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| Titel |
Planktic foraminiferal stable-isotopes across the EECO: investigating the
coupling between temperature and the exogenic carbon pool (ODP Site 1263,
Walvis Ridge) |
| VerfasserIn |
Cindy Schrader, Vittoria Lauretano, James C. Zachos, Lucas J. 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 |
250129703
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| Publikation (Nr.) |
 EGU/EGU2016-9850.pdf |
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| Zusammenfassung |
| The Late Paleocene to Early Eocene warming trend is characterized by a gradual temperature
rise of 5-6˚ C resulting in the Early Eocene Climatic Optimum “EECO”. This warming trend
was punctuated by several so-called “hyperthermals”, which were geologically brief
(<200kyr) episodes of extreme warmth. Recently, a new, ∼4.7 million year (Myr) long,
high-resolution benthic foraminiferal stable isotope record of ODP Site 1263 has been
presented, which encompasses the peak of the early Eocene “hothouse” (∼49.5 -
54.2 Ma). This record confirms the presence of hyperthermals during and at the
termination of the EECO as was previously found for ODP Site 1258. In addition, the
record reveals a highly significant linear relationship between ∂18O and ∂13C for
these events, similar as for their early Eocene counterparts. This indicates a strong
coupling between global warming and the release of isotopically light carbon into
the ocean-atmosphere system throughout the EECO. Whilst the coupling between
temperature changes and perturbations in the exogenic carbon pool remain stable on
short-term time scales, they do not for the long-term trends at ∼52 Ma when a
rapid 13C enrichment in carbon data is not accompanied by changes in the oxygen
record. It was hypothesized that enhanced carbonate and organic carbon burial rates
might be responsible for this shift in average isotopic values during a temporary
reduced efficiency of the biological pump. Such a scenario may explain the elevated
atmospheric pCO2 as well as increased weathering rates and runoff. To test this
hypothesis, we will present our first (preliminary) stable isotopic results of two planktic
foraminiferal species derived from the same samples of ODP Site 1263, which portray
changes in surface water (Acarinina ssp.) and thermocline waters (Subbotina ssp.). |
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