Marine deposits of methane hydrate are estimated to be large and are thought to be important to climate change and seafloor stability, as well as representing a potentially exploitable energy resource. The extent of these deposits can usually be inferred from seismic imaging. In this study, using high-resolution seismic sections of seafloor sediments in the Cascadia margin off the coast of Vancouver Island, Canada, lateral variations in the base of hydrate stability zone (upper 220 m of sediment) are observed, including gas-rich vertical intrusions into the hydrate stability zone. The presence of gas within the hydrate stability zone suggests that the zone might have been perturbed by warm fluids, occasionally resulting in a seafloor pockmark. These perturbations significantly increase the surface area and subsequently the volatility of the methane hydrate reservoir. Increased area implies that significanty more methane hydrate lies close to being unstable and hence closer to dissociation in the event of a lowering of pressure due to sea-level fall. The high-resolution images of the methane hydrate stability zone and its lower boundary depicted here support a model of hydrate distribution strongly affected, if not dominated, by focused vertical fluid flux. This complicates the estimation of methane hydrate quantities obtained through extrapolation from a single drill hole, and indicates that of the estimated 10000 Gt of carbon sequestered in methane hydrates, a significantly greater portion might lie closer to the stability boundary than if it were evenly distributed throughout an unperturbed stability zone.


    Zugriff

    Zugriff über TIB

    Verfügbarkeit in meiner Bibliothek prüfen

    Bestellung bei Subito €


    Exportieren, teilen und zitieren



    Titel :

    Decreased stability of methane hydrates in marine sediments owing to phase-boundary roughness


    Weitere Titelangaben:

    Die Verringerung der Stabilität von Methanhydraten in marinen Sedimenten durch die Phasengrenzen-Rauhigkeit


    Beteiligte:
    Wood, W.T. (Autor:in) / Gettrust, J.F. (Autor:in) / Chapman, N.R. (Autor:in) / Spence, G.D. (Autor:in) / Hyndman, R.D. (Autor:in)

    Erschienen in:

    Nature ; 420 , 6916 ; 656-660


    Erscheinungsdatum :

    2002


    Format / Umfang :

    5 Seiten, 4 Bilder, 21 Quellen




    Medientyp :

    Aufsatz (Zeitschrift)


    Format :

    Print


    Sprache :

    Englisch





    Methane Hydrates: More Than a Viable Aviation Fuel Feedstock Option

    Hendricks, R. / American Institute of Aeronautics and Astronautics | British Library Conference Proceedings | 2007


    Effect of roughness on the stability of boundary layers

    NAYFEH, ALI / RAGAB, SAAD / AL-MAAITAH, AYMAN | AIAA | 1986


    Marine sediments acoustics

    Stoll, R. | Tema Archiv | 1985


    The Role of Methane Hydrates in the Failure of a Gas Pipeline

    Caputo, Francesco / Cascetta, F. / Lamanna, Giuseppe et al. | Tema Archiv | 2013