georefid:2011-056395SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1073/pnas.0908874106<gco:CharacterString>Absence of geochemical evidence for an impact event at the Bolling-Allerod/Younger Dryas transition</gco:CharacterString>2009-01-01publicationgeorefid:2011-056395doi:10.1073/pnas.0908874106Paquay, Francois S.University of Hawaii at Manoa, Department of Geology and Geophysics, Honolulu, HI, United StatesauthorCoderis, StevenVirje Universiteit Brussel, BelgiumauthorRavizza, GregUniversiteit Ghent, BelgiumauthorVanhaecke, FrankLakehead University, CanadaauthorBoyd, MatthewUniversity of Wyoming, United StatesauthorSurovell, Todd A.University of Arizona, United StatesauthorHolliday, Vance T.authorHaynes, C. Vance, Jr.authorClaeys, PhilippeauthorNational Academy of Sciences, Washington, DC, United StatespublisherdocumentDigitalProceedings of the National Academy of Sciences of the United States of America106 (51)21505-21510High concentrations of iridium have been reported in terrestrial sediments dated at 12.9 ka and are interpreted to support an extraterrestrial impact event as the cause of the observed extinction in the Rancholabrean fauna, changes in the Paleoindian cultures, and the onset of the Younger Dryas cooling [Firestone RB, et al. (2007) Proc. Natl. Acad. Sci. USA 104:16016-16021]. Here, we report platinum group element (PGE; Os, Ir, Ru, Rh, Pt, Pd), gold (Au) concentrations, and (super 187) Os/ (super 188) Os ratios in time-equivalent terrestrial, lacustrine, and marine sections to seek robust evidence of an extraterrestrial contribution. First, our results do not reproduce the previously reported elevated Ir concentrations. Second, (super 187) Os/ (super 188) Os isotopic ratios in the sediment layers investigated are similar to average crustal values, indicating the absence of a significant meteoritic Os contribution to these sediments. Third, no PGE anomalies distinct from crustal signatures are present in the marine record in either the Gulf of California (DSDP 480, Guaymas Basin) or the Cariaco Basin (ODP 1002C). Our data show no evidence of an extraterrestrial (ET)-PGE enrichment anomaly in any of the investigated depositional settings investigated across North America and in one section in Belgium. The lack of a clear ET-PGE signature in this sample suite is inconsistent with the impact of a large chondritic projectile at the Bolling-Allerod/Younger Dryas transition.completedIsotope geochemistryQuaternary geologyAllerodAtlantic Oceanblack mat layerBollingCariaco BasinCaribbean SeaCenozoicclimate changeClovisconcentrationDeep Sea Drilling ProjectdiamondDSDP Site 480East PacificextinctionGuaymas BasinGulf of CaliforniaimpactsIPODisotope ratiosisotopesLeg 165Leg 64metalsnanodiamondnative elementsNorth AtlanticNorth PacificNortheast PacificOcean Drilling ProgramODP Site 1002Os-188/Os-187osmiumPacific Oceanpaleoclimatologypaleoindianplatinum groupPleistoceneQuaternaryRancholabreansea waterstable isotopesstratigraphic boundaryupper Pleistoceneupper WeichselianWeichselianYounger Dryasurn:org.iodp:exp:165urnlargerWorkCitationcampaignurn:org.iodp:exp:64urnlargerWorkCitationcampaignurn:org.iodp:exp:64:site:480urnlargerWorkCitationstudyurn:org.iodp:exp:64urnlargerWorkCitationcampaignurn:org.iodp:exp:165:site:1002urnlargerWorkCitationstudyurn:org.iodp:exp:165urnlargerWorkCitationcampaignEnglishgeoscientificInformation-110.3921-65.101110.422227.5406Supplemental information/data is available in the online version of this article; University of Hawaii, School of Ocean and Earth Science and Technology Contrib. No. 7773application/pdfunknownSEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContacthttp://www.pnas.org/content/106/51/local/masthead.pdfdownload