The World of Underground Ice

ABSTRACT Underground ice is restricted to permafrost areas where its distribution is sporadic and often unpredictable. A knowledge of the distribution and abundance of underground ice is essential to northern development, because a variety of man induced disturbances can cause underground ice to thaw, often with serious consequences. The criteria for a classification of the principal types of underground ice are the source of the water prior to freezing and the processes which transfer water to the freezing plane. The origin of massive icy bodies in the Western Arctic of North America is explained by a water expulsion theory. The excess water now found in the icy bodies is attributed to water expelled from coarse textured sediments by the downward growth of permafrost. The suggested mechanism is illustrated by three pingos which have grown since 1950. The role of glaciation in the formation of relic offshore permafrost in relatively shallow Arctic coastal areas is examined. The evidence suggests that offshore permafrost is present in some shallower portions of the Beaufort Sea from northeastern Alaska eastwards to the high Arctic islands of Canada. If offshore permafrost with underground ice is present, then thermal disturbance problems must be taken into consideration in future offshore exploration.