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Methane clathrates (hydrates) are also commonly formed during natural gas production operations, when liquid water is condensed in the presence of methane at high pressure. It is known that larger hydrocarbon molecules like ethane and propane can also form hydrates, although longer molecules (butanes, pentanes) cannot fit into the water cage ...
Methane clathrate, also known commonly as methane hydrate, is a form of water ice that contains a large amount of methane within its crystal structure. Potentially large deposits of methane clathrate have been found under sediments on the ocean floors of the Earth, although the estimates of total resource size given by various experts differ by ...
Methane clathrate block embedded in the sediment of hydrate ridge, off Oregon, USA. Clathrate hydrates, or gas hydrates, clathrates, or hydrates, are crystalline water-based solids physically resembling ice, in which small non-polar molecules (typically gases) or polar molecules with large hydrophobic moieties are trapped inside "cages" of hydrogen bonded, frozen water molecules.
Methane clathrates feature the hydrogen-bonded framework contributed by water and the guest molecules of methane. Large amounts of methane naturally frozen in this form exist both in permafrost formations and under the ocean sea-bed. [8] Other hydrogen-bonded networks are derived from hydroquinone, urea, and thiourea.
The largest reservoir of methane is under the seafloor in the form of methane clathrates. When methane reaches the surface and the atmosphere, it is known as atmospheric methane. [10] The Earth's atmospheric methane concentration has increased by about 160% since 1750, with the overwhelming percentage caused by human activity. [11]
Permafrost and clathrates degrade on warming, [23] thus large releases of methane from these sources may arise as a result of global warming. [ 24 ] [ 25 ] [ 26 ] Other sources of methane include submarine taliks , river transport, ice complex retreat, submarine permafrost and decaying gas hydrate deposits. [ 27 ]
The gas trapped inside the clathrates is predominantly thermogenic methane that generated due to a thermal alteration of organic material. Given the chemical and carbon-isotope compositions of the organic matter, the organic material is predominantly composed of a variety of higher land plants with a terrestrial origin.
Methane hydrate dissolution has been invoked as a highly plausible causal mechanism for the carbon isotope excursion and warming observed at the PETM. [195] The most obvious feedback mechanism that could amplify the initial perturbation is that of methane clathrates. Under certain temperature and pressure conditions, methane – which is being ...