Glacier Processes Flashcards
What is the glacier system?
Consists of inputs, transfers (flows), stores and outputs in the same way as a river.
What are inputs?
Come from avalanches along the sides of the glacier but mainly from snow precipitation.
What are stores?
Overtime snow accumulates and is compressed into ice. The water held in storage is the glacier.
What are flows?
Under the force of gravity, a glacier flows downhill.
What is the main output of a glacier?
Meltwater is the main output from the glacier, along with some evaporation.
what is accumulation+ ablation?
Balance between inputs and outputs varies.
In winter, inputs usually exceed outputs near to the head of a glacier (ACCUMULATION)
In summer, and at lower altitudes, outputs will exceed inputs (ABLATION)
What does the balance between the annual rate of accumulation and ablation determine?
Whether the glacier will advance/retreat
A Glacier endures 3 types of erosion. What are these?
Frost shattering, Abrasion, Plucking
What is frost shattering?
Water enters cracks in the rocks. During colder temperatures, this water freezes, making it expand (widening the crack).
When this is repeated several times, the crack gets wider until eventually pieces of rock break off.
What is abrasion in a glacier?
Occurs when rocks and stones, picked up by the glacier are rubbed against the bedrock at the bottom and side of the glacier, as the glacier moves downhill. (CAUSES WEARING OF LANDSCAPE)
This grinding leaves long grooves in bedrocks called striations or smooth polish (Rock which is smooth and shiny)
What is Plucking?
When rocks and stones become frozen to the base of the glacier, and are plucked from ground as glacier moves.
What is another name for frost shattering?
Freeze-thaw weathering.
What are striations?
Long grooves in bedrock (rock with smooth and shiny surface). They tell us what direction the glacier was flowing.
