Global carbon cycle perturbation across the Eocene-Oligocene climate transition
The Eocene-Oligocene transition (EOT), ~34?Ma, marks a tipping point in the long-term Cenozoic greenhouse to icehouse climate transition. Paleorecords reveal stepwise rapid cooling and ice growth across the EOT tightly coupled to a transient benthic ?13C excursion and a major and permanent deepening...
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Online Access: | https://eprints.soton.ac.uk/388252/ https://eprints.soton.ac.uk/388252/1/palo20297.pdf |
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ftsouthampton:oai:eprints.soton.ac.uk:388252 2024-02-11T10:04:42+01:00 Global carbon cycle perturbation across the Eocene-Oligocene climate transition Armstrong Mckay, David Tyrrell, Toby Wilson, Paul A. 2016-02-20 text https://eprints.soton.ac.uk/388252/ https://eprints.soton.ac.uk/388252/1/palo20297.pdf en English eng https://eprints.soton.ac.uk/388252/1/palo20297.pdf Armstrong Mckay, David, Tyrrell, Toby and Wilson, Paul A. (2016) Global carbon cycle perturbation across the Eocene-Oligocene climate transition. Paleoceanography, 31 (2), 311-329. (doi:10.1002/2015PA002818 <http://dx.doi.org/10.1002/2015PA002818>). cc_by_4 Article PeerReviewed 2016 ftsouthampton https://doi.org/10.1002/2015PA002818 2024-01-25T23:18:59Z The Eocene-Oligocene transition (EOT), ~34?Ma, marks a tipping point in the long-term Cenozoic greenhouse to icehouse climate transition. Paleorecords reveal stepwise rapid cooling and ice growth across the EOT tightly coupled to a transient benthic ?13C excursion and a major and permanent deepening of the carbonate compensation depth (CCD). Based on biogeochemical box modeling, Merico et al. (2008) suggested that a combination of (1) glacioeustatic sea level fall-induced shelf-basin carbonate burial fractionation and (2) shelf carbonate weathering can account for the carbon cycle perturbation, but this finding has been questioned. Alternative proposed mechanisms include increased ocean ventilation, decreased carbonate burial, increased organic carbon burial, increased silicate weathering, and increased ocean calcium concentration. Here we use an improved version of the biogeochemical box model of Merico et al. (2008) to reevaluate these competing hypotheses and an additional mechanism, the expansion of “carbon capacitors” such as permafrost and peatlands. We find that changes in calcium concentration, silicate weathering, and carbonate or organic carbon burial each yield a response that is fundamentally at odds with the form and/or sign of the paleorecords. Shelf-basin carbonate burial fractionation (CCD change), plus shelf carbonate weathering, sequestration of 12C-enriched carbon into carbon capacitors, and possibly increased ocean ventilation (?13C excursion), offers the best fit to the paleorecords. Further work is needed to understand why the EOT carbon cycle perturbation is so unique when the forcing mechanisms hypothesized to be responsible (cooling and ice growth) are not peculiar to this event. Article in Journal/Newspaper Ice permafrost University of Southampton: e-Prints Soton Paleoceanography 31 2 311 329 |
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Open Polar |
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University of Southampton: e-Prints Soton |
op_collection_id |
ftsouthampton |
language |
English |
description |
The Eocene-Oligocene transition (EOT), ~34?Ma, marks a tipping point in the long-term Cenozoic greenhouse to icehouse climate transition. Paleorecords reveal stepwise rapid cooling and ice growth across the EOT tightly coupled to a transient benthic ?13C excursion and a major and permanent deepening of the carbonate compensation depth (CCD). Based on biogeochemical box modeling, Merico et al. (2008) suggested that a combination of (1) glacioeustatic sea level fall-induced shelf-basin carbonate burial fractionation and (2) shelf carbonate weathering can account for the carbon cycle perturbation, but this finding has been questioned. Alternative proposed mechanisms include increased ocean ventilation, decreased carbonate burial, increased organic carbon burial, increased silicate weathering, and increased ocean calcium concentration. Here we use an improved version of the biogeochemical box model of Merico et al. (2008) to reevaluate these competing hypotheses and an additional mechanism, the expansion of “carbon capacitors” such as permafrost and peatlands. We find that changes in calcium concentration, silicate weathering, and carbonate or organic carbon burial each yield a response that is fundamentally at odds with the form and/or sign of the paleorecords. Shelf-basin carbonate burial fractionation (CCD change), plus shelf carbonate weathering, sequestration of 12C-enriched carbon into carbon capacitors, and possibly increased ocean ventilation (?13C excursion), offers the best fit to the paleorecords. Further work is needed to understand why the EOT carbon cycle perturbation is so unique when the forcing mechanisms hypothesized to be responsible (cooling and ice growth) are not peculiar to this event. |
format |
Article in Journal/Newspaper |
author |
Armstrong Mckay, David Tyrrell, Toby Wilson, Paul A. |
spellingShingle |
Armstrong Mckay, David Tyrrell, Toby Wilson, Paul A. Global carbon cycle perturbation across the Eocene-Oligocene climate transition |
author_facet |
Armstrong Mckay, David Tyrrell, Toby Wilson, Paul A. |
author_sort |
Armstrong Mckay, David |
title |
Global carbon cycle perturbation across the Eocene-Oligocene climate transition |
title_short |
Global carbon cycle perturbation across the Eocene-Oligocene climate transition |
title_full |
Global carbon cycle perturbation across the Eocene-Oligocene climate transition |
title_fullStr |
Global carbon cycle perturbation across the Eocene-Oligocene climate transition |
title_full_unstemmed |
Global carbon cycle perturbation across the Eocene-Oligocene climate transition |
title_sort |
global carbon cycle perturbation across the eocene-oligocene climate transition |
publishDate |
2016 |
url |
https://eprints.soton.ac.uk/388252/ https://eprints.soton.ac.uk/388252/1/palo20297.pdf |
genre |
Ice permafrost |
genre_facet |
Ice permafrost |
op_relation |
https://eprints.soton.ac.uk/388252/1/palo20297.pdf Armstrong Mckay, David, Tyrrell, Toby and Wilson, Paul A. (2016) Global carbon cycle perturbation across the Eocene-Oligocene climate transition. Paleoceanography, 31 (2), 311-329. (doi:10.1002/2015PA002818 <http://dx.doi.org/10.1002/2015PA002818>). |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.1002/2015PA002818 |
container_title |
Paleoceanography |
container_volume |
31 |
container_issue |
2 |
container_start_page |
311 |
op_container_end_page |
329 |
_version_ |
1790601414460833792 |