FN Archimer Export Format
PT J
TI Hydrate dissolution as a potential mechanism for pockmark formation in the Niger delta
BT 
AF SULTAN, Nabil
   MARSSET, Bruno
   KER, Stephan
   MARSSET, Tania
   VOISSET, Michel
   VERNANT, Antoine-Mathieu
   BAYON, Germain
   CAUQUIL, Eric
   ADAMY, J.
   COLLIAT, J. L.
   DRAPEAU, D.
AS 1:1;2:1;3:1;4:1;5:1;6:1,3;7:1;8:1,2;9:2;10:2;11:2;
FF 1:PDG-DOP-DCB-GM-LES;2:PDG-DOP-DCB-GM-LGG;3:PDG-DOP-DCB-GM-LGG;4:PDG-DOP-DCB-GM-LES;5:PDG-DOP-DCB-GM-CTD;6:PDG-DOP-DCB-GM-LES;7:PDG-DOP-DCB-GM-LGM;8:;9:;10:;11:;
C1 IFREMER, Dept Geosci Marines, F-29280 Plouzane, France.
   Total, F-92069 Paris, France.
C2 IFREMER, FRANCE
   TOTAL, FRANCE
   NOW CATHIES ASSOCIATES, BELGIUM
SI BREST
   AUTRES
SE PDG-DOP-DCB-GM-LES
   PDG-DOP-DCB-GM-LGG
   PDG-DOP-DCB-GM-CTD
   PDG-DOP-DCB-GM-LGM
   EXTERIEUR
IN WOS Ifremer jusqu'en 2018
   copubli-france
   copubli-europe
IF 3.303
TC 94
UR https://archimer.ifremer.fr/doc/00012/12300/9092.pdf
LA English
DT Article
CR ERIG 3D
BO Pourquoi pas ?
DE ;methane gas hydrate;sea floor;marine sediments;pore pressure;porous media;continental margin;clathrate hydrate;fluid flow;stability;slope
AB Based on acquired geophysical, geological and geotechnical data and modeling, we suggest hydrate dissolution to cause sediment collapse and pockmark formation in the Niger delta. Very high-resolution bathymetry data acquired from the Niger delta reveal the morphology of pockmarks with different shapes and sizes going from a small ring depression surrounding an irregular floor to more typical pockmarks with uniform depression. Geophysical data, in situ piezocone measurements, piezometer measurements and sediment cores demonstrate the presence of a common internal architecture of the studied pockmarks: inner sediments rich in gas hydrates surrounded by overpressured sediments. The temperature, pressure and salinity conditions of the studied area have allowed us to exclude the process of gas-hydrate dissociation (gas hydrate turns into free gas/water mixture) as a trigger of the observed pockmarks. Based on numerical modeling, we demonstrate that gas-hydrate dissolution (gas hydrate becomes mixture of water and dissolved gas) under a local decrease of the gas concentration at the base of the gas-hydrate occurrence zone (GHOZ) can explain the excess pore pressure and fluid flow surrounding the central hydrated area and the sediment collapse at the border of the GHOZ. The different deformation (or development) stages of the detected pockmarks confirm that a local process such as the amount of gas flow through faults rather than a regional one is at the origin of those depressions.
PY 2010
PD AUG
SO Journal Of Geophysical Research-solid Earth
SN 0148-0227
PU Amer Geophysical Union
VL 115
IS B08101
UT 000280957600001
BP 1
EP 33
DI 10.1029/2010JB007453
ID 12300
ER

EF