Glacial movement - Key terms Flashcards
What is a temperate (warm-based) glacier?
A temperate glacier is a glacier characterised throughout its depth by temperatures close to 0 degrees celsius.
What is a polar (cold based) glacier?
A polar glacier is a glacier characterised by temperatures below freezing point.
What is a polythermal glacier?
A polythermal glacier is a glacier that is warm based in its thicker, central regions as a result of geothermal heating and cold based at its surface and near its margins where it is frozen to the bed.
What is basal sliding?
Basal sliding is the act of a glacier sliding over the bed due to meltwater under the ice acting as a lubricant.
What is the pressure melting melting point?
The pressure melting point is the temperature at which ice melts at a given pressure. The melting point of ice is 0 degrees near the surface but at deeper levels ice melts at a slightly lower temperature because of the increased pressure (weight) of overlying glacier ice. The pressure melting point of ice beneath 2000 meters is -1.6 degrees celsius.
