Environmental magnetic record of Antarctic palaeoclimate from Eocene/Oligocene glaciomarine sediments, Victoria Land Basin
The onset of continent‐wide glaciation in Antarctica is still poorly understood, despite being one of the most important palaeoclimatic events in the Cenozoic. The Eocene/Oligocene boundary interval has recently been recognized as a critical time for Antarctic climatic evolution, and it may mark the...
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1998
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fthighwire:oai:open-archive.highwire.org:gji:134/3/653 2023-05-15T13:52:21+02:00 Environmental magnetic record of Antarctic palaeoclimate from Eocene/Oligocene glaciomarine sediments, Victoria Land Basin Sagnotti, Leonardo Florindo, Fabio Verosub, Kenneth L. Wilson, Gary S. Roberts, Andrew P. 1998-09-01 00:00:00.0 text/html http://gji.oxfordjournals.org/cgi/content/short/134/3/653 https://doi.org/10.1046/j.1365-246x.1998.00559.x en eng Oxford University Press http://gji.oxfordjournals.org/cgi/content/short/134/3/653 http://dx.doi.org/10.1046/j.1365-246x.1998.00559.x Copyright (C) 1998, Oxford University Press Articles TEXT 1998 fthighwire https://doi.org/10.1046/j.1365-246x.1998.00559.x 2015-02-28T21:53:18Z The onset of continent‐wide glaciation in Antarctica is still poorly understood, despite being one of the most important palaeoclimatic events in the Cenozoic. The Eocene/Oligocene boundary interval has recently been recognized as a critical time for Antarctic climatic evolution, and it may mark the preglacial–glacial transition. Magnetic susceptibility, intensity of natural and artificial remanences, hysteresis parameters and magnetic anisotropy of the lower half (late Eocene/early Oligocene) of the CIROS‐1 core (from McMurdo Sound, Antarctica) reveal alternating intervals of high and low magnetic mineral concentrations that do not correspond to lithostratigraphic units in the core. Pseudo‐single‐domain magnetite is the main magnetic mineral throughout the sequence, and sharp changes in magnetite concentration match changes in clay mineralogy beneath and at the Eocene/Oligocene boundary. The detrital magnetite originated from weathering of the Ferrar Group (which comprises basic extrusive and intrusive igneous rocks). Weathering processes and input of magnetite to the Victoria Land Basin were intense during periods when the Antarctic climate was warmer than today, but during intervals when the climate was relatively cool, chemical weathering of the Ferrar Group was suppressed and input of detrital magnetite to the Victoria Land Basin decreased. Our results also indicate that a cold and dry climate was not established in Antarctica until the Eocene/Oligocene boundary, with major ice sheet growth occurring at the early/late Oligocene boundary. Some earlier cold intervals are identified, which indicate that climate had begun to deteriorate by the middle/late Eocene boundary. Text Antarc* Antarctic Antarctica Ice Sheet McMurdo Sound Victoria Land HighWire Press (Stanford University) Antarctic The Antarctic Victoria Land McMurdo Sound Geophysical Journal International 134 3 653 662 |
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English |
topic |
Articles |
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Articles Sagnotti, Leonardo Florindo, Fabio Verosub, Kenneth L. Wilson, Gary S. Roberts, Andrew P. Environmental magnetic record of Antarctic palaeoclimate from Eocene/Oligocene glaciomarine sediments, Victoria Land Basin |
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Articles |
description |
The onset of continent‐wide glaciation in Antarctica is still poorly understood, despite being one of the most important palaeoclimatic events in the Cenozoic. The Eocene/Oligocene boundary interval has recently been recognized as a critical time for Antarctic climatic evolution, and it may mark the preglacial–glacial transition. Magnetic susceptibility, intensity of natural and artificial remanences, hysteresis parameters and magnetic anisotropy of the lower half (late Eocene/early Oligocene) of the CIROS‐1 core (from McMurdo Sound, Antarctica) reveal alternating intervals of high and low magnetic mineral concentrations that do not correspond to lithostratigraphic units in the core. Pseudo‐single‐domain magnetite is the main magnetic mineral throughout the sequence, and sharp changes in magnetite concentration match changes in clay mineralogy beneath and at the Eocene/Oligocene boundary. The detrital magnetite originated from weathering of the Ferrar Group (which comprises basic extrusive and intrusive igneous rocks). Weathering processes and input of magnetite to the Victoria Land Basin were intense during periods when the Antarctic climate was warmer than today, but during intervals when the climate was relatively cool, chemical weathering of the Ferrar Group was suppressed and input of detrital magnetite to the Victoria Land Basin decreased. Our results also indicate that a cold and dry climate was not established in Antarctica until the Eocene/Oligocene boundary, with major ice sheet growth occurring at the early/late Oligocene boundary. Some earlier cold intervals are identified, which indicate that climate had begun to deteriorate by the middle/late Eocene boundary. |
format |
Text |
author |
Sagnotti, Leonardo Florindo, Fabio Verosub, Kenneth L. Wilson, Gary S. Roberts, Andrew P. |
author_facet |
Sagnotti, Leonardo Florindo, Fabio Verosub, Kenneth L. Wilson, Gary S. Roberts, Andrew P. |
author_sort |
Sagnotti, Leonardo |
title |
Environmental magnetic record of Antarctic palaeoclimate from Eocene/Oligocene glaciomarine sediments, Victoria Land Basin |
title_short |
Environmental magnetic record of Antarctic palaeoclimate from Eocene/Oligocene glaciomarine sediments, Victoria Land Basin |
title_full |
Environmental magnetic record of Antarctic palaeoclimate from Eocene/Oligocene glaciomarine sediments, Victoria Land Basin |
title_fullStr |
Environmental magnetic record of Antarctic palaeoclimate from Eocene/Oligocene glaciomarine sediments, Victoria Land Basin |
title_full_unstemmed |
Environmental magnetic record of Antarctic palaeoclimate from Eocene/Oligocene glaciomarine sediments, Victoria Land Basin |
title_sort |
environmental magnetic record of antarctic palaeoclimate from eocene/oligocene glaciomarine sediments, victoria land basin |
publisher |
Oxford University Press |
publishDate |
1998 |
url |
http://gji.oxfordjournals.org/cgi/content/short/134/3/653 https://doi.org/10.1046/j.1365-246x.1998.00559.x |
geographic |
Antarctic The Antarctic Victoria Land McMurdo Sound |
geographic_facet |
Antarctic The Antarctic Victoria Land McMurdo Sound |
genre |
Antarc* Antarctic Antarctica Ice Sheet McMurdo Sound Victoria Land |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet McMurdo Sound Victoria Land |
op_relation |
http://gji.oxfordjournals.org/cgi/content/short/134/3/653 http://dx.doi.org/10.1046/j.1365-246x.1998.00559.x |
op_rights |
Copyright (C) 1998, Oxford University Press |
op_doi |
https://doi.org/10.1046/j.1365-246x.1998.00559.x |
container_title |
Geophysical Journal International |
container_volume |
134 |
container_issue |
3 |
container_start_page |
653 |
op_container_end_page |
662 |
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1766256632642142208 |