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
- Basal Thermal Regime
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