating recent sediments by analyzing multiple subsamples to characterize the precision and accuracy of SCP concentration measurements. Notably, we do not use the conventional SCP quantification method and focus on samples with lower concentrations and larger SCPs than are typically quantified in the literature. However, we base our conclusions and inferences on insights gained from analyses of the effects of subsampling on SCP numerosity (counts), which are translatable insights to all sizes and methods of SCPs quantification which rely on particle counts. We quantified SCPs in sets of 30 subsamples for 14 riverine sites (n = 420). SCP concentrations varied (0 SCPs/gDM – 2141±825 SCPs/gDM), but reflect the typical ranges of SCP concentrations quantified in modern sediments in other environmental settings. For each site, we used a bootstrapping method to approximate the theoretical mean of SCPs at 1–30 subsample sizes, then compared the theoretical mean and relative standard deviation. We found that enumerating 10 subsamples per sample better represents the theoretical mean of SCPs than the enumeration of 1 subsample, especially for lower SCP concentration samples. The greatest chance for falsely reporting the absence of SCPs was when <10 SCPs/gDM were measured in fewer than 10 subsamples, indicating that more replicates could provide greater confidence in SCP-based dating of geologic archives. If aiming to delineate the stratigraphic onset of SCP presence for dating purposes, we recommend enumerating a minimum of 10 subsamples for samples with low SCP concentrations to ensure the reliability of these measurements. We acknowledge that enumerating multiple subsamples is time and resource intensive, but provide some strategies (e.g., limiting subsampling) for minimizing additional cost and argue that the advantages afforded for dating reliability outweigh the costs in paleoenvironmental research.
{"title":"Testing assumptions of spheroidal carbonaceous particle (SCP) quantification at very low concentrations: Implications for dating geologic archives","authors":"Emma D. Henderson, Ann S. Ojeda, Richard S. Vachula","doi":"10.1016/j.quascirev.2024.109092","DOIUrl":"10.1016/j.quascirev.2024.109092","url":null,"abstract":"<div><div>Spheroidal carbonaceous particles (SCPs) are preserved in geologic archives such as lake sediments, ice cores, or peatlands, and can provide chronology for cores. SCPs are only produced during the combustion of coal and fuel oil, so they are a reliable global marker of the onset of industrialization and can be used to track deposition from these sources. While the usage of SCPs as chronostratigraphic indicators in recent sediments is common, the enumerative method of quantifying their sedimentary concentrations has remained virtually unchanged, and assumes that one subsample is representative of the entire sediment sample. We test this assumption and explore its implications for the SCP chronological method of dating recent sediments by analyzing multiple subsamples to characterize the precision and accuracy of SCP concentration measurements. Notably, we do not use the conventional SCP quantification method and focus on samples with lower concentrations and larger SCPs than are typically quantified in the literature. However, we base our conclusions and inferences on insights gained from analyses of the effects of subsampling on SCP numerosity (counts), which are translatable insights to all sizes and methods of SCPs quantification which rely on particle counts. We quantified SCPs in sets of 30 subsamples for 14 riverine sites (n = 420). SCP concentrations varied (0 SCPs/gDM – 2141±825 SCPs/gDM), but reflect the typical ranges of SCP concentrations quantified in modern sediments in other environmental settings. For each site, we used a bootstrapping method to approximate the theoretical mean of SCPs at 1–30 subsample sizes, then compared the theoretical mean and relative standard deviation. We found that enumerating 10 subsamples per sample better represents the theoretical mean of SCPs than the enumeration of 1 subsample, especially for lower SCP concentration samples. The greatest chance for falsely reporting the absence of SCPs was when <10 SCPs/gDM were measured in fewer than 10 subsamples, indicating that more replicates could provide greater confidence in SCP-based dating of geologic archives. If aiming to delineate the stratigraphic onset of SCP presence for dating purposes, we recommend enumerating a minimum of 10 subsamples for samples with low SCP concentrations to ensure the reliability of these measurements. We acknowledge that enumerating multiple subsamples is time and resource intensive, but provide some strategies (e.g., limiting subsampling) for minimizing additional cost and argue that the advantages afforded for dating reliability outweigh the costs in paleoenvironmental research.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"347 ","pages":"Article 109092"},"PeriodicalIF":3.2,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722384","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}
Pub Date : 2024-11-20DOI: 10.1016/j.quascirev.2024.109090
Yukun Zheng , Zhengyu Liu , Weipeng Zheng , Hongyan Liu
The classical Holocene temperature reconstruction indicates a cooling trend following the mid-Holocene thermal maximum. However, significant discrepancies exist between the temperature changes predicted by climate models and those derived from proxy data. Proxy sites are predominantly concentrated in the Northern Hemisphere mid-latitudes, where temperature variations align closely with global climate trends. Notably, in the Northern Hemisphere mid-latitudes, the differences between climate model simulations and proxy data are most pronounced. As such, the Northern Hemisphere mid-latitudes represent a crucial region for reconciling Holocene climate dynamics and addressing the Holocene temperature conundrum. Through an analysis of the latitudinal variation in solar radiation and its impact on temperature, this study underscores the pivotal role of this region in temperature reconstructions, particularly in resolving the ongoing discrepancies in Holocene temperature trends.
