Role of the Greenland-Scotland Ridge in Neogene Climate Changes
Abstract Cenozoic climates are marked by long-term cooling since the early Eocene that evolved into the large amplitude glacial/interglacial cycles of the late Pleistocene. Circulation models (both atmospheric and oceanic) have simulated these changes by altering the concentration of atmospheric tra...
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| Format: | Book Part |
| Language: | unknown |
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Oxford University PressNew York, NY
1998
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| Online Access: | http://dx.doi.org/10.1093/oso/9780195112450.003.0009 https://academic.oup.com/book/chapter-pdf/52433466/isbn-9780195112450-book-part-9.pdf |
| Summary: | Abstract Cenozoic climates are marked by long-term cooling since the early Eocene that evolved into the large amplitude glacial/interglacial cycles of the late Pleistocene. Circulation models (both atmospheric and oceanic) have simulated these changes by altering the concentration of atmospheric trace gases (i.e., increased CO2) or by changing the meridional heat transports (increased delivery of heat to the poles via oceanic circulation) (e.g., Barron, 1983, 1987; Manabe and Bryan, 1985; Rind, 1987; Covey and Barron, 1988; Covey and Thompson, 1989; Manabe et al., 1990; Rind and Chandler, 1991). There is evidence in support of both mechanisms, leaving unclear the fundamental cause of the long-term climate change during the Cenozoic. Identifying mechanisms that triggered Cenozoic cooling has focused on tectonic changes, both marine and terrestrial, that fundamentally altered the ocean-atmosphere system. Arrangements of continents and marine gateways dictate surface and deep-water circulation patterns, and therefore, how water masses communicate between the ocean basins. Opening of the Drake Passage and uplift of the Central American Isthmus are two gateways that are often associated with climate change. The Drake Passage gateway is thought to be a critical “valve” in the development of a circumpolar circulation that led to the thermal isolation of Antarctica (Kennett, 1977). The closure of the Central American Isthmus has been implicated as a potential causes for largescale Northern Hemisphere glaciation (Keigwin, 1982) and the formation of deepwater in the North Atlantic (Keigwin, 1982; Maier-Reimer et al., 1990). |
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