Factors Affecting Glacial Erosion

  • Created by: BluJay117
  • Created on: 02-10-18 15:18
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  • Factors Affecting Glacial Erosion
    • Basal Thermal Regime
      • Where glaciers are cold-based erosion is of very low intensity because most glacial erosion processes require the presence of meltwater beneath the ice
      • all types of glacial erosion operate far more effectively when glaciers are warm-based
      • The presence of meltwater at the base of a glacier allows for basal sliding, internal deformation, (both greatly increasing abrasion)  and regelation (an essential part of glacial plucking
    • Ice Velocity
      • Abrasion is more intense when basal sliding is faster because basal debris is moved at a more rapid rate across the bedrock surface
      • Higher ice velocity will create greater shear stress along the bed
    • Ice Thickness
      • Abrasion is generally more effective when ice is thicker because there is a greater weight pressing down on the underlying material
      • However, a point can be reached where increased friction causes the abrading rock to stop moving and to become wedged into the bed: this will tend to reduce abrasion
      • thick ice with abundant basal  meltwater  under pressure is important for loosening rock
    • Bedrock Permeability
      • The permeability of bedrock affects all of the processes of erosion because it influences the amount of meltwater at the glacier/ bedrock interface
      • Some permeability helps meltwater to exploit joints and fractures within rock, but too much permeability can reduce meltwater pressure under the glacier
    • Jointing
      • Glacial plucking is more effective on bedrock that is highly fractured and jointed
    • Rock Debris
      • Rates of abrasion will be higher if the abrading rocks have sharp edges and are harder than the bedrock, and if there is constant replenishment of rock debris from up-glacier

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