georefid:2006-051795SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1130/G22545.12006-01-01publicationgeorefid:2006-051795doi:10.1130/G22545.1Via, Rachael K.Texas A&M University, Department of Oceanography, College Station, TX, United StatesauthorThomas, Deborah J.authorGeological Society of America (GSA), Boulder, CO, United StatespublisherdocumentHardcopyGeology (Boulder)34 (6)441-444The 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.completedStratigraphyIsotope geochemistryAtlantic OceanCenozoicclimate changecoolingcoresdeep-sea environmentdeep-water environmentgeochemistryIceland-Faeroe Ridgeisotope ratiosisotopesLeg 113Leg 208lower Oligocenemarine environmentmarine sedimentsmetalsmid-ocean ridgesNd-144/Nd-143neodymiumNorth Atlanticocean circulationOcean Drilling ProgramODP Site 1262ODP Site 1263ODP Site 1264ODP Site 689Oligocenepaleo-oceanographypaleocirculationpaleoclimatologyPaleogeneplate tectonicsrare earthsreconstructionsedimentsSouth AtlanticSouthern Oceanstable isotopesTertiarythermohaline circulationWalvis Ridgeurn:org.iodp:exp:113urnlargerWorkCitationcampaignurn:org.iodp:exp:208urnlargerWorkCitationcampaignurn:org.iodp:exp:208:site:1262urnlargerWorkCitationstudyurn:org.iodp:exp:208urnlargerWorkCitationcampaignurn:org.iodp:exp:208:site:1263urnlargerWorkCitationstudyurn:org.iodp:exp:208urnlargerWorkCitationcampaignurn:org.iodp:exp:208:site:1264urnlargerWorkCitationstudyurn:org.iodp:exp:208urnlargerWorkCitationcampaignurn:org.iodp:exp:113:site:689urnlargerWorkCitationstudyurn:org.iodp:exp:113urnlargerWorkCitationcampaignEnglishgeoscientificInformation1.34003.0600-64.3101-27.1100With GSA Data Repository Item 2006087