permafrost Permanently frozen ground, typical of the treeless plains of Siberia (tundra), though common through arctic, sub-arctic, and antarctic regions on Earth to a depth of as much as 600 meters. Permafrost also exists in the upper part of the crust on Mars. Related category GEOLOGY AND PLANETARY SCIENCE Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) |