{"@context":{"@vocab":"https://cir.nii.ac.jp/schema/1.0/","rdfs":"http://www.w3.org/2000/01/rdf-schema#","dc":"http://purl.org/dc/elements/1.1/","dcterms":"http://purl.org/dc/terms/","foaf":"http://xmlns.com/foaf/0.1/","prism":"http://prismstandard.org/namespaces/basic/2.0/","cinii":"http://ci.nii.ac.jp/ns/1.0/","datacite":"https://schema.datacite.org/meta/kernel-4/","ndl":"http://ndl.go.jp/dcndl/terms/","jpcoar":"https://github.com/JPCOAR/schema/blob/master/2.0/"},"@id":"https://cir.nii.ac.jp/crid/1362825893873550336.json","@type":"Article","productIdentifier":[{"identifier":{"@type":"DOI","@value":"10.1029/2002pa000848"}},{"identifier":{"@type":"URI","@value":"https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1029%2F2002PA000848"}},{"identifier":{"@type":"URI","@value":"https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2002PA000848"}}],"dc:title":[{"@value":"Extreme polar warmth during the Cretaceous greenhouse? Paradox of the late Turonian δ<sup>18</sup>O record at Deep Sea Drilling Project Site 511"}],"description":[{"type":"abstract","notation":[{"@value":"<jats:p>Oxygen isotope data for upper Turonian planktonic foraminifera at Deep Sea Drilling Project Site 511 (Falkland Plateau, 60°S paleolatitude) exhibit an ∼2‰ excursion to values as low as −4.66‰ (Vienna Peedee belemnite standard; PDB) coincident with the warmest tropical temperature estimates yet obtained for the open ocean. The lowest planktonic foraminifer δ<jats:sup>18</jats:sup>O values suggest that the upper ocean was as warm as 30–32°C. This is an extraordinary temperature for 60°S latitude but is consistent with temperatures estimated from apparently coeval mollusc δ<jats:sup>18</jats:sup>O from nearby James Ross Island (65°S paleolatitude). Glassy textural preservation, a well‐defined depth distribution in Site 511 planktonics, low sediment burial temperature (∼32°C), and lack of evidence of highly depleted pore waters argue against diagenesis (even solid state diffusion) as the cause of the very depleted planktonic values. The lack of change in benthic foraminifer δ<jats:sup>18</jats:sup>O suggests brackish water capping as the mechanism for the low planktonic δ<jats:sup>18</jats:sup>O values. However, mixing ratio calculations show that the amount of freshwater required to produce a 2‰ shift in ambient water would drive a 7 psu decrease in salinity. The abundance and diversity of planktonic foraminifera and nannofossils, high planktonic:benthic ratios, and the appearance of keeled foraminifera argue against lower‐than‐normal marine salinities. Isotope calculations and climate models indicate that we cannot call upon more depleted freshwater δ<jats:sup>18</jats:sup>O to explain this record. Without more late Turonian data, especially from outside the South Atlantic basin, we can currently only speculate on possible causes of this paradoxical record from the core of the Cretaceous greenhouse.</jats:p>"}]}],"creator":[{"@id":"https://cir.nii.ac.jp/crid/1382825893873550337","@type":"Researcher","foaf:name":[{"@value":"Karen L. Bice"}],"jpcoar:affiliationName":[{"@value":"Department of Geology and Geophysics Woods Hole Oceanographic Institution  Woods Hole Massachusetts USA"}]},{"@id":"https://cir.nii.ac.jp/crid/1382825893873550336","@type":"Researcher","foaf:name":[{"@value":"Brian T. Huber"}],"jpcoar:affiliationName":[{"@value":"Department of Paleobiology Smithsonian National Museum of Natural History  Washington, D. C. USA"}]},{"@id":"https://cir.nii.ac.jp/crid/1382825893873550338","@type":"Researcher","foaf:name":[{"@value":"Richard D. Norris"}],"jpcoar:affiliationName":[{"@value":"Scripps Institution of Oceanography University of California, San Diego  La Jolla California USA"}]}],"publication":{"publicationIdentifier":[{"@type":"PISSN","@value":"08838305"},{"@type":"EISSN","@value":"19449186"}],"prism:publicationName":[{"@value":"Paleoceanography"}],"dc:publisher":[{"@value":"American Geophysical Union (AGU)"}],"prism:publicationDate":"2003-05-07","prism:volume":"18","prism:number":"2","prism:startingPage":"1031"},"reviewed":"false","dc:rights":["http://onlinelibrary.wiley.com/termsAndConditions#vor"],"url":[{"@id":"https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1029%2F2002PA000848"},{"@id":"https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2002PA000848"}],"createdAt":"2003-05-23","modifiedAt":"2023-10-13","relatedProduct":[{"@id":"https://cir.nii.ac.jp/crid/1360565169499510784","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@language":"ja","@value":"Tectonic, paleoclimate, and paleoceanographic history of high-latitude southern margins of Australia during the Cretaceous"}]},{"@id":"https://cir.nii.ac.jp/crid/1360576118733830656","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"Exploring the paleoceanographic changes registered by planktonic foraminifera across the Cenomanian-Turonian boundary interval and Oceanic Anoxic Event 2 at southern high latitudes in the Mentelle Basin (SE Indian Ocean)"}]},{"@id":"https://cir.nii.ac.jp/crid/2050025942136465280","@type":"Article","resourceType":"学術雑誌論文(journal article)","relationType":["isReferencedBy"],"jpcoar:relatedTitle":[{"@value":"Perspective on the response of marine calcifiers to global warming and ocean acidification : behavior of corals and foraminifera in a high CO2 world “hot house”"}]}],"dataSourceIdentifier":[{"@type":"CROSSREF","@value":"10.1029/2002pa000848"},{"@type":"CROSSREF","@value":"10.14379/iodp.pr.369.2018_references_DOI_AI0VJ7islkee15x56CdS1LEMVI2"},{"@type":"CROSSREF","@value":"10.1016/j.gloplacha.2021.103595_references_DOI_AI0VJ7islkee15x56CdS1LEMVI2"},{"@type":"CROSSREF","@value":"10.1186/s40645-018-0239-9_references_DOI_AI0VJ7islkee15x56CdS1LEMVI2"}]}