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| Titel |
The MMCO-EOT conundrum: same benthic δ18O, different CO2 |
| VerfasserIn |
Lennert Stap, Roderik van de Wal, Bas De Boer, Richard Bintanja, Lucas Lourens |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250123754
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| Publikation (Nr.) |
 EGU/EGU2016-3059.pdf |
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| Zusammenfassung |
| Knowledge on temporal variations of Earth’s climate over the past 38 Myr largely stems from
benthic δ18O records. These records are difficult to interpret, however, since they document
combined effects of deep-sea temperature and ice volume variations. Information
on CO2 is expanding, but remains highly uncertain and intermittent. Attempts to
determine the long-term relations between δ18O, sea level and CO2 from proxy data
suffer from paucity of data and apparent inconsistency among different records.
One outstanding issue is the difference recorded in proxy CO2 data between the
Eocene-Oligocene boundary (EOT) and the Middle-Miocene Climatic Optimum (MMCO),
while similar levels of benthic δ18O are shown during these time periods. Here, we take
a model-based approach to deconvolute the benthic δ18O signal, and reconcile
knowledge on benthic δ18O, sea level, CO2 and temperature. We obtain continuous
and mutually consistent 38-Myr-long simulations of these variables, by forcing a
coupled ice sheet-climate model inversely with benthic δ18O observations. We
investigate the factors influencing Arctic and Antarctic polar amplification, and the
relation between sea level and CO2. Furthermore, we show that different CO2
between the EOT and MMCO, as indicated by proxy data, can only be obtained
if we impose erosion or tectonic movement of the Antarctic continent over time. |
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