|
|
|
|
|
| Hoogakker, Babette A. A.; Chapman, Mark R.; Mccave, I. Nick; Hillaire-marcel, Claude; Ellison, Christopher R. W.; Hall, Ian R.; Telford, Richard J.. |
| High resolution flow speed reconstructions of two core sites located on Gardar Drift in the northeast Atlantic Basin and Orphan Knoll in the northwest Atlantic Basin reveal a long-term decrease in flow speed of Northeast Atlantic Deep Water (NEADW) after 6,500 years. Benthic foraminiferal oxygen isotopes of sites currently bathed in NEADW show a 0.2 parts per thousand depletion after 6,500 years, shortly after the start of the development of a carbon isotope gradient between NEADW and Norwegian Sea Deep Water. We consider these changes in near-bottom flow vigor and benthic foraminiferal isotope records to mark a significant reorganization of the Holocene deep ocean circulation, and attribute the changes to a weakening of NEADW flow during the mid to late... |
| Tipo: Text |
|
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00227/33787/32562.pdf |
| |
|
|
| Davies, Siwan M.; Abbott, Peter M.; Meara, Rhian H.; Pearce, Nicholas J. G.; Austin, William E. N.; Chapman, Mark R.; Svensson, Anders; Bigler, Matthias; Rasmussen, Tine L.; Rasmussen, Sune O.; Farmer, Elizabeth J.. |
| Building chronological frameworks for proxy sequences spanning 130-60 ka b2k is plagued by difficulties and uncertainties. Recent developments in the North Atlantic region, however, affirm the potential offered by tephrochronology and specifically the search for cryptotephra. Here we review the potential offered by tephrostratigraphy for sequences spanning 130-60 ka b2k. We combine newly identified cryptotephra deposits from the NGRIP ice-core and a marine core from the Iceland Basin with previously published data from the ice and marine realms to construct the first tephrostratigraphical framework for this time-interval. Forty-three tephra or cryptotephra deposits are incorporated into this framework; twenty three tephra deposits are found in the... |
| Tipo: Text |
Palavras-chave: Tephra; Cryptotephra; Tephrostratigraphy; Greenland ice-cores; North Atlantic marine cores; Iceland; Tephra correlations; Glass-shard analysis; Rapid climate changes. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00289/40029/39255.pdf |
| |
|
|
| Farmer, Elizabeth J.; Chapman, Mark R.; Andrews, Julian E.. |
| A high-resolution record of Mg/Ca ratios from the planktonic foraminifer Globigerina bulloides has been produced for IMAGES core MD99-2251 from the subpolar North Atlantic. The record extends from the Younger Dryas-Preboreal transition through the Holocene at similar to 70 year resolution, with a more detailed section at similar to 20 year resolution through the interval encompassing the major cooling episode 8200 years ago. Mg/Ca derived temperatures show significant variations through the Holocene, with surface temperatures ranging from similar to 8 to 13 degrees C. The onset of the Holocene is marked by an abrupt warming, with a further increase in early Holocene temperatures occurring prior to 9.5 ka. This is followed by a mid-Holocene period of cooler... |
| Tipo: Text |
Palavras-chave: Planktonic foraminifera; Mg/Ca; G. bulloides; North Atlantic; Holocene. |
| Ano: 2008 |
URL: https://archimer.ifremer.fr/doc/00236/34760/33396.pdf |
| |
|
| |
|
|
|
