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In this article we are discussing the geomorphic processes.
a) While learning about the Earth we always wonder, why is its surface uneven?
b) It is so because of the dynamic nature of the Earth’s crust that moves in a horizontal and vertical direction.
c) This movement is directed by external and internal forces acting on the Earth’s crust. The external forces are known as exogenic forces and internal forces are known as endogenic forces.
d) These forces cause physical stress and effect chemical reactions, thereby changing the configuration of the Earth’s surface. They are thus called ‘geomorphic processes’.
Exogenic forces:
i) Exogenic forces wear down (erode) relief/elevations and fill up (aggrade) basins/depressions.
ii) When Earth’s surface erodes, the phenomenon is called gradation. Exogenic forces are generally land-wearing forces.
iii) Weathering, mass wasting, erosion and deposition are exogenic processes.
iv) Natural elements (like ice, water and wind) and celestial bodies (like comets and meteorites) are some examples of exogenic elements. They are capable of changing the configuration of the Earth’s surface and hence are called geomorphic agents.
v) Gravity is a major component of exogenic forces as it facilitates downslope movement thereby activating waves and tides to induce currents and winds.
Endogenic Forces:
a) Energy contained in the Earth’s interior is the main source of endogenic forces.
b) This energy is usually generated by radio activity, rotational and tidal friction and primordial heat (heat imparted to a planet during the process of its formation).
c) This heat induces diastrophism and volcanism in lithosphere.
d) Three main endogenic processes are: folding, faulting and volcanism.
e) Endogenic processes are not uniform due to variations in geothermal gradients and heat from within the Earth. Hence, the surface of the blue planet is uneven.
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