Middle Miocene ice sheet dynamics, deep-sea temperatures, and carbon cycling: A Southern Ocean perspective
Relative contributions of ice volume and temperature change to the global similar to 1 parts per thousand delta O-18 increase at similar to 14 Ma are required for understanding feedbacks involved in this major Cenozoic climate transition. A 3-ma benthic foraminifer Mg/Ca record of Southern Ocean tem...
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ftucl:oai:eprints.ucl.ac.uk.OAI2:1302365 2023-12-24T10:10:01+01:00 Middle Miocene ice sheet dynamics, deep-sea temperatures, and carbon cycling: A Southern Ocean perspective Shevenell, AE Kennett, JP Lea, DW 2008-02-09 application/pdf https://discovery.ucl.ac.uk/id/eprint/1302365/1/2007GC001736.pdf https://discovery.ucl.ac.uk/id/eprint/1302365/ eng eng AMER GEOPHYSICAL UNION https://discovery.ucl.ac.uk/id/eprint/1302365/1/2007GC001736.pdf https://discovery.ucl.ac.uk/id/eprint/1302365/ open Geochemistry, Geophysics, Geosystems , 9 , Article Q02006. (2008) Paleoceanography Cenozoic climate Geochemistry Antarctica Benthic foraminiferal Mg/Ca Climate-change Surface temperature Dioxide Evolution Record Paleothermometry Circulation Glaciation Hypothesis Article 2008 ftucl 2023-11-27T13:07:32Z Relative contributions of ice volume and temperature change to the global similar to 1 parts per thousand delta O-18 increase at similar to 14 Ma are required for understanding feedbacks involved in this major Cenozoic climate transition. A 3-ma benthic foraminifer Mg/Ca record of Southern Ocean temperatures across the middle Miocene climate transition reveals similar to 2 +/- 2 degrees C cooling (14.2-13.8 Ma), indicating that similar to 70% of the increase relates to ice growth. Seawater delta O-18, calculated from Mg/Ca and delta O-18, suggests that at similar to 15 Ma Antarctica's cryosphere entered an interval of apparent eccentricity-paced expansion. Glaciations increased in intensity, revealing a central role for internal climate feedbacks. Comparison of ice volume and ocean temperature records with inferred pCO(2) levels indicates that middle Miocene cryosphere expansion commenced during an interval of Southern Ocean warmth and low atmospheric pCO(2). The Antarctic system appears sensitive to changes in heat/moisture supply when atmospheric pCO(2) was low, suggesting the importance of internal feedbacks in this climate transition. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Southern Ocean University College London: UCL Discovery Antarctic Southern Ocean The Antarctic |
institution |
Open Polar |
collection |
University College London: UCL Discovery |
op_collection_id |
ftucl |
language |
English |
topic |
Paleoceanography Cenozoic climate Geochemistry Antarctica Benthic foraminiferal Mg/Ca Climate-change Surface temperature Dioxide Evolution Record Paleothermometry Circulation Glaciation Hypothesis |
spellingShingle |
Paleoceanography Cenozoic climate Geochemistry Antarctica Benthic foraminiferal Mg/Ca Climate-change Surface temperature Dioxide Evolution Record Paleothermometry Circulation Glaciation Hypothesis Shevenell, AE Kennett, JP Lea, DW Middle Miocene ice sheet dynamics, deep-sea temperatures, and carbon cycling: A Southern Ocean perspective |
topic_facet |
Paleoceanography Cenozoic climate Geochemistry Antarctica Benthic foraminiferal Mg/Ca Climate-change Surface temperature Dioxide Evolution Record Paleothermometry Circulation Glaciation Hypothesis |
description |
Relative contributions of ice volume and temperature change to the global similar to 1 parts per thousand delta O-18 increase at similar to 14 Ma are required for understanding feedbacks involved in this major Cenozoic climate transition. A 3-ma benthic foraminifer Mg/Ca record of Southern Ocean temperatures across the middle Miocene climate transition reveals similar to 2 +/- 2 degrees C cooling (14.2-13.8 Ma), indicating that similar to 70% of the increase relates to ice growth. Seawater delta O-18, calculated from Mg/Ca and delta O-18, suggests that at similar to 15 Ma Antarctica's cryosphere entered an interval of apparent eccentricity-paced expansion. Glaciations increased in intensity, revealing a central role for internal climate feedbacks. Comparison of ice volume and ocean temperature records with inferred pCO(2) levels indicates that middle Miocene cryosphere expansion commenced during an interval of Southern Ocean warmth and low atmospheric pCO(2). The Antarctic system appears sensitive to changes in heat/moisture supply when atmospheric pCO(2) was low, suggesting the importance of internal feedbacks in this climate transition. |
format |
Article in Journal/Newspaper |
author |
Shevenell, AE Kennett, JP Lea, DW |
author_facet |
Shevenell, AE Kennett, JP Lea, DW |
author_sort |
Shevenell, AE |
title |
Middle Miocene ice sheet dynamics, deep-sea temperatures, and carbon cycling: A Southern Ocean perspective |
title_short |
Middle Miocene ice sheet dynamics, deep-sea temperatures, and carbon cycling: A Southern Ocean perspective |
title_full |
Middle Miocene ice sheet dynamics, deep-sea temperatures, and carbon cycling: A Southern Ocean perspective |
title_fullStr |
Middle Miocene ice sheet dynamics, deep-sea temperatures, and carbon cycling: A Southern Ocean perspective |
title_full_unstemmed |
Middle Miocene ice sheet dynamics, deep-sea temperatures, and carbon cycling: A Southern Ocean perspective |
title_sort |
middle miocene ice sheet dynamics, deep-sea temperatures, and carbon cycling: a southern ocean perspective |
publisher |
AMER GEOPHYSICAL UNION |
publishDate |
2008 |
url |
https://discovery.ucl.ac.uk/id/eprint/1302365/1/2007GC001736.pdf https://discovery.ucl.ac.uk/id/eprint/1302365/ |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Antarctica Ice Sheet Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Southern Ocean |
op_source |
Geochemistry, Geophysics, Geosystems , 9 , Article Q02006. (2008) |
op_relation |
https://discovery.ucl.ac.uk/id/eprint/1302365/1/2007GC001736.pdf https://discovery.ucl.ac.uk/id/eprint/1302365/ |
op_rights |
open |
_version_ |
1786212554104635392 |