Characteristics and occurrence of wind erosion features in the namib desert. Causes, effects and types of erosion water, wind, glacier. Desert regions with igneous or metamorphic bedrock also develop characteristic landforms with. Causes of wind erosion bare, unprotected soil is extremely vulnerable to wind erosion erosion occurs with strong, turbulent winds blowing across a soil surface that is smooth, loose, dry and finely granulated. Significant wind erosion occurs when strong winds blow over lighttextured soils that have been heavily grazed during periods of drought. Pdf the history and nature of wind erosion in deserts. Abrasion by wind carried sand can polish rock and causes little erosion.
Deflation is the main way wind causes erosion, it usually has a great effect on the land and it can create blowouts. Usdaars wind erosion research formerly in manhattan, kansas problem wind erosion is a serious problem in the united states and the world. These depositional features are more obvious than erosional features. The carrying away of dry soil and loose sand particles is known as deflation. By definition, a desert has less than 10 in 25 cm of precipitation per year. Following are the major landforms produced by wind erosion.
Dust storms like the one in figure above are more common in dry climates. Aeolian erosion develops through two principal processes. The particles deposited are of sand, silt and clay size see table 2. Wind moves across the land in a turbulent, erratic fashion. Desert features created by wind erosion gcse geography. Elongate ridge or remnant rock feature sculpted by abrasive wind erosion.
Soil may blow into, within, and out of a field in several directions in a single storm. The erosion of surface soil by wind renders the soil less productive by removing the most fertile part of the soil, namely, the clays and. After reading this article you will learn about wind erosion. Wind speed and the length of time the wind blows aremajor factors in wind erosion. Home engineer reference and training manuals depositional features created by wind action. Based on the above erosion process, the wind tunnel model was tested with three different types of erosion features. Yardangs, iran result from wind erosion of partially lithified dunes. Wind erosion is a serious environmental problem attracting the attention of many across the globe. Wind causes small particles to be lifted and moved away. Zones of erosion which have little or no soil or vegetation. Department of agriculture manhattan, kansas wind erosion is a serious problem in portions of the usa and becomes more widespread and severe during droughts. Wind erosion is a natural process that moves soil from one location to another by wind power. The action of wind continues until that time when the power and momentum of wind cannot move the loose particles.
It is responsible for about half of the more than two billion tons of soil lost from u. Abrasion when wind loaded with sand grains erodes the rock by grinding against its walls is called abrasion or sandblasting. Significant wind erosion occurs when strong winds blow over lighttextured soils that have been heavily grazed. Wind is the weakest agent in shaping the land, but can be powerful in shaping the land in areas where.
Small scale features resulting from wind erosion are widespread in the namib desert. Erosion and deposition by wind earth science in maine. Result from wind erosion of partially lithified dunes. Characteristics and occurrence of wind erosion features in. Tables listing the prevailing wind erosion direction by month for many locations in the united states are available see nrcs weq web site address at the end of this document. Both forms of erosion selectively carry off fine particles from the soil surface, and both are eliminated by mulching the soil or by providing an adequate. Dry, bare soil is more easily blown away by the wind than wetter soil or soil held in place by plant roots. Effects of leading edge erosion on wind turbine blade. It is a dynamic, physical process where loose, dry, bare. Wind erosion assumes significant proportions only when the wind carries a load of sand grains which bombard the bare soil surface, and sheet erosion occurs when rain splashes on naked soil. Like any other landform, desert landforms are also the result of erosional and depositional processes. Sand sheets these are flat areas of sand with sand grains that are too large to saltate. They include selective erosion of lithological variations etching. It can cause significant economic and environmental damage.
Features produced by wind deposition alevel geography. Wind erosion and deposition continued deflation wind can blow tiny particles away from larger rock pieces during deflation. It is one of the processes leading to desertification. Ventifact is a windfeceted cobble or pebble loess silt and claysized particles are deposited by wind in wetter regions. The broadest application of the term erosion embraces the general wearing down and molding of all landforms on earths surface, including the weathering of rock in its original position, the transport of weathered material, and erosion caused by. Wind erosion and landforms in arid environments youtube.
Susceptibility to wind erosion is related rather definitely to the moisture content of soils. The critical wind erosion period is that part of the year when agricultural fields are particularly vulnerable to wind erosion. It can produce desert pavement, which is a surface made of peb. Deserts, wind erosion and deposition by definition, a desert has less than 10 in 25 cm of precipitation per year. Geomorphology of desert environments pp 597627 cite as. Characteristics and occurrence of wind erosion features in the. The main features deposited by wind are sand dunes. This natural process is caused by the dynamic activity of erosive agents, that is.
