What weathering process involves the repeated thawing and freezing of water within the cracks of rocks?

Frost wedging is a specific type of mechanical weathering that occurs when water infiltrates cracks in rocks. During cold periods, this water freezes, expanding in volume as it turns into ice. When temperatures rise again, the ice thaws and contracts. This repeated cycle of freezing and thawing exerts pressure on the surrounding rock, gradually widening the cracks and breaking apart the rock. Over time, this process can lead to significant fragmentation of the rock, contributing to erosion and the overall breakdown of the landscape.

The other processes mentioned relate to different aspects of weathering. Chemical weathering involves the alteration of the chemical composition of rocks due to various reactions, typically involving water and other chemicals, but does not specifically refer to the physical expansion and contraction caused by freezing and thawing. Exfoliation refers to the peeling away of outer layers of rock, often due to pressure release rather than temperature fluctuations. Mechanical breakdown, while it sounds similar to frost wedging, is a broader term that encompasses various physical processes of breaking apart rocks without changing their chemical composition, and it does not specifically involve the freeze-thaw cycles characteristic of frost wedging.