Geography Answer Writing Practice 2018 - Week 1 - Question 3
90 Days Geography Answer Writing Practice Question 1 for 14-Nov-2018
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14-Nov-2018 - Question 1
Explain weathering and mass wasting and describe their geomorphic significance. 300 words (2014)
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Weathering refers to the breakdown or disintegration and decomposition of rocks in situ through mechanical and chemical changes in the rocks and their minerals affected by water, temperature, wind, different atmospheric gases and organisms provided that there is no large-scale transport of weathered products by denudational processes except mass movement of rock wastes down the slope under impact of gravity.
It involves two types of changes - physical and chemical. Weathering processes are classified into three types on the basis of weathering agents:
Physical and mechanical weathering - block disintegration due to temperature, granular disintegration due to temperature, exfoliation, block disintegration due to frost.
Chemical weathering - Oxidation, carbonation, solution, hydration, chelation and hydrolysis
Biotic and biochemical weathering - plant weathering, animal weathering, biochemical weathering and anthropogenic weathering.
Mass wasting refers to the detachment and downslope transport of soil and rock material under the influence of gravity. The transport is solely due to gravity and other transporting media are excluded. It is classified into three -
Vertical movement (fall and subsidence),
Lateral movement (slides and spreading)
Diagonal movement (Creeping, slide and flows).
It is affected by various factors that affect the shear strength of materials on the slope.
The geomorphic significance of weathering and mass wasting can be seen as follows:
Weathering produces rock wastes which help in the process of soil formation and expose minerals that have economic significance.
The rock-wastes move down the slope due to mass wasting causing damage to human settlements in foothill zones, causing obstruction in the river flow and damming of lakes due to debris fall.
Weathering loosens the rock material and accelerates the erosional processes.
Continuous removal and transfer of weathered material by mass wasting lead to lowering of the surface.
Differential weathering produces different types of landforms. It plays an important role in the development of stone lattice in hot deserts, tor, buttes, talus cones etc.
Thus, weathering and mass wasting have an enormous impact both physically as well as economically on the geography of the earth.