Orbital forcing, ice volume, and CO 2 across the Oligocene-Miocene Transition
Paleoclimate records suggest that a rapid major transient Antarctic glaciation occurred across the Oligocene-Miocene transition (OMT; ca. 23 Ma; ~50-m sea level equivalent in 200–300 kyr). Orbital forcing has long been cited as an important factor determining the timing of the OMT glacial event. A s...
Published in: | Paleoceanography and Paleoclimatology |
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ftsouthampton:oai:eprints.soton.ac.uk:429475 2024-02-11T09:57:26+01:00 Orbital forcing, ice volume, and CO 2 across the Oligocene-Miocene Transition Greenop, Rosanna Sosdian, Sindia M. Henehan, Michael J. Wilson, Paul A. Lear, Caroline H. Foster, Gavin L. 2019-01-18 text https://eprints.soton.ac.uk/429475/ https://eprints.soton.ac.uk/429475/1/Greenop_etal_OM_manuscript_GREEN_OA.pdf https://eprints.soton.ac.uk/429475/2/Greenop_et_al_2019_Paleoceanography_and_Paleoclimatology.pdf https://eprints.soton.ac.uk/429475/3/Greenop_etal_OM_manuscript_GREEN_OA.pdf en English eng https://eprints.soton.ac.uk/429475/1/Greenop_etal_OM_manuscript_GREEN_OA.pdf https://eprints.soton.ac.uk/429475/2/Greenop_et_al_2019_Paleoceanography_and_Paleoclimatology.pdf https://eprints.soton.ac.uk/429475/3/Greenop_etal_OM_manuscript_GREEN_OA.pdf Greenop, Rosanna, Sosdian, Sindia M., Henehan, Michael J., Wilson, Paul A., Lear, Caroline H. and Foster, Gavin L. (2019) Orbital forcing, ice volume, and CO 2 across the Oligocene-Miocene Transition. Paleoceanography and Paleoclimatology. (doi:10.1029/2018PA003420 <http://dx.doi.org/10.1029/2018PA003420>). other Article PeerReviewed 2019 ftsouthampton https://doi.org/10.1029/2018PA003420 2024-01-25T23:19:29Z Paleoclimate records suggest that a rapid major transient Antarctic glaciation occurred across the Oligocene-Miocene transition (OMT; ca. 23 Ma; ~50-m sea level equivalent in 200–300 kyr). Orbital forcing has long been cited as an important factor determining the timing of the OMT glacial event. A similar orbital configuration occurred 1.2 Myr prior to the OMT, however, and was not associated with a major climate event, suggesting that additional mechanisms play an important role in ice sheet growth and decay. To improve our understanding of the OMT, we present a boron isotope-based CO 2 record between 22 and 24 Ma. This new record shows that δ 11 B/CO 2 was comparatively stable in the million years prior to the OMT glaciation and decreased by 0.7‰ (equivalent to a CO 2 increase of ~65 ppm) over ~300 kyr during the subsequent deglaciation. More data are needed, but we propose that the OMT glaciation was triggered by the same forces that initiated sustained Antarctic glaciation at the Eocene-Oligocene transition: long-term decline in CO 2 to a critical threshold and a superimposed orbital configuration favorable to glaciation (an eccentricity minimum and low-amplitude obliquity change). When comparing the reconstructed CO 2 increase with estimates of δ 18 O sw during the deglaciation phase of the OMT, we find that the sensitivity of the cryosphere to CO 2 forcing is consistent with recent ice sheet modeling studies that incorporate retreat into subglacial basins via ice cliff collapse with modest CO 2 increase, with clear implications for future sea level rise. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet University of Southampton: e-Prints Soton Antarctic Paleoceanography and Paleoclimatology 34 3 316 328 |
institution |
Open Polar |
collection |
University of Southampton: e-Prints Soton |
op_collection_id |
ftsouthampton |
language |
English |
description |
