Temperate Glaciers

Description

A-Levels Glaciation Mind Map on Temperate Glaciers, created by EmmaSmile on 06/05/2013.
EmmaSmile
Mind Map by EmmaSmile, updated more than 1 year ago
EmmaSmile
Created by EmmaSmile over 11 years ago
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Resource summary

Temperate Glaciers
  1. The Alps and Rockies
    1. Conditions
      1. Usually high altitude
        1. Areas of high accumulation in winter, rapid ablation in summer - large volumes of ice move over the firn line (firn is partially compacted neve)
          1. Milder climate - summer melting, fluvial glacial features
            1. Base temperature of 0C, at or below pressure melting point
              1. Often steeper gradients
                1. Rapid movement 20-200 m per year
                  1. Powerful erosive agent
                  2. The main mechanism for movement in temperate glaciers is basal slippage
                    1. Represents 80% of glacial movement. Most temperate glaciers are at pressure melting point at their base and sometimes within the glacier itself.
                      1. Friction and pressure within the bedrock raises the temperature above 0C so meltwater acts as a lubricant, enabling ice to move slowly, picking up material and erode. At PMP as ice on point of melting and deforms more easily.
                      2. Basal Slippage - Relegation slip
                        1. Basal ice is forced against a rock obstacle, pressure melting point may be reached due to increase in pressure. Meltwater released at base, enabling ice to move over obstacle. Meltwater quickly refreezes on other side due to reduction in PMP.
                        2. Basal slippage - creep
                          1. Where ice comes across an obstacle, increase in pressure can cause ice to behave like plastic and deform to flow around obstacle.
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