Erosion (Encyclopedia of Science)
Erosion is the general term for the processes that wear down Earth's surfaces, exposing the rocks below. The natural forces responsible for this endless sculpting include running water, near-shore waves, ice, wind, and gravity. The material produced by erosion is called sediment or sedimentary particles. Covering most of Earth's surface is a thin layer of sediment known as regolith, which is produced by the erosion of bedrock, or the solid rock surface underlying Earth's surface.
Natural sources of erosion
Running water. Everywhere on the planet, running water continuously reshapes the land by carrying soil and debris steadily downslope. As the sediment and other eroded materials are carried along the bottoms of streams and rivers, they scour away the bedrock underneath, eventually carving deep gorges or openings. A classic example of the erosive power of running water over a great period of time is the Grand Canyon of the Colorado River.
Rain falling on dry land also can result in erosion. When raindrops strike bare ground that is not protected by vegetation, they loosen particles of soil, spattering them in all directions. During heavy rains on sloped surfaces, the dislodged soil is carried off in a flow of water.
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Erosion (Science Experiments)
Is erosion a problem in the United States?
Plants and Erosion: How do plants affect the rate of soil erosion?
Soil erosionThe process by which topsoil is carried away by water, wind, or ice action. is the process by which is carried away by water, wind, or ice. Different types of soil have different abilities to absorb water, and so, are affected by erosion in varying degrees. Bare soil and soil on steep slopes are especially vulnerable to erosion.
Throughout history, people have been affected by soil erosion due to natural conditions, as well as erosion caused by their own actions. As long ago as 4500 B.C., the Sumerians cleared land to grow food. They irrigated the land by building canals in the fertile valley where the Tigris and Euphrates rivers meet (in present-day Iraq). During the time of the Babylonian culture, which followed the Sumerians in about 1800 B.C., the people continued to dig canals. The rivers became muddy, and deposits of , medium-sized soil particles, settled in the irrigation canals and clogged them. The people had to carry silt out...
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Erosion (World of Earth Science)
Erosion is the reduction or breakdown of landforms exposed to the forces of weathering (disintegration and decomposition). Weathering and subsequent erosion may be caused by both chemical or mechanical forces. Mechanical weathering agents include wind, water, and ice. Chemical weathering leading to erosion results from bio-organic breakdown, hydration, hydrolysis, and oxidation processes. The process of transportation describes the movements of eroded materials.
Erosion requires a transport mechanism (e.g., gravity, wind, water, or ice). Wind, water, and ice are also agents of erosion that cause the physical breakdown of rock and landforms.
A special form of erosion, mass wasting, describes the transport of material downslope under the influence of gravity. Landslides are a common example of mass wasting.
Erosion processes can also cause indirect landform alteration by breaking down overburden of rock and precipitating a pressure release that can crack and shift rock layers. The cracking process results in peels, exfoliation, or spalling. For example, the erosion of overburden can expose batholiths and these exposed formations can form exfoliation domes.
Organic materials can frequently contribute to erosion by pressure that results in structural cracking or in the formation of acidic compounds that weather rock.
Rapid temperature changes or large diurnal temperature changes (the difference between the highest daytime temperature and the coolest nighttime temperature) can accelerate erosional exfoliation, jointing, and ice wedging.
See also Acid rain; Catastrophic mass movements; Depositional environments; Dunes; Eolian processes; Faults and fractures; Freezing and melting; Glacial landforms; Glaciation; Hydrothermal processes; Ice heaving and ice wedging; Impact crater; Landforms; Landscape evolution; Leaching; Oxidation-reduction reaction; Precipitation; Rapids and waterfalls; Rate factors in geologic processes; Rock; Rockfall; Salt wedging; Seawalls and beach erosion; Soil and soil horizons; Talus pile or talus slope.