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Methane clathrate (CH 4 ·5.75H 2 O) or (4CH 4 ·23H 2 O), also called methane hydrate, hydromethane, methane ice, fire ice, natural gas hydrate, or gas hydrate, is a solid clathrate compound (more specifically, a clathrate hydrate) in which a large amount of methane is trapped within a crystal structure of water, forming a solid similar to ice.
The present-day global methane hydrate reserve was once considered to be between 2,000 and 10,000 Gt C (billions of tons of carbon), but is now estimated between 1500 and 2000 Gt C. [37] However, because the global ocean bottom temperatures were ~6 °C higher than today, which implies a much smaller volume of sediment hosting gas hydrate than ...
The existence and depth of a hydrate deposit is often indicated by the presence of a bottom-simulating reflector (BSR). A BSR is a seismic reflection indicating the lower limit of hydrate stability in sediments due to the different densities of hydrate saturated sediments, normal sediments and those containing free gas. [2]
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.
The Nankai Trough is located beneath the Pacific Ocean off the southeast coast of Japan, and extends more than 700 km in a southwest-northward trending direction. The Nankai Trough is not only known as an active subduction and earthquake zone, but also for its large clathrate hydrate deposits occurring on the shelf and continental slope.
The free gas zone is a zone of freed methane in a hydrate formation, beneath the hydrate stability zone. It can influence the rate of methane output at a ridge or ridge region. A large free gas zone makes more methane available to be released into the open ocean, and, thus, can likely be more influential on climate change than a smaller one. [11]
One of these explanations is the vast field of methane hydrates present on the bottom of the ocean in the Dragon's Triangle area. Methane clathrates (methane hydrates gas) will "explode" when it rises above 18 °C (64 °F). Methane hydrate gases are described as icelike deposits that break off from the bottom and rise, forming bubbles on the ...
At water depths of 500 m to 1,000 m, and at the low temperatures typical of the seafloor (close to 4 °C), water and methane combine to create a substance known as methane hydrate. Within a few metres to hundreds of metres of the seafloor, the temperature is low enough for methane hydrate to be stable and hydrates accumulate within the sediment.