georefid:2012-099718SEDIS Publication Catalogue
ana.macario@awi.de
http://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1029/2008PA001645<gco:CharacterString>Early Pliocene increase in thermohaline overturning; a precondition for the development of the modern Equatorial Pacific cold tongue</gco:CharacterString>2010-01-01publicationgeorefid:2012-099718doi:10.1029/2008PA001645Steph, SilkeAlfred Wegener Institute for Polar and Marine Research, Bremerhaven, GermanyauthorTiedemann, RalfUniversity of Bremen, GermanyauthorPrange, MatthiasUniversity of Hawaii-Manoa, United StatesauthorGroeneveld, JeroenLeibniz Institute of Marine Sciences, GermanyauthorSchulz, MichaelBundesanstalt fuer Geowissenschaften und Rohstoffe, GermanyauthorTimmermann, AxelETH Zurich, SwitzerlandauthorNuernberg, DirkauthorRuehlemann, CarstenauthorSaukel, CorneliaauthorHaug, Gerald H.authorAmerican Geophysical Union, Washington, DC, United StatespublisherdocumentHardcopyPaleoceanography25 (2)Unraveling the processes responsible for Earth's climate transition from an "El Nino-like state" during the warm early Pliocene into a modern-like "La Nina-dominated state" currently challenges the scientific community. Recently, the Pliocene climate switch has been linked to oceanic thermocline shoaling at approximately 3 million years ago along with Earth's final transition into a bipolar icehouse world. Here we present Pliocene proxy data and climate model results, which suggest an earlier timing of the Pliocene climate switch and a different chain of forcing mechanisms. We show that the increase in North Atlantic meridional overturning circulation between 4.8 and 4.0 million years ago, initiated by the progressive closure of the Central American Seaway, triggered overall shoaling of the tropical thermocline. This preconditioned the turnaround from a warm eastern equatorial Pacific to the modern equatorial cold tongue state about 1 million years earlier than previously assumed. Since approximately 3.6-3.5 million years ago, the intensification of Northern Hemisphere glaciation resulted in a strengthening of the trade winds, thereby amplifying upwelling and biogenic productivity at low latitudes.completedStratigraphyalkaline earth metalsalkenonesAtlantic OceanC-13/C-12calciumcarbonCaribbean SeaCarnegie RidgeCenozoicchemostratigraphyCocos RidgeColombian Basincoresdepthdigital simulationEast PacificEquatorial PacificForaminiferaframework silicatesgeneral circulation modelsInvertebrataisotope ratiosisotopesketonesLeg 165Leg 202lower Pliocenemagnesiummarine sedimentsmetalsMg/CamicrofossilsNeogeneNicaragua RiseNorth Atlanticnumerical modelsO-18/O-16ocean circulationOcean Drilling ProgramODP Site 1000ODP Site 1239ODP Site 1241ODP Site 999opalorganic compoundsoxygenPacific Oceanpaleo-oceanographypaleoclimatologypaleotemperaturePlioceneProtistasea-surface temperaturesedimentationsedimentation ratessedimentssilica mineralssilicatesSouth PacificSoutheast Pacificstable isotopesTertiarythermoclinethermohaline circulationurn:org.iodp:exp:165urnlargerWorkCitationcampaignurn:org.iodp:exp:202urnlargerWorkCitationcampaignurn:org.iodp:exp:165:site:1000urnlargerWorkCitationstudyurn:org.iodp:exp:165urnlargerWorkCitationcampaignurn:org.iodp:exp:202:site:1239urnlargerWorkCitationstudyurn:org.iodp:exp:202urnlargerWorkCitationcampaignurn:org.iodp:exp:202:site:1241urnlargerWorkCitationstudyurn:org.iodp:exp:202urnlargerWorkCitationcampaignurn:org.iodp:exp:165:site:999urnlargerWorkCitationstudyurn:org.iodp:exp:165urnlargerWorkCitationcampaignEnglishgeoscientificInformation-86.2700-78.4422-0.400016.3313