KERALA PSC / PHYSICAL GEOGRAPHY / MOVEMENTS OF THE EARTH’S CRUST / NOTES

 KERALA PSC / PHYSICAL GEOGRAPHY / MOVEMENTS OF THE EARTH’S CRUST / NOTES

KERALA PSC / PHYSICAL GEOGRAPHY / MOVEMENTS OF THE EARTH’S CRUST / NOTES

 

·       The earth movements are to two types:

Ø Vertical Movements

Ø Horizontal Movements

·       Vertical movements are responsible for a rise or a fall of a portion of the earth’s surface

·       When a part of the earth’s crust rises in relation to surrounding portions it is known as uplift or emergence

·       When the sinking of a part of the earths crust relative to surrounding portion takes place, it is called subsidence

·       The formation of continents and plateaus are also due to vertical movement and hence these are also referred to as continent building or plateau building movements

·       Horizontal movements involve compression and tension

·       These compressional or tensional forces are horizontal or tangential movements

·       These movements are also referred to as mountain building movements

·       Warping and Isostasy constitute vertical movements, while folding, faulting and continental drift constitutes horizontal movement

·       Warping is the deformation of earth’s crust which affects very large areas on the earth’s surface. It results in the formation of domes, shields and depressions

·       Isostasy is a condition of gravitational balance between the crustal segments of different thickness.

·       Folding is the process whereby the rock strata are bent into a series of arches (anticlines) and troughs (synclines) as a result of the horizontal earth movements which cause compression within the crust.

·       Faulting is the process by which the tensional earth movements under the effect of considerable pressure creates a fracture in the earth’s crust.

·       Faulting gives rise to relief features such as block mountains and rift valleys

·       Continental drift refers to the horizontal movements of the continents on a vast scale.

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KERALA PSC / PHYSICAL GEOGRAPHY / MOVEMENTS OF THE EARTH’S CRUST / NOTES