Work of a River
The running water in the river erodes the landscape.When the river tumbles at steep angle over hard rocks or down a steep valley side it forms a waterfall.
As the river enters the plain it twists and turns forming large bends known as meanders. Due to continuous erosion and deposition along the sides of the meander,the ends of the meander loop come closer and 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.
At times the river overflows its banks.This leads to the flooding of the neighbouring areas.As it floods,it deposits layers of fine soil and other material called sediments 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 river become so slow that it begins to deposit its load.Each distributary forms its own sediments form all the mouths forms a delta.
Waves of Sea Waves
The erosion and deposition of the sea waves gives rise to coastal landforms. Seawaves continuously strike at the rocks.Cracks develop.Over time they become larger and wider .Thus ,hollow like caves are formed on the rocks.They are called sea caves. As these cavities become bigger and bigger only the roof of the caves remain,thus forming sea arches. Further, erosion breaks the roof and only walls are left.These wall like features are called stacks.
The steep rocky coast rising almost vertically above sea water is called sea cliff.
The sea waves deposit sediments along the shores forming beaches.
Work of Ice
Glaciers are "rivers of ice"which too erode the landscape by bulldozing soil and stones ti expose the solid rock below.
Glaciers carve out deep hollows there .As the ice melts they get filled up with water and become beautiful lakes in the mountains.The material carried by the glacier such as rocks big and small,sand and silt gets deposited. These deposits form Glacial moraines.
A Glacier
Work of 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 .In deserts you can see rocks in the shape of a mushroom,commonly called mushroom rocks.Winds erode the lower section of the rock more than the upper part. Therefore,such rocks have narrower base and wider top.when the wind blows,its 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. When the grains of sand are very fine and light.the wind can carry it over very long distances. When such sand is deposited in large areas,it is called loess. Large deposits of loess is found in China.
Sand dunes
