| Passive Margin | Active Margin | Siberian Margin | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| A passive (nonsubducting) continental margin simulation based on the Atlantic coast of the United States. Left panel includes the impact of vertical chimneys of high permeability, right panel assumes lateral homogeneity. Color scales show dissolved methane concentration. Sea level and the boundary of the methane hydrate stabililty zone are also shown in black lines. | An active (subducting) margin modeled after the Pacific coast of Canada (Vancouver Island). The underlying ocean crust is subducting to the left, and the sediment is deformed into an accretionary grid. Variant to the right assumes lateral variation in the deformability of the sediment column, leading to irregular lateral compression. Color scales show dissolved methane concentration. Sea level and the boundary of the methane hydrate stabililty zone are also shown in black lines. | A simulation of the Siberian continental margin after glacial sea level drop and exposure to the cold atmosphere, snapshot as sea level rises during the deglaciation. The colors indicate dissolved methane concentration. Red contours show the ice fraction in permafrost. The black contour shows the limits of the methane hydrate stability zone. The movies (after the first two) show four 100-kyr sawtooth-shaped glacial/interglacial cycles (62-62.4 Myr) followed by 100 kyr of a global warming scenario (62.4-62.5 Myr). The first deglaciation (62.08-62.1 Myr) zooms in in time, with frames from 10 times as often through the simulation. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Archer, D.E., B.A. Buffett, and P.C. McGuire (2012). A two-dimensional model of the passive coastal margin deep sedimentary carbon and methane cycles. Biogeosciences., 9, 1-20, doi:10.5194/bg-9-1-2012, 2012 |
Archer, D.E. and B.A. Buffett (2012) A two-dimensional model of the methane cycle in a sedimentary accretionary wedge. Biogeosciences, 9, 3323–3336, 2012 |
Archer, D.E. (2014) A model of the methane cycle, permafrost, and hydrology of the Siberian continental margin Biogeosciences Discuss 11, 7853-7900, 2014 |
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Sensitivity Studies
Movies show the variant on the right, compared with the base case on
the left. Four glacial cycles span the first 400,000 years, followed
by 100,000 of "Anthropocene".
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