{"title":"Northern hemisphere mid-latitudes as a key region for reconciling the Holocene temperature conundrum","authors":"Yukun Zheng , Zhengyu Liu , Weipeng Zheng , Hongyan Liu","doi":"10.1016/j.quascirev.2024.109090","DOIUrl":"10.1016/j.quascirev.2024.109090","url":null,"abstract":"<div><div>The classical Holocene temperature reconstruction indicates a cooling trend following the mid-Holocene thermal maximum. However, significant discrepancies exist between the temperature changes predicted by climate models and those derived from proxy data. Proxy sites are predominantly concentrated in the Northern Hemisphere mid-latitudes, where temperature variations align closely with global climate trends. Notably, in the Northern Hemisphere mid-latitudes, the differences between climate model simulations and proxy data are most pronounced. As such, the Northern Hemisphere mid-latitudes represent a crucial region for reconciling Holocene climate dynamics and addressing the Holocene temperature conundrum. Through an analysis of the latitudinal variation in solar radiation and its impact on temperature, this study underscores the pivotal role of this region in temperature reconstructions, particularly in resolving the ongoing discrepancies in Holocene temperature trends.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"347 ","pages":"Article 109090"},"PeriodicalIF":3.2,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721729","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}
Pub Date : 2024-11-19DOI: 10.1016/j.quascirev.2024.109086
Hua Tu , Xinfeng Zhang , Lan Luo , Fei Xie , Fei Han , Zhongping Lai , Darryl E. Granger , Guanjun Shen
The Paleolithic site of Majuangou-III (MJG-III) in the Nihewan Basin, magnetostratigraphically dated to 1.66 million years ago (Ma), has been widely cited as documenting one of the earliest human settlements in China. Nevertheless, it remains important to cross-check the paleomagnetic dating with an independent and well-established radio-isotopic dating method. Here we report the application of 26Al/10Be burial dating to the Majuangou sites, assigning 1.28 ± 0.11 Ma (1σ), >1.49 Ma and close to 1.63 ± 0.09 Ma to Banshan, MJG-I and MJG-III, respectively. The proposed age sequence is supported by the general consistency between dates and stratigraphy as well as the consistency of dates between the samples from excavated cross-sections and those from deeply buried sediment cores. The age results agree with the previous magnetostratigraphy, providing the first radio-isotopic age for the earliest human occupation in high-latitude northern China.
