Summary: | Systematic observations of the distribution and thickness of the permafrost were made in northeastern British Columbia, Canada, along a traverse extending northeastward from Fort Nelson (58 49 N, 122 41 W) situated at an elevation of about 1000 ft (305 m) above sea level, across the southwest-facing Etsho Escarpment which rises to an elevation exceeding 2200 ft (671 m), and to the boundary of the Northwest Territories at an elevation of about 1500 ft (457 m) . The traverse was underlain mostly by cretaceous shales, with sandstone forming the higher land. . The thickness of the active layer was measured by probing with thin steel rods. . Wherever possible, seismic lines were used for this measurement, since probing is then more likely to indicate the approximate base of the permafrost in the area. . Probing below permafrost bodies from seismic lines and natural depressions in the landscape revealed, however, no inconsistent results within the study area.
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