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| Registros recuperados: 21 | |
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| Toucanne, Samuel; Zaragosi, S.; Bourillet, Jean-francois; Gibbard, P. L.; Eynaud, F.; Giraudeau, J.; Turon, J. L.; Cremer, M.; Cortijo, E.; Martinez, P.; Rossignol, L.. |
| The correlation of continental sedimentary records with the marine isotope stratigraphy is a challenge of central importance in Quaternary stratigraphy, particularly in Western Europe where long records of glaciation on land areas are particularly rare. Here we demonstrate for the first time the interrelationship of events during the last 1.2 Ma in an ocean-sediment core from the Bay of Biscay (NE Atlantic), SW of the Channel. The identification of discharge variations from tributary river systems to the 'Fleuve Manche' palaeoriver during glacio-eustatic sea-level lowstands demonstrates the correlation of the marine sediment stratigraphy to the expansion and recession of the European ice-sheets. The amplitude and chronology of European ice-sheet... |
| Tipo: Text |
Palavras-chave: Middle pleistocene transition; Ice sheet dynamics; Sea level; Climate change; North Atlantic; English channel; Heinrich events; Fleuve manche; Deep; Origin. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6956.pdf |
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| Wiersma, Ane P.; Jongma, Jochem I.. |
| We investigate the potential role of icebergs in the 8.2 ka climate event, using a coupled climate model equipped with an iceberg component. First, we evaluate the effect of a large iceberg discharge originating from the decaying Laurentide ice sheet on ocean circulation, compared to a release of an identical volume of freshwater alone. Our results show that, on top of the freshwater effect, a large iceberg discharge facilitates sea-ice growth as a result of lower sea-surface temperatures induced by latent heat of melting. This causes an 8% increased sea-ice cover, 5% stronger reduction in North Atlantic Deep Water production and 1A degrees C lower temperature in Greenland. Second, we use the model to investigate the effect of a hypothetical two-stage lake... |
| Tipo: Text |
Palavras-chave: 8.2 ka event; Climate modeling; Icebergs; Laurentide ice sheet; Hudson Strait; Holocene; Heinrich events. |
| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00496/60749/65152.pdf |
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| Toucanne, Samuel; Zaragosi, S; Bourillet, Jean-francois; Naughton, F; Cremer, M; Eynaud, F; Dennielou, Bernard. |
| High-resolution sedimentological and micropaleontological studies of several deep-sea cores retrieved from the levees of the Celtic and Armorican turbidite systems (Bay of Biscay - North Atlantic Ocean) allow the detection of the major oscillations of the British-Irish Ice Sheet (BIIS) and 'Fleuve Manche' palaeoriver discharges over the last 30,000 years, which were mainly triggered by climate changes. Between 30 and 20 cal ka, the turbiditic activity on the Celtic-Annorican margin was weak, contrasting with previous stratigraphic models which predicted a substantial increase of sediment supply during low sea-level stands. This low turbidite deposit frequency was most likely the result of a weak activity of the 'Fleuve Manche' palaeoriver and/or of a... |
| Tipo: Text |
Palavras-chave: Turbidites; Heinrich events; LGM; Last deglaciation; Palaeoriver; Fleuve Manche; British irish ice sheet; Bay of Biscay. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-3729.pdf |
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| Hulbe, Cl; Macayeal, Dr; Denton, Gh; Kleman, J; Lowell, Tv. |
| Heinrich layers of the glacial North Atlantic record abrupt widespread iceberg rafting of detrital carbonate and other lithic material at the extreme-cold culminations of Bond climate cycles. Both internal (glaciologic) and external ( climate) forcings have been proposed. Here we suggest an explanation for the iceberg release that encompasses external climate forcing on the basis of a new glaciological process recently witnessed along the Antarctic Peninsula: rapid disintegrations of fringing ice shelves induced by climate-controlled meltwater infilling of surface crevasses. We postulate that peripheral ice shelves, formed along the eastern Canadian seaboard during extreme cold conditions, would be vulnerable to sudden climate-driven disintegration during... |
| Tipo: Text |
Palavras-chave: Heinrich events; Ice shelf disintegration. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00228/33921/32219.pdf |
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| Rashid, H; Hesse, R; Piper, Djw. |