位于泥河湾盆地的旧石器时代遗址马庄沟-III（MJG-III）的磁地层年代为距今 166 万年（Ma），被广泛认为是中国最早的人类聚落之一。尽管如此，用一种独立的、成熟的放射性同位素测年方法来核对古地磁测年仍然非常重要。在此，我们报告了 26Al/10Be 埋藏年代测定法在马庄沟遗址的应用情况，并将 1.28 ± 0.11 Ma (1σ)、>1.49 Ma 和接近 1.63 ± 0.09 Ma 的年代分别赋予半山、MJG-I 和 MJG-III。年代与地层之间的普遍一致性，以及出土断面样品与深埋沉积物岩心样品之间年代的一致性，都支持了所提出的年代序列。年代结果与之前的磁地层学结果一致，首次为中国北方高纬度地区最早的人类活动提供了放射性同位素年代。
{"title":"26Al/10Be burial dating of Majuangou sites in Nihewan Basin, northern China","authors":"Hua Tu , Xinfeng Zhang , Lan Luo , Fei Xie , Fei Han , Zhongping Lai , Darryl E. Granger , Guanjun Shen","doi":"10.1016/j.quascirev.2024.109086","DOIUrl":"10.1016/j.quascirev.2024.109086","url":null,"abstract":"<div><div>The Paleolithic site of Majuangou-III (MJG-III) in the Nihewan Basin, magnetostratigraphically dated to 1.66 million years ago (Ma), has been widely cited as documenting one of the earliest human settlements in China. Nevertheless, it remains important to cross-check the paleomagnetic dating with an independent and well-established radio-isotopic dating method. Here we report the application of <sup>26</sup>Al/<sup>10</sup>Be burial dating to the Majuangou sites, assigning 1.28 ± 0.11 Ma (1σ), >1.49 Ma and close to 1.63 ± 0.09 Ma to Banshan, MJG-I and MJG-III, respectively. The proposed age sequence is supported by the general consistency between dates and stratigraphy as well as the consistency of dates between the samples from excavated cross-sections and those from deeply buried sediment cores. The age results agree with the previous magnetostratigraphy, providing the first radio-isotopic age for the earliest human occupation in high-latitude northern China.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"346 ","pages":"Article 109086"},"PeriodicalIF":3.2,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697549","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}
Pub Date : 2024-11-19DOI: 10.1016/j.quascirev.2024.109070
Yanna Wang , Jinqing Zhou , Xiaoshuang Zhao , David Kaniewski , Nick Marriner , Alaa Salem , Jing Chen , Zhongyuan Chen
This study analyses diatom assemblages from a Nile Delta core (B-1) to probe Holocene hydroclimate changesand their influence on the ecological habitats of the delta coast, with a further focus on the effects of relative sea-level rise. We found that the freshwater diatom Aulacoseira granulata varied in tandem with hydroclimate pulses in the Nile watershed, driven by the shift of the Intertropical Convergence Zone (ITCZ), therefore serving as a proxy for palaeo-Nile flow. Based on the ecological affinities of diatom taxa, we defined 5 diatom assemblages (I-V). Assemblage I (>10.0-8.5 ka BP) shows high A. granulata abundance (60–80%), implying peak Nile flow during the African Humid Period (AHP), at least 3 times greater than that of the recent past. Assemblage II (8.5-7.5 ka BP) sees decreased A. granulata (20–40%) and emergence of freshwater diatoms with benthic-oligotrophic characteristics (e.g. Epithemia gibba), suggesting reduced Nile flow and a delta estuary where the habitat became shallower with lower nutrient content. Assemblage III (7.5-6.0 ka BP) shows A. granulata resurgence (50–80%), reflecting Nile hydroclimate variability post-AHP due to the migration of the Intertropical Convergence Zone (ITCZ). The high-resolution- diatom spectra of B-1 also revealed major habitat changes, from saline to fluvial-dominated environments, around 6.0 ka BP. Assemblage IV (6.0-3.2 ka BP) indicates a notable Nile flow decline and freshwater community proliferation, coinciding with coastal habitat expansion and delta progradation due to RSL stablisation and basin-wide aridification. Assemblage V (3.2-2.0 ka BP) is marked by drought-tolerant diatoms (Nitzchia amphibia, Hantzschia amphioxys and Cavinula cocconeiformis), indicating intensified aridification.
