A gas hydrate pingo is a submarine dome structure formed by the accumulation of gas hydrates under the seafloor. Gas hydrate pingos resemble the pingo landforms found on land in periglacial regions.The crystallized gas particles form when a gas particle is surrounded by water molecules. The water molecules create a lattice structure that encages the gas molecule. Most gas hydrates contain methane, while other rare gas hydrates contain hydrogen sulfate or carbon dioxide. Submarine pingoes are found along continental margins.
Gas hydrate pingos may accumulate non-hydrate gas under pressure leading to explosions that forms craters. Crater depressions of this type have been found on the seafloor of Barents Sea. A trigger for the explosions may be drop in pressure as result of lowering of the sea level.
A study in the Norwegian Sea found that gas hydrate pingos were covered by bacterial mats and by Polychaete tubeworms that are associated with methane.