georefid:2002-035471SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=2002-035471Escape of methane gas through sediment waves in a large methane hydrate province2002-01-01publicationgeorefid:2002-035471
Holbrook, W. S.University of Wyoming, Department of Geology and Geophysics, Laramie, WY, United StatesauthorLizarralde, D.Georgia Institute of Technology, United StatesauthorPecher, I. A.University of Texas at Austin, United StatesauthorGorman, A. R.authorHackwith, K. L.authorHornbach, M.authorSaffer, D.authorGeological Society of America (GSA), Boulder, CO, United StatespublisherdocumentHardcopyGeology (Boulder)30 (5)467-470Despite paleoceanographic evidence that large quantities of methane have escaped from marine gas hydrates into the oceans, the sites and mechanisms of methane release remain largely speculative. New seismic data from the Blake Ridge, a hydrate-bearing drift deposit in the western Atlantic, show clear evidence for methane release and suggest a new mechanism by which methane gas can escape, without thermal or mechanical disruption of the hydrate-bearing layer. Rapid, post-2.5 Ma formation of large sediment waves and associated seafloor erosion created permeable pathways connecting free gas to the seafloor, allowing methane gas expulsion. The amount of missing methane, 0.6 Gt, is equivalent to approximately 12% of total present-day atmospheric methane. Our results imply that significant amounts of methane gas can bypass the hydrate stability zone and escape into the ocean. Mechanisms of tapping methane directly from the free-gas zone, such as widespread seafloor erosion, should be considered when seeking the causes of large negative carbon isotope excursions in the geological record.completedOceanographyApplied geophysicsaliphatic hydrocarbonsalkanesAtlantic Oceanbathymetrybedding plane irregularitiesBlake Ridge DepressionBlake-Bahama Outer Ridgebottom featuresbottom-simulating reflectorsclastic sedimentsdeep-sea sedimentationdepressionsdrifterosiongas hydratesgeophysical methodsgeophysical profilesgeophysical surveyshydrocarbonsmarine sedimentationmarine sedimentsmethaneNorth Atlanticocean floorsorganic compoundspermeabilitysand wavessedimentary structuressedimentationsedimentsseismic methodsseismic profilessurveysventsEnglishgeoscientificInformation-76.0000-75.180031.360032.2400