Notes On Earth Movements - CBSE Class 7 Geography
Alfred Wegener’s theory of continental drift proved that millions of years ago, all the continents were joined in a super-continent, which he called Pangaea. Due to the movements of the lithospheric plates, the super continent broke into large landmasses that drifted away. The big landmasses became continents and Water collected between these landmasses to form the oceans. The lithosphere consists of a number of plates called the lithospheric plates or the tectonic plates. The circular movement of the molten magma inside the earth causes the tectonic plates to move slowly. The earth’s movements can be categorised into two types based on the forces that initiate these movements i.e. endogenic or exogenic. Some movements are caused by forces acting in the interior of the earth called endogenic movements. Forces on the surface of the earth result in exogenic movements. Endogenic forces can be sudden or diastrophic. Sudden endogenic movements may result in natural disasters, like earthquakes, eruptions of volcanoes and landslides. Diastrophic forces refer to forces generated by the movement of the solid material of the earth’s crust. Exogenic forces can take the form of weathering, erosion and deposition. Weathering is the breaking of rocks on the earth’s surface by different agents like rivers, wind, sea waves and glaciers. Erosion is the carrying of broken rocks from one place to another by natural agents like wind, water and glacier.

#### Summary

Alfred Wegener’s theory of continental drift proved that millions of years ago, all the continents were joined in a super-continent, which he called Pangaea. Due to the movements of the lithospheric plates, the super continent broke into large landmasses that drifted away. The big landmasses became continents and Water collected between these landmasses to form the oceans. The lithosphere consists of a number of plates called the lithospheric plates or the tectonic plates. The circular movement of the molten magma inside the earth causes the tectonic plates to move slowly. The earth’s movements can be categorised into two types based on the forces that initiate these movements i.e. endogenic or exogenic. Some movements are caused by forces acting in the interior of the earth called endogenic movements. Forces on the surface of the earth result in exogenic movements. Endogenic forces can be sudden or diastrophic. Sudden endogenic movements may result in natural disasters, like earthquakes, eruptions of volcanoes and landslides. Diastrophic forces refer to forces generated by the movement of the solid material of the earth’s crust. Exogenic forces can take the form of weathering, erosion and deposition. Weathering is the breaking of rocks on the earth’s surface by different agents like rivers, wind, sea waves and glaciers. Erosion is the carrying of broken rocks from one place to another by natural agents like wind, water and glacier.

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