Sea ice diatoms from Late Quaternary sediments in the Scotia Sea
Fuente:
PANGAEA
Gespeichert in:
| Hauptverfasser: | , , |
|---|---|
| Format: | Dataset Open Access |
| Sprache: | en |
| Veröffentlicht: |
PANGAEA
2011
|
| Schlagworte: | |
| Online-Zugang: | |
| Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
| _version_ | 1867170460088664064 |
|---|---|
| author | Allen, Claire Susannah Pike, Jennifer Pudsey, Carol J |
| author_facet | Allen, Claire Susannah Pike, Jennifer Pudsey, Carol J |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Sea-ice growth and decay in Antarctica is one of the biggest seasonal changes on Earth, expanding ice cover from 4x10**6 km**2 to a maximum of 19x10**6 km**2 during the austral winter. Analyses of six marine sediment cores from the Scotia Sea, SW Atlantic, yield records of sea-ice migration across the basin since the Lateglacial. The cores span nearly ten degrees of latitude from the modern seasonal sea-ice zone to the modern Polar Front. Surface sediments in the cores comprise predominantly diatomaceous oozes and muddy diatom oozes that reflect Holocene conditions. The cores exhibit similar down-core stratigraphies with decreasing diatom concentrations and increasing magnetic susceptibility from modern through to the Last Glacial Maximum (LGM). Sediments in all cores contain sea-ice diatoms that preserve a signal of changing sea-ice cover and permit reconstruction of past sea-ice dynamics. The sea-ice records presented here are the first to document the position of both the summer and winter sea-ice cover at the Last Glacial Maximum (LGM) in the Scotia Sea. Comparison of the LGM and Holocene sea-ice conditions shows that the average winter sea-ice extent was at least 5° further north at the LGM. Average summer sea-ice extent was south of the most southerly core site at the LGM, and suggests that sea-ice expanded from approximately 61°S to 52°S each season. Our data also suggest that the average summer sea-ice position at the LGM was not the maximum extent of summer sea-ice during the last glacial. Instead, the sediments contain evidence of a pre-LGM maximum extent of summer sea-ice between ab. 30 ka and 22 ka that extended to ab. 59°S, close to the modern average winter sea-ice limit. Based on our reconstruction we propose that the timing of the maximum extent of summer sea-ice and subsequent retreat by 22 ka, could be insolation controlled and that the strong links between sea-ice and bottom water formation provide a potential mechanism by which Southern Hemisphere regional sea-ice dynamics at the LGM could have a global impact and promote deglaciation. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_762140 |
| institution | PANGAEA |
| language | en |
| publishDate | 2011 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Sea ice diatoms from Late Quaternary sediments in the Scotia Sea Allen, Claire Susannah Pike, Jennifer Pudsey, Carol J COMPCORE; Composite Core; KAL; Kasten corer; KC81; PC; PC287; Piston corer; Scotia Sea; Scotia Sea, southwest Atlantic; TC; TC287; TPC034; TPC036; TPC063; TPC078; Trigger corer Sea-ice growth and decay in Antarctica is one of the biggest seasonal changes on Earth, expanding ice cover from 4x10**6 km**2 to a maximum of 19x10**6 km**2 during the austral winter. Analyses of six marine sediment cores from the Scotia Sea, SW Atlantic, yield records of sea-ice migration across the basin since the Lateglacial. The cores span nearly ten degrees of latitude from the modern seasonal sea-ice zone to the modern Polar Front. Surface sediments in the cores comprise predominantly diatomaceous oozes and muddy diatom oozes that reflect Holocene conditions. The cores exhibit similar down-core stratigraphies with decreasing diatom concentrations and increasing magnetic susceptibility from modern through to the Last Glacial Maximum (LGM). Sediments in all cores contain sea-ice diatoms that preserve a signal of changing sea-ice cover and permit reconstruction of past sea-ice dynamics. The sea-ice records presented here are the first to document the position of both the summer and winter sea-ice cover at the Last Glacial Maximum (LGM) in the Scotia Sea. Comparison of the LGM and Holocene sea-ice conditions shows that the average winter sea-ice extent was at least 5° further north at the LGM. Average summer sea-ice extent was south of the most southerly core site at the LGM, and suggests that sea-ice expanded from approximately 61°S to 52°S each season. Our data also suggest that the average summer sea-ice position at the LGM was not the maximum extent of summer sea-ice during the last glacial. Instead, the sediments contain evidence of a pre-LGM maximum extent of summer sea-ice between ab. 30 ka and 22 ka that extended to ab. 59°S, close to the modern average winter sea-ice limit. Based on our reconstruction we propose that the timing of the maximum extent of summer sea-ice and subsequent retreat by 22 ka, could be insolation controlled and that the strong links between sea-ice and bottom water formation provide a potential mechanism by which Southern Hemisphere regional sea-ice dynamics at the LGM could have a global impact and promote deglaciation. |
| title | Sea ice diatoms from Late Quaternary sediments in the Scotia Sea |
| topic | COMPCORE; Composite Core; KAL; Kasten corer; KC81; PC; PC287; Piston corer; Scotia Sea; Scotia Sea, southwest Atlantic; TC; TC287; TPC034; TPC036; TPC063; TPC078; Trigger corer |
| url | https://doi.org/10.1594/PANGAEA.762140 |