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| White, Lee F.; Bailey, Ian; Foster, Gavin L.; Allen, Georgina; Kelley, Simon P.; Andrews, John T.; Hogan, Kelly; Dowdeswell, Julian A.; Storey, Craig D.. |
| The provenance of sand-sized ice-rafted debris (IRD) sourced from Greenland is currently difficult to determine. Such knowledge, if it could be ascertained with a high degree of certainty, could be applied to the Greenland-proximal marine records to improve both our understanding of modern-day spatial patterns of iceberg rafting and the past history of the Greenland Ice Sheet (GIS). Recent studies have highlighted the utility of the Pb-isotope composition of individual sand-sized feldspars and the Ar-40/Ar-39 ages of individual sand-sized hornblendes in this regard. However, before any such provenance toolkit can be applied to the palaeo-record, it is necessary first to determine whether this approach can be used to track the sources of known recent... |
| Tipo: Text |
Palavras-chave: Greenland; Ice rafted debris; Ar-Ar; Pb isotopes; Icebergs; Provenance. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53292/54130.pdf |
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| Bugelmayer-blaschek, Marianne; Roche, Didier M.; Renssen, Hans; Andrews, John T.. |
| The climate of the Holocene, the current interglacial covering the past 11,700 years, has been relatively stable compared to previous periods. Nevertheless, repeating occurrence of rapid natural climate changes that challenged human society are seen in proxy reconstructions. Ocean sediment cores for example display prominent peaks of enhanced ice rafted debris (IRD) during the Holocene with a multidecadal to millennial scale periodicity. Different mechanisms were proposed that caused these enhanced IRD events, for example variations in the incoming total solar irradiance (TSI), volcanic eruptions and the combination of internal climate variability and external forcings. We investigate the probable mechanisms causing the occurrence of IRD-events over the... |
| Tipo: Text |
Palavras-chave: Greenland ice sheet; Holocene; Bond events; Icebergs; Climate modeling. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53253/54711.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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| Mayet, C.; Testut, L.; Legresy, B.; Lescarmontier, L.; Lyard, F.. |
| In February 2010, the Mertz Glacier Tongue (MGT) calved, releasing an 80 x 40 km iceberg. We have developed a high-resolution barotropic ocean model of the region to simulate the local circulation in response to tides and atmospheric forcing. We improved the coastline, grounding line position and built a new bathymetry using satellite imagery and older bathymetry data to derive the best available tidal model for the region. We compared this and other available models to seven different sea level observations available in the area and significantly improved the tidal solutions reaching a root sum square of 2.3 cm. This model was then run in different bathymetric configurations, considering the ice draft of the major icebergs B9B and C28, to simulate the... |
| Tipo: Text |
Palavras-chave: Mertz Glacier; Icebergs; Calving; Barotropic; Model. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00244/35568/34097.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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