Glacial movement

• How does gravity affect glacial movement?

  Weight causes gravitational forces which increases the slope angle making the glacier advance.
• How does thermal regime affect glacial movement?

  Temperature causes glaciers to have meltwater, which makes it easier to slide down.
• How does thickness affect glacial movement?

  Pressure from weight causes ice to deform.
• How does bedrock affect glacial movement?

  Soft rock increases the rate of basal sliding.
• How does gradient affect glacial movement?

  The steeper the gradient of the ground surface, the faster the ice will move.
• How does glacial budget affect glacial movement?

  A positive balance causes glacial advance.
• What is the pressure melting point?

  It is when the melting point differs depending on the pressure.
• What are the characteristics of temperate glaciers?

  They are high altitude, have steep relief, are more dynamic, and are close to the pressure melting point (PMP).
• What are the characteristics of polar glaciers?

  They are found in high latitudes, have low relief, are below the PMP, and have frozen bedrock.
• Which parts of the glaciers move the furthest?

  The top and the middle move the furthest due to less friction holding them back.
• How does PMP affect the speed of the glacier?

  When the PMP is close to 0 degrees, the bed will melt more, causing basal sliding.
• How quickly do cold-based glaciers move?

  They move slowly because the bedrock is below PMP, so it is frozen and there’s no meltwater.
• What are three types of ways temperate glaciers move?

  Basal sliding occurs through slippage, creep, and internal deformation.
• What is internal deformation?


  It is where gravity and the pressure of ice in the accumulation zone cause ice crystals to slide over each other, resulting in deep crevasses.
• What is creep in glacial movement?

  Creep occurs when ice deforms under pressure due to obstructions, spreads over because of pressure, and then refreezes to keep moving.
• What is slippage?


  Slippage is when ice slides across the valley flow.
• What is bed deformation?

  Bed deformation occurs when the sediment underneath the ice is saturated and gets carried along with it due to high pressures.
• Where does internal deformation occur?

  It occurs on a slope as gravity pulls it down.
• What is extending flow?

  Extending flow occurs when the ice moves over a steep slope and is unable to deform quickly enough, creating crevasses.
• What are the two ways polar glaciers move?

  Polar glaciers move through intergranular flow and laminar flow.
• Define laminar flow.


  Laminar flow is the movement of individual layers within the glacier, often layers of annual accumulation.
• Define intergranular flow.


  Intergranular flow is when individual ice crystals re-orientate and move in relation to each other.
• What is compressing flow?

  Compressing flow occurs when the gradient is reduced, causing thickness and ice to push over the slower moving ice.
• What are the two zones of glaciers?

  • Rigid zone
  • Plastic zone
• How does ice move in the rigid zone?

  In the rigid zone, ice is solid and brittle, so it breaks, causing crevasses.
• How does ice move in the plastic flow zone?

  Under pressure, the ice deforms and acts more like a fluid.
• What does the speed of the glacier depend on?

  The speed of the glacier depends on the degree of imbalance between the two zones.
• How is equilibrium maintained in glaciers?

  Equilibrium is maintained by the momentum of the ice going into the ablation zone, which prevents further build-up.
• When does mass movement occur?

  Mass movement occurs when forces acting on slopes exceed the forces trying to keep the material on the slope, such as friction.
• Explain the process of rockfall.

  Rockfall occurs on a slope with a 40-degree angle or more, especially if the surface below becomes detached from the slope by physical weathering, caused by gravity and transportation removing this material.
• Explain the process of slides.

  Slides can be a linear movement along a straight slip plane; rotational slides are called slumps, and in glaciated landscapes, slides may occur due to steepening or undercutting of valley sides by erosion.