Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 1: Insights from late Oligocene astronomically paced contourite sedimentation
Antarctic ice sheet and Southern Ocean paleoceanographic configurations during the late Oligocene are not well resolved. They are however important to understand the influence of high-latitude Southern Hemisphere feedbacks on global climate under CO2 scenarios (between 400 and 750 ppm) projected by...
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Online Access: | https://doi.org/10.5194/cp-14-991-2018 https://cp.copernicus.org/articles/14/991/2018/ |
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fttriple:oai:gotriple.eu:GjfQqtfPcKwg8oX3a6OBp 2023-05-15T14:02:27+02:00 Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 1: Insights from late Oligocene astronomically paced contourite sedimentation Salabarnada, Ariadna Escutia, Carlota Röhl, Ursula Nelson, C. Hans McKay, Robert Jiménez-Espejo, Francisco J. Bijl, Peter K. Hartman, Julian D. Strother, Stephanie L. Salzmann, Ulrich Evangelinos, Dimitris López-Quirós, Adrián Flores, José Abel Sangiorgi, Francesca Ikehara, Minoru Brinkhuis, Henk 2019-04-11 https://doi.org/10.5194/cp-14-991-2018 https://cp.copernicus.org/articles/14/991/2018/ en eng Copernicus Publications doi:10.5194/cp-14-991-2018 10670/1.8d1cij 1814-9324 1814-9332 https://cp.copernicus.org/articles/14/991/2018/ undefined Geographica Helvetica - geography eISSN: 1814-9332 geo envir Text https://vocabularies.coar-repositories.org/resource_types/c_18cf/ Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2019 fttriple https://doi.org/10.5194/cp-14-991-2018 2023-01-22T17:39:06Z Antarctic ice sheet and Southern Ocean paleoceanographic configurations during the late Oligocene are not well resolved. They are however important to understand the influence of high-latitude Southern Hemisphere feedbacks on global climate under CO2 scenarios (between 400 and 750 ppm) projected by the IPCC for this century, assuming unabated CO2 emissions. Sediments recovered by the Integrated Ocean Drilling Program (IODP) at Site U1356, offshore of the Wilkes Land margin in East Antarctica, provide an opportunity to study ice sheet and paleoceanographic configurations during the late Oligocene (26–25 Ma). Our study, based on a combination of sediment facies analysis, magnetic susceptibility, density, and X-ray fluorescence geochemical data, shows that glacial and interglacial sediments are continuously reworked by bottom currents, with maximum velocities occurring during the interglacial periods. Glacial sediments record poorly ventilated, low-oxygenation bottom water conditions, interpreted as resulting from a northward shift of westerly winds and surface oceanic fronts. Interglacial sediments record more oxygenated and ventilated bottom water conditions and strong current velocities, which suggests enhanced mixing of the water masses as a result of a southward shift of the polar front. Intervals with preserved carbonated nannofossils within some of the interglacial facies are interpreted as forming under warmer paleoclimatic conditions when less corrosive warmer northern component water (e.g., North Atlantic sourced deep water) had a greater influence on the site. Spectral analysis on the late Oligocene sediment interval shows that the glacial–interglacial cyclicity and related displacements of the Southern Ocean frontal systems between 26 and 25 Ma were forced mainly by obliquity. The paucity of iceberg-rafted debris (IRD) throughout the studied interval contrasts with earlier Oligocene and post-Miocene Climate Optimum sections from Site U1356 and with late Oligocene strata from the Ross Sea, which contain ... Article in Journal/Newspaper Antarc* Antarctic Antarctica East Antarctica Ice Sheet Iceberg* North Atlantic Ross Sea Southern Ocean Wilkes Land Unknown Antarctic Southern Ocean East Antarctica Ross Sea Wilkes Land ENVELOPE(120.000,120.000,-69.000,-69.000) Climate of the Past 14 7 991 1014 |
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Open Polar |
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language |
English |
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geo envir |
spellingShingle |
geo envir Salabarnada, Ariadna Escutia, Carlota Röhl, Ursula Nelson, C. Hans McKay, Robert Jiménez-Espejo, Francisco J. Bijl, Peter K. Hartman, Julian D. Strother, Stephanie L. Salzmann, Ulrich Evangelinos, Dimitris López-Quirós, Adrián Flores, José Abel Sangiorgi, Francesca Ikehara, Minoru Brinkhuis, Henk Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 1: Insights from late Oligocene astronomically paced contourite sedimentation |
topic_facet |
geo envir |
description |
