Geomorphologg

• Geomorphology


  The study of the earth's landforms, their origin and the processes that have created them
• Geomorphology


  • The study of the changing surface of the earth by internal forces as well as external forces
• Internal forces


  • volcano
  • faulting
  • earthquakes
  • holding
  • warping
• External forces


  • erosion
  • weathering
  • mass wasting
• Factors responsible for formation of landforms


  • Plate tectonics
  • Climate
  • Time
• Plate tectonics


  The movement of the earth's crust which is broken into plates
• Folding


  The bending of rock layers when they converge or are pushed together
• Faulting


  The cracking and fracturing of fault layers
• Volcano


  The eruption of magma
• Earthquake


  The vibration or shaking of the earth
• Climate affects the process that changes solid rock into sediments</b>
• Sediments


  Weathered rock materials e.g. sand particles, pebbles
• Weathering


  The breaking down of rock into small particles or pieces chemically, physically or biologically
• Types of weathering


  • Chemical weathering
  • Physical/mechanical weathering
  • Biological weathering
• Physical weathering


  The breaking down of rock into small particles due to temperature differences
• Chemical weathering


  The breaking down of rock into small particles due to chemical reactions between minerals in rocks and water
• Biological weathering


  The breaking down of rock into small particles by the action of plants and animals
• Erosion


  The transportation of weathered material (sediments) by water, wind or glacier
• Mass wasting


  The movement of weathered material down the slope under the influence of gravity
• Building up and breaking down processes take a very long time, over millions of years
• Structural geomorphology


  Looks at how the underlying rock structure affects the formation of landforms
• Fluvial geomorphology


  Investigates how rivers shape the earth's surface
• Topics in geomorphology


  • Topography associated with horizontal strata
  • Topography associated with inclined strata
  • Topography associated with massive igneous rock
  • Slopes
  • Mass wasting
• Stratified rock


  Rocks with layers (strata)
• Massive rock


  Large rock masses without strata or layers
• Bedding plane


  Junction between layers/strata of horizontal strata
• Horizontal strata of equal resistance to erosion


  • Hilly landscape in humid region
  • Basaltic plateau
• Horizontal strata of unequal resistance to erosion

  • Canyon landscape
  • Karoo landscape
• Hilly landscape in humid region


  • Gentle, rounded slopes
  • Deep, thick soil
  • Fine soil texture
  • Dominated by chemical weathering
  • High rainfall leads to sheet erosion
• Hilly landscape in arid region


  • Steep, angular slopes
  • Rugged, uneven landscape
  • Coarse soil texture
  • Dominated by physical weathering
• Basaltic plateau


  • High-lying area with flat top and steep sides
  • Formed from lava flows
  • Vertical erosion creates deep valleys
• Canyon landscape


  • Deep, narrow valley with steep stepped sides
  • Formed from horizontal strata of soft and hard rock layers
  • Physical weathering is dominant
• Basaltic plateaus and canyons have little value for human use due to their steep sides, but can attract tourists for their scenic beauty
• Canyon


  • Deep and narrow valley
  • Steep-stepped side
  • Develop in arid or dry semi-arid climate
  • Physical weathering most active in horizontal strata
• Canyon landscape


  • Step-like appearance
  • Soft and hard rock layers
  • Hard rock layers stand out as steep cliff, soft rock layers form gentle slope
  • Deep and narrow
  • Wide top and narrow floor
  • Physical/mechanical weathering most active in development
• Development of canyon landforms


  1. Tectonic uplift

  2. Rivers undergo rejuvenation

  3. Rivers erode vertically or downward along joints and cracks
• Canyon landscapes


  • Grand Canyon in California, USA
  • Blyde River Canyon in Mpumalanga, South Africa
• Canyons are barriers to communication because they are difficult to construct bridges in
• River in canyon is too deep to be used for navigation
• Valley floor is too narrow to be utilized or used for industrial development