本研究分析了尼罗河三角洲岩芯（B-1）中的硅藻群，以探究全新世水文气候的变化及其对三角洲沿岸生态栖息地的影响，并进一步关注海平面相对上升的影响。我们发现，淡水硅藻 Aulacoseira granulata 随尼罗河流域水文气候脉冲的变化而变化，这是由热带辐合带（ITCZ）的移动所驱动的，因此可作为古尼罗河水流的替代物。根据硅藻类群的生态亲缘关系，我们定义了 5 个硅藻集合体（I-V）。集合体 I（10.0-8.5 ka BP）显示了较高的 A. granulata 丰度（60-80%），这意味着在非洲湿润期（AHP）尼罗河流量达到峰值，至少是近代尼罗河流量的 3 倍。第二组（8.5-7.5 ka BP）颗粒藻数量减少（20-40%），并出现了具有底栖-寡养特征的淡水硅藻（如 Epithemia gibba），这表明尼罗河流量减少，三角洲河口的生境变浅，营养物质含量降低。第 III 组（7.5-6.0 ka BP）显示了 A. granulata 的恢复（50-80%），反映了由于热带辐合带（ITCZ）的迁移造成的 AHP 后尼罗河水文气候的变化。B-1 的高分辨率硅藻谱图还显示，在公元前 6.0 kaP 前后，栖息地发生了重大变化，从盐碱环境变为以河流为主的环境。第四组（6.0-3.2 ka BP）表明尼罗河水流明显减少，淡水群落增多，同时由于 RSL 的稳定和全流域的干旱化，沿岸生境扩大，三角洲逐渐退化。组合 V（3.2-2.0 ka BP）的特征是耐旱硅藻（Nitzchia amphibia、Hantzschia amphioxys 和 Cavinula cocconeiformis），表明干旱化加剧。
{"title":"Reconstructing Holocene hydroclimate variability and coastal dynamics of the Nile Delta: A diatom perspective","authors":"Yanna Wang , Jinqing Zhou , Xiaoshuang Zhao , David Kaniewski , Nick Marriner , Alaa Salem , Jing Chen , Zhongyuan Chen","doi":"10.1016/j.quascirev.2024.109070","DOIUrl":"10.1016/j.quascirev.2024.109070","url":null,"abstract":"<div><div>This study analyses diatom assemblages from a Nile Delta core (B-1) to probe Holocene hydroclimate changesand their influence on the ecological habitats of the delta coast, with a further focus on the effects of relative sea-level rise. We found that the freshwater diatom <em>Aulacoseira granulata</em> varied in tandem with hydroclimate pulses in the Nile watershed, driven by the shift of the Intertropical Convergence Zone (ITCZ), therefore serving as a proxy for palaeo-Nile flow. Based on the ecological affinities of diatom taxa, we defined 5 diatom assemblages (I-V). Assemblage I (>10.0-8.5 ka BP) shows high <em>A. granulata</em> abundance (60–80%), implying peak Nile flow during the African Humid Period (AHP), at least 3 times greater than that of the recent past. Assemblage II (8.5-7.5 ka BP) sees decreased <em>A. granulata</em> (20–40%) and emergence of freshwater diatoms with benthic-oligotrophic characteristics (e.g. <em>Epithemia gibba</em>), suggesting reduced Nile flow and a delta estuary where the habitat became shallower with lower nutrient content. Assemblage III (7.5-6.0 ka BP) shows <em>A. granulata</em> resurgence (50–80%), reflecting Nile hydroclimate variability post-AHP due to the migration of the Intertropical Convergence Zone (ITCZ). The high-resolution- diatom spectra of B-1 also revealed major habitat changes, from saline to fluvial-dominated environments, around 6.0 ka BP. Assemblage IV (6.0-3.2 ka BP) indicates a notable Nile flow decline and freshwater community proliferation, coinciding with coastal habitat expansion and delta progradation due to RSL stablisation and basin-wide aridification. Assemblage V (3.2-2.0 ka BP) is marked by drought-tolerant diatoms (<em>Nitzchia amphibia, Hantzschia amphioxys</em> and <em>Cavinula cocconeiformis</em>), indicating intensified aridification.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"346 ","pages":"Article 109070"},"PeriodicalIF":3.2,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697543","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}
Pub Date : 2024-11-19DOI: 10.1016/j.quascirev.2024.109065
Véronique Michel , Fred Jourdan , Marie-Hélène Moncel , Bernard Gratuze , Guanjun Shen , Wei Wang , Celia Mayers , Adam Frew , Dominique Cauche , Patricia Valensi , Sylvain Gallet , Anatoly P. Derevianko , Alexander V. Kandyba , Sergey A. Gladyshev , Henry de Lumley
Bifacial tools discovered at about a hundred Lower Palaeolithic sites in the Bose Basin, southern China, have been previously dated to around 800,000 years ago. This age was obtained by dating four tektites directly associated with the tools at the Nalai site using the 40Ar/39Ar method (Michel et al., 2021). Similar ages on tektites from the Bogu and Yangwu sites had been previously published, albeit with limited analytical details, by Hou et al. (2000). In this study, a total of eight tektites, discovered alongside abundant lithic artefacts including bifacial tools, were dated with the 40Ar/39Ar technique, using an incremental temperature increase approach. Six of these tektites are from two Lower Palaeolithic sites in the Bose Basin; three from Xiaomei and three others from Fengshudao (China). The remaining two tektites come from two sites in Vietnam, one from Go Da and the other from Roc-Tung 1. With the exception of the site of Go Da, the tektites were buried in lateritic sediments associated with the stone tools. At the Go Da site, the tektites were found in a layer overlying the deposit containing bifacial tools. The tektites display no signs of fluvial abrasion or reworking, making them potentially strong chronological markers. Chemical analyses of major elements and rare earth elements indicate that the tektites belong to the Australasian tektite group. This is further confirmed by new 40Ar/39Ar analyses with a weighted mean age of 787.2 ± 8.2 ka (2σ) (MSWD = 0.96, P = 0.45). Therefore, when combined with the available results on Australasian tektites, this suggests a highly precise age of 788.0 ± 2.6 ka (2σ; P = 0.84) for these tektites and consequently, for the bifacial tools in this part of Southeast Asia, located east of the Movius Line. The presence of bifacial tools attests to either a diffusion of the Acheulean from Africa or a local emergence from previous occupations and traditions in Asia.
