Evolution of Atlantic thermohaline circulation: Early Oligocene onset of deep-water production in the North Atlantic

Research Article| June 01, 2006 Evolution of Atlantic thermohaline circulation: Early Oligocene onset of deep-water production in the North Atlantic Rachael K. Via; Rachael K. Via 1Department of Oceanography, Texas A Evolution of Atlantic thermohaline circulation: Early Oligocene onset of deep-water production in the North Atlantic. Geology 2006;; 34 (6): 441–444. doi: https://doi.org/10.1130/G22545.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search 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 ∼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. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.