Environmental responses to Lateglacial climatic fluctuations recorded in the sediments of pre‐Alpine Lake Mondsee (northeastern Alps)     

Stefan Lauterbach  Achim Brauer  Nils Andersen  Dan L. Danielopol  Peter Dulski  Matthias Hüls  Krystyna Milecka  Tadeusz Namiotko  Milena Obremska  Ulrich Von Grafenstein  Declakes Participants 《第四纪科学杂志》2011,26(3):253-267

Investigation of the sedimentary record of pre‐Alpine Lake Mondsee (Upper Austria) focused on the environmental reaction to rapid Lateglacial climatic changes. Results of this study reveal complex proxy responses that are variable in time and influenced by the long‐term evolution of the lake and its catchment. A new field sampling approach facilitated continuous and precisely controlled parallel sampling at decadal to sub‐annual resolution for µ‐XRF element scanning, carbon geochemistry, stable isotope measurements on ostracods, pollen analyses and large‐scale thin sections for microfacies analysis. The Holocene chronology is established through microscopic varve counting and supported by accelerator mass spectrometry ¹⁴C dating of terrestrial plant macrofossils, whereas the Lateglacial age model is based on δ¹⁸O wiggle matching with the Greenland NGRIP record, using the GICC05 chronology. Microfacies analysis enables the detection of subtle sedimentological changes, proving that depositional processes even in rather large lake systems are highly sensitive to climate forcing. Comparing periods of major warming at the onset of the Lateglacial and Holocene and of major cooling at the onset of the Younger Dryas reveals differences in proxy responses, reflecting threshold effects and ecosystem inertia. Temperature increase, vegetation recovery, decrease of detrital flux and intensification of biochemical calcite precipitation at the onset of the Holocene took place with only decadal leads and lags over a ca. 100 a period, whereas the spread of woodlands and the reduction of detrital flux lagged the warming at the onset of the Lateglacial Interstadial by ca. 500–750 a. Cooling at the onset of the Younger Dryas is reflected by the simultaneous reaction of δ¹⁸O and vegetation, but sedimentological changes (reduction of endogenic calcite content, increase in detrital flux) were delayed by about 150–300 a. Three short‐term Lateglacial cold intervals, corresponding to Greenland isotope substages GI‐1d, GI‐1c2 and GI‐1b, also show complex proxy responses that vary in time. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Cosmogenic 10Be insights into the extent and chronology of the last deglaciation in Wester Ross,northwest Scotland     

Deborah C. McCormack  Simon H. Brocklehurst  Duncan H.B. Irving  Derek Fabel 《第四纪科学杂志》2011,26(1):97-108

Cosmogenic ¹⁰Be surface exposure ages for bedrock sites around Torridon and the Applecross Peninsula in Wester Ross, northwest Scotland, provide new insights into the Lateglacial transition. Accounting for postglacial weathering, six statistically comparable exposure ages give a late Younger Dryas (G‐1) exposure age of 11.8 ± 1.1 ka. Two further outliers are tentative pre‐Younger Dryas exposure ages of 13.4 ± 0.5 ka in Torridon, and 17.5 ± 1.2 ka in Applecross. The Younger Dryas exposure ages have compelling implications for the deglaciation of marginal Loch Lomond Stadial ice fields in Torridon and Applecross. Firstly, they conflict with predictions of restricted ice cover and rapid retreat based on modelling experiments and climate proxies, instead fitting a model of vertically extensive and prolonged ice coverage in Wester Ross. Secondly, they indicate that >2 m of erosion took place in the upper valleys of Torridon and Applecross during the Younger Dryas, implying a dominantly warm‐based glacial regime. Finally, the exposure ages have clarified that corrie (cirque) glaciers did not readvance in Wester Ross, following final deglaciation. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Surface exposure dating (36Cl and 10Be) of post‐Last Glacial Maximum valley moraines,Lake District,northwest England: some issues and implications     

PETER WILSON  CHRISTOPH SCHNABEL  KLAUS M. WILCKEN  PETER J. VINCENT 《第四纪科学杂志》2013,28(4):379-390

  相似文献   

Holocene and Lateglacial relative sea‐level change in north‐west England: implications for glacial isostatic adjustment models     

Jeremy M. Lloyd  Yongqiang Zong  Paul Fish  James B. Innes 《第四纪科学杂志》2013,28(1):59-70

