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Erosion, The transfer of rock particles formed by, physical, chemical or biological weathering, processes from one place to another by, external agencies such as running water,, wind, glaciers, sea waves etc. is called, erosion, , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Factors determining the flow of a river., , ●, , Volume of water, Rock structure, Slope of the terrain, Amount of sediments, Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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The place of origin of a river is called its source, and the place at which it discharges into the sea or, to a water body is called the river mouth., , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada, www.shenischool.in
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Course of a river, The course of a river can generally be, divided into three stages based on the, difference in slope from its source to, mouth., , • Upper course, • Middle course, • Lower cours, Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Upper course, 12, , 10, , , , Place of origin of the river, 8, , , , Column 1, Column 2, Column 3, , River flows through steep slopes, 6, , 4, , , , Intense rate of erosion, 2, , , , No deposition, , , , Kulathoor, Landforms suchSheela, asN,HSA(SS)Govt.V&HSS, valley, waterfall,, etc are seen, Uchakkada, , 0, , Row 1, , Row 2, , Row 3, , Row 4
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Factors affecting the intensity of River erosion, , Velocities of water flow, slope of the terrain,, and rock structure are the factors affecting the, intensity of river erosion., , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Abrasion or corrasion., The rock particles like gravel, sand, pebbles, etc., carried by the river rub against the rocks along, the bed and both the sides of the river. This results, in the wearing down of rocks. Such erosion is known, as abrasion or corrasion. Through these processes, the river can polish even the hard rocks along, its course., Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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V-shaped valleys, , The valleys take a distinct shape as a result, of the intensity of erosion along the river bed., Such valleys are called V-shaped valleys, Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Water falls, Waterfalls are generally formed at the, upper course of rivers as a result of, Erosion. Soft rocks are easily eroded, in the valleys where soft and hard, Rocks are found intermingled. This, results in the formation of waterfalls, Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Meanders, The rate of erosion along the river bed, decreases as the river leaves, the upper course. However, Lateral, erosion dominates. The river, flowing through Comparatively, gentle slopes takes deviation when, the sediments or rock-forms, create obstruction to the flow., The sinuous curves formed along, the river course are called meanders., Meanders are usually formed, in the middle and lower courses of, Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada, wide rivers.
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oxbow lakes, Meanders may further curve through, continuous erosion and deposition., Finally the river takes a straight course., Due to deposition the curves may get, detached from the main river form, isolated water bodies. Such water bodies, are called oxbow lakes, Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Flood plains, The rivers overflowing their banks, during rainy seasons. Flood water, may cover extensive areas on both, sides of the river. The deposition, of alluvium along both the flooded, banks may cause the formation of, plains. Such plains are called flood, plains, Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Solution, Most of the minerals present in the, rocks get dissolved as water pass, through them. This process is called, solution., Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Stalactites, , ., , The water with dissolved limestone in it drips from, the roof of caves. A portion of this mixture remains, on the roof of the caves itself. This deposit of lime, grows upside down due to this long continued, process. They are called stalactites., , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Stalagmites., The deposit of lime on the floor of the, cave also grows upward . These are, called stalagmites., , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Limestone pillars, Stalactites and stalagmites do merge together with to form, pillars These are called Limestone pillars, , Stalactites, stalagmites,, , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada, and, limestone pillars are, , formed by deposition.
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Sea cliffs, ➢, , ➢, , ➢, , The steep hillocks facing the sea are, called sea cliffs., These steep structures are formed by, the crumbling of the sea-facing slopes, due to wave erosion., A sea cliff at the Varkala beach in, Thiruvananthapuram district., , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Stacks, The strong blast of sea waves on the rocky coasts, causes the wearing down of rocks. As a result of, such abrasion by waves, isolated rock pillars are, formed from coastal rocks. Such pillar like rocks, standing upright along the coastline are called, stacks, Eg.stacks found along the coast of Thalassery in, Kannur, , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada, www.shenischool.in
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Deflation, , ., , The strong whirl winds carry away, the dry desert sands from one place, to another. This process of wind, erosion is called deflation., , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Abrasion, As a result of the continued erosion, caused by sand and other rock particles, carried by strong winds, rocks in deserts, get worn down. This process of wind, erosion is called abrasion., Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Sand dunes, The sand dunes formed in the deserts are a, result of the deposition by wind., , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Glacier, , The snow-covered mountains extend over vast, Areas and have kilometre-thick massive ice sheets., These slowly crawl down from the, regions of their formation., Such slow moving mass of ice is called a glacier, , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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U-shaped valleys, , The erosion caused by the continuous movement, of glaciers along the valleys carves out steep sided, and flat bottomed U-shaped valleys, , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
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Moraines, , The sediments carried down by the glaciers, will be deposited in various parts of the, valley. These depositional features by, glaciers are called moraines., ., , Sheela N,HSA(SS)Govt.V&HSS Kulathoor, Uchakkada
