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Definition:
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A layer or body of Unfrozen Ground occurring in a Permafrost area due to a local anomaly in thermal, hydrological, hydrogeological, or hydrochemical conditions. Taliks may have temperatures above 0C (non-cryotic) or below 0C (cryotic). Some Taliks may be affected by seasonal freezing. Several types of Taliks can be distinguished on the basis of their relationship to the Permafrost (closed, open, lateral, isolated and transient Taliks), and on the basis of the mechanism responsible for their unfrozen condition (hydrochemical, hydrothermal and thermal Taliks): _ Closed Talik - a non-cryotic Talik occupying a depression in the Permafrost Table below a lake or river (also called 'lake Talik' and 'river Talik'); its temperature remains above 0C because of the heat storage effect of the surface water; Hydrochemical Talik - a cryotic Talik in which freezing is prevented by mineralized groundwater flowing through the Talik. _ Hydrothermal Talik - a non-cryotic Talik, the temperature of which is maintained above 0C by the heat supplied by groundwater flowing through the Talik; _ Isolated Talik - a Talik entirely surrounded by perennially Frozen Ground; usually cryotic, but may be non-cryotic; _ Lateral Talik - a Talik overlain and underlain by perennially Frozen Ground; can be noncryotic or cryotic; _ Open Talik - a Talik that penetrates the Permafrost completely, connecting supraPermafrost and Subpermafrost Water. It may be non-cryotic or cryotic. _ Thermal Talik - a non-cryotic Talik, the temperature of which is above 0C due to the local thermal regime of the ground; _ Transient Talik - a Talik that is gradually being eliminated by freezing.
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