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| Titel |
Evidence from "Köppen signatures" of fossil plant assemblages for effective heat transport of Gulf Stream to subarctic North Atlantic during Miocene cooling |
| VerfasserIn |
T. Denk, G. W. Grimm, F. Grímsson, R. Zetter |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 12 ; Nr. 10, no. 12 (2013-12-06), S.7927-7942 |
| Datensatznummer |
250085458
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| Publikation (Nr.) |
 copernicus.org/bg-10-7927-2013.pdf |
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| Zusammenfassung |
| Shallowing of the Panama Sill and the closure of the Central American Seaway
initiated the modern Loop Current–Gulf Stream circulation pattern during the
Miocene, but no direct evidence has yet been provided for effective heat
transport to the northern North Atlantic during that time. Climatic signals
from 11 precisely dated plant-bearing sedimentary rock formations in Iceland,
spanning 15–0.8 million years (Myr), resolve the impacts of the developing
Miocene global thermohaline circulation on terrestrial vegetation in the
subarctic North Atlantic region. "Köppen signatures" were implemented
to express climatic properties of fossil plant taxa and their potential
modern analogues using the principal concept of the generic Köppen–Geiger
climate system, which is based on plant distribution patterns. Using
Köppen signatures and the correlation between Köppen climate zones
and major global vegetation zones, fossil assemblages were used to trace
major vegetation shifts. This evidence was combined with evidence from
tectonics and palaeoceanography. In contrast to the global climatic trend,
the vegetation record reveals no cooling between ~ 15 and 12 Myr,
whereas periods of climatic deterioration between 12 and 10 Myr, 8 and 4 Myr, and
in the Pleistocene are in phase with increased pulses of ice-rafted debris in
the Northern Hemisphere. The observed sequence of climate change in the
northern North Atlantic can most likely be explained by an effective Gulf
Stream-mediated heat transport from the middle Miocene onwards. |
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