Antarctic ice sheet and Southern Ocean paleoceanographic configurations during the late Oligocene are not well resolved. They are however important to understand the influence of high-latitude Southern Hemisphere feedbacks on global climate under CO2 scenarios (between 400 and 750 ppm) projected by the IPCC for this century, assuming unabated CO2 emissions. Sediments recovered by the Integrated Ocean Drilling Program (IODP) at Site U1356, offshore of the Wilkes Land margin in East Antarctica, provide an opportunity to study ice sheet and paleoceanographic configurations during the late Oligocene (26–25 Ma). Our study, based on a combination of sediment facies analysis, magnetic susceptibility, density, and X-ray fluorescence geochemical data, shows that glacial and interglacial sediments are continuously reworked by bottom currents, with maximum velocities occurring during the interglacial periods. Glacial sediments record poorly ventilated, low-oxygenation bottom water conditions, interpreted as resulting from a northward shift of westerly winds and surface oceanic fronts. Interglacial sediments record more oxygenated and ventilated bottom water conditions and strong current velocities, which suggests enhanced mixing of the water masses as a result of a southward shift of the polar front. Intervals with preserved carbonated nannofossils within some of the interglacial facies are interpreted as forming under warmer paleoclimatic conditions when less corrosive warmer northern component water (e.g., North Atlantic sourced deep water) had a greater influence on the site. Spectral analysis on the late Oligocene sediment interval shows that the glacial–interglacial cyclicity and related displacements of the Southern Ocean frontal systems between 26 and 25 Ma were forced mainly by obliquity. The paucity of iceberg-rafted debris (IRD) throughout the studied interval contrasts with earlier Oligocene and post-Miocene Climate Optimum sections from Site U1356 and with late Oligocene strata from the Ross Sea, which contain ... |
format |
Article in Journal/Newspaper |
author |
Salabarnada, Ariadna Escutia, Carlota Röhl, Ursula Nelson, C. Hans McKay, Robert Jiménez-Espejo, Francisco J. Bijl, Peter K. Hartman, Julian D. Strother, Stephanie L. Salzmann, Ulrich Evangelinos, Dimitris López-Quirós, Adrián Flores, José Abel Sangiorgi, Francesca Ikehara, Minoru Brinkhuis, Henk |
author_facet |
Salabarnada, Ariadna Escutia, Carlota Röhl, Ursula Nelson, C. Hans McKay, Robert Jiménez-Espejo, Francisco J. Bijl, Peter K. Hartman, Julian D. Strother, Stephanie L. Salzmann, Ulrich Evangelinos, Dimitris López-Quirós, Adrián Flores, José Abel Sangiorgi, Francesca Ikehara, Minoru Brinkhuis, Henk |
author_sort |
Salabarnada, Ariadna |
title |
Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 1: Insights from late Oligocene astronomically paced contourite sedimentation |
title_short |
Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 1: Insights from late Oligocene astronomically paced contourite sedimentation |
title_full |
Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 1: Insights from late Oligocene astronomically paced contourite sedimentation |
title_fullStr |
Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 1: Insights from late Oligocene astronomically paced contourite sedimentation |
title_full_unstemmed |
Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 1: Insights from late Oligocene astronomically paced contourite sedimentation |
title_sort |
paleoceanography and ice sheet variability offshore wilkes land, antarctica – part 1: insights from late oligocene astronomically paced contourite sedimentation |
publisher |
Copernicus Publications |
publishDate |
2019 |
url |
https://doi.org/10.5194/cp-14-991-2018 https://cp.copernicus.org/articles/14/991/2018/ |
long_lat |
ENVELOPE(120.000,120.000,-69.000,-69.000) |
geographic |
Antarctic Southern Ocean East Antarctica Ross Sea Wilkes Land |
geographic_facet |
Antarctic Southern Ocean East Antarctica Ross Sea Wilkes Land |
genre |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet Iceberg* North Atlantic Ross Sea Southern Ocean Wilkes Land |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Ice Sheet Iceberg* North Atlantic Ross Sea Southern Ocean Wilkes Land |
op_source |
Geographica Helvetica - geography eISSN: 1814-9332 |
op_relation |
doi:10.5194/cp-14-991-2018 10670/1.8d1cij 1814-9324 1814-9332 https://cp.copernicus.org/articles/14/991/2018/ |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/cp-14-991-2018 |
container_title |
Climate of the Past |
container_volume |
14 |
container_issue |
7 |
container_start_page |
991 |
op_container_end_page |
1014 |
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1766272728887721984 |