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					   Walther Penck (1888-1923)



    Morphological Analysis
        Of Landforms

         Translated (1953)
by Hella Czech & Katharine Boswell

          From (1924)
  Die Morphologische Analyse
Walther Penck (1888-1923)

Born in Vienna (1888)
Son of Albrecht Penck
Walther Penck (1888-1923)

Born in Vienna (1888)
Son of Albrecht Penck


Professional Activities
     University of Berlin
     University of Heidelberg
     Studied in Vienna
     Direccion General de Minas
        (Buenos Aires)
     Served with Germans in Alsace
     Leipzig University
     University of Constantinople
        (Istanbul)
     Professorship at Agricultural
        College of Halkaly
     Professor at University of Leipzig
        (unpaid)
     *all before the age of 35

Der sudrand der Puna de Atacama
     (1920) based on 1912 field work

Morphological Analysis
    published posthumously
   Walther Penck (1888-1923)



    Morphological Analysis
        Of Landforms

         Translated (1953)
by Hella Czech & Katharine Boswell

          From (1924)
  Die Morphologische Analyse
                                1. Nature of the Problem
                   2. Basis, Nature and Aim of Morphological Analysis
 The Problem
     • study of morphology goes beyond limits of geography
     • need to understand forces that produce land forms
     • „problem‟ is that of crustal movement

3 elements forming the substance of geomorphology

    1. Exogenetic Activity (destructive)
         - reduction and removal of rock
         - transport of sediment from higher to lower (gravity)
         - remove uneveness that endogenetic forces cause
         - require a surface to attack
               Earth sculpture is due to exogenetic transference of material. The sum total of this
               constitutes denudation.”

    2. Edogenetic Forces (constructive)
         - originate within planet
         - creates relief and uneveness
         - independent of gravity forces (really?)
         - all we know about them is from the effects they have produced

    3. Earth‟s surface
         - “is a limiting surface between different forces working in opposition to one another”
                               1. Nature of the Problem
                               1. Nature of the Problem/
                  2. Basis, Nature and Aim of Morphological Analysis


Morphological Study

Seeks to understand the interaction between three factors
          (endogenetic, exogenetic, landforms)

“Therefore it is possible to see plainly in the forms of denudation not merely the results of
endogenetic and exogenetic transference of material; but even more that they owe their origin
and their development to a relationship of forces, to the ratio of intensity between exogenetic
and endogenetic processes.


 Discussion Point

 “Crustal movements cannot be observed directly, and no adequate tectonic
 method is known for ascertaining their characteristics. Thus in studying land
 forms, it is not permissible to make definite assumptions as to their course and
 development, and to base morphogenetic hypotheses upon them.”

 “Morphological analysis is this procedure of deducing the course and
 development of crustal movements from the exogenetic processes and the
 morphological features.”
                              3. Critical Survey of Methods
                              3. Critical Survey Of Methods

Penck on Davis
So what were Penck’s beefs with Davis?
   - does not include endogenetic processes
   - rapidly uplifted during which no denudation processes occur
   - once denudation processes begin, block remains at rest
             (uplift and denudation are NOT successive processes)
   - applying a „special case‟ as a „general rule‟
   - followers only see landforms as a realization of the cycle (misunderstanding Davis?)

   (b) facts on which the assumptions are based
   (a) deduction as a method of morphological research




  What are the main flaws Penck sees in the cycle of erosion?

  What, if anything, did Davis get right?

  How were Davis and Penck‟s approaches to describing landscape
  development/processes fundamentally different?
                       3. Critical Survey of Methods
                       3. Critical Survey Of Methods




Davis on Penck

“He seems first to misunderstand a general scheme for a very limited, rigid,
spechal scheme; and second equally determined to show how the work of an
earlier time than his ought to have been done.
You do not mention A. Penck,….the father is as exasperating as the son.”

               Excerpt from Chorley et al (1991) History of the Study of Landforms
               Or the Development of Geomorphology
                               3. Critical Survey of Methods
                   (b) Relationship between endogenetic and exogenetic processes



  …it is essential, when investigating the origin and development of
  denudational forms as they appear at the earth’s surface, to ascertain
  the relationship between the intensity of the endogenetic and of
  the exogenetic processes, in short, between uplift and
  denudation; and it is necessary to follow out how this changes as
  time goes on.”

What is his thought process leading up to this?

