Walther%20Penck%20(1888-1923)

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Walther Penck (1888-1923)

Morphological Analysis Of Landforms Translated
(1953) by Hella Czech Katharine Boswell From
(1924) Die Morphologische Analyse
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Walther Penck (1888-1923)
Born in Vienna (1888) Son of Albrecht Penck

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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
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Walther Penck (1888-1923)

Morphological Analysis Of Landforms Translated
(1953) by Hella Czech Katharine Boswell From
(1924) Die Morphologische Analyse
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• 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. Earths surface
• - is a limiting surface between different
  forces working in opposition to one another

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• Nature of the Problem/
• 2. Basis, Nature and Aim of Morphological Analysis

• 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.
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3. Critical Survey Of Methods
3. Critical Survey of Methods
Penck on Davis So what were Pencks 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 Pencks approaches to
describing landscape development/processes
fundamentally different?
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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
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• 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 earths 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 earths 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.
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• Critical Survey of Methods
• (c) The Differential Method

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Pencks 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

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Chapter 6 Development of Slopes
Chapter 6 Development of Slopes
SUMMARY OF SLOPE DEVELOPMENT SECTIONS

• Form of slopes
• The case of no incision (flattening of slopes)
• 3-7. The case of active incision
• Ratio of erosion intensity to denudation
  intensity

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Chapter 6 Development of Slopes 1. Gradient
and Form of Slopes
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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
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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
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Chapter 6 Development of Slopes
Chapter 6 Development of Slopes
SUMMARY OF SLOPE DEVELOPMENT SECTIONS

• Form of slopes
• The case of no incision (flattening of slopes)
• 3-7. The case of active incision
• Ratio of erosion intensity to denudation
  intensity

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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
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Chapter 6 Development of Slopes
Chapter 6 Development of Slopes Questions
Q How does Pencks model of slope development
compare to that of Davis?
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Chapter 6 Development of Slopes
Chapter 6 Development of Slopes Questions
Q Does Pencks 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
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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.
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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)
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Chapter 6 Development of Slopes 5. Convex
breaks of gradient (p. 150)
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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
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Chapter 6 Development of Slopes 7. Rates of
Growth and Areas of Slope Units
Erosion intensity continually increasing over
time.
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Chapter 6 Development of Slopes 8. Rise in the
general base level of denudation (p. 161)
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Chapter 6 Development of Slopes 9. Influence
exerted by rocks of heretogeneous character upon
the development of slopes
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Chapter 6 Development of Slopes 9. Influence
exerted by rocks of heretogeneous character upon
the development of slopes