在中国南方博斯盆地约一百个下旧石器时代遗址中发现的双面工具，其年代已被确定为距今约 80 万年前。这一年代是通过使用 40Ar/39Ar 方法对纳莱遗址中与这些工具直接相关的四块沱石进行年代测定而得出的（Michel 等人，2021 年）。Hou等人（2000年）曾发表过博古遗址和扬武遗址出土的沱石的类似年代，尽管分析细节有限。在这项研究中，采用温度递增法，用 40Ar/39Ar 技术对与包括双面工具在内的大量石器一起发现的八块沱石进行了年代测定。其中六块岩石来自博斯盆地的两个下旧石器时代遗址；三块来自小梅，另外三块来自丰树岛（中国）。其余两块石器来自越南的两个遗址，一块来自 Go Da，另一块来自 Roc-Tung 1。除 Go Da 遗址外，其他鹤顶红都被埋在与石器相关的红土沉积物中。在 Go Da 遗址，箭石被发现于包含双面工具的沉积层之上。这些沱石没有任何被河水冲刷或再加工的痕迹，因此有可能成为强有力的年代标记。主要元素和稀土元素的化学分析表明，这些沱石属于澳大拉西亚沱石群。新的 40Ar/39Ar 分析进一步证实了这一点，其加权平均年龄为 787.2 ± 8.2 ka (2σ) (MSWD = 0.96, P = 0.45)。因此，结合澳大拉西亚沱石的现有结果，这表明这些沱石的年龄高度精确，为 788.0 ± 2.6 ka (2σ; P = 0.84)，因此，位于莫维乌斯线以东的东南亚地区的双面工具的年龄也高度精确。双面工具的出现证明了阿切列人是从非洲扩散过来的，或者是从亚洲以前的职业和传统中在当地出现的。
{"title":"High-precision 40Ar/39Ar dating of Australasian tektites associated with bifacial tools in the Bose Basin (Xiaomei and Fengshudao sites), South China and in Vietnam (Go Da and Roc Tung 1 sites)","authors":"Véronique Michel , Fred Jourdan , Marie-Hélène Moncel , Bernard Gratuze , Guanjun Shen , Wei Wang , Celia Mayers , Adam Frew , Dominique Cauche , Patricia Valensi , Sylvain Gallet , Anatoly P. Derevianko , Alexander V. Kandyba , Sergey A. Gladyshev , Henry de Lumley","doi":"10.1016/j.quascirev.2024.109065","DOIUrl":"10.1016/j.quascirev.2024.109065","url":null,"abstract":"<div><div>Bifacial tools discovered at about a hundred Lower Palaeolithic sites in the Bose Basin, southern China, have been previously dated to around 800,000 years ago. This age was obtained by dating four tektites directly associated with the tools at the Nalai site using the <sup>40</sup>Ar/<sup>39</sup>Ar method (Michel et al., 2021). Similar ages on tektites from the Bogu and Yangwu sites had been previously published, albeit with limited analytical details, by Hou et al. (2000). In this study, a total of eight tektites, discovered alongside abundant lithic artefacts including bifacial tools, were dated with the <sup>40</sup>Ar/<sup>39</sup>Ar technique, using an incremental temperature increase approach. Six of these tektites are from two Lower Palaeolithic sites in the Bose Basin; three from Xiaomei and three others from Fengshudao (China). The remaining two tektites come from two sites in Vietnam, one from Go Da and the other from Roc-Tung 1. With the exception of the site of Go Da, the tektites were buried in lateritic sediments associated with the stone tools. At the Go Da site, the tektites were found in a layer overlying the deposit containing bifacial tools. The tektites display no signs of fluvial abrasion or reworking, making them potentially strong chronological markers. Chemical analyses of major elements and rare earth elements indicate that the tektites belong to the Australasian tektite group. This is further confirmed by new <sup>40</sup>Ar/<sup>39</sup>Ar analyses with a weighted mean age of 787.2 ± 8.2 ka (2σ) (MSWD = 0.96, P = 0.45). Therefore, when combined with the available results on Australasian tektites, this suggests a highly precise age of 788.0 ± 2.6 ka (2σ; P = 0.84) for these tektites and consequently, for the bifacial tools in this part of Southeast Asia, located east of the Movius Line. The presence of bifacial tools attests to either a diffusion of the Acheulean from Africa or a local emergence from previous occupations and traditions in Asia.</div></div>","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"346 ","pages":"Article 109065"},"PeriodicalIF":3.2,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697541","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}
Pub Date : 2024-11-18DOI: 10.1016/j.quascirev.2024.109058
Elinor Andrén , Olena Vinogradova , Mikael Lönn , Simon Belle , Martin Dahl , Veronica Palm , Christos Katrantsiotis , Anne Birgitte Nielsen , Martin Jakobsson , Johan Rönnby , Thomas Andrén
