Lithalsa is a frost-induced raised land form in

permafrost Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean. Most common in the Northern Hemisphere, around 15% of the Northern Hemisphere or 11% of the global surface ...

areas with mineral-rich soils, where a perennial

ice lens Ice lenses are bodies of ice formed when moisture, diffused within soil or rock, accumulates in a localized zone. The ice initially accumulates within small collocated pores or pre-existing crack, and, as long as the conditions remain favorable, ...

has developed within the soil. The term sometimes also refers to

palsa Palsas are peat mounds with a permanently frozen peat and mineral soil core. They are a typical phenomenon in the polar and subpolar zone of discontinuous permafrost. One of their characteristics is having steep slopes that rises above the mire ...

s and

pingo Pingos are intrapermafrost ice-cored hills, high and in diameter. They are typically conical in shape and grow and persist only in permafrost environments, such as the Arctic and subarctic. A pingo is a periglacial landform, which is defin ...

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External links

Stone Circles Explained
about stone structures created by frost heaving Geomorphology Glaciology Ground freezing Palsas Patterned grounds Periglacial landforms Soil {{geology-stub