FN Archimer Export Format
PT J
TI Anomalously deep BSR related to a transient state of the gas hydrate system in the western Black Sea
BT 
AF KER, Stephan
   THOMAS, Yannick
   RIBOULOT, Vincent
   SULTAN, Nabil
   BERNARD, Céline
   SCALABRIN, Carla
   ION, G
   MARSSET, Bruno
AS 1:1;2:1;3:1;4:1;5:1,2;6:1;7:3;8:1;
FF 1:PDG-REM-GM-LAD;2:PDG-REM-GM-LAD;3:PDG-REM-GM-LAD;4:PDG-REM-GM;5:;6:PDG-REM-GM-LCG;7:;8:PDG-REM-GM-LAD;
C1 IFREMER, REM GM, Plouzane, France
   ENSTA Bretagne, 2 rue François Verny, 29806 Brest Cedex 6, France
   GeoEcoMar, 23-25 Dimitrie Onciul Street, RO-024053, Romania
C2 IFREMER, FRANCE
   ENSTA BRETAGNE, FRANCE
   GEOECOMAR, ROMANIA
SI BREST
SE PDG-REM-GM-LAD
   PDG-REM-GM
   PDG-REM-GM-LCG
IN WOS Ifremer UPR
   copubli-france
   copubli-europe
IF 2.623
TC 24
UR https://archimer.ifremer.fr/doc/00474/58531/61081.pdf
LA English
DT Article
CR GHASS
BO Pourquoi pas ?
DE ;gas hydrate;BSR;excess pore pressure;Black Sea
AB A comprehensive characterization of the gas hydrate system offshore the western Black Sea was performed through an integrated analysis of geophysical data. We detected the Bottom Simulating Reflector (BSR), which marks, in this area, the base of gas hydrate stability. The observed BSR depth does not fit the theoretical steady-state base of gas hydrate stability zone (BGHSZ). We show that the disparity between the BSR and predicted BGHSZ is the result of a transient state of the hydrate system due to the ongoing re-equilibrium since the Last Glacial Maximum. When gas hydrates are brought outside the stability zone due to changes in temperature and sea level, their dissociation generates an increase in interstitial pore pressure. This process is favorable to the re-crystallization of gas hydrates and delays the upward migration of the hydrate stability zone explaining the anomalously deep BSR. The BSR depth, which is commonly used to derive geothermal gradient values by assuming steady state conditions, is used here to derive the maximum excess pore pressure at the base of the gas hydrate stability zone. Derived excess pore pressure values of 1-2 MPa are probably the result of the low permeability of hydrate-bearing sediments. Higher pore pressure values derived at the location of a fault system could cause hydro-fracturing enabling the free gas to cross the gas hydrate stability zone and emerge at the seafloor, forming the flares observed in close vicinity to where the shallow gas hydrates were sampled. 
PY 2019
PD JAN
SO Geochemistry Geophysics Geosystems
SN 1525-2027
PU American Geophysical Union
VL 20
IS 1
UT 000458607200023
BP 442
EP 459
DI 10.1029/2018GC007861
ID 58531
ER

EF