New Study Reveals Cracks Beneath Giant, Methane Gushing Craters

A gas hydrate is a an icy solid form of gas, often methane. (Image: CAGE)
A gas hydrate is a an icy solid form of gas, often methane. (Image: CAGE)

The 250-million-year-old cracks in the seafloor feed the greenhouse gas methane into giant craters in the Barents Sea. More than 100 craters, presently expelling enormous amounts of the greenhouse gas into the ocean, are found in the area. A CAGE paper published in Science in 2017 described hundreds of massive, kilometer-wide, craters on the ocean floor in the Barents Sea. Today, more than 600 gas flares are identified in and around these craters, releasing the greenhouse gas steadily into the water column. Another CAGE study, published in PNAS, mapped several methane mounds, some 500 m wide, in the Barents Sea.

The methane craters in the Barents Sea are profusely leaking the greenhouse gas methane into the Arctic waters. (Illustration: Malin Waage)

The methane craters in the Barents Sea are profusely leaking the greenhouse gas methane into the Arctic waters. (Illustration: Malin Waage)

The mounds were considered to be signs of soon-to-happen methane expulsions that have created the craters. The most recent study in Scientific Reports looks into the depths far beneath the sediment in the ocean floor and reveals the geological structures that have made the area prone to crater formation and subsequent methane expulsions, according to Malin Waage, a postdoc at CAGE and the first author of the study:

Cutting edge 3D seismic technology

The deep origin of craters and mounds was discovered using cutting edge 3D seismic technology that can penetrate deep into the ocean floor and help scientists visualize the structures in the hard bedrock underneath. Waage said:

Gas hydrates are a solid form of methane, among others, that is stable in cold temperatures and under pressure, which an enormous ice sheet provides. As the ocean warmed up, and the pressure of the ice sheet lifted, the methane ice in the seafloor melted and thus the craters were formed. Waage explained:

The study covered 20 percent of the crater area in the Barents Sea. (Illustration: Malin Waage)

The study covered 20 percent of the crater area in the Barents Sea. (Illustration: Malin Waage)

The Barents Sea is poorly understood

The exploration of petroleum resources in the Barents Sea is a hot topic in Norway and beyond, as the area is a part of a vulnerable Arctic ecosystem. But the area’s geological system is poorly understood. Waage said:

Some of the questions that scientists, society, and the industry do not know the answers to are: Will these weak structures lead to unpredictable and explosive methane release? Can such release and related geohazards be triggered by drilling? And can the gas reach the atmosphere in case of abrupt blow-outs, adding to the greenhouse gas budget? Waage said:

Provided by: Maja Sojtaric, CAGE — Center for Arctic Gas Hydrate, Climate and Environment [Note: Materials may be edited for content and length.]

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