Relative sea‐level (RSL) change is reconstructed for central Cumbria, UK, based on litho‐ and biostratigraphical analysis from the Lateglacial to the late Holocene. The RSL curve is constrained using ten new radiocarbon‐dated sea‐level index points in addition to published data. The sea‐level curve identifies a clear Lateglacial sea‐level highstand approximately 2.3 m OD at c. 15–17 k cal a BP followed by rapid RSL fall to below ?5 m OD. RSL then rose rapidly during the early Holocene culminating in a mid‐Holocene highstand of approximately 1 m OD at c. 6 k cal a BP followed by gradual fall to the present level. These new data provide an important test for the RSL predictions from glacial isostatic adjustment models, particularly for the Lateglacial where there are very little data from the UK. The new RSL curve shows similar broad‐scale trends in RSL movement predicted by the models. However, the more recent models fail to predict the Lateglacial sea level highstand above present reconstructed by the new data presented here. Future updates to the models are needed to reduce this mismatch. This study highlights the importance for further RSL data to constrain Lateglacial sea level from sites in northern Britain. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Pliocene‐Quaternary history of Futuna Island,south Vanuatu,southwest Pacific     

G. Neef  M. T. McCulloch 《Australian Journal of Earth Sciences》2013,60(6):805-814

U‐series ages from thermal ionisation mass spectrometry are reported here for the raised coral reefs of Futuna Island, which lies adjacent to the eastern margin of the backarc Futuna Trough in south Vanuatu, southwest Pacific. U‐series ages from coral from the lowest raised reef indicate that its upper part is most likely to be ca 210 ka, whereas the most elevated raised reef has a likely age of ca 520 ka (range 600–440 ka). The inferred Pliocene‐Quaternary history for Futuna Island and the adjacent Futuna Trough is: (i) formation of the Pliocene—Early Quaternary basaltic‐andesite cone in a southeast part of the Vanuatu Island Arc; (ii) inception of the Futuna Trough (adjacent to the west margin of Futuna Island) since 1.8 Ma; (iii) subsequent uplift of the volcanic cone above sea‐level caused ～500 m of its upper part to be removed by marine erosion; (iv) the island then subsided and at least 160 m of limestone was deposited on the truncated cone; and (v) during the period 520 ka to ca 210 ka seven fringing reefs formed at the margin of the cone as the island was uplifted. Since ca 210 ka Futuna further subsided and, as a result, the post ca 210 ka history of the island is obscure.  相似文献   

Coversand and Pleistocene palaeosols in the Landes region,southwestern France     

Pascal Bertran  Giselle Allenet  Thierry Gé  Filipa Naughton  Philippe Poirier  Maria F. Sanchez Goñi 《第四纪科学杂志》2009,24(3):259-269

New sections in the coversand of the Landes region, southwestern France, show at least two main depositional phases corresponding to the Upper Pleniglacial and the Lateglacial, which are separated by palaeosols. The lower palaeosol, a gleyic to histic cryosol overlying a net of sand wedges and dated to ca. 23 ¹⁴C ka BP, testifies to a short occurrence of permafrost. Impeded drainage due to the frozen subsoil is assumed to be the main factor involved in lowered aeolian transport and soil formation. Pollen analysis indicates a shrub tundra‐type environment. The overlying coversand unit is associated with small transverse ridges or sheet‐like deposits, and corresponds to the maximal extension of the sands, Upper Pleniglacial in age. An incipient podzol developed on the dunes under a boreal pine forest, and has been dated to 11.5–12 ¹⁴C ka BP, i.e. to the Allerød period. This has been buried by the second coversand unit during the Younger Dryas, typified by abundant denivation features and root imprints. Although preliminary, the chronology of sand deposition in the Landes region appears thus to be roughly similar to that found for the other European coversands, showing that all were the result of similar western European climatic changes, i.e. repeated episodes of increasing aridity related to the Upper Pleniglacial and the Younger Dryas episode. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

白洋淀地区晚冰期以来的气候和环境演变     

王娜  许清海  张生瑞  阳小兰  王丹丹  孙沅浩  王涛 《地理学报》2022,77(5):1195-1210

华北平原晚冰期以来气候环境演变研究对该地区社会发展、灾害风险评估和科学应对未来全球增温背景下极端降水和洪涝事件具有重要意义。本文以华北平原中部白洋淀地区高阳剖面（BG-2019）为研究对象,通过高精度AMS¹⁴C、OSL定年技术和高分辨率孢粉组合、粒度组分分析,恢复和重建了白洋淀地区晚冰期以来（距今13710 a—今）区域植被演替和气候环境变化历史。结果显示：BG-2019剖面在距今10270~13710 a和距今4630~5400 a发育湖相沉积,距今3470~3700 a发育沼泽相沉积;距今7130~8000 a发育河流—入湖三角洲相沉积,距今3700~4630 a和距今3230~3470 a发育河流相沉积;距今8000~10270 a和距今5400~7130 a存在明显的沉积间断/地层缺失;表明采样剖面所在位置缺乏连续的湖相地层。晚冰期白洋淀为局地小湖沼;中全新世湖沼较发育、范围广,但也不是连续广袤的湖相沉积;晚全新世湖泊范围收缩。晚冰期和全新世白洋淀流域植被景观存在显著差异;晚冰期气候寒冷干燥,平原发育以蒿属、藜亚科、禾本科和菊科等为主的草地,周围山地森林覆盖度低;中全新世气候温暖湿润,平原大部仍发育以蒿属、藜亚科和禾本科为主的草地,湖区水蕨和水生植物繁盛,周围山地生长松属、栎属为主的针阔混交林,森林覆盖度增高;晚全新世气候温和偏干,平原仍是以蒿属、藜亚科和禾本科等为主的草地,西部山地生长以松属为主的针阔混交林,森林覆盖度较高。  相似文献   

