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| Titel |
A two-dimensional model of the methane cycle in a sedimentary accretionary wedge |
| VerfasserIn |
D. E. Archer, B. A. Buffett |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 9, no. 8 ; Nr. 9, no. 8 (2012-08-24), S.3323-3336 |
| Datensatznummer |
250007250
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| Publikation (Nr.) |
 copernicus.org/bg-9-3323-2012.pdf |
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| Zusammenfassung |
| A two-dimensional model of sediment column geophysics and geochemistry has
been adapted to the problem of an accretionary wedge formation, patterned
after the margin of the Juan de Fuca plate as it subducts under the North
American plate. Much of the model description is given in a companion paper
about the application of the model to an idealized passive margin setting;
here we build on that formulation to simulate the impact of the sediment
deformation, as it approaches the subduction zone, on the methane cycle. The
active margin configuration of the model shares sensitivities with the
passive margin configuration, in that sensitivities to organic carbon
deposition and respiration kinetics, and to vertical bubble transport and
redissolution in the sediment, are stronger than the sensitivity to ocean
temperature. The active margin simulation shows a complex sensitivity of
hydrate inventory to plate subduction velocity, with results depending
strongly on the geothermal heat flux. In low heat-flux conditions, the model
produces a larger inventory of hydrate per meter of coastline in the passive
margin than active margin configurations. However, the local hydrate
concentrations, as pore volume saturation, are higher in the active setting
than in the passive, as generally observed in the field. |
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