| An additional Heinrich ice-rafting event is identified between Heinrich events 5 and 6 in eight cores from the Labrador Sea and the northwest Atlantic Ocean. It is characterized by sediment rich in detrital carbonate (40% CaCO3) with high concentration of floating dropstones, high coarse-fraction (% > 150 mum) content, and has a sharp contact with the underlying but grades into the overlying hemipelagic sediment. It also shows lighter delta(18)O(Npl) values, indicating freshening due to iceberg rafting and/or meltwater discharge. This event is correlated with Dansgaard-Oeschger event 14 and interpreted as an additional Heinrich event, H5a. The thickness of H5a in the Labrador Sea reaches up to 220 cm. This additional Heinrich event has also been... |
| Tipo: Text |
Palavras-chave: Heinrich events; Nepheloid flow deposits; GISP2; Dansgaard-Oeschger cycle; Labrador Sea. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/00225/33658/32098.pdf |
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| Bagniewski, Witold; Meissner, Katrin J.; Menviel, Laurie. |
| We present the first transient simulations of Marine Isotope Stage 3 (MIS 3) performed with an oxygen isotope-enabled climate model. Our simulations span several Dansgaard-Oeschger cycles and three Heinrich stadials and are directly compared with oxygen isotope records from 13 sediment and 2 ice cores. Our results are consistent with a 30-50% weakening of the Atlantic Meridional Overturning Circulation during Dansgaard-Oeschger stadials and a complete shutdown during Heinrich stadials. We find that the simulated delta O-18 anomalies differ significantly between Heinrich stadials and non-Heinrich stadials. This difference is mainly due to different responses in ocean circulation, and therefore climate, impacting oceanic delta O-18, while the volume of... |
| Tipo: Text |
Palavras-chave: MIS3; Model-data comparison; Heinrich events; Dansgaard-Oeschger cycles; Delta O-18; AMOC. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00420/53180/55067.pdf |
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| Hemming, Sidney R.. |
| Millennial climate oscillations of the glacial interval are interrupted by extreme events, the so-called Heinrich events of the North Atlantic. Their near-global footprint is a testament to coherent interactions among Earth's atmosphere, oceans, and cryosphere on millennial timescales. Heinrich detritus appears to have been derived from the region around Hudson Strait. It was deposited over approximately 500 +/- 250 years. Several mechanisms have been proposed for the origin of the layers: binge-purge cycle of the Laurentide ice sheet, jokulhlaup activity from a Hudson Bay lake, and an ice shelf buildup/collapse fed by Hudson Strait. To determine the origin of the Heinrich events, I recommend (1) further studies of the timing and duration of the events,... |
| Tipo: Text |
Palavras-chave: Climate; Heinrich layers; Heinrich events; Ice-rafted detritus. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00224/33549/32033.pdf |
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| Voelker, A. H. L.; De Abreu, L.; Schoenfeld, J.; Erlenkeuser, H.; Abrantes, F.. |
| The surface water hydrography along the western Iberian margin, as part of the North Atlantic's eastern boundary upwelling system, consists of a complex, seasonally variable system of equatorward and poleward surface and subsurface currents and seasonal upwelling. Not much information exists to ascertain if the modern current and productivity patterns subsisted under glacial climate conditions, such as during marine isotope stage (MIS) 2, and how North Atlantic meltwater events, especially Heinrich events, affected them. To help answer these questions we are combining stable isotope records of surface to subsurface dwelling planktonic foraminifer species with sea surface temperature and export productivity data for four cores distributed along the western... |
| Tipo: Text |
Palavras-chave: Iberian margin; Last Glacial Maximum; Heinrich events; Planktonic foraminifer; Stable isotopes; Productivity. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32906/31419.pdf |
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| Sierro, Fj; Hodell, Da; Curtis, Jh; Flores, Ja; Reguera, I; Colmenero-hidalgo, E; Barcena, Ma; Grimalt, Jo; Cacho, I; Frigola, J; Canals, M. |
| Down-core samples of planktonic and benthic foraminifera were analyzed for oxygen and carbon isotopes in International Marine Past Global Changes Study (IMAGES) core MD99-2343 in order to study the interactions between climate change in the Northern Hemisphere and the western Mediterranean thermohaline circulation at times of Heinrich events (HE). Our results confirm the antiphase correlation between enhanced North Atlantic Deep Water formation and low ventilation in the Mediterranean. However, this study reveals that this antiphase relationship in deepwater formation between the North Atlantic and Mediterranean was interrupted during times of HE when the injection of large volumes of water from melting icebergs reached the entrance to the Mediterranean.... |