Wind is a stronger erosional force in arid regions than it is in humid regions because winds are stronger. It is a dynamic, physical process where loose, dry, bare soils are transported by strong winds. Particle dynamics are described in terms of suspension, saltation, surface creep, abrasion, sorting and. Creep is when a particle rolls or slides across the surface. This article throws light upon the six main features of wind erosion. Wind erosion in the united states is most widespread on agricultural land in the great plains states. Strong, steady, prevailing winds come from a single direction. Large scale features are tentatively identified and are restricted to the southern namib, with its high energy, unidirectional wind regime. Landforms, landscapes, and processes of aeolian erosion. Erosionthe process by which wind, water, ice, or gravity transports soil and sediment from one location to another.
One of americas worst environmental disasters happened on the prairies of the southern great plains. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Wind sediments that have been transported by wind appear pitted holes and frosted glazed effective in moving small, loose material occurs in areas where there is not enough rainfall to support vegetation main effects. Features produced by wind erosion geography alevel revision. Water, ice, students describe how natural weather events like wind and rain contribute to changes in. Deflation happens when wind removes the top layers of fine sediment or soil and leaves behind larger rock pieces. Erosion and wind erosion geolearning department of. Wind erosion can be caused by a light wind that rolls soil particles along the surface through to a strong wind that lifts a large volume of soil particles into the air to create dust storms.
They are oriented towards or parallel to modern strong winds. In aeolian processes, wind transports and deposits particles of sediment. Pdf recently, the importance of wind erosion has been reevaluated. A level geography revision covering rock pedestals, yardangs, zeugens, inselbergs, bornhardt formation, kopje formation and deflation hollows. Wind erosion is a common cause of land degradation in the arid and semi arid grazing lands of inland queensland. Soil erosion by wind is a serious problem in the united states and the world. They include selective erosion of lithological variations etching, flutes. Erosion is defined as the set of natural processes that loosen, remove and transport weathered or unweathered solid material such as soil, sediment, mud, regolith, rock fragments and other particles from the landscape by downhill or downwind displacement the mediums required to for material displacement can be wind, running water, waves, ice glaciers, underground water. Explain to students that we are going to make a model of a windstorm so we can. Wind causes erosion of rock particles driven by soil and sand particles that are not tightly glued together and not insulated by vegetation. The direction, velocity, duration, and variability of the wind all affect the erosion that occurs from a windstorm. The particles are entrained in by one of four processes. Erosion is the process by which soil and rock are removed from the earths surface by exogenetic processes such as wind or water flow, and then transported and deposited in other locations.
Students use evidence to explain the process of weathering and erosion. Rock pedestals wind sculpts stratified rock into pedestals by wind abrasion and weathering, e. Dunes migrate by erosion of sand by the wind on the gentle upwind slope and deposition and sliding on the slip face. Sand dunes have coarse grained sediments, loess has finer sediments, both are caused by wind erosion. It is a common phenomenon occurring mostly in flat, bare areas. Aeolian features form in areas where wind is the primary source of erosion. Basic wind erosion processes are discussed under the major headings of soil particle dynamics, particle flow rates, and principles and general strategies of control. Wind can erode nonvegetated areas and was responsible for the great dust bowl in the early 1900s. Winddeposited materials occur as sand sheets, ripples and dunes. Wind erosion is a threat to the sustainability of the land as well as the viability and quality of life for rural as well as urban communities. Wind erosion can be a threat to agriculture productivity and the sustainability of the earths natural resources. All the sediment picked up by wind eventually falls to the ground.
When the force of wind is exerted on a land surface, the soil moves. Wind is an element that speeds the erosion process. Attrition attrition refers to wear and tear of the sand particles while they are being transported. Request pdf wind erosion wind erosion refers to the detachment, transport, and deposition of sediment by wind. Wind is caused by uneven heating of the earths surface by the sun. Landforms of wind erosion in desert iasmania civil. Abstract small scale features resulting from wind erosion are widespread in the namib desert. Loess can be found far from its source because it is fine and can be carried. Landforms from wind erosion and deposition read earth. Loess is a wellsorted deposit of winddeposited silt and clay sized particles.
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