Geophysical studies of massive ground ice, Fosheim Peninsula, Ellesmere Island, Northwest Territories

Abstract

Three geophysical techniques were employed to study massive ground ice found as a component of the raised marine sediments of the Fosheim Peninsula, Ellesmere Island, N.W.T. The EM-31 terrain conductivity meter was hampered by the highly variable overburden salt content, especially in the vicinity of thaw disturbances. The heterogeneous surface terrain also hindered ground penetrating radar surveys, however some reflectors noted at 10 to 15 m depth could represent the base of massive ice. Gravity surveying showed several of the flat-topped hills in the area to be cored with massive ice up to 17 m thick. Materials encountered in shallow boreholes agreed with geophysical interpretations. Although evidence of past thermokarst is abundant over much of the region, the large amount of deep and shallow ice still remaining suggests that there is the potential for severe terrain disturbance in the future.