Via, Rachael K.; Thomas, Deborah J. (2006): Evolution of Atlantic thermohaline circulation; early Oligocene onset of deep-water production in the North Atlantic. Geological Society of America (GSA), Boulder, CO, United States, Geology (Boulder), 34 (6), 441-444, georefid:2006-051795
Abstract:
The flow of deep-water masses is a key component of heat transport in the modern climate system, yet the role of deep-ocean heat transport during periods of extreme warmth is poorly understood. The present mode of meridional overturning circulation is characterized by deep-water formation in both the North Atlantic and the Southern Ocean. However, a different mode of meridional overturning circulation operated during the extreme greenhouse warmth of the early Cenozoic, during which time the Southern Ocean was the dominant region of deep-water formation. The combination of general global cooling and tectonic evolution of the Atlantic basins over the past approximately 55 m.y. ultimately led to the development of a mode of overturning circulation characterized by both Southern Ocean and North Atlantic deep-water sources. The change in deep-water circulation mode may, in turn, have affected global climate; however, unraveling the causes and consequences of this transition requires a better understanding of the timing of the transition. New Nd isotope data from the southeastern Atlantic Ocean indicate that the initial transition to a bipolar mode of deep-water circulation occurred in the early Oligocene, ca. 33 Ma. The likely cause of significant deep-water production in the North Atlantic was tectonic deepening of the sill separating the Greenland-Norwegian Sea from the North Atlantic.
Coverage:
West: 1.3400 East: 3.0600 North: -27.1100 South: -64.3101
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Supplemental Information:
With GSA Data Repository Item 2006087
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