 |
| Titel |
A two-dimensional model of the passive coastal margin deep sedimentary carbon and methane cycles |
| VerfasserIn |
D. E. Archer, B. A. Buffett, P. C. McGuire |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 8 ; Nr. 9, no. 8 (2012-08-01), S.2859-2878 |
| Datensatznummer |
250007222
|
| Publikation (Nr.) |
 copernicus.org/bg-9-2859-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| We present a new geologic-time and basin-spatial scale model of the
continental margin methane cycle. The model, SpongeBOB, is used to simulate
evolution of the carbon cycle in a passive sedimentary continental margin in
response to changing oceanographic and geologic forcing over a time scale of
200 million years. The geochemistry of the sediment column is altered by the
addition of vertical high-permeability channels intended to mimic the
effects of heterogeneity in the real sediment column due to faults, and
produces results consistent with measured pore-water tracers SO42−
and 129I. Pore water dissolved inorganic carbon (DIC) concentrations
are consistent with chemical weathering (CaCO3 formation from igneous
rocks) at depth within the sediment column. The carbon isotopic composition
of the DIC is consistent with a methane production efficiency from
particulate organic carbon (POC) of 50%, which is somewhat lower than
redox balance with the H / C of organic matter in the model. The hydrate
inventory in the model is somewhat less sensitive to temperature than our
previous results with a one-dimensional model, quite sensitive to
reasonable changes in POC, and extremely sensitive to the ability of methane
bubbles to rise within the sediment column, and how far gas-phase methane
can get through the sediment column before it redissolves when it reaches
undersaturated conditions. Hydrate formation is also sensitive to deep
respiration of migrating petroleum. Other phenomena which we simulated had
only a small impact on the hydrate inventory, including thermogenic methane
production and production/decomposition of dissolved organic carbon. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|