Evidence of large-scale absence of frozen ground and gas hydrates in the northern part of the East Siberian Arctic shelf (Laptev and East Siberian seas)

This study investigated the zones associated with the potential distribution and absence of frozen ground and gas hydrates on the East Siberian Arctic Shelf in the Laptev and East Siberian seas. The investigation was based on an analysis of velocities of refracted waves registered as first breaks from common-shot gathers along 71 common depth point seismic lines with a total length of 15 630 km acquired by JSC MAGE in 2007-2016. Consequently, essentially new data that illustrate the state of the cryolithozone on the East Siberian Arctic Shelf were obtained. In particular, this study confirmed a significant decrease in the area of possible existence of frozen ground and methane hydrates in the postglacial period. Based on an extensive analysis of subsea frozen ground degradation zones on the shelves of the Laptev, East Siberian, Chukchi, and Beaufort seas (similar to 57% of the total area), it can be concluded that there is a low probability of considerable contribution of methane, being released from the dissociating gas hydrates, to climate change.