Palsas and Lithalsas

• Main Author: Pissart, Albert
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier Inc. 2013
• Subjects: Aggradational ice; Frost thrusting; Lapland; Lithalsa; Mineral palsa; Northern Québec; Palsa; Periglacial mound; Remnant of lithalsas; Segregation ice; Physical; chemical; mathematical & earth Sciences; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences de la terre & géographie physique; Ice; palsa; palsas; permafrost
• Online Access: https://orbi.uliege.be/handle/2268/250188; https://orbi.uliege.be/bitstream/2268/250188/1/Palsas%20and%20Lithalsasppa.pdf; https://doi.org/10.1016/B978-0-12-374739-6.00210-4

Palsas and lithalsas are mounds that contain lenses of segregation ice. They are islands of permafrost. These two kinds of mounds are very similar in shape, size, and origin. However, the palsas have a cover of peat which does not exist in lithalsas. The formation of ice in the core of these mounds requires material in which capillary water undergoes slow freezing. The remnants of lithalsas are depressions surrounded by ramparts, which does not exist after the melting of palsas. The processes involved in the formation of segregation ice are described in the beginning of the chapter. © 2013 Elsevier Inc. All rights reserved.