Constraining the age of Lateglacial and early Holocene pollen zones and tephra horizons in southern Sweden with Bayesian probability methods     

B. Wohlfarth  M. Blaauw  S. M. Davies  M. Andersson  S. Wastegrd  A. Hormes  G. Possnert 《第四纪科学杂志》2006,21(4):321-334

  相似文献   

Late Weichselian fluvio‐aeolian sands and coversands of the type locality Grubbenvorst (southern Netherlands): sedimentary environments,climate record and age     

C. Kasse  D. Vandenberghe  F. De Corte  P. Van Den Haute 《第四纪科学杂志》2007,22(7):695-708

The Weichselian Late Pleniglacial and Lateglacial aeolian stratigraphy (Older Coversand I, Beuningen Gravel Bed, Older Coversand II, Younger Coversand I, Usselo Soil, Younger Coversand II) in the southern Netherlands has been reinvestigated in its type locality (Grubbenvorst). Sedimentary environments have been reconstructed and related to their climatic evolution based on periglacial structures. In addition, 22 optically stimulated luminescence (OSL) ages have been determined that provide an absolute chronology for the climatic evolution and environmental changes of the coversand area. From this work it appears that, prior to 25 ka fluvial deposition by the Maas dominated. After 25 ka fluvial activity reduced and deposition occurred in a fluvio‐aeolian environment with continuous permafrost (Older Coversand I). This depositional phase was dated between 25.2 ± 2.0 and 17.2 ± 1.2 ka. The upward increase of aeolian activity and cryogenic structures in this unit is related to an increase of climatic aridity and a decrease in sedimentation rate during the Last Glacial Maximum (LGM). The Beuningen Gravel Bed, that results from deflation with polar desert conditions and that represents a stratigraphic marker in northwestern Europe, was bracketed between 17.2 ± 1.2 and 15.3 ± 1.0 ka. Based on this age result a correlation with Heinrich event H1 is suggested. Permafrost degradation occurred at the end of this period. Optical ages for the Older Coversand II unit directly overlying the Beuningen Gravel Bed range from 15.3 ± 1.0 ka at the base to 12.7 ± 0.9 ka at the top. Thus this regionally important Older Coversand II unit started at the end of the Late Pleniglacial and continued throughout the early Lateglacial. Its formation after the Late Pleniglacial (LP) maximum cold and its preservation are related to rapid climatic warming around 14.7 ka cal. BP. The Allerød age of the Usselo Soil was confirmed by the optical ages. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Reconstruction of a complex late Quaternary glacial landscape in the Cordillera de Cochabamba (Bolivia) based on a morphostratigraphic and multiple dating approach     

Jan-Hendrik May  Jana Zech  Frank Preusser  Jaime Argollo  Heinz Veit 《Quaternary Research》2011,76(1):106-118

Although glacial landscapes have previously been used for the reconstruction of late Quaternary glaciations in the Central Andes, only few data exist for the Eastern Cordillera in Bolivia. Here, we present results from detailed morphostratigraphic mapping and new data of surface exposure dating (SED), optically stimulated luminescence (OSL), and radiocarbon dating (¹⁴C) from the Huara Loma Valley, Cordillera de Cochabamba (Bolivia). Discrepancies between individual dating methods could be addressed within the context of a solid geomorphic framework. We identified two major glaciations. The older is not well constrained by the available data, whereas the younger glaciation is subdivided into at least four major glacial stages. Regarding the latter, a first advance dated to ~ 29-25 ka occurred roughly contemporaneous with the onset of the global last glacial maximum (LGM) and was followed by a less extensive (re-)advance around 20-18 ka. The local last glacial maximum (LLGM) in the Huara Loma Valley took place during the humid lateglacial ~ 17-16 ka, followed by several smaller readvances until ~ 10-11 ka, and complete deglaciation at the end of the Early Holocene.  相似文献