Kerguelen Plateau Quaternary-late Pliocene palaeoenvironments: from diatom, silicoflagellate and sedimentological data
Gravity cores from the South Kerguelen Plateau contain sections representing two Quaternary intervals: (1) <0.62 Ma and (2) 1.6-1.25 Ma; three Pliocene intervals: (1) 2.2-1.6 Ma, (2) 3.1/3.0-2.64 Ma, (3) 3.2-3.1/3.0 Ma, and at least three disconformities: (1) 0.62 Ma until possibly the Last Glaci...
Published in: | Palaeogeography, Palaeoclimatology, Palaeoecology |
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ftunivtasecite:oai:ecite.utas.edu.au:25734 2023-05-15T13:59:07+02:00 Kerguelen Plateau Quaternary-late Pliocene palaeoenvironments: from diatom, silicoflagellate and sedimentological data Whitehead, JM McMinn, A 2002 https://doi.org/10.1016/S0031-0182(02)00424-8 http://ecite.utas.edu.au/25734 en eng Elsevier http://dx.doi.org/10.1016/S0031-0182(02)00424-8 Whitehead, JM and McMinn, A, Kerguelen Plateau Quaternary-late Pliocene palaeoenvironments: from diatom, silicoflagellate and sedimentological data, Palaeogeography, Palaeoclimatology, Palaeoecology, 186, (3-4) pp. 335-368. ISSN 0031-0182 (2002) [Refereed Article] http://ecite.utas.edu.au/25734 Earth Sciences Geology Stratigraphy (incl. Biostratigraphy and Sequence Stratigraphy) Refereed Article PeerReviewed 2002 ftunivtasecite https://doi.org/10.1016/S0031-0182(02)00424-8 2019-12-13T21:06:46Z Gravity cores from the South Kerguelen Plateau contain sections representing two Quaternary intervals: (1) <0.62 Ma and (2) 1.6-1.25 Ma; three Pliocene intervals: (1) 2.2-1.6 Ma, (2) 3.1/3.0-2.64 Ma, (3) 3.2-3.1/3.0 Ma, and at least three disconformities: (1) 0.62 Ma until possibly the Last Glacial Maximum, (2) 2.2-1.6 Ma, and (3) 3.1-2.2 Ma. The disconformities probably formed during intense glacial intervals when the velocity of the Antarctic Circumpolar Current increased. Increased current velocity winnowed away finer biogenic sediment, to create ice rafted debris lags that protected the underlying sediment. Sediment deposition occurred during the less cold climatic intervals. In these deposits, three diatom assemblages were identified by comparison with extant diatoms. The diatom data indicate fluctuating Quaternary open pack-ice and open water conditions. The open pack-ice assemblage differs from modern sea-ice assemblages, and may reflect differences in the sea-ice setting during past colder intervals at latitudes north of the Antarctic Divergence. A silicoflagellate ratio was used to reconstruct Pliocene summer sea-surface temperatures. Two intervals with surface water temperatures warmer than today were identified, during which conditions were 3.0-4.5C warmer (3.1-2.64 Ma), and 4.5C warmer (3.2-3.1 Ma) as far south as 62S. This would have occurred if either the Antarctic Polar Front Zone was 1200 km further south, or if the temperature gradient across the associated oceanic fronts would have been significantly lower. The Pliocene intervals contain a large amount of ice rafted debris that may reflect an environment heavily influenced by icebergs due to warmer glacial conditions in Antarctica, with increased sediment discharge and iceberg calving. 2002 Elsevier Science B.V. All rights reserved. Article in Journal/Newspaper Antarc* Antarctic Antarctica Iceberg* Sea ice eCite UTAS (University of Tasmania) Antarctic Kerguelen The Antarctic Palaeogeography, Palaeoclimatology, Palaeoecology 186 3-4 335 368 |
institution |
Open Polar |
collection |
eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Earth Sciences Geology Stratigraphy (incl. Biostratigraphy and Sequence Stratigraphy) |
spellingShingle |
Earth Sciences Geology Stratigraphy (incl. Biostratigraphy and Sequence Stratigraphy) Whitehead, JM McMinn, A Kerguelen Plateau Quaternary-late Pliocene palaeoenvironments: from diatom, silicoflagellate and sedimentological data |
topic_facet |
