HR: 16:20h
AN: GC14A-02    [Abstracts]
TI: Impacts, Salinity, and Climate Change: Global-Scale Triggers for Hydrate Dissociation
AU: * Elwood Madden, M E
EM: melwood@ou.edu
AF: ConnocoPhillips School of Geology and Geophysics, University of Oklahoma, 100 E. Boyd St., Suite 800, Norman, OK 73072, United States
AU: Ulrich, S M
EM: ulrichsm@ornl.gov
AF: BioSciences Division, Oak Ridge National Laboratory, PO Box 2000 Bethel Valley Rd., Oak Ridge, TN 37831, United States
AU: Phelps, T J
EM: phelpstj@ornl.gov
AF: BioSciences Division, Oak Ridge National Laboratory, PO Box 2000 Bethel Valley Rd., Oak Ridge, TN 37831, United States
AB: The release of greenhouse gases from gas hydrate reservoirs likely leads to increased global temperatures initiating a positive feed-back trend of increased warming and further hydrate dissociation. However, the initial geologic trigger which instigates hydrate dissociation may vary. Impacts will disrupt both the water column and shallow sediments in marine and continental shelf environments or expose and/or heat hydrate deposits in the subsurface within permafrost. The effects of marine or coastal impacts may be seen far from the point of impact as waves or surges disrupt sediments hundreds of meters below the water surface and reduce temperature and chemical stratifications within the water column. These disruptions could perhaps destabilize regional scale (i.e. Gulf of Mexico) gas hydrate deposits. Regional changes in salinity may also result in significant hydrate dissociation as the activity of water decreases due to mixing of higher salinity fluids or evaporation. Salinity- triggered hydrate dissociation is likely to be most effective in relatively isolated basins such as the Mediterranean, Black Sea, or perhaps ancient seas on Mars.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 1621 Cryospheric change (0776)
DE: 3004 Gas and hydrate systems
DE: 5420 Impact phenomena, cratering (6022, 8136)
DE: 5422 Ices
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting