Crevices

A crevice is a narrow crack or fissure in rock or earth's surface. Crevices can occur in bedrock, talus slopes, cliffs, granite outcrops, and in man-made walls. They are typically smaller than crevasses, which are wide cracks associated with glaciers.

Formation occurs through physical weathering, such as freezing and thawing, thermal expansion and contraction, and root wedging, as well as chemical weathering, including dissolution and hydration. Tectonic stresses can also produce joints that develop into crevices. Over time, erosion may widen them into larger channels. Water often concentrates in crevices, promoting further weathering and providing a microenvironment.

Crevices support ecological diversity by offering microhabitats for plants and animals, retaining moisture and sheltering organisms from sun and wind. Lichens, mosses, and small invertebrates may inhabit crevices, and seeds can lodge there and germinate in sheltered pockets.

Types and contexts vary: crevices occur in natural settings such as cliff faces, rock outcrops, deserts, and cave entrances, as well as in constructed structures where weathering exposes fractures. In glaciated terrains, crevices differ from crevasses, which are typically larger and related to glacier movement.

Human relevance includes hazards for hikers and climbers due to hidden voids or unstable rock, as well as ecological and geological significance. Crevices are sites of mineral deposition and natural shelters, and they help researchers understand rock mechanics and the history of weathering.