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| Titel |
Frequency, magnitude and character of hyperthermal events at the onset of the Early Eocene Climatic Optimum |
| VerfasserIn |
V. Lauretano, K. Littler, M. Polling, J. C. Zachos, L. J. Lourens |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 11, no. 10 ; Nr. 11, no. 10 (2015-10-07), S.1313-1324 |
| Datensatznummer |
250117432
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| Publikation (Nr.) |
 copernicus.org/cp-11-1313-2015.pdf |
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| Zusammenfassung |
| Recent studies have shown that the Early Eocene Climatic Optimum (EECO) was
preceded by a series of short-lived global warming events, known as
hyperthermals. Here we present high-resolution benthic stable carbon and
oxygen isotope records from ODP Sites 1262 and 1263 (Walvis Ridge, SE
Atlantic) between ~ 54 and ~ 52 million years
ago, tightly constraining the character, timing, and magnitude of six
prominent hyperthermal events. These events, which include Eocene Thermal
Maximum (ETM) 2 and 3, are studied in relation to orbital forcing and
long-term trends. Our findings reveal an almost linear relationship between
δ13C and δ18O for all these hyperthermals,
indicating that the eccentricity-paced covariance between deep-sea
temperature changes and extreme perturbations in the exogenic carbon pool
persisted during these events towards the onset of the EECO, in accordance with
previous observations for the Paleocene Eocene Thermal Maximum (PETM) and
ETM2. The covariance of δ13C and δ18O during H2
and I2, which are the second pulses of the "paired" hyperthermal events
ETM2-H2 and I1-I2, deviates with respect to the other events. We hypothesize
that this could relate to a relatively higher contribution of an
isotopically heavier source of carbon, such as peat or permafrost, and/or to
climate feedbacks/local changes in circulation. Finally, the δ18O records of the two sites show a systematic offset with on average
0.2 ‰ heavier values for the shallower Site 1263, which
we link to a slightly heavier isotopic composition of the intermediate water
mass reaching the northeastern flank of the Walvis Ridge compared to that of
the deeper northwestern water mass at Site 1262. |
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