|
Parameter
|
Model I
|
Model II
|
Model III
|
|---|---|---|---|
| Depth of calculation xtop–xbottom | 0–400 m | 100–500 m | 300–600 m |
| Water depth | 4376.3 m | 4182.8 m | 4311.6 m |
| Water temperature | 2°C | 2°C | 2°C |
| Salinity | 34.5 | 34.5 | 34.5 |
Sedimentation rate   |
4.1 cm/k.y. | NA | NA |
| Advection rate u0 (vertical fluid flow scenario)* | 0.15 cm/yr | 0.4 cm/yr | 0.4 cm/yr |
| Advection rate u0 (pure diffusion scenario)* | 0.0 cm/yr | NA | NA |
Porosity at sediment surface  0 |
0.747 | 0.592 | 0.592 |
|
Porosity at infinity |
0 | 0.364 | 0.364 |
Porosity attenuation coefficient  |
2.69 x 10–6/cm | 4.83 x 10–5/cm | 4.83 x 10–5/cm |
| [SO42–] (xtop, t) | 27.5 mM | NA | 27.5 mM |
| [SO42–] (xbottom, t) | 27.5 mM | NA | 27.5 mM |
| [C3H8] (xtop, t) | NA | 0 ppmv | NA |
| [C3H8] (xbottom, t) | NA | 0 ppmv | NA |
| [CH4] (xtop, t) | NA | NA | 60 mM |
| [CH4] (xbottom, t) | NA | NA | 0 mM |
| [HS–] (xtop, t) | 0 mM | NA | 0 mM |
| [HS–] (xbottom, t) | 0 mM | NA | 0 mM |
| [HCO3–] (xtop, t) | 2.2 mM | NA | 2.2 mM |
| [HCO3–] (xbottom, t) | 2.2 mM | NA | 2.2 mM |
| [Ba2+](xtop, t) | NA | NA | 0 mM |
| d[Ba2+]/dx (xbottom, t) | NA | NA | 0 mM/cm |
| Rate constant for OM degradation kG0 (vertical fluid flow scenario)* | 1.6 x 10–8/yr | NA | NA |
| Rate constant for OM degradation kG0 (pure diffusion scenario)* | 2.0 x 10–3/yr | NA | NA |
| Monod constant for SO42– KSO4 | 1 mM | NA | NA |
| Rate for propane source Rprop* | NA | 22 ppmv/yr | NA |
| Barite solubility constant Kbarite | NA | NA | 3.72 x 10–5/mM2 |
| Rate for barite dissolution RBa* | NA | NA | 1.2 x 10–5 mM/yr |
| Rate constant for AMO kAMO* | NA | NA | 1 x 103/(mM yr) |
Notes: NA = not applicable. * = parameter adjusted in model runs. Below the décollement, the porosity is set to a constant value of 0.6 to match observed data. Model I Monod constant from Boudreau (1996). Model III Barite solubility constant from Stumm and Morgan (1996).