5 February 2007
Methane bubbling through sea floor creates undersea hills called "pingo-like features."
Geophysical Research Letters,Origin of pingo-like features on the Beaufort Sea shelf and their possible relationship to decomposing methane gas hydrates geologists Charlie Paull and William Ussler Beaufort Sea Shelf off North coast of Canada.
The Arctic shelf is currently undergoing dramatic thermal changes caused by the continued warming associated with Holocene sea level rise. During this transgression, comparatively warm waters have flooded over cold permafrost areas of the Arctic Shelf. A thermal pulse of more than 10°C is still propagating down into the submerged sediment and may be decomposing gas hydrate as well as permafrost.
According to the paper methane gas bubbling through sea floor sediments has created hundreds of low hills on the floor of the Arctic Ocean. These features, which can grow up to 40 meters (130 feet) tall and several hundred meters across, The paper says the pingo-like features form when methane hydrate (a frozen mixture of gas and seawater) decomposes beneath the sea floor, releasing gas that squeezes deep sediments up onto the sea floor like toothpaste from a tube. Finally, many of the pingo-like features were surrounded by shallow "moats," where the sea floor within a kilometer of the hill had apparently subsided.