The Process of Physical Weathering

Definition

• Physical weathering is the gradual wearing away of larger rocks into smaller rocks right where they stand.

Function

• Physical weathering loosens and crumbles surface minerals of rocks so that they can be more easily transported by wind and water in the erosion process.

Mechanical Exfoliation Process

• Eastern Illinois University explains that when a previously buried slab of rock is uncovered, the rock expands due to a change in pressure. This expansion often causes cracks, called joints, to form. These joints run parallel to the surface of the exposed rock, forming layers. In mechanical exfoliation, the topmost layers break off and fall away.

Weathering from Physical Stress

• Rocks can weaken and crumble when extreme temperature changes force them to expand and contract. Freezing temperatures can cause ice crystals to form in crevices, which stress the rock as they expand. Plant roots break up rocks as they grow. And continuous abrasion from sand carried by the wind can wear holes into rocks.