Periglacial processes and landform1

Periglacial processes and landform1 - Periglacial processes...

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Periglacial processes and landforms Periglacial processes and landforms 1. frost action o dominant set of periglacial processes given freeze thaw cycles and commonly wet conditions of the active layer o produces characteristic periglacial landforms and deposits, such as the mantle of coarse angular debris, which can become relict and diagnostic features with a change in climate o shattering (wedging, splitting) mechanical weathering (disintegration) caused by force of ice and dense water in fractures o heave displacement of soil and rock with the growth of segregated ground ice as free water migrates to the freezing plane (lower vapour pressure) produces hills (pingos) and mounds (palsas, thufurs) with a core of segregated ice also results in the size sorting of heterogenous materials, as larger clasts migrate to the surface at rates up to 5 cm/yr frost pull o the entire soil mantle expands, or is pulled up, as the freezing plane descends from the surface o with thawing, the cohesive matrix of fine material retracts, filling the space beneath clasts and leaving them in a slightly elevated position relative to the preceding thaw season o this process can pull clasts towards the surface, but not through it
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This note was uploaded on 12/15/2011 for the course GLY GLY100 taught by Professor Jaymuza during the Fall '10 term at Broward College.

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Periglacial processes and landform1 - Periglacial processes...

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