ABSTRACT: Ground probing radar investigations of ground ice on the Fosheim Peninsula, Ellesmere Island, Northwest Territories.

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Abstract

Near-surface segregated and massive ice in permafrost has been detected and mapped using a Pulse EKKO III ground probing radar system at Hot Weather Creek, Ellesmere Island, NWT. This geophysical instrument transmits an electromagnetic pulse into the ground and records the amount of time required for the pulse to be reflected back from boundaries of dielectric contrast below the surface. These changes in the electrical character of the ground are often caused by variation in soil moisture or ice content, as well as material contrasts. Profiles were conducted at centre frequencies of 25, 50, and 200 MHz near an active ground ice thaw slump. The 50 MHz surveys revealed an apparent layer of massive ice or ice-rich sediments. Air bubbles and silt layers in ice observed in shallow drill cores and on the slump face exposure appear to have been responsible for weak multiple reflections observed within the ice bodies. Typical penetration depths at 25 MHz were on the order of 25 metres with an average EM wave velocity of 0.1 m/ns. This continuing project is being carried out as part of a general ground ice mapping program on the Fosheim Peninsula. Preliminary results indicate that massive ice occurs at a number of locations. It is hoped that by studying ground ice conditions in this area, a base line of observations may be obtained against which future geomorphic change may be charted. (Author) | Near-surface segregated and massive ice in permafrost was detected and mapped at Hot Weather Creek, in 1990. Frequencies of 25, 50 and 200 MHz were used

Bibliography of Canadian Geomorphology