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Distribution and height of methane bubble plumes on the Cascadia Margin characterized by acoustic imaging

ScholarsArchive at Oregon State University

Field Value
Title Distribution and height of methane bubble plumes on the Cascadia Margin characterized by acoustic imaging
Names Heeschen, Katja U. (creator)
Tréhu, Anne Martine (creator)
Collier, Robert W. (creator)
Suess, Erwin (creator)
Rehder, Gregor (creator)
Date Issued 2003-06-26 (iso8601)
Note Copyrighted by American Geophysical Union.
Abstract Submersible investigations of the Cascadia accretionary
complex have identified localized venting of methane gas
bubbles in association with gas hydrate occurrence. Acoustic
profiles of these bubble plumes in the water column in the
vicinity of Hydrate Ridge offshore Oregon provide new
constraints on the spatial distribution of these gas vents and
the fate of the gas in the water column. The gas vent sites
remained active over the span of two years, but varied
dramatically on time scales of a few hours. All plumes
emanated from local topographic highs near the summit of
ridge structures. The acoustic images of the bubble plumes in
the water column disappear at water depths between 500 to
460 m, independent of the seafloor depth. This coincides with
the predicted depth of the gas hydrate stability boundary of
510 to 490 m, suggesting that the presence of a hydrate skin
on the bubble surface prevents them from rapid dissolution.
The upper limit of the acoustic bubble plumes at 460 m
suggests that dissolution of the residual bubbles is relatively
rapid above the hydrate stability zone.
Genre Article
Identifier Heeschen, K. U., A. M. Tre´hu, R. W. Collier, E. Suess, and G. Rehder, Distribution and height of methane bubble plumes on the Cascadia Margin characterized by acoustic imaging, Geophys. Res. Lett., 30(12), 1643, 2003.

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