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| Refers to nonglacial processes and landforms associated with various aspects of frozen ground |
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| The approx. 9% expansion of water when it freezes is a critical process in periglacial areas |
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| The segregation of freezing water into ice lenses in the ground - especially prominent in fine grained materials frozen water tends to be confined to pore spaces between grains |
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| Occurs near the frost line and is related to the expansion of water as it freezes & to the creation of ice lenses |
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| Develops within frozen layers at various temperatures; annual ground displacements of several centimeters are common |
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| The progressive upward movement of stones & other objects during frost heaving |
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| Complex process by which migrating particles are sorted into uniform particle sizes by freezing and thawing |
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| The downslope movement of particles resulting from frost heaving of the ground perpendicular to the slope and subsequent nearly vertical setting upon thawing |
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| The process of slow downslope flowage of unconsolidated material saturated with water |
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| A tongue like body of boulders which moves slowly down valley under the influence of ice between the particles |
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| Block Fields or Felsenmeer |
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| Broad, relatively level mountainous areas covered with moderate to large angular blocks of rock produced in situ from frost wedging |
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| Similar deposits found on slopes steeper than 12 degrees |
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| Similar accumulations confined to valleys |
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| A condition existing below the ground surface, irrespective of texture, water content, or geological character |
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| Surface zone in permafrost areas that thaws out seasonally |
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| Greatest depth of permafrost |
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| Bands, layers, wedges of segregated ice; can grow to up to 65-feet thick; tends to cause much heaving |
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| Nearly vertical, downward tapering lenses of subsurface ice; can extend to 33 feet below surface and 3 feet wide |
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| Isolated, dome shaped, ice cored mounds |
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| Low permafrost mounds with cores of inter-layered segregated ice & peat or soil |
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| Includes a diverse assemblage of collapsed landforms resulting from the thawing of ground ice; best developed where numerous, thick ground ice masses occur in the upper permafrost |
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| Linear & Polygonal Troughs |
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| Form from the melting of ice wedges |
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| Some ground ice melts & depressions fill with water |
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| Created when thawing at the junctions of ice wedge polygons creates small ponds that may then be connected by short, straight streams flowing along thawing ice wedges |
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| A specific type of closed thermokarst depression identified in Siberia; have steep sides and flat floors, formed by subsidence following the melting of ground ice |
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| Ground having distinct, symmetrical forms, such as polygons, nets & stripes, characteristic of areas subject to intense frost action |
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