FROST CRACK

A fissure formed as a result of stresses generated in frozen soil or rock by thermal changes. In permafrost regions, frost cracks in sediments usually result from thermal contraction cracking. Seasonal frost cracking may also occur in regions of seasonally frozen ground where there is deep penetration of the freezing front. Frost cracks in rocks and boulders are thought to occur because of the 9 per cent volume expansion of water upon freezing when water penetrates the cracks, joints, and bedding planes. Differential thermal stresses generated at subzero temperatures may also cause cracking.

[See alsofrost weathering, ice wedge, periglacial landforms, periglacial landscape evolution, periglacial sediments]