3842:278 Geomorphology

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38/42278Geomorphology

• Topic 1 Introduction
• Chapter 1 Ritter et al.
• Chapter 1 Trenhaile
• Chapter 1 Easterbrook

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Origins of Geomorphology?

• Human awareness of the physical env.
• Important in terms of
• where we live
• how we survive
• Not environmental determinism
• Dictates a range of possibilities

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What is Geomorphology?

• Study of landforms
• Landform
• element of the landscape
• can be viewed in entirety
• usually result of one or more specific processes
• Landscape
• assemblage of landforms
• usually result of related set of processes
• but could also be polygentic

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What is Geomorphology?

• Two streams
• Origin of Landforms (Historical)
• description of polygenetic landforms
• landscape evolution
• Processes that create/modify landforms (Modern)
• quantitative analysis
• measurement/monitoring of variables
• modeling

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Characteristics

• Landforms composed of and preserved in
• rock
• sediment
• soil
• Created, modified and destroyed by
• erosion
• transport
• deposition

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Characteristics

• Temporal Scale
• focus on recent events
• shorter geologic time frames (lt periods)
• Focus on
• surface processes
• less on subsurface

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Characteristics

• Spatial
• occasionally sub-continental
• more often regional
• typically local
• Analysis of form over time and space
• geographic approach - what is where and why

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Characteristics

• Study of form processes allows us to
• understand cause and effect relationships
• predict outcomes, what if scenarios
• extrapolate to unknown environments

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What does it include?

• Numerous branches
• Morphometric measurement classification
• Climatic landform/process by climatic regime
• Process mesoscale analysis of process
• Geotechnical engineering properties
• Applied env. mgmt. disasters
• Humans as geomorphic agents
• anthropogenic influences/impacts

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What do Geomorphologists do?

• Field-oriented discipline
• Map and photo interpretation
• Laboratory analysis/experimentation
• Observation and experience imp.
• Geomorphic insight a learned skill

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Early Scientific History

• First insights by Greek scholars based on casual
  observation
• Effects of flooding
• Landslides
• Erosion
• Weathering

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18th Century Revitalization

• Development impacted by strict biblical
  interpretation of Genesis
• Neptunist theory proposed by Werner
• Catastrophism proposed by Cuvier
• Both well received

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Hutton Theory of the Earth (1788)

• Opposed Neptunist/Catastrophist theory
• Proposed slow cyclic evolution of landforms
  governed by processes currently observable
• Uniformatarianism present is the key to the
  past
• Not initially well received, but rewritten by
  Playfair (1802)

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New Age

• Lyell (1830) Principles of Geology popularized
  Huttons theory
• added concept of gradualism
• Neptunists/Catastrophists discredited
• Acceptance of older age of Earth
• Rapid growth in 19th century Europe

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North American Geomorphology

• J.W. Powell surveyed American west proposed
  concept of base level
• G.K. Gilbert (1870s) suggests balance exists
  between process and form, no change in form over
  time
• Davis (1909) cycle of erosion, downwasting
• Penck (1924) parallel retreat, subadjacent
  scarps, backwasting, treppen concept
• King (1953) backwasting controlled by base level
• Hack (1960) dynamic equilibrium theory, form
  stable until balance upset, then rapidly readjusts

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Whats Ahead?

• In this course we focus on
• Description identification of landforms
• Processes operating on landforms
• Erosion
• Transport
• Deposition