Paleoclimate records suggest that a rapid major transient Antarctic glaciation occurred across the Oligocene-Miocene transition (OMT; ca. 23 Ma; ~50-m sea level equivalent in 200–300 kyr). Orbital forcing has long been cited as an important factor determining the timing of the OMT glacial event. A similar orbital configuration occurred 1.2 Myr prior to the OMT, however, and was not associated with a major climate event, suggesting that additional mechanisms play an important role in ice sheet growth and decay. To improve our understanding of the OMT, we present a boron isotope-based CO 2 record between 22 and 24 Ma. This new record shows that δ 11 B/CO 2 was comparatively stable in the million years prior to the OMT glaciation and decreased by 0.7‰ (equivalent to a CO 2 increase of ~65 ppm) over ~300 kyr during the subsequent deglaciation. More data are needed, but we propose that the OMT glaciation was triggered by the same forces that initiated sustained Antarctic glaciation at the Eocene-Oligocene transition: long-term decline in CO 2 to a critical threshold and a superimposed orbital configuration favorable to glaciation (an eccentricity minimum and low-amplitude obliquity change). When comparing the reconstructed CO 2 increase with estimates of δ 18 O sw during the deglaciation phase of the OMT, we find that the sensitivity of the cryosphere to CO 2 forcing is consistent with recent ice sheet modeling studies that incorporate retreat into subglacial basins via ice cliff collapse with modest CO 2 increase, with clear implications for future sea level rise. |
format |
Article in Journal/Newspaper |
author |
Greenop, Rosanna Sosdian, Sindia M. Henehan, Michael J. Wilson, Paul A. Lear, Caroline H. Foster, Gavin L. |
spellingShingle |
Greenop, Rosanna Sosdian, Sindia M. Henehan, Michael J. Wilson, Paul A. Lear, Caroline H. Foster, Gavin L. Orbital forcing, ice volume, and CO 2 across the Oligocene-Miocene Transition |
author_facet |
Greenop, Rosanna Sosdian, Sindia M. Henehan, Michael J. Wilson, Paul A. Lear, Caroline H. Foster, Gavin L. |
author_sort |
Greenop, Rosanna |
title |
Orbital forcing, ice volume, and CO 2 across the Oligocene-Miocene Transition |
title_short |
Orbital forcing, ice volume, and CO 2 across the Oligocene-Miocene Transition |
title_full |
Orbital forcing, ice volume, and CO 2 across the Oligocene-Miocene Transition |
title_fullStr |
Orbital forcing, ice volume, and CO 2 across the Oligocene-Miocene Transition |
title_full_unstemmed |
Orbital forcing, ice volume, and CO 2 across the Oligocene-Miocene Transition |
title_sort |
orbital forcing, ice volume, and co 2 across the oligocene-miocene transition |
publishDate |
2019 |
url |
https://eprints.soton.ac.uk/429475/ https://eprints.soton.ac.uk/429475/1/Greenop_etal_OM_manuscript_GREEN_OA.pdf https://eprints.soton.ac.uk/429475/2/Greenop_et_al_2019_Paleoceanography_and_Paleoclimatology.pdf https://eprints.soton.ac.uk/429475/3/Greenop_etal_OM_manuscript_GREEN_OA.pdf |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_relation |
https://eprints.soton.ac.uk/429475/1/Greenop_etal_OM_manuscript_GREEN_OA.pdf https://eprints.soton.ac.uk/429475/2/Greenop_et_al_2019_Paleoceanography_and_Paleoclimatology.pdf https://eprints.soton.ac.uk/429475/3/Greenop_etal_OM_manuscript_GREEN_OA.pdf Greenop, Rosanna, Sosdian, Sindia M., Henehan, Michael J., Wilson, Paul A., Lear, Caroline H. and Foster, Gavin L. (2019) Orbital forcing, ice volume, and CO 2 across the Oligocene-Miocene Transition. Paleoceanography and Paleoclimatology. (doi:10.1029/2018PA003420 <http://dx.doi.org/10.1029/2018PA003420>). |
op_rights |
other |
op_doi |
https://doi.org/10.1029/2018PA003420 |
container_title |
Paleoceanography and Paleoclimatology |
container_volume |
34 |
container_issue |
3 |
container_start_page |
316 |
op_container_end_page |
328 |
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1790609733642616832 |