<div><div>This study aims to investigate and disentangle the impact of land use and climate variability on the Baltic Sea coastal zone from a millennial perspective. To assess the environmental status of the coastal zone we make use of siliceous microfossils (mainly diatoms), stable nitrogen and carbon isotopes, organic carbon accumulation rates, and lithological changes analyzed in a sediment core collected in Gamlebyviken, Swedish east coast, dated to cover the last 3000 years. Changes in land use and vegetation cover are modelled using pollen stratigraphical data to obtain the percentage coverage of coniferous woodland (<em>Pinus</em> and <em>Picea</em>), deciduous woodland, wetland (Cyperaceae), grassland (including <em>Juniperus</em>) and cropland (cereals) while changes in climatic conditions are assessed through well-documented climatic periods that have occurred in the Baltic Sea region.</div><div>The reconstructed regional vegetation cover shows that already 3000 years ago, humans used the landscape for both animal husbandry (grasslands) and farming (cropland), but the impact on the Baltic coastal waters was minor. The diatom accumulation rates were quite high (∼3100–2600 cal yr BP) containing taxa indicative of high nutrient conditions/upwelling, and stable carbon isotopes show that the carbon was produced in the basin but did not result in elevated organic carbon accumulation rates. A gradual change to less marine conditions in Gamlebyviken from about 2500 to 1400 cal yr BP can be attributed to the ongoing land uplift which resulted in a more enclosed embayment with only a narrow inlet area today.</div><div>The Medieval Climate Anomaly (1000–700 cal yr BP/950–1250 CE) is a time where extensive eutrophication is registered in the open Baltic Sea, but afforestation is recorded between 1000 and 500 cal yr BP and attributed to the expansion of spruce favored by land-use reorganization with a transition from a one-course rotation system to the three-course rotation system fully established in southern Sweden in the 13th century, and only minor environmental change is recorded in the coastal zone.</div><div>The Little Ice Age is documented in our data between 400 and 250 cal yr BP/1550–1700 CE as a decrease in regional cropland (cereals) cover, possibly indicating years of poor crop harvest, and changes in the Baltic coastal zone are evidenced as low carbon and diatom accumulation rates, increase in benthic diatom taxa (low turbidity), and high abundance in diatom taxa associated with sea ice indicating a cold climate.</div><div>The most significant changes occurred from about 100 cal yr BP/1850 CE up to present, with a maximum regional cover of grassland and cropland (ca. 35%) at the expense of deciduous woodland, and major changes indicative of a highly eutrophic environment recorded in the coastal zone. Organic carbon accumulation rates peaked in 1968 CE at approximately 134 g C m<sup>2</sup> yr<sup>−1</sup> before subsequently declining
{"title":"Modern land use changes drive shifts in nutrient cycling and diatom assemblages in the Baltic Sea coastal zone: A millennial perspective with a case study from Gamlebyviken, Swedish east coast","authors":"Elinor Andrén , Olena Vinogradova , Mikael Lönn , Simon Belle , Martin Dahl , Veronica Palm , Christos Katrantsiotis , Anne Birgitte Nielsen , Martin Jakobsson , Johan Rönnby , Thomas Andrén","doi":"10.1016/j.quascirev.2024.109058","DOIUrl":"10.1016/j.quascirev.2024.109058","url":null,"abstract":"<div><div>This study aims to investigate and disentangle the impact of land use and climate variability on the Baltic Sea coastal zone from a millennial perspective. To assess the environmental status of the coastal zone we make use of siliceous microfossils (mainly diatoms), stable nitrogen and carbon isotopes, organic carbon