georefid:2005-030937SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1130/G21378.1<gco:CharacterString>Jurassic-Cretaceous boundary age and mid-ocean-ridge-type mantle source for Shatsky Rise</gco:CharacterString>2005-01-01publicationgeorefid:2005-030937doi:10.1130/G21378.1Mahoney, J. J.University of Hawaii, School of Ocean and Earth Science and Technology, Honolulu, HI, United StatesauthorDuncan, R. A.Oregon State University, United StatesauthorTejada, M. L. G.University of the Philippines, PhilippinesauthorSager, W. W.Texas A&M University, United StatesauthorBralower, T. J.Pennsylvania State University, United StatesauthorGeological Society of America (GSA), Boulder, CO, United StatespublisherdocumentHardcopyGeology (Boulder)33 (3)185-188Basalt sills cored in lowermost Berriasian sediments on Shatsky Rise in the northwest Pacific yield a mean (super 40) Ar- (super 39) Ar incremental heating age of 144.6+ or -0.8 Ma, providing a minimum estimate on the age of the Jurassic-Cretaceous boundary. The largest part of the rise was emplaced at rates similar to those of several continental flood basalts. The rise formed at an oceanic triple junction, and the sills, as well as lavas from two dredge sites, exhibit an ocean ridge-type Nd-Pb-Sr isotope signature. This signature is provisionally consistent with either a perisphere or meteorite-impact model, but is not predicted by the plume-head model of plateau formation. However, no model can yet be rejected, given the very sparse sampling of Shatsky Rise.completedGeochronologyIsotope geochemistryabsolute agealkaline earth metalsAr/ArbasaltsCretaceousdatesdredged samplesgeochemistryigneous rocksintrusionsisotope ratiosisotopesJurassicJurassic-Cretaceous boundarylavaleadLeg 191Leg 198Lower CretaceousmantleMesozoicmetabasaltmetaigneous rocksmetalsmetamorphic rocksmid-ocean ridge basaltsNd-144/Nd-143neodymiumNorth PacificNorthwest PacificOcean Drilling ProgramODP Site 1179ODP Site 1213Pacific OceanPb-206/Pb-204plate tectonicsradioactive isotopesrare earthsShatsky Risesillsstable isotopesstratigraphic boundarystrontiumtriple junctionsUpper Jurassicvolcanic rocksWest Pacificurn:org.iodp:exp:191urnlargerWorkCitationcampaignurn:org.iodp:exp:198urnlargerWorkCitationcampaignurn:org.iodp:exp:191:site:1179urnlargerWorkCitationstudyurn:org.iodp:exp:191urnlargerWorkCitationcampaignurn:org.iodp:exp:198:site:1213urnlargerWorkCitationstudyurn:org.iodp:exp:198urnlargerWorkCitationcampaignEnglishgeoscientificInformation157.1800160.000031.350041.0500With GSA Data Repository Item 2005034