GAS-RELATED SEA-FLOOR CRATERS IN THE BARENTS SEA

A cluster of craterlike depressions in the central Barents Sea are several hundred meters across, have steep walls, and are cut into underlying Triassic rocks. Their formation is explained in relation to the glacial history of the region, and a possible model suggests that gas from a deeper, thermogenic source allowed a hydrate layer of considerable thickness to form during the Late Weichselian, when grounded ice covered the area and increased the hydrostatic pressure. After a rapid retreat of the marine-based ice sheet, the hydrates decomposed and the layer thinned rapidly until pressurized free gas, trapped below the hydrates, erupted and formed the sea-floor depressions.