Earth Sciences Geology Stratigraphy (incl. Biostratigraphy and Sequence Stratigraphy) |
description |
Gravity cores from the South Kerguelen Plateau contain sections representing two Quaternary intervals: (1) <0.62 Ma and (2) 1.6-1.25 Ma; three Pliocene intervals: (1) 2.2-1.6 Ma, (2) 3.1/3.0-2.64 Ma, (3) 3.2-3.1/3.0 Ma, and at least three disconformities: (1) 0.62 Ma until possibly the Last Glacial Maximum, (2) 2.2-1.6 Ma, and (3) 3.1-2.2 Ma. The disconformities probably formed during intense glacial intervals when the velocity of the Antarctic Circumpolar Current increased. Increased current velocity winnowed away finer biogenic sediment, to create ice rafted debris lags that protected the underlying sediment. Sediment deposition occurred during the less cold climatic intervals. In these deposits, three diatom assemblages were identified by comparison with extant diatoms. The diatom data indicate fluctuating Quaternary open pack-ice and open water conditions. The open pack-ice assemblage differs from modern sea-ice assemblages, and may reflect differences in the sea-ice setting during past colder intervals at latitudes north of the Antarctic Divergence. A silicoflagellate ratio was used to reconstruct Pliocene summer sea-surface temperatures. Two intervals with surface water temperatures warmer than today were identified, during which conditions were 3.0-4.5C warmer (3.1-2.64 Ma), and 4.5C warmer (3.2-3.1 Ma) as far south as 62S. This would have occurred if either the Antarctic Polar Front Zone was 1200 km further south, or if the temperature gradient across the associated oceanic fronts would have been significantly lower. The Pliocene intervals contain a large amount of ice rafted debris that may reflect an environment heavily influenced by icebergs due to warmer glacial conditions in Antarctica, with increased sediment discharge and iceberg calving. 2002 Elsevier Science B.V. All rights reserved. |
format |
Article in Journal/Newspaper |
author |
Whitehead, JM McMinn, A |
author_facet |
Whitehead, JM McMinn, A |
author_sort |
Whitehead, JM |
title |
Kerguelen Plateau Quaternary-late Pliocene palaeoenvironments: from diatom, silicoflagellate and sedimentological data |
title_short |
Kerguelen Plateau Quaternary-late Pliocene palaeoenvironments: from diatom, silicoflagellate and sedimentological data |
title_full |
Kerguelen Plateau Quaternary-late Pliocene palaeoenvironments: from diatom, silicoflagellate and sedimentological data |
title_fullStr |
Kerguelen Plateau Quaternary-late Pliocene palaeoenvironments: from diatom, silicoflagellate and sedimentological data |
title_full_unstemmed |
Kerguelen Plateau Quaternary-late Pliocene palaeoenvironments: from diatom, silicoflagellate and sedimentological data |
title_sort |
kerguelen plateau quaternary-late pliocene palaeoenvironments: from diatom, silicoflagellate and sedimentological data |
publisher |
Elsevier |
publishDate |
2002 |
url |
https://doi.org/10.1016/S0031-0182(02)00424-8 http://ecite.utas.edu.au/25734 |
geographic |
Antarctic Kerguelen The Antarctic |
geographic_facet |
Antarctic Kerguelen The Antarctic |
genre |
Antarc* Antarctic Antarctica Iceberg* Sea ice |
genre_facet |
Antarc* Antarctic Antarctica Iceberg* Sea ice |
op_relation |
http://dx.doi.org/10.1016/S0031-0182(02)00424-8 Whitehead, JM and McMinn, A, Kerguelen Plateau Quaternary-late Pliocene palaeoenvironments: from diatom, silicoflagellate and sedimentological data, Palaeogeography, Palaeoclimatology, Palaeoecology, 186, (3-4) pp. 335-368. ISSN 0031-0182 (2002) [Refereed Article] http://ecite.utas.edu.au/25734 |
op_doi |
https://doi.org/10.1016/S0031-0182(02)00424-8 |
container_title |
Palaeogeography, Palaeoclimatology, Palaeoecology |
container_volume |
186 |
container_issue |
3-4 |
container_start_page |
335 |
op_container_end_page |
368 |
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1766267525742460928 |