Landforms

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The landscape is being continuously worn down by two processes – weathering and erosion.Weathering is the breaking and falling apart into small pieces of the rocks on the earth’s surface.Erosion is the wearing down of the landscape by different agents like water,wind,ice and sea waves.The eroded material is carried away by water,wind ,etc.and eventually deposited.This process of erosion and deposition create different landforms on the surface of the earth.

River

The water flowing from its source to river mouth,along a definite course is called a River.Rivers generally originate from a mountain or hill.The place of origin from a mountain or hill.The place of origin of the river is known as it’s source.The place where it joins a lake or sea or an ocean is known as River mouth

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The running water in the river erodes the mountains track,which creates a steep-sided valley like the letter’V’ known as ‘V’shaped valley.

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Falling of river water over a vertical step in the river bed is called waterfall.It is formed when the soft rocks are removed by erosion.E.g.Coutrallam falls across the river Chittar in Tamil Nadu.Plunge pool is a hollow feature at the base of a waterfall which is formed by cavitation.Alluvial fan is a deposition of sediment occurs at which the rivers enters a plain or the foot-hills.As the river enters the plain it twists and turns forming large bends known as Meanders.Eg.Meanders along the river Vellar near Sethiyathope in Cuddalore District,Tamil Nadu.Due to Continuous erosion and deposition along the sides of the meander,the ends of the meanders loops come closer.In due course of time the meander loop cuts off from the river and forms a cut-off lake,also called an Ox-bow lake

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At times the river overflows its banks.This leads to the following of the neighbouring areas.As the river floods,it deposits layers of fine soil and other material called Sendiments along its banks.This leads to the formation of a flat fertile floodplain.The raised banks are called levees.As the river approaches the sea,the speed of the flowing water decreases and the river begins to break up into a number of streams called distributaries.The velocity of the river becomes so slow that it begins to depositi its load.The collection of sediments from all the mouths form Delta.Deltas are excellent productive lands.E.g.Cauvery delta,Ganges delta,Mississippi delta.

Glacier

A large body of ice moving slowly down a slope or valley due to gravity is called a glacier.Glaciers are grouped into Mountain or valley Glaciers and Continental Glaciers.

Continental Glacier

The glacier covering vast areas of a continent with thick ice sheets.E.g.Antarctica,Freeland

Mountain or valley Glaciers

Is a stream of ice, flowing along a valley.It usually follows former river courses and are bounded by steep sides.E.g.The Himalayas and the Alps.Glaciers ,expose the solid rocks of earth by removing the loose materials found on it.

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Cirque is a glacially eroded rock basin,with a steep side wall and steep head wall, surrounding an armchair-shaled depression.E.g.Corrie-Scotland (United Kingdom),Kar-Germany.As the ice melts,they get filled up the cirque with water and become beautiful lakes in the mountains called as Tarn Lake.when two adjacent cirques erode towards each other,the previously rounded landscape is transformed into a narrow rocky,steep-sided ridges called Arete.

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U’ shaped valley is found beneath the Glaciers which is deepened and widened by the lateral and vertical erosion.The material carried by the glacier such as rocks – big and small,sand and silt get deposited.These deposits form glacial moraines.

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Wind

Have you ever visited a desert? Try to collect some pictures of sand dunes.An active agent of erosion and deposition in the deserts is wind.

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Winds erode the lower section of the rock more than the upper part.Therefore ,such rocks have narrower base and wider top wider top rocks in the shape of a mushroom, commonly called mushroom rocks.An isolated residual hill, standing like a pillar with rounded tops are called Inselbergs.E.g.Inselberg in the Kalahari Desert of South Africa.

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When the wind blows,it lifts and transports sand from one place to another.when it stops blowing the sand falls and gets deposited in low hill-like structures.These are called sand dunes.The crescent shaped sand dunes are called When the grains of sand are very fine and light,the wind can carry it over very very long distances.when such sand is deposited in large areas,it is called Loess.Large deposits of loess are found in China

Sea waves

A part of the land adjoining or near the sea is called the Sea coast.The boundary of a coast line.The coastal areas are subject to change due to wave erosion and wave deposition.

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The erosion and deposition of the sea waves give rise to coastal landforms.Sea Cliffs are steep rock faces formed, when the sea waves dash against them.Sea waves continuously

Strike at the rocks.So cracks develop.Over time they become larger and wider.Thus,hollow like caves are formed on the rocks.They are called Sea waves.