georefid:2008-039782SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-07-06T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1029/2006GL029134<gco:CharacterString>First determination of gas hydrate crystallite size distributions using high-energy synchrotron radiation</gco:CharacterString>2007-01-01publicationgeorefid:2008-039782doi:10.1029/2006GL029134Klapp, S. A.Universitaet Goettingen, Geowissenschaftliches Zentrum, Gottingen, Federal Republic of GermanyauthorKlein, H.University of Bremen, Federal Republic of GermanyauthorKuhs, W. F.authorAmerican Geophysical Union, Washington, DC, United StatespublisherdocumentDigitalGeophysical Research Letters34 (13)Due to experimental difficulties grain size distributions of gas hydrate crystallites are largely unknown in natural samples. For the first time, we were able to determine grain size distributions of six natural gas hydrates for samples retrieved from the Gulf of Mexico and from Hydrate Ridge offshore Oregon from varying depths. High-energy synchrotron radiation provides high photon fluxes as well as high penetration depth and thus allows for investigation of bulk sediment samples. The gas hydrate crystallites appear to be (log-) normally distributed in the natural samples and to be of roughly globular shape. The mean grain sizes are in the range from 300-600 mu m with a tendency for bigger grains to occur in greater depth, possibly indicating a difference in the formation age. Laboratory produced methane hydrate, starting from ice and aged for 3 weeks, shows half a log-normal curve with a mean value of approximately 40 mu m. This one order-of-magnitude smaller grain sizes suggests that care must be taken when transposing grain-size sensitive (petro-)physical data from laboratory-made gas hydrates to natural settings. Copyright 2007 by the American Geophysical Union.completedOceanographyAtlantic Oceancrystal structurecrystallitesEast Pacificexperimental studiesgas hydratesgrain sizegranulometryGulf of MexicoHydrate RidgeiceLeg 204marine sedimentsmeasurementNorth AtlanticNorth PacificNortheast PacificOcean Drilling ProgramOregonPacific Oceansamplingsedimentssingle-crystal methodsize distributionsynchrotron radiationUnited Statesurn:org.iodp:exp:204urnlargerWorkCitationcampaignEnglishgeoscientificInformation-125.1200-80.300018.000046.2000Gulf of MexicoHydrate RidgeOregonapplication/pdfunknownSEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContacthttp://www.agu.org/journals/gl/gl0713/2006GL029134/2006GL029134.pdfdownload