Feeding methane vents and gas hydrate deposits at south Hydrate Ridge.

Tréhu, Anne M., Flemings, Peter B., Bangs, Nathan L., Chevallier, Johanna, Gràcia, Eulàlia, Johnson, Joel E., Liu, C.-S., Liu, Xiaoli, Riedel, Michael and Torres, Marta E. (2004) Feeding methane vents and gas hydrate deposits at south Hydrate Ridge. Geophysical Research Letters, 31 (23). L23310. DOI 10.1029/2004GL021286.

[img] Text
Trehu.pdf - Published Version
Restricted to Registered users only

Download (239Kb) | Contact

Supplementary data:

Abstract

Log and core data document gas saturations as high as 90% in a coarse-grained turbidite sequence beneath the gas hydrate stability zone (GHSZ) at south Hydrate Ridge, in the Cascadia accretionary complex. The geometry of this gas-saturated bed is defined by a strong, negative-polarity reflection in 3D seismic data. Because of the gas buoyancy, gas pressure equals or exceeds the overburden stress immediately beneath the GHSZ at the summit. We conclude that gas is focused into the coarse-grained sequence from a large volume of the accretionary complex and is trapped until high gas pressure forces the gas to migrate through the GHSZ to seafloor vents. This focused flow provides methane to the GHSZ in excess of its proportion in gas hydrate, thus providing a mechanism to explain the observed coexistence of massive gas hydrate, saline pore water and free gas near the summit.

Document Type: Article
Keywords: Methane, gas hydrate deposits, south Hydrate Ridge
Refereed: Yes
DOI etc.: 10.1029/2004GL021286
ISSN: 0094-8276
Date Deposited: 06 Jan 2016 14:08
Last Modified: 06 Jan 2016 14:08
URI: http://oceanrep.geomar.de/id/eprint/30839

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...