georefid:2013-035818SEDIS 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=10.1029/2010PA0019502011-01-01publicationgeorefid:2013-035818doi:10.1029/2010PA001950Pusz, A. E.University of South Carolina, Department of Earth and Ocean Sciences, Columbia, SC, United StatesauthorThunell, R. C.Rutgers University, United StatesauthorMiller, K. G.authorAmerican Geophysical Union, Washington, DC, United StatespublisherdocumentHardcopyPaleoceanography26 (2)Paired benthic foraminiferal stable isotope and Mg/Ca data are used to estimate bottom water temperature (BWT) and ice volume changes associated with the Eocene-Oligocene Transition (EOT), the largest global climate event of the past 50 Myr. We utilized ODP Sites 1090 and 1265 in the South Atlantic to assess seawater delta (super 18) O (delta (sub w) ), Antarctic ice volume, and sea level changes across the EOT ( approximately 33.8-33.54 Ma). We also use benthic delta (super 13) C data to reconstruct the sources of the deep water masses in this region during the EOT. Our data, together with previously published records, indicate that a pulse of Northern Component Water influenced the South Atlantic immediately prior to and following the EOT. Benthic delta (super 18) O records show a 0.5ppm increase at approximately 33.8 Ma (EOT-1) that represents a approximately 2 degrees C cooling and a small ( approximately 10 m) eustatic fall that is followed by a 1.0 ppm increase associated with Oi-1. The expected cooling of deep waters at Oi-1 ( approximately 33.54 Ma) is not apparent in our Mg/Ca records. We suggest the cooling is masked by coeval changes in the carbonate saturation state (Delta [CO (sub 3) (super 2-) ]) which affect the Mg/Ca data. To account for this, the BWT, ice volume, and delta (sub w) estimates are corrected for a change in the Delta [CO (sub 3) (super 2-) ] of deep waters on the basis of recently published work. Corrected BWT at Sites 1090 and 1265 show a approximately 1.5 degrees C cooling coincident with Oi-1 and an average delta (sub w) increase of approximately 0.75ppm. The increase in ice volume during Oi-1 resulted in a approximately 70 m drop in global sea level and the development of an Antarctic ice sheet that was near modern size or slightly larger.completedStratigraphyalkaline earth metalsAtlantic OceanC-13/C-12calciumcarboncarbonate ionCenozoicchemostratigraphyclimate changecoresEoceneForaminiferaInvertebrataisotope ratiosisotopesLeg 177Leg 208lithostratigraphylower Oligocenemagnesiummarine sedimentsmetalsMg/CamicrofossilsO-18/O-16Ocean Drilling ProgramODP Site 1090ODP Site 1265Oligoceneoxygenpaleo-oceanographypaleoclimatologyPaleogenepaleotemperatureProtistasedimentsSouth Atlanticstable isotopesTertiaryupper EoceneWalvis Ridgeurn:org.iodp:exp:177urnlargerWorkCitationcampaignurn:org.iodp:exp:208urnlargerWorkCitationcampaignurn:org.iodp:exp:177:site:1090urnlargerWorkCitationstudyurn:org.iodp:exp:177urnlargerWorkCitationcampaignurn:org.iodp:exp:208:site:1265urnlargerWorkCitationstudyurn:org.iodp:exp:208urnlargerWorkCitationcampaignEnglishgeoscientificInformation2.38008.5359-42.5449-28.5000