accumulation rates, and lithological changes analyzed in a sediment core collected in Gamlebyviken, Swedish east coast, dated to cover the last 3000 years. Changes in land use and vegetation cover are modelled using pollen stratigraphical data to obtain the percentage coverage of coniferous woodland (<em>Pinus</em> and <em>Picea</em>), deciduous woodland, wetland (Cyperaceae), grassland (including <em>Juniperus</em>) and cropland (cereals) while changes in climatic conditions are assessed through well-documented climatic periods that have occurred in the Baltic Sea region.</div><div>The reconstructed regional vegetation cover shows that already 3000 years ago, humans used the landscape for both animal husbandry (grasslands) and farming (cropland), but the impact on the Baltic coastal waters was minor. The diatom accumulation rates were quite high (∼3100–2600 cal yr BP) containing taxa indicative of high nutrient conditions/upwelling, and stable carbon isotopes show that the carbon was produced in the basin but did not result in elevated organic carbon accumulation rates. A gradual change to less marine conditions in Gamlebyviken from about 2500 to 1400 cal yr BP can be attributed to the ongoing land uplift which resulted in a more enclosed embayment with only a narrow inlet area today.</div><div>The Medieval Climate Anomaly (1000–700 cal yr BP/950–1250 CE) is a time where extensive eutrophication is registered in the open Baltic Sea, but afforestation is recorded between 1000 and 500 cal yr BP and attributed to the expansion of spruce favored by land-use reorganization with a transition from a one-course rotation system to the three-course rotation system fully established in southern Sweden in the 13th century, and only minor environmental change is recorded in the coastal zone.</div><div>The Little Ice Age is documented in our data between 400 and 250 cal yr BP/1550–1700 CE as a decrease in regional cropland (cereals) cover, possibly indicating years of poor crop harvest, and changes in the Baltic coastal zone are evidenced as low carbon and diatom accumulation rates, increase in benthic diatom taxa (low turbidity), and high abundance in diatom taxa associated with sea ice indicating a cold climate.</div><div>The most significant changes occurred from about 100 cal yr BP/1850 CE up to present, with a maximum regional cover of grassland and cropland (ca. 35%) at the expense of deciduous woodland, and major changes indicative of a highly eutrophic environment recorded in the coastal zone. Organic carbon accumulation rates peaked in 1968 CE at approximately 134 g C m<sup>2</sup> yr<sup>−1</sup> before subsequently declining ","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"346 ","pages":"Article 109058"},"PeriodicalIF":3.2,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697542","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}
Pub Date : 2024-11-18DOI: 10.1016/j.quascirev.2024.109052
J.L. Hopkins , P.D. McIntosh , J. Vink , A. Slee , P. Moss
{"title":"Response to comments by Shane et al. (2024) on Hopkins, J.L., McIntosh, P.D., Vink, J., Slee, A. and Moss, P., 2024. First detection in Australia of cryptotephra likely to be derived from the 25.6 ka Ōruanui supereruption in New Zealand. Quaternary Science Reviews, 341 DOI: 10.1016/j.quascirev.2024.108856","authors":"J.L. Hopkins , P.D. McIntosh , J. Vink , A. Slee , P. Moss","doi":"10.1016/j.quascirev.2024.109052","DOIUrl":"10.1016/j.quascirev.2024.109052","url":null,"abstract":"","PeriodicalId":20926,"journal":{"name":"Quaternary Science Reviews","volume":"346 ","pages":"Article 109052"},"PeriodicalIF":3.2,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747850","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}
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