Earth Hummocks of the Canadian Arctic and Subarctic^∗

Abstract

Studies in the western Arctic and Subarctic and in the central Arctic indicate that earth hummocks have an average diameter of 80 to 160 cm and an average height of 40 to 60 cm. They have developed on materials having 58 to 99% total clay and silt content and either high ice content or pure ice layers in the nearsurface permafrost. Earth hummocks are cryogenic in origin with their development being controlled by three major factors: soil texture, soil moisture, and soil temperature. Most of the earth hummocks have developed during the last 5000 yr, when the climate became colder.