Occurs when temperatures fluctuate,
rising during day but dropping below
freezing at night
Water enters cracks in rocks and freezes overnight
- expanding by volume of 10% exerting pressure on
crack
As this process continues, cracks
widen and eventually pieces of rock
break off. Weathering process
important as helps produce some of
debris used in abrasion.
Dilation
When overlying pressure is
released, such as when a
glacier begins to melt and loses
weight, underlying rock
expands (Dilates) and fractures;
joints created and existing
joints in rock are enlarged. This
enables glacial erosion to be
more effective.