No abstract

To provide high sensitivity and to observe a representative sample of the earth's surface, a laser extensometer having a length of 1020 m has been built and is in operation. The sensitivity of the instrument described is at present about Δl/l≅6 × 10−12.

Geophysical evidence indicates that the delta area of the Mackenzie River, Northwest Territories, is affected by tectonic subsidence. Pingos are of sparse occurrence in the Arctic as a whole but they occur in hundreds in the Mackenzie River delta. In a region of subsidence, as recent sediments pass through the base of permafrost, compaction becomes possible. The resulting water expulsion produces an artesian head responsible for building pingos.

No abstract

Geophysical evidence indicates that the delta area of the Mackenzie River, Northwest Territories, is affected by tectonic subsidence. Pingos are of sparse occurrence in the Arctic as a whole but they occur in hundreds in the Mackenzie River delta.In a region of subsidence, as recent sediments pass through the base of permafrost, compaction becomes possible. The resulting water expulsion produces an artesian head responsible for building pingos.