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Normal cycle of erosion notes

Normal cycle of erosion
The concept of cycle of erosion was first discovered by the Scottish Geologist James Hutton in the year 1785. In these Normal cycle of erosion notes, a central idea will be developed in one's mind regarding the development of landforms. Structure, process and time plays an important role in the development of landforms.

William Morris Davis, was the first American Geomorphologist to present a general theory of landform development. The basic goal and theme behind Davisian model of landform development was to provide a systematic description and classification of landforms.

The development of landforms undergo sequential changes through time. They pass through three stages youth, mature and old. As different processes operate through time landforms changes in an orderly manner. Let's explore more about it through Normal cycle of erosion notes discussed below.

Normal cycle of erosion notes 

normal-cycle-of-erosion-notes


The cycle of erosion which is carried by running water is known as normal cycle of erosion. This is because running water or fluvial processes are most widespread all over the world. It plays an important role in the regions of glacial and arid.

The normal cycle of erosion begins when a landmass gets uplifted in accordance with the sea level. As the land gets uplifted, the rivers get originated and erosional processes begins thereafter. After some duration of time the upliftment of the landmass stops resulting the erosional processes to be more active. 

There is crustal stability for a long duration of time, and during that period the landmass neither gets uplifted nor gets subsided. River valleys gets originated in sequential order and the whole area of land passes through stages of youth mature and old. And at last, low featureless plain which is known as peneplain gets resulted.

Youthful stage :
(i) This stage gets originated when the landmass gets uplifted. The streams are short in length and number. The master consequent streams gets originated in very less number.

(ii) Several gullies and rills dominate the slopes. Through headward erosion gullies and rills  lengthens their longitudinal profile.

(iii) The development of the tributaries from the master consequent streams, gives rise to dendritic drainage pattern.

(iv) The valleys are experienced through rapid rate of down cutting by the rivers. This is because the transporting capacity of rivers becomes maximum due to steep channel gradient.

(v) The valleys become narrow and steep having convex side slopes. This results the juvenile valleys to be V- shaped.

Mature stage :
(i) This stage is characterised by decrease in the valley deepening from the youthful stage, which results in decrease in channel gradient and flow velocity.

(ii) Early maturity gets arrived which is indicated by decrease in the transporting capacity, decrease in the channel gradient and decrease in the river velocity.

(iii) Valley widening becomes dominant at this stage, through active rate of lateral erosion.

(iv) Big bolders and sediments are deposited by the rivers at the foothill zones, due to the decrease in the transporting capacity of the rivers. The deposition of these materials results in the formation of alluvial fans and cones, which further results in the formation of pied mont plains due their gradual expansion.

(v) As there is decrease in the channel gradient, the rivers carves their courses resulting in the formation of several meanders and loops.

Old stage :
(i) This stage is characterised by more decrease in the channel gradient and there is total absence of valley deepening.

(ii) There is decrease in the number of tributary streams. Moreover the valleys become broad and flat comprising of concave slopes.

(iii) The transporting capacity of the rivers becomes minimum at this stage. Sedimentation and weathering becomes more active.

(iv) Rivers carves their courses to an extreme form and forms extensive deltas at the mouth of the rivers. 

(v) At this stage, the landscape gets transformed into extensive flat plains which is known as peneplain.

Through the above discussion Normal cycle of erosion notes, it is clear and certain that the different landforms on the earth's surface undergo the stages of youth, mature and old. They have to undergo these stages as no landform can maintain its crustal stability for a long duration of time.

The functioning of the normal cycle of erosion maybe disturbed through tectonic activities. They cannot operate in a smooth manner.

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