The Norwegian-Barents-Svalbard (NBS) continental margin: Introducing a natural laboratory of mass wasting, hydrates, and ascent of sediment, pore water, and methane

Side-scan sonar mapping and ground-truthing of the Norwegian-Barents-Svalbard continental margin shed new light on shelf glaciation, mass wasting, hydrates, and features like the Hakon Mosby mud volcano (HMMV), reflecting upward mobility of gas, pore fluids, and sediments. Detailed HMMV examination revealed thermal gradients to 10 degrees/m, bottom-water CH4 and temperature anomalies, H2S- and CH4-based chemosynthetic ecosystems, and subbottom methane hydrate (to 25%). Seismic and chemical data suggest HMMV origins at 2-3 km depth within the 6-km-thick depocenter. The HMMV and mound fields bordering the Bjornoyrenna slide valley and pockmarks bordering the Storegga slide may all have formed in response to sediment failure.