erosion

Typical features of coastal erosion: from the initial cracks in less resistant rock through to arches, stacks, and stumps that can occur as erosion progresses.

The physical weathering and erosion of a limestone landscape. The freezing and thawing of rain and its mild acidic properties cause cracks and joints to enlarge, forming limestone pavements, potholes, caves, and caverns.

When water flows over hard rock and soft rock, the soft rocks erode creating waterfalls. As the erosion processes continue, the falls move backwards, in the opposite direction of the water

Eroded sandstone, Utah, USA.

The South Rim of the Grand Canyon in Arizona, USA. Erosion has created dramatic configurations in the sedimentary rock formations in and around the gorge.

Hoodoos, east of Drumheller in Alberta Province, Canada. Sandstone rock has eroded into curious columns in the badlands of southern Alberta.

Track marks from vehicles are clearly visible on the sand dunes at Studland Beach, Dorset, England. Sand dunes are vulnerable ecosystems. They are easily disrupted by activities such as trampling, camping, and driving. The concentration of people and vehicles at particular places can cause great ecological damage.

Cheddar Gorge is a steep, narrow limestone gorge. Gorges are formed in many ways: by caves collapsing, by waterfalls retreating, and by rapid river erosion. Cheddar Gorge was formed by rapid river erosion about 18,000 years ago. As glaciers over Britain melted, huge volumes of melt water were able to erode resistant rocks, such as limestone. The winding road that now runs through the gorge marks the position of the melt water river.

A mountainous ridge in the Canadian Rocky Mountains. The slopes here have been eroded by rain and melting snow to form steep-sided gullies.

Wearing away of the Earth's surface by a moving agent, caused by the breakdown and transport of particles of rock or soil. Agents of erosion include the sea, rivers, glaciers, and wind. By contrast, weathering does not involve transportation.

The most powerful forms of erosion are water, consisting of sea waves and currents, rivers, and rain; ice, in the form of glaciers; and wind, hurling sand fragments against exposed rocks and moving dunes along. People also contribute to erosion by poor farming practices and the cutting down of forests, which can lead to increased overland water run-off.

There are several processes of river erosion including hydraulic action, corrasion, attrition, and solution.