1. 1. The History of geomorphology
(a) Pre-Davisian era
Catastrophism
Uniformitarianism
Glacial theory
(b) Process-oriented work
(c) The work of W. M. Davis

2. Geomorphology
“Term Geomorphology refers to the scientific study of the morphology of the surface of the Earth and the processes that operate on it”
Form and processes studied at a range of spatial and temporal scales

3. Modern geomorphology is process-based and a widely recognized interdisciplinary science.
Historical perspective:

4. Pre-Davisian development (before Davis)
Catastrophism
View of the earth dominated by religion beliefs
Remained important until mid-19th century
Scientific progress in “surface earth science” made by engineers and geologists

5. Uniformitarisnism …the present is the key to the past
“landforms have been formed by present-day processes operating slowly over long periods”
Hutton ( ); 1788: The Theory of the Earth
Lyell ( ); 1830: Principles of Geology
Playfair (19th century); concept of hierarchy of streams…

6. Glacial theory….
In 19th century, development of the idea that the ice cover had been more extensive before (when compared with today’s conditions) and that glaciers can shape landforms
Louis Agassiz (1840s)

7. Process geomorphology
End of 19th & beginning of 20th century: emergence of process-oriented work
Origin of this type of approach closely related to expeditions and exploratory surveys conducted by the United States Geological Survey (USGS)

8. Process Geomorphology
Process: Action produced when a force induces a change in the materials or forms at the Earth surface

9. Development of process-based work:
Three names attached to this period:
Powell
Dutton
Gilbert (e.g. 1917: The Transportation of Debris by running Water)
They worked in Western USA (little or no vegetation- active erosional processes). Allowed direct observations of landforms and related processes.

10. Most of the initial process-based work was concerned with slope form and processes as well as fluvial processes
This process-oriented work did not immediately become important.
Instead beginning of 20th century marked is related to the influential work of Davis (William Morris Davis).

11. The work of Davis The Cycle of Erosion End of 19th century
Sequential landform changes through time (progressive change in the geometry of landforms over geological time scales)
Simply related to origin and evolution of landforms

12. The cycle of erosion: Simple, descriptive approach
Initially, nearly flat landscape uplifted
Period of tectonic stability; erosion proceeds
Landscape goes through a sequence of stages, each of them having distinctive characteristics
End result: peneplain

13. Assumptions of Davis’ model
Potential energy of landform initial uplift IS the dominant source of energy input to system
Uniform lithology
Considerable relief due to rapid uplift

14. Stages in Davis’ model:
Initial stage:
.vertical incision of drainage network
. Steep V-shaped valleys
Maturity:
. Drainage network ceases to increase
. Topography dominated by valley-side slopes and floodplains
Final stage:
. Broad floodplains; lowering rounded divides
. Peneplanation: 10 to 50 million years to develop.

17. Criticisms of Davis’ work:
In response to Davis’ work, parallel development of climatic geomorphology and structural geomorphology.
Climatic Geomorphology: …different climates produce different processes which in turn produce different landforms…elaboration of “morphoclimatic regions”…

18. Structural geomorphology:
Landforms are partly the result of structural movements within the earth’s crust
e.g. plate tectonics

19. Climatic geomorphology - problems
. Use of crude climatic statistics and parameters
. Few landforms restricted to just one morphoclimatic region
. Same processes BUT different frequencies and intensities
. Regions not sufficiently homogeneous