Frost mounds: Active and relict forms

Abstract

Frost mounds are widely found in regions of permafrost. This chapter describes perennial and seasonal frost mounds and summarizes their origin and collapsed relict forms. “Frost mounds” are typically identified on the basis of the genesis of their contained water/ground ice (e.g., intrusive or segregated ice), the formation of which heaves up the mounds. The genetic types of frost mounds include open- and closed-system pingos and other ice-cored mounds (palsas, lithalsas, frost blisters) as well as gas-domed mounds or blowout craters. The majority of frost mounds result from frost heave, though thaw and subsidence of ice-rich ground surrounding syngenetic ice wedges can form thermokarst mounds (or baydzherakhs in Siberia), which are included here as a type of frost mound. Pingos and pingo-like features (PLFs) are distributed in permafrost regions in the Northern Hemisphere. Pingos have been identified and studied in the arctic regions of Svalbard, Greenland, Canada, Alaska, and Siberia, and in central Asia, Mongolia, and China. They have not been reported along the equator or in the Southern Hemisphere. PLFs may occur on the planet Mars and elsewhere in the outer Solar System.