| Tipo: Text |
Palavras-chave: Climatic change; Heinrich events; Mediterranean Sea; Carbon and oxygen isotopes; Thermohaline circulation; Pleistocene. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00232/34354/32759.pdf |
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| Lekens, W. A. H.; Sejrup, H. P.; Haflidason, H.; Knies, J.; Richter, T.. |
| [ 1] The timing of meltwater release in the southern Norwegian Sea in relation to millennial-scale climate variability is studied from core MD99-2283 based on down-core analysis of stable oxygen and carbon isotopes, calcium carbonate and ice-rafted debris (IRD). Between 20 and 40 calendar (cal) kyr B. P., strong Dansgaard-Oeschger cyclicity is expressed in increased carbonate content and reduced total organic carbon during warm interstadials and IRD marking the end of cold stadials. The planktonic delta(18)O record of core MD99-2283 compared to available isotopic records in the region confirms the existence of multisourced, synchronized meltwater anomalies during Heinrich ( H) events 2 to 4. It was found that the sudden release of meltwater occurs near... |
| Tipo: Text |
Palavras-chave: Meltwater; Nordic Seas; Heinrich events. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00234/34525/33431.pdf |
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| Bigg, Grant R.; Levine, Richard C.; Green, Clare L.. |
| The abrupt delivery of large amounts of freshwater to the North Atlantic in the form of water or icebergs has been thought to lead to significant climate change, including abrupt slowing of the Atlantic Ocean meridional overturning circulation. In this paper we examine intermediate complexity coupled modelling evidence to estimate the rates of change, and recovery, in oceanic climate that would be expected for such events occurring during glacial times from likely sources around the North Atlantic and Arctic periphery. We show that rates of climate change are slower for events with a European or Arctic origin. Palaeoceanographic data are presented to consider, through the model results, the origin and likely strength of major ice-rafting, or Heinrich,... |
| Tipo: Text |
Palavras-chave: Heinrich events; Modelling; Quaternary; Icebergs. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00227/33777/82665.pdf |
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| Hoffman, Jeremy Scott. |
| This dissertation explores one overarching question relevant to the paleoclimate of the latest Pleistocene glacial cycle (approximately the last 130,000 years): “How did spatial and temporal evolution of ocean temperature, both at the surface and interior, relate to other parts of the climate system in the late Pleistocene?” Results from three studies are presented that seek to address longstanding questions in paleoceanography and paleoclimatology for the late Pleistocene using a combination of novel and accepted statistical and geochemical analysis techniques and leveraging comparisons with available global climate model data. The last interglaciation (LIG; ~129-116 ka) was the most recent period in Earth’s history with higher-than-present global sea... |
| Tipo: Text |
Palavras-chave: Paleoclimate; Interglacial; Heinrich events; Deglacial; Paleoceanography; Climate. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00505/61702/65670.pdf |
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| Eynaud, Frederique; De Abreu, Lucia; Voelker, Antje; Schoenfeld, Joachim; Salgueiro, Emilia; Turon, Jean-louis; Penaud, Aurelie; Toucanne, Samuel; Naughton, Filipa; Goni, Maria Fernanda Sanchez; Malaize, Bruno; Cacho, Isabel. |
| This paper documents the migration of the Polar Front (PF) over the Iberian margin during some of the cold climatic extremes of the last 45 ka. It is based on a compilation of robust and coherent paleohydrological proxies obtained from eleven cores distributed between 36 and 42 degrees N. Planktonic delta O-18 (Globigerina bulloides), ice-rafted detritus concentrations, and the relative abundance of the polar foraminifera Neogloboquadrina pachyderma sinistral were used to track the PF position. These three data sets, compared from core to core, show a consistent evolution of the sea surface paleohydrology along the Iberian margin over the last 45 ka. We focused on five time slices representative of cold periods under distinct paleoenvironmental forcings:... |
| Tipo: Text |
Palavras-chave: Polar Front; LGM; Heinrich events. |
| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00218/32909/31415.pdf |
