The University of Texas logo
\
Simulations of Seafloor Methane Venting from Warming-Induced Hydrate Destabilization

UTIG Seminars


Simulations of Seafloor Methane Venting
from Warming-Induced Hydrate Destabilization

By:
Kristopher Darnell
UTIG Graduate Student

When: Friday, May 2, 2014, 10:30 a.m. to 11:30 a.m.
Join us for coffee beginning at 10:00 a.m.
Where: Seminar Conference Room, 10100 Burnet Road, Bldg 196-ROC, Austin, Texas 78758
UTIG Supervisor: Peter Flemings

Click for a Live Broadcast.

 

Abstract
We show with a dynamic, multiphase, fluid-flow model that free gas can temporarily vent through the marine hydrate stability zone and flux into the ocean during the transient response to warming. Our analysis indicates that the venting results from elevated salinities in the upper regions of the sediment column as dissociated free gas migrates upward and forms secondary hydrate, expelling salt from the hydrate cage. The elevated salinities produce a temporary three-phase equilibrium co-existence throughout the sediment column that persists until the gas charge is depleted. The salinity eventually relaxes to a steady-state seawater profile and a hydrate deposit of decreased mass spans the hydrate stability zone. This transient behavior provides a new explanation for methane vents that appear to display gas flow through the hydrate stability zone and, furthermore, may explain past venting events that were the sources for now relict seafloor pockmarks.