georefid:2012-019576SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=2012-019576<gco:CharacterString>Review of paleoceanographic transition during the Oligocene in the eastern Equatorial Pacific Ocean</gco:CharacterString>2007-01-01publicationgeorefid:2012-019576Takata, HiroyukiShimane University, Research Center for Coastal Lagoon Environments, Matsue, JapanauthorNomura, RitsuoauthorSeto, KojiauthorPalaeontological Society of Japan, [Tokyo], JapanpublisherdocumentHardcopyKaseki = Fossils815-14Paleoceanographic condition in the deep-sea ocean during the Eocene-Oligocene transition is affected by change in ice volume in the Antarctic region and deep-water formation in the Southern Ocean. ODP Leg 199 in the eastern equatorial Pacific Ocean recovered continuous sections containing well-preserved microfossils during the Eocene-Oligocene interval, and provides an opportunity to study this transition. In this paper, we review recent results of the Oligocene paleoceanography and outlines of faunal change in benthic foraminifers in the eastern equatorial Pacific Ocean. Sedimentary records from ODP Leg 199 represent a deepening of calcite compensation depth (CCD) more than 1 km near the Eocene/Oligocene boundary in the eastern equatorial Pacific Ocean. Around the interval of CCD change, two-step positive sifts of oxygen isotope occurred in benthic foraminifers within approximately 300 kyrs. The glaciation events marked by the Oil isotope event coincide with the intervals of low eccentricity and low obliquity amplitude variations, due to absence of warm summer. Other three glacial events of 29.16, 27.91 and 26.76 Ma during the Oligocene are probably related to low obliquity amplitude variation fluctuating with about a 1200 kyr.-cycle. Abyssal benthic foraminifers show an increase in Antarctic-bottom water fauna (Nuttallides umbonifer) around the Early/Late Oligocene boundary in the eastern equatorial Pacific Ocean. The short-term abundance peaks of Nuttalides umbonifer are correlative with the Oi event, suggesting that this species could be useful as a proxy of the Antarctic ice-sheet expansions.completedStratigraphyAntarcticaassemblagesAtlantic OceanBay of Biscaybenthic taxaCantabria SeamountCenozoicDeep Sea Drilling Projectdeep-sea environmentDSDP Site 119DSDP Site 317DSDP Site 526DSDP Site 558DSDP Site 563East PacificEquatorial PacificForaminiferaglaciationInvertebrataIPODLeg 12Leg 199Leg 33Leg 74Leg 82Manihiki Plateaumarine environmentmicrofossilsMid-Atlantic RidgeNorth AtlanticNorth PacificNortheast PacificOcean Drilling ProgramODP Site 1218ODP Site 1219OligocenePacific Oceanpaleo-oceanographypaleoclimatologypaleoenvironmentPaleogeneProtistaSouth AtlanticSouth PacificSoutheast PacificSouthern OceanTertiaryWalvis Ridgeurn:org.iodp:exp:12urnlargerWorkCitationcampaignurn:org.iodp:exp:199urnlargerWorkCitationcampaignurn:org.iodp:exp:33urnlargerWorkCitationcampaignurn:org.iodp:exp:74urnlargerWorkCitationcampaignurn:org.iodp:exp:82urnlargerWorkCitationcampaignurn:org.iodp:exp:12:site:119urnlargerWorkCitationstudyurn:org.iodp:exp:12urnlargerWorkCitationcampaignurn:org.iodp:exp:33:site:317urnlargerWorkCitationstudyurn:org.iodp:exp:33urnlargerWorkCitationcampaignurn:org.iodp:exp:74:site:526urnlargerWorkCitationstudyurn:org.iodp:exp:74urnlargerWorkCitationcampaignurn:org.iodp:exp:82:site:558urnlargerWorkCitationstudyurn:org.iodp:exp:82urnlargerWorkCitationcampaignurn:org.iodp:exp:82:site:563urnlargerWorkCitationstudyurn:org.iodp:exp:82urnlargerWorkCitationcampaignurn:org.iodp:exp:199:site:1218urnlargerWorkCitationstudyurn:org.iodp:exp:199urnlargerWorkCitationcampaignurn:org.iodp:exp:199:site:1219urnlargerWorkCitationstudyurn:org.iodp:exp:199urnlargerWorkCitationcampaignJapanesegeoscientificInformation-162.15473.0818-30.072437.4615