<gco:CharacterString>Testing for ice sheets during the mid-Cretaceous greenhouse using glassy foraminiferal calcite from the mid-Cenomanian tropics on Demerara Rise</gco:CharacterString>

georefid:2007-075934SEDIS 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/G23589A.1<gco:CharacterString>Testing for ice sheets during the mid-Cretaceous greenhouse using glassy foraminiferal calcite from the mid-Cenomanian tropics on Demerara Rise</gco:CharacterString>2007-01-01publicationgeorefid:2007-075934doi:10.1130/G23589A.1Moriya, KazuyoshiSouthampton School of Ocean & Earth Science, National Oceanography Centre, Southampton, United KingdomauthorWilson, Paul A.Bundesanstalt fuer Geowissenschaften und Rohstoffe, Federal Republic of GermanyauthorFriedrich, OliverUniversity of Tokyo, JapanauthorErbacher, JochenauthorKawahata, HodakaauthorGeological Society of America (GSA), Boulder, CO, United StatespublisherdocumentHardcopyGeology (Boulder)35 (7)615-618The mid-Cretaceous is widely considered the archetypal ice-free greenhouse interval in Earth history, with a thermal maximum around Cenomanian-Turonian boundary time (ca. 90 Ma). However, contemporaneous glaciations have been hypothesized based on sequence stratigraphic evidence for rapid sea-level oscillation and oxygen isotope excursions in records generated from carbonates of questionable preservation and/or of low resolution. We present new oxygen isotope records for the mid-Cenomanian Demerara Rise that are of much higher resolution than previously available, taken from both planktic and benthic foraminifers, and utilizing only extremely well preserved glassy foraminifers. Our records show no evidence of glaciation, calling into question the hypothesized ice sheets and rendering the origin of inferred rapid sea-level oscillations enigmatic. Simple mass-balance calculations demonstrate that this Cretaceous sea-level paradox is unlikely to be explained by hidden ice sheets existing below the limit of delta (super 18) O detection.completedStratigraphyAtlantic OceanbiochemistrycalcitecarbonatesCenomaniancorescovariance analysisCretaceousDemerara RiseEquatorial AtlanticForaminiferageochemical indicatorsgeochemistryglaciationglass materialsgreenhouse effectice sheetsInvertebrataisotope ratiosisotopesLeg 171BLeg 207mass balanceMesozoicmicrofossilsMiddle CretaceousNorth AtlanticNorthwest AtlanticO-18/O-16Ocean Drilling ProgramODP Site 1050ODP Site 1258oxygenpaleo-oceanographypaleoclimatologypreservationProtistasea-level changesstable isotopesstatistical analysistestingtropical environmentUpper Cretaceousurn:org.iodp:exp:171BurnlargerWorkCitationcampaignurn:org.iodp:exp:207urnlargerWorkCitationcampaignurn:org.iodp:exp:171B:site:1050urnlargerWorkCitationstudyurn:org.iodp:exp:171BurnlargerWorkCitationcampaignurn:org.iodp:exp:207:site:1258urnlargerWorkCitationstudyurn:org.iodp:exp:207urnlargerWorkCitationcampaignEnglishgeoscientificInformation-125.0900-54.44009.260044.3400With GSA Data Repository Item 2007153