Theory question 303
Weathering, Erosion and Mass Movement(a) State the difference between erosion and mass movement. (b) List four agents responsible for modifying landforms. (c) Outline three factors that influence mass movement.
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(a) Erosion is the wearing away and removal of rock materials by moving agents (running water, wind, ice, waves), whereas mass movement is the downslope movement of weathered material under the direct influence of gravity, without a transporting agent.
(b) Running water (rivers); wind; moving ice (glaciers); waves and sea currents; underground water; man; animals.
(c) Gradient (steepness) of slope; amount of water/rainfall lubricating the material; nature and structure of the rocks (loose, jointed, clay); vegetation cover; earthquakes and volcanic activity; human activities (quarrying, road cutting, deforestation); gravity.
Stress the role of gravity in mass movement.