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A review of the geochemistry of methane in natural gas hydrate

January 1, 1995

The largest accumulations on Earth of natural gas are in the form of gas hydrate, found mainly offshore in outer continental margin sediment and, to a lesser extent, in polar regions commonly associated with permafrost. Measurements of hydrocarbon gas compositions and of carbon-isotopic compositions of methane from natural gas hydrate samples, collected in subaquatic settings from around the world, suggest that methane guest molecules in the water clathrate structures are mainly derived by the microbial reduction of CO2 from sedimentary organic matter. In only 2 regions, the Gulf of Mexico and the Caspian Sea, has mainly thermogenic methane been found in gas hydrate. At a few locations, where the gas hydrate contains a mixture of microbial and thermal methane, microbial methane is always dominant. Continental gas hydrate, identified in Alaska and Russia, also has hydrocarbon gases composed of >99% methane, with carbon-isotopic compositions ranging from -41 to -49???. -from Author

Publication Year 1995
Title A review of the geochemistry of methane in natural gas hydrate
Authors K. A. Kvenvolden
Publication Type Article
Publication Subtype Journal Article
Series Title Organic Geochemistry
Index ID 70018724
Record Source USGS Publications Warehouse