   “So long as uplift is at work, denudation cannot be idle.”
   “…the fundamental law of morphology: the modeling of the earth’s surface is determined by
   the ratio of the intensity of the endogenetic to that of the exogenetic displacements of
   material.”
   “But the relationship is not an unchanging one.”
   “…exogenetic happenings is subordinate to that of endogenetic processes”
   “Any change in kind or in intensity which these movements undergo must therefore – as has
   long been known – leave its traces upon the landscape.”
3. Critical Survey of Methods
    (c) The Differential Method




                       cycle of erosion
                    Penck‟s Key Points from Introduction



- Uplift and denudation are NOT successive processes; denudation is
  concurrent with uplift

- Crustal processes are important (but not observable…)

- Ratio of the intensity of endogenetic and exogenetic processes is key

- These intensities are constantly changing

- There is no one successive generation of landscape forms
                Chapter 6: Development of Slopes
                Chapter 6: Development of Slopes

      SUMMARY OF SLOPE DEVELOPMENT SECTIONS

1.   Form of slopes

2.   The case of no incision (flattening of slopes)

3-7. The case of active incision
       Ratio of erosion intensity to denudation intensity
Chapter 6: Development of Slopes
 1. Gradient and Form of Slopes
                Chapter 6: Development of Slopes
                     2. Flattening of Slopes

In the case of the cessation of incision (erosion), denudation proceeds…..




  Cliff-slope recedence and the development of the basal slope
                           Chapter 6: Development of Slopes
                                2. Flattening of Slopes


     “It is now quite clear that the process obeys a law: Flattening of slopes always
     takes place from below upwards” (p. 138)




 “If left undisturbed, a slope
 of any gradient whatsoever,
 provided it is uniform,
 becomes a slope system
 concave in profile” (p. 140)




Cliff-slope recedence and the development of the basal slope and diminishing slope
               Chapter 6: Development of Slopes
               Chapter 6: Development of Slopes


     SUMMARY OF SLOPE DEVELOPMENT SECTIONS

1.   Form of slopes

2.   The case of no incision (flattening of slopes)

3-7. The case of active incision
       Ratio of erosion intensity to denudation intensity
                    Chapter 6: Development of Slopes
                    Chapter 6: Development of Slopes

                     Slope Development Summary

All slopes form at the local base level and propagate upwards

    2. Erosion intensity controls gradient!

        Convex slope = increase in erosion intensity (p. 150)
        Concave slope = decrease in erosion intensity
        Straight slope = no change

        Amount of concavity or convexity indicates the rate of change
               Chapter 6: Development of Slopes
               Chapter 6: Development of Slopes
                           Questions



Q: How does Penck’s model of slope development compare to
   that of Davis?
                    Chapter 6: Development of Slopes
                    Chapter 6: Development of Slopes
                                Questions


  Q: Does Penck’s discussion of slope development follow the
     methodological theory he used to criticize Davis’ work (i.e.,
     inductive vs. deductive)?

              How does Penck rely on observation?



“It is now possible to
give a complete
survey of the origin
and development of
slopes” p. 177
        Chapter 6: Development of Slopes
4. Straight slope profiles. Uniform development. (p. 143)




                                                    The cliff will recede
                                                    from the river as the
                                                    basal slope and
                                                    diminishing slope form
                                                    UNLESS there is…..

                                                    “a constant ratio
                                                    between the intensity
                                                    of the denudation
                                                    acting on the slope
                                                    unit and the intensity
                                                    of erosion by the
                                                    stream”.
    Chapter 6: Development of Slopes
4. Straight slope profiles. Uniform development.




                                        “If uniform development
                                        lasts sufficiently long,
                                        straight slope units are
                                        produced in every case.”
                                        (p. 148)
Chapter 6: Development of Slopes
5. Convex breaks of gradient (p. 150)
  Chapter 6: Development of Slopes
7. Rates of Growth and Areas of Slope Units




                                     Erosion intensity increasing over
                                     time…..

                                     Intermediate slope units vanish
                                     as higher gradient slopes grow
                                     more quickly

                                     Results in more sharply convex
                                     breaks in gradient
   Chapter 6: Development of Slopes
7. Rates of Growth and Areas of Slope Units




Erosion intensity continually increasing over time.
        Chapter 6: Development of Slopes
8. Rise in the general base level of denudation (p. 161)
                        Chapter 6: Development of Slopes
9. Influence exerted by rocks of heretogeneous character upon the development of slopes
                        Chapter 6: Development of Slopes
9. Influence exerted by rocks of heretogeneous character upon the development of slopes

				
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