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Erosion
Erosion is the process by which earth's surface is worn away by agents such as water, wind, and ice. There are several types of erosion. Water erosion includes splash erosion, sheet erosion, rill erosion, and gully erosion caused by rain and moving water. Streams erode their banks through hydraulic action, corrosion, and impact of particles. Coastal erosion is caused by the pounding of ocean waves, which carve out sea caves, arches, and sea stacks. Wind erosion occurs in deserts and polishes rocks. Glacial erosion processes include abrasion, plucking, and thrusting, which carve out valleys and leave behind moraines. Human activities like agriculture and defore
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Erosion
- 1. Prepared by: Ida LynA. Azuelo BSED- Physics 2 Earth Science EROSION
- 2. Erosion is theact in which earth is worn away, often by water, wind, or ice.
- 3. A similar process,weathering, breaks down or dissolves rock, weakening it or turning it into tiny fragments.
- 4. Erosion is anatural process; it is part of the constant recycling of Earth materials that is called the rock cycle.
- 8. »Water »Wind »Ice The agents oferosion that wear away at the surface of the Earth:
- 9. Erosion by Water Movingwater is the major agent of erosion. Rain carries away bits of soil and slowly washes away rock fragments.
- 10. • Four primarytypes of erosion that occur as a direct result of rainfall: 1. Splash erosion - the impact of a falling raindrop creates a small crater in the soil, ejecting soil particles. 2. Sheet erosion - the transport of loosened soil particles by overland flow.
- 11. 3. Rill erosion- refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes. 4. Gully erosion - occurs when runoff water accumulates and rapidly flows in narrow channels during or immediately after heavy rains or melting snow, removing soil to a considerable depth.
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- 15. A spoil tipcovered in rills and gullies in Rummu, Estonia
- 17. Erosion by Water Rushingstreams and rivers wear away their banks, creating larger and larger valleys.
- 18. Streams erode theirbanks in three different ways: 1) the hydraulic action of the water itself moves the sediments, 2) water acts to corrode sediments by removing ions and dissolving them, and 3) particles in the water strike bedrock and erode it.
- 19. The water ofstreams can erode in three different places: 1) lateral erosion erodes the sediment on the sides of the stream channel, 2) down cutting erodes the stream bed deeper, and 3) headward erosion erodes the channel upslope.
- 24. Erosion by waterchanges the shape of coastlines. Waves constantly crash against shores. They pound rocks into pebbles and reduce pebbles to sand. Water sometimes takes sand away from beaches. This moves the coastline farther inland. Erosion by Water
- 25. Waves in oceansand other large bodies of water produce coastal erosion. The power of oceanic waves is awesome, large storm waves can produce 2000 pounds of pressure per square foot. The pure energy of waves along with the chemical content of the water is what erodes the rock of the coastline. Erosion by Water
- 27. The battering ofocean waves also erodes seaside cliffs. It sometimes bores holes that form caves. When water breaks through the back of the cave, it creates an arch. The continual pounding of the waves can cause the top of the arch to fall, leaving nothing but rock columns. These are called sea stacks. All of these features make rocky beaches beautiful, but also dangerous.
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- 31. White Cliffs ofDover
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- 35. Acantilados de LosGigantes
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- 39. The battering ofocean waves also erodes seaside cliffs. It sometimes bores holes that form caves. When water breaks through the back of the cave, it creates an arch. The continual pounding of the waves can cause the top of the arch to fall, leaving nothing but rock columns. These are called sea stacks. All of these features make rocky beaches beautiful, but also dangerous.
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- 42. Matainaka Cave, NewZealand
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- 44. Sandstone sea Caveon Sand Island 07, Lake Superior, Apostle Islands National Lakeshore, Wisconsin
- 48. The battering ofocean waves also erodes seaside cliffs. It sometimes bores holes that form caves. When water breaks through the back of the cave, it creates an arch. The continual pounding of the waves can cause the top of the arch to fall, leaving nothing but rock columns. These are called sea stacks. All of these features make rocky beaches beautiful, but also dangerous.
- 49. Lunch Sea Archat Cabo
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- 52. The battering ofocean waves also erodes seaside cliffs. It sometimes bores holes that form caves. When water breaks through the back of the cave, it creates an arch. The continual pounding of the waves can cause the top of the arch to fall, leaving nothing but rock columns. These are called sea stacks. All of these features make rocky beaches beautiful, but also dangerous.
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- 61. Old Man ofHoy
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- 63. Erosion by windis known as Aeolian erosion and occurs almost always in deserts. Aeolian erosion of sand in the desert is partially responsible for the formation of sand dunes. The power of the wind erodes rock and sand. Erosion by Wind
- 69. In dry areas,windblown sand blasts against rock with tremendous force, slowly wearing away the soft rock. It also polishes rocks and cliffs until they are smooth. Wind is responsible of the dramatic arches. Erosion by Wind
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- 74. Sipapu Natural Bridge,Utah, USA
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- 81. Árbol de Piedra,Altiplano, Bolivia
- 83. The erosive powerof moving ice is actually a bit greater than the power of water but since water is much more common, it is responsible for a greater amount of erosion on the earth's surface. Erosion by Ice
- 84. Glaciers erode predominantlyby three different processes: • Abrasion/Scouring • Plucking • Ice Thrusting Erosion by Ice
- 85. The rocks carriedby a glacier rub against the ground below, eroding both the ground and the rocks. Glaciers grind up rocks and scrape away the soil. Moving glaciers gouge out basins and form steep-sided mountain valleys. Eroded sediment is often visible on and around glaciers. This material is called moraine. Erosion by Ice
- 86. Glacial moraines aboveLake Louise, in Alberta, Canada
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- 94. Mass movement isthe downward and outward movement of rock and sediments on a sloped surface, mainly due to the force of gravity. Mass movement is an important part of the erosional process, and is often the first stage in the breakdown and transport of weathered materials in mountainous areas. Gravitational Erosion
- 95. Wadi in MakhteshRamon, Israel, showing gravity collapse erosion on its banks.
- 96. Exfoliation • a typeof erosion that occurs when a rock is rapidly heated up by the sun. This results in the expansion of the rock.
- 97. Lightning When water incracked rock is rapidly heated by a lightning strike, the resulting steam explosion can erode rock and shift boulders. It may be a significant factor in erosion of tropical and subtropical mountains that have never been glaciated. Evidence of lightning strikes include craters, partially melted rock and erratic magnetic fields.
- 98. Factors affecting erosionrates • Precipitation and wind speed • Soil structure and composition • Vegetative cover • Topography Human activities • Agricultural practices • Deforestation • Roads and urbanization • Climate change
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- 102. Prevention and Remediation Themost effective known method for erosion prevention is to increase vegetative cover on the land, which helps prevent both wind and water erosion. Terracing is an extremely effective means of erosion control, which has been practiced for thousands of years by people all over the world.
- 105. Prevention and Remediation Windbreaks(also called shelterbelts) are rows of trees and shrubs that are planted along the edges of agricultural fields, to shield the fields against winds.
- 108. Thank you forlistening.
- 109. Prepared by: Ida LynA. Azuelo BSED- Physics 2 Earth Science EROSION