Landscapes Theories

• What are landforms

  • Landforms are a feature on the Earth’s surface with a morphology that results from the interaction of physical processes.
  • The past of geomorphic landscapes is the key to the future
• Processes of landform development

  • These processes can be better understood by categorising them in exogenic and endogenic
  • Exogenic – Forces within the Earth, generally constructional. Includes processes such as uplift of mountains, formation of new rock, and relief
  • Endogenic – Surface processes either destructional or constructional. Includes processes such as weathering, erosion, transport and deposition by ice, water, wind etc
  • The scale of endogenic processes can be fast or slow. E.g., sudden = volcanism, slow = orogenic events
• Landscapes and Scales

  • Landscapes are also understood by their temporal and spatial scales
  • Spatial scales range from micro to mega. Where micro scales are easily observable but mega persist over geological time scales
  • Across all scales there are theoretical concepts that apply
• Theoretical concepts


  • Landscapes are thought of as “systems”: Any change will tend to cause a readjustment of form and process
  • Conservation of mass and energy. Input = output
  • Base levels set the erosional level of environments
  • Force balances exist in every system
  • Equilibrium and thresholds: geomorphic systems will fluctuate between different states
  • Feedback loops: Positive and negative
  • Magnitude and frequency. Higher magnitude = less frequent
• Theory- Landscapes are systems

  • Any change in the system will result in a readjustment of form or processes
  • There are both open and closed systems, with geomorphic systems being open
  • Example: River basins are an open system, especially the boundary with coastal where sediments and energy are exchanged
• Theory - Conservation of Mass and Energy

  Mass and energy are conserved through the systems
• Theory - Base Levels

  • Base levels are the lower limit of erosion
  • Sea level is the ultimate base level, but lakes can act as local base levels
  • Example: Mountain River environments interact with a base level at their discharge point
• Theory- Force balances

  • The balance between opposing forces determines the change in stability of an environments
  • Example: Hillslope environment or sediment moving along a channel bed
• Theory - Feedback Loops

  • Positive and negative feedback loops
  • Positive - Change drives further change. E.g., ice melting leads to more heat getting absorbed, which leads to more ice melting
  • Negative – Change works to limit further changes. E.g., Dust in the atmosphere blocks heat from reaching the surface
• Theory - Magnitude and Freqeuncy

  • High magnitude events occur less frequently because of the mass amounts of energy that they require.
  • E.g., large avalanches from hillslope environments are not as common as smaller landslides