In 1924, German scholar Walter Penck introduced a new format of the erosion cycle in the book Die Morphologische Analyse, published in German. Panc opposes Davis' view and states that the action of erosion does not wait for complete regeneration, but that erosion begins as soon as regeneration begins. Panc also stated that a lowland uplift becomes a dome by uplift and that the rate of uplift of the terrain is not always the same.
According to Peck, the landscape development
commences with the upliftment of primasumpf which is the initial surface representing either newly emerged or a I surface from below sea level or a fastenbene peneplain like land surface converted into featureless land mass by uplift. He also assumed that in the beginning the uplift was exceedingly slow and continued for a sufficiently long time. Thereafter the rate of uplift is accelerated which ultimately comes to a halt after passing through the intermediate phases of uniform and accelerated rates of upheaval. In short Penck's model of cycle of erosion is based on the following principles or assumptions:
1. Landform is an expression of mutual interaction between endogenetic and exogenetic movements of the earth.
2. Most tectonic movements are slow in the beginning and in the end. The sequence of movements is (i) slow initial uplift, (ii) an accelerated uplift, (iii) a decelerated uplift and finally (iv) quiescence.
3. Upheaval and erosion occur simultaneously and erosion does wait for the completion upliftment.
Panc has considered the following three stages of uplift of the landmass:
1. Aufsteigende Entwicklung - This is the first stage of regeneration. At the beginning of this stage, the land segment gradually rises. But after a short time, the speed becomes excessive. In this, the expansion and development of topography takes place at a rapid pace.
2. Gleichformige Entwicklung - This is a moderate state of regeneration in which regeneration is at the same speed.
3. Absteigende Entwicklung - This is the last stage of regeneration in which regeneration occurs at low speed.
Graphically demonstrating Panc's erosion cycle
Like Davis' erosion cycle, Panc's erosion cycle can also be shown diagrammatically (Figure). In this diagram, the upper curve represents the maximum average height and the lower curve represents the lowest average height. The horizontal line b shows the time and the long line b shows the height c. Panks divided the entire curve into the following five states.
First stage - In this state both regeneration and erosion occur. But the elevation is greater than erosion and the elevation of the terrain increases. In this state, the Doab in the middle of the rivers is flat. They are less wear by erosion.In this state, both height and relief increase.
Second stage - Second stage also has the dominance of regeneration and erosion. The uplift is the same on both curves. The erosion is also the same on both curves. But the amount of erosion is less than the amount of uplift and the absolute height increases at a slow speed. The elevation remains constant due to the elevation and erosion being the same on both curves. So both Curves are parallel but not horizontal.
Third stage - In this state, there is a balance between regeneration and erosion. The average elevation of the highlands does not increase because erosion works on them as well. The average elevation of the lower terrain is also the same. There is no difference in the relief.
Fourth stage - In this state, regeneration ceases. The valley continues to deepen for some time. A doavas start coming down. Elevation starts decreasing, but the relief still remains the same.
Fifth state - This is the last stage of the erosion cycle of the tank in which the deepening of the valley is reduced.
The main merits and demerits of the review-cycle erosion cycle are as follows:
Properties: The erosion cycle of the panc has the following characteristics:
1. Elaborated and well-organized manner - Panc presented the concept of erosion cycle in detail in a very systematic way have done
2. Deductive method -Panc extracted results from his discovery in a deductive manner. So pank's the results do not approve any particular condition.
3. Interrelationship in Elevation and Erosion — The greatest feature of the Erosion Cycle of Panks is that according to this the cyclic conditions are dependent on the reciprocal rates of deepening of the valley at the top of the terrain. His third state appears to be true about the rise in the intermediate parts of the Alps and Himalayan mountain regions.
Demerits
1.Penck was a German geomorphological who could not be properly interpreted in the English knowing world.
2. He has been much misunderstood and misrepresented, and with good reason. He wrote in difficult prose that reads awkwardly even in original German, the need for translation made his work obscurve to most English speaking geomorphologists, his ideas seemed weird and unfamiliar to the Davisian school. 1
3. Given Penck's complex writing style it is not really feasible for the average academic equipped with basic German language skills to read or translate the original text and grasp the full range of subtleties involved. Therefore, it seems better to rely on Czech and Boswall's (1972) translation, than to run the risks associated with an amateur translation.
4. The terminology used by Penck was difficult to grasp. ill. defined, vague, obscure and at some places self contradictory .
Penck tried to highlight some of the weaknesses of Davis's model, but there are practical difficulties in accepting. Penck's concept as an alternative to Davis's concept.
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