GAS-RELATED SEA-FLOOR CRATERS IN THE BARENTS SEA

A cluster of craterlike depressions in the central Barents Sea are sev eral hundred meters across, have steep walls, and are cut into underly ing Triassic rocks. Their formation is explained in relation to the gl acial history of the region, and a possible model suggests that gas fr om a deeper, thermogenic source allowed a hydrate layer of considerabl e thickness to form during the Late Weichselian, when grounded ice cov ered the area and increased the hydrostatic pressure. After a rapid re treat of the marine-based ice sheet, the hydrates decomposed and the l ayer thinned rapidly until pressurized free gas, trapped below the hyd rates, erupted and formed the sea-floor depressions.