pitformation

Pit formation refers to the creation of pits, small hollows or cavities, on a surface through a range of natural and human-driven processes. The term is used across disciplines such as geology, materials science, and planetary science to describe localized depressions that differ in origin, scale, and context.

In natural settings, pit formation commonly results from weathering and erosion. Dissolution of soluble rocks in karst environments creates pits and sinkholes; abrasion and conveyance of sediments in rivers produce bedrock pits or potholes; wind and freeze–thaw cycles can yield micro-pits on rock surfaces. In soils and landscapes, pits can form around biological activity, such as root channels or burrows, and can develop into larger depressions over time.

In materials science, pit formation often denotes pitting corrosion, a localized attack on metal surfaces. Pits initiate when protective oxide films break down in aggressive environments (for example, in the presence of chlorides or acids) and the metal preferentially corrodes at defects. Pitting can propagate beneath surfaces and lead to through-thickness failure if unchecked. This form of pit formation is a major consideration in corrosion prevention and inspection.

Other contexts include planetary and cave sciences, where pits can appear on airless bodies due to impacts, sublimation, or outgassing, and in speleology where pits develop as cave features. Pit morphology is typically described by diameter, depth, density, and spatial distribution, using imaging and profilometry for study.

See also: pitting corrosion, sinkhole, pothole, weathering.