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| Peck, V. L.; Hall, I. R.; Zahn, R.; Scourse, J. D.. |
| We present high-resolution benthic delta C-13 records from intermediate water depth core site MD01-2461 ( 1153 m water depth), from the Porcupine Seabight, NE Atlantic, spanning 43 to 8 kyr B. P. At an average proxy time step of 160 +/- 56 years this core provides information on the linkage between records from the Portuguese Margin and high-latitude North Atlantic basin, allowing additional insights into North Atlantic thermohaline circulation (THC) variability during millennial-scale climatic events of the last glacial. Together, these records document both discrete and progressive reductions in Glacial North Atlantic Intermediate Water (GNAIW) formation preceding Heinrich ( H) events 1, 2, and 4, recorded through the apparent interchange of glacial... |
| Tipo: Text |
Palavras-chave: Atlantic thermohaline circulation; Benthic carbon isotopes; Heinrich events; Meltwater forcing. |
| Ano: 2007 |
URL: https://archimer.ifremer.fr/doc/00238/34945/33241.pdf |
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| Samartin, Stephanie; Heiri, Oliver; Kaltenrieder, Petra; Kühl, Norbert; Tinner, Willy. |
| Vegetation and climate during the last ice age and the Last Glacial Maximum (LGM, similar to 23,000-19,000 cal BP) were considerably different than during the current interglacial (Holocene). Cold climatic conditions and growing ice-sheets during the last glaciation radically reduced forest extent in Europe to a restricted number of so-called "refugia", mostly located in the southern part of the continent. On the basis of paleobotanical analyses the Euganian Hills (Colli Euganei) in northeastern Italy have previously been proposed as one of the northernmost refugia of temperate trees (e.g. deciduous Quercus, Tilia, Ulmus, Fraxinus excelsior, Acer, Abies alba, Fagus sylvatica, Carpinus and Castanea) in Europe. In this study we provide the first... |
| Tipo: Text |
Palavras-chave: Chironomids; Refugia; Vegetation; Northern Italy; Mediterranean; Climate; Last Glacial; LGM; Heinrich events; Paleoecology; Paleoclimatology. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53234/54773.pdf |
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| Jouet, Gwenael; Berne, Serge; Rabineau, Marina; Bassetti, Maria-angela; Bernier, P.; Dennielou, Bernard; Sierro, F.j.; Flores, J.a.; Taviani, M.. |
| The BourcartHérault canyon interfluve in the Gulf of Lions (NW Mediterranean) was the site of very high sedimentation (up to 2.5 m/kyr) around the Last Glacial Maximum, due to the vicinity of major fluvial systems that fed the shelf edge. Shoreface deposits and offshore muds deposited during each glacial/interglacial 100 kyr-cycle, created a repeated motif with high-angle and low-angle clinoforms on seismic profiles. New detailed morphological, sedimentological and paleo-environmental data, constrained by 14C dating, allow us to propose a scenario for the evolution of this critical area between 46 and 15 cal. kyr BP. The major seismic sequence (S5), formed as a forced regression during the overall sea-level fall between MIS-3 and MIS-2, can be sub-divided... |
| Tipo: Text |
Palavras-chave: Heinrich events; Western Mediterranean; High resolution sedimentary record; Relative sea level; Last Glacial Maximum. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2328.pdf |
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| Toucanne, Samuel; Zaragosi, S.; Bourillet, Jean-francois; Cremer, M.; Eynaud, Frederique; Van Vliet-lanoe, B.; Penaud, A.; Fontanier, C.; Turon, J. L.; Cortijo, E.; Gibbard, P. L.. |
| Continuous high-resolution mass accumulation rates (MAR) and X-ray fluorescence (XRF) measurements from marine sediment records in the Bay of Biscay (NE Atlantic) have allowed the determination of the timing and the amplitude of the ‘Fleuve Manche’ (Channel River) discharges during glacial stages MIS 10, MIS 8, MIS 6 and MIS 4–2. These results have yielded detailed insight into the Middle and Late Pleistocene glaciations in Europe and the drainage network of the western and central European rivers over the last 350 kyr. This study provides clear evidence that the ‘Fleuve Manche’ connected the southern North Sea basin with the Bay of Biscay during each glacial period and reveals that ‘Fleuve Manche’ activity during the glaciations MIS 10 and MIS 8 was... |
| Tipo: Text |
Palavras-chave: Northern north sea; Late weichselian glaciation; Western iberian margin; Abrupt climate change; C 14 YR BP; Deep sea; Heinrich events; Norwegian margin; Millennial scale; English channel. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00011/12261/9037.pdf |
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| Registros recuperados: 21 | |
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