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| Titel |
Mountain uplift and the glaciation of North America – a sensitivity study |
| VerfasserIn |
G. L. Foster, D. J. Lunt, R. R. Parrish |
| 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 ; 6, no. 5 ; Nr. 6, no. 5 (2010-10-25), S.707-717 |
| Datensatznummer |
250003763
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| Publikation (Nr.) |
 copernicus.org/cp-6-707-2010.pdf |
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| Zusammenfassung |
| The Miocene (~24 to ~5 million years ago) was a period of
relative global warmth compared to the Quaternary (~2 million years
ago to present; e.g. Zachos et al., 2001) and was characterised by the
intermittent glaciation of Antarctica only. Paradoxically, the majority of
available proxy data suggest that during the Miocene, pCO2 was similar,
or even lower, than the pre-industrial levels (280 ppmv; Pagani et al.,
1999; Pearson and Palmer, 2000; Kürschner et al., 1996, 2008) and at
times probably crossed the modelled threshold value required for sustained
glaciation in the Northern Hemisphere (DeConto et al., 2008). Records of ice
rafted debris and the oxygen isotope composition of benthic foraminifera
suggest that at several times over the last 25 million years substantial
amounts of continental ice did build up in the Northern Hemisphere but none
of these led to prolonged glaciation. In this contribution, we review
evidence that suggests that in the Miocene the North American Cordillera
was, at least in parts, considerably lower than today. We present new GCM
simulations that imply that small amounts of uplift of the North American
Cordillera result in significant cooling of the northern North American
Continent. Offline ice sheet modelling, driven by these GCM outputs,
suggests that with a reduced topography, inception of the Cordilleran ice
sheet is prohibited. This suggests that uplift of the North American
Cordillera in the Late Miocene may have played an important role in priming
the climate for the intensification of Northern Hemisphere glaciation in the
Late Pliocene. |
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