Gas hydrate can precipitate in pore space of marine sediment when gas concentrations exceed
solubility conditions within a gas hydrate stability zone (GHSZ). Here we present analytical
expressions that relate the top of the GHSZ and the amount of gas hydrate within the GHSZ to the
depth of the sulfate-methane transition (SMT). The expressions are strictly valid for steady-state
systems in which (1) all gas is methane, (2) all methane enters the GHSZ from the base, and (3)
no methane escapes the top through seafloor venting. These constraints mean that anaerobic
oxidation of methane (AOM) is the only sink of gas, allowing a direct coupling of SMT depth to
net methane flux. We also show that a basic gas hydrate saturation profile can be determined from
the SMT depth via analytical expressions if site-specific parameters such as sedimentation rate,
methane solubility and porosity are known. We evaluate our analytical model at gas hydrate
bearing sites along the Cascadia margin where methane is mostly sourced from depth. The
analytical expressions provide a fast and convenient method to calculate gas hydrate saturation
for a given geologic setting.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:BVAU.2429/1179 |
| Date | 07 1900 |
| Creators | Bhatnagar, Gaurav, Chapman, Walter G., Hirasaki, George J., Dickens, Gerald R., Dugan, Brandon |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | text |
| Rights | Bhatnagar, Gaurav; Chapman, Walter G.; Hirasaki, George J.; Dickens, Gerald R.; Dugan, Brandon |
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