georefid:2001-025801georefid:2001-025795SEDIS 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/odp.proc.sr.164.206.2000<gco:CharacterString>Gas hydrate estimates from newly determined oxygen isotopic fractionation (alpha (sub GH-IW) ) and delta (sub 18) O anomalies of the interstitial waters; Leg 164, Blake Ridge</gco:CharacterString>2000-01-01publicationgeorefid:2001-025801doi:10.2973/odp.proc.sr.164.206.2000Matsumoto, RyoUniversity of Tokyo, Geological Institute, Tokyo, JapanauthorBorowski, Walter S.University of Tokyo, JapanauthorTexas A & M University, Ocean Drilling Program, College Station, TX, United StatespublisherdocumentHardcopyIn: Paull, Charles K., Matsumoto, Ryo, Wallace, Paul J., Black, Nancy R., Borowski, Walter S., Collett, Timothy S., Damuth, John E., Dickens, Gerald R., Egeberg, Per Kristian, Goodman, Kim, Hesse, Reinhard F., Hiroki, Yoshihisa, Holbrook, W. Steven, Hoskins, Hartley, Ladd, John, Lodolo, Emanuele, Lorenson, Thomas D., Musgrave, Robert J., Naehr, Thomas H., Okada, Hisatake, Pierre, Catherine, Ruppel, Carolyn D., Satoh, Mikio, Thiery, Regis, Watanabe, Yoshio, Wehner, Hermann, Winters, William J., Wood, Warren T., Miller, Christine M. (editor), Reigel, Ruth (editor), Proceedings of the Ocean Drilling Program; volume 164; scientific results; gas hydrate sampling on the Blake Ridge and Carolina Rise; covering Leg 164 of the cruises of the drilling vessel JOIDES Resolution, Halifax, Nova Scotia, to Miami, Florida, sites 991-997, 31 October-19 December 199516459-66The delta (super 18) O values of interstitial waters from Site 994 and Site 997 sediments, Blake Ridge, western Atlantic, tend to decrease with depth from 0.3 per mil to -0.5 per mil Standard Mean Ocean Water in the upper 200 mbsf, then fluctuate with significant positive spikes of Delta = 0.2 per mil-0.5 per mil in the gas hydrate zone (200 to 450 mbsf), and finally increase from -0.4 per mil to -0.2 per mil toward 700 mbsf. Positive shifts of delta (super 18) O (sub IW) in the gas hydrate zone are probably caused by the dissociation of gas hydrates originally contained in sediment cores. Gas hydrates recovered from the sites are enriched in (super 18) O, delta (super 18) O ranging between 2.7 per mil and 3.5 per mil. delta (super 18) O values of gas hydrates and ambient interstitial waters give an oxygen isotopic fractionation factor of 1.0034-1.0040 at 12 degrees -16 degrees C and approximately 31 MPa (3 km below sea level). Based on this fractionation and observed isotopic anomalies in the gas hydrate zone, gas hydrates occupy 6% to 12% of pore-space volume within Blake Ridge sediments.completedGeneral geochemistryaliphatic hydrocarbonsalkanesAtlantic OceanBlake-Bahama Outer Ridgegas hydrateshydrocarbonsisotope fractionationisotope ratiosisotopesLeg 164marine sedimentsmethaneNorth AtlanticNorthwest AtlanticO-18/O-16Ocean Drilling ProgramODP Site 994ODP Site 997organic compoundsoxygenP-T conditionspore watersedimentsstable isotopesurn:org.iodp:exp:164urnlargerWorkCitationcampaignurn:org.iodp:exp:164:site:994urnlargerWorkCitationstudyurn:org.iodp:exp:164urnlargerWorkCitationcampaignurn:org.iodp:exp:164:site:997urnlargerWorkCitationstudyurn:org.iodp:exp:164urnlargerWorkCitationcampaignEnglishgeoscientificInformation-75.3245-75.280731.470831.5035