Gas Hydrates

In this data package you can learn about gas hydrates located off of the coast of Vancouver Island in Barkley Canyon by watching video clips and answering questions. Background information on gas hydrates can be found below and in the word document.

Gas hydrates are naturally occurring solids, each comprised of a small natural gas molecule, mainly methane, surrounded by a rigid cage of hydrogen bonded water molecules. They form in regions where light hydrocarbons are abundant, temperatures are sufficiently low, and pressure is high (Haacke et al., 2007). These conditions are satisfied worldwide in some permafrost polar regions and oceanic sediment on outer continental margins. In oceanic regions, gas hydrates can form where the bottom water temperatures approach zero ºC and water depths exceed about 300-500 metres (Kvenvolden, 1993).

Gas hydrates are of global significance because they are a valuable potential energy resource (Haacke et al., 2007). They are widely distributed and there is an enormous amount of methane sequestered at shallow sediment depths within 2000 metres of the Earth’s surface. Gas hydrates are also a significant geologic hazard. An increase in sedimentation, lowering of sea level, or an increase in bottom water temperatures can cause gas hydrate dissociation. This can lead to zones of weakness that are especially vulnerable to gravitational loading or seismic disturbances, causing submarine slope failure.

The destabilization of gas hydrates and the subsequent release of methane into the atmosphere can accelerate climate change. Methane is a greenhouse gas that has global warming potential 20 times larger than an equivalent amount of carbon dioxide when integrated over a 100 year span of time. A large release of methane could have a significant impact on atmosphere composition and the warming of our planet (Kvenvolden, 1993).

References:

Haacke, R.R. Westbrook, G.K., Hyndman, R.D., 2007, Gas hydrate, fluid flow and free gas: Formation of the bottom-simulating reflector, Earth and Planetary Science Letters, 261(3-4), 407-420, doi:10.1016/j.epsl.2007.07.008.

Kvenvolden, K.A., 1993, Gas hydrates - geological perspective and global change, Review of Geophysics, 31(2), 173-187, doi:10.1029/93RG00268.

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Grade Level

  • Undergraduate

Resource Category

Author

Kara Aschenbrenner

Last Updated

Aug 9, 2016

Created Date

Aug 15, 2013