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| Hill, Hw; Flower, Bp; Quinn, Tm; Hollander, Dj; Guilderson, Tp. |
| A leading hypothesis to explain abrupt climate change during the last glacial cycle calls on fluctuations in the margin of the North American Laurentide Ice Sheet ( LIS), which may have routed fresh water between the Gulf of Mexico (GOM) and the North Atlantic, affecting North Atlantic Deep Water variability and regional climate. Paired measurements of delta O-18 and Mg/Ca of foraminiferal calcite from GOM sediments reveal five episodes of LIS meltwater input from 28 to 45 thousand years ago (ka) that do not match the millennial-scale Dansgaard-Oeschger warmings recorded in Greenland ice. We suggest that summer melting of the LIS may occur during Antarctic warming and likely contributed to sea level variability during marine isotope stage 3. |
| Tipo: Text |
Palavras-chave: Laurentide Ice Sheet; Meltwater; Marine isotope stage 3; Gulf of Mexico. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00235/34587/33071.pdf |
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| Shakun, Jeremy D.; Raymo, Maureen E.; Lea, David W.. |
| Early Pleistocene glacial cycles in marine O-18 exhibit strong obliquity pacing, but there is a perplexing lack of precession variability despite its important influence on summer insolation intensity - the presumed forcing of ice sheet growth and decay according to the Milankovitch hypothesis. This puzzle has been explained in two ways: Northern Hemisphere ice sheets instead respond to insolation integrated over the summer, which is mostly controlled by obliquity, or anti-phased precession-driven variability in ice volume between the hemispheres cancels out in global O-18, leaving the in-phase obliquity signal to dominate. We evaluated these ideas by reconstructing Laurentide Ice Sheet (LIS) meltwater discharge to the Gulf of Mexico from 2.55-1.70Ma using... |
| Tipo: Text |
Palavras-chave: Glacial cycles; Milankovitch hypothesis; Laurentide Ice Sheet; Gulf of Mexico; Early Pleistocene. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00421/53233/54774.pdf |
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| Andrews, J. T.; Barber, D. C.; Jennings, A. E.; Eberl, D. D.; Maclean, B.; Kirby, M. E.; Stoner, J. S.. |
| Core HU97048-007PC was recovered from the continental Labrador Sea slope at a water depth of 945?m, 250?km seaward from the mouth of Cumberland Sound, and 400?km north of Hudson Strait. Cumberland Sound is a structural trough partly floored by Cretaceous mudstones and Paleozoic carbonates. The record extends from similar to 10 to 58?ka. On-board logging revealed a complex series of lithofacies, including buff-colored detrital carbonate-rich sediments [Heinrich (H)-events] frequently bracketed by black facies. We investigate the provenance of these facies using quantitative X-ray diffraction on drill-core samples from Paleozoic and Cretaceous bedrock from the SE Baffin Island Shelf, and on the?<?2-mm sediment fraction in a transect of five cores from... |
| Tipo: Text |
Palavras-chave: Baffin Bay; Detrital carbonate (DC-) events; Heinrich events; Labrador Sea; Laurentide Ice Sheet. |
| Ano: 2012 |
URL: https://archimer.ifremer.fr/doc/00265/37644/35823.pdf |
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| Jansson, Kn; Kleman, J. |
| [1] In this paper we analyze drainage routes and estimate fluxes of meltwater released from Labrador-Ungava glacial lakes into the Labrador Sea, Ungava Bay, and Hudson Bay between 7.5 and 6.0 kyr BP (8.4 - 7.0 calendar (cal) years ka). The analysis and estimates are based on landform- based reconstructions of the Laurentide Ice Sheet ( LIS) decay pattern and the associated glacial lake evolution. Geomorphological data constraining the spatial extent of glacial lakes are coupled to a digital terrain model for meltwater volume calculations. The LIS ice recession between 7.5 and 6.0 kyr BP led to the formation of a large number of glacial lakes, which drained in approximately 30 meltwater pulses, with fluxes exceeding 0.015 Sv (1 Sv = 10(6) m(3) s(-1)), into... |
| Tipo: Text |
Palavras-chave: Laurentide Ice Sheet; Glacial lake; Labrador Sea. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00504/61613/65521.pdf |
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