georefid:1981-027023georefid:1981-026994SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/dsdp.proc.55.129.1980<gco:CharacterString>K-Ar minimum age for Meiji Guyot, Emperor seamount chain</gco:CharacterString>1980-01-01publicationgeorefid:1981-027023doi:10.2973/dsdp.proc.55.129.1980Dalrymple, G. BrentU. S. Geol. Surv., Menlo Park, CA, United StatesauthorLanphere, Marvin A.Scripps. Inst. Oceanogr., DSDP, La Jolla, CA, United StatesauthorNatland, James H.authorTexas A & M University, Ocean Drilling Program, College Station, TX, United StatespublisherdocumentDigitalIn: Shambach, James (editor), Jackson, Everett Dale, Koizumi, Itaru, Avdeiko, Gennady, Butt, Arif, Clague, David, Dalrymple, G. Brent, Greene, H. Gary, Karpoff, Anne Marie, Kirkpatrick, R. James, Kono, Masaru, Hsin Yi Ling, McKenzie, Judith, Morgan, Jason, Takayama, Toshiaki, Initial reports of the Deep Sea Drilling Project covering Leg 55 of the cruises of the drilling vessel Glomar Challenger, Honolulu, Hawaii to Yokohama, Japan; July-September 197755677-681Conventional K-Ar and 40Ar/39Ar age data on altered basalts from DSDP Hole 192A on Meiji Guyot, Emperor Seamount chain, indicate a minimum age for the volcano of 61.9 + or - 5.0 m.y. The K-Ar data are consistent with the early Maestrichtian date of the overlying sediments, but do not provide either a positive or negative test of the hypothesis that Meiji is older than Emperor volcanoes to the south. The most prominent alteration affecting the age measurements is potassium metasomatism, particularly of feldspar phenocrysts. The K-Ar apparent ages of feldspar separates from the Meiji basalts show that more than half of the potassium metasomatism occurred within the last 25 m.y. or so, and that if the potassium replacement rate has been constant, then the alteration of the Meiji basalts did not begin for 10 to 20 m.y. after the volcano formed.completedGeochronologyabsolute agebasaltsCenozoiccompositiondatesDeep Sea Drilling ProjectEmperor Seamountsgeochronologyigneous rocksIPODK/ArLeg 55mineral compositionNorth PacificNorthwest Pacificocean floorsoceanographyPacific Oceanseamountsvolcanic rocksWest Pacificurn:org.iodp:exp:55urnlargerWorkCitationcampaignEnglishgeoscientificInformation162.0000167.000052.000055.0000application/pdfunknownSEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContacthttp://deepseadrilling.org/55/volume/dsdp55_29.pdfdownload