FN Archimer Export Format
PT J
TI Evidence from three-dimensional seismic tomography for a substantial accumulation of gas hydrate in a fluid-escape chimney in the Nyegga pockmark field, offshore Norway
BT 
AF PLAZA-FAVEROLA, Andreia
   WESTBROOK, Graham K.
   KER, Stephan
   EXLEY, Russell J. K.
   GAILLER, Audrey
   MINSHULL, Tim A.
   BROTO, Karine
AS 1:1,2;2:3;3:1;4:3;5:3,4;6:5;7:6;
FF 1:;2:;3:;4:;5:;6:;7:;
C1 IFREMER, Dept Marine Geosci, F-29280 Plouzane, France.
   Univ Tromso, Dept Geol, N-9037 Tromso, Norway.
   Univ Birmingham, Sch Geog Earth & Environm Sci, Birmingham B15 2TT, W Midlands, England.
   Univ Europeenne Bretagne, Inst Univ Europeen Mer, CNRS, UMR 6538, F-29280 Plouzane, France.
   Univ Southampton, Natl Oceanog Ctr, Southampton SO14 3ZH, Hants, England.
   Inst Francais Petr, F-92852 Rueil Malmaison, France.
C2 IFREMER, FRANCE
   UNIV TROMSO, NORWAY
   UNIV BIRMINGHAM, UK
   UEB, FRANCE
   NOC, UK
   IFP, FRANCE
   UBO, FRANCE
SI BREST
IN WOS Ifremer jusqu'en 2018
   copubli-france
   copubli-europe
   copubli-univ-france
IF 3.303
TC 42
TU Centre national de la recherche scientifique
   Institut français de recherche pour l'exploitation de la mer
   Service Hydrographique et Océanographique de la Marine
   Université de Bretagne Occidentale
   Université de Bretagne-Sud
UR https://archimer.ifremer.fr/doc/00012/12326/9111.pdf
LA English
DT Article
CR VICKING
BO Unknown
DE ;travel time tomography;mid norwegian margin;storegga slide;bearing sediments;voring plateau;reflection tomography;continental margins;marine sediments;atlantic margin;velocity models
AB In recent years, it has become evident that features commonly called gas chimneys provide major routes for methane to pass through the methane-hydrate stability zone in continental margins and escape to the ocean. One of many such chimneys lying beneath pockmarks in the southeastern Voring Plateau off Norway was investigated with a high-resolution seismic experiment employing a 2-D array of sixteen 4-component ocean bottom seismic recorders at approximately 100 m separation and a dense network of shots to define the 3-D variation of the chimney's structure and seismic properties. The tomographic model derived from P wave travel times shows that P wave velocity inside the chimney is up to 300 m/s higher than in the surrounding strata within the methane-hydrate stability zone. The zone of anomalously high velocity, about 500 m wide near its base, narrowing to about 200 m near the seabed, extends to a depth of 250 m below the seafloor. The depth extent of this zone and absence of high velocity beneath the base of the methane-hydrate stability field make it more likely that it contains hydrate rather than carbonate. If a predominantly fracture-filling model is appropriate for the formation of hydrate in low-permeability sediment, the maximum hydrate concentration in the chimney is estimated to be 14%-27% by total volume, depending on how host-sediment properties are affected by hydrate formation. Doming of the strata penetrated by the chimney appears to be associated with the emplacement of hydrate, accompanying the invasion of the gas hydrate stability zone by free gas.
PY 2010
PD AUG
SO Journal Of Geophysical Research-solid Earth
SN 0148-0227
PU Amer Geophysical Union
VL 115
IS B08104
UT 000281146000002
BP 1
EP 24
DI 10.1029/2009JB007078
ID 12326
ER

EF