Glaciation Part 2 Flashcards
Weathering
Uses heat energy to produce physically or chemically altered materials from surface or near surface rock.
What are the processes for physical or mechanical weathering?
Freeze-thaw, frost shattering and pressure release.
Physical or mechanical weathering
The break down of rock that produces small fragments of the same rock.
Freeze thaw
Water enters cracks and expands by almost 10% when it freezes. In confined spaces, the exerts pressure on the rock, causing it to split or break.
Frost shattering
At really low temperatures, water trapped in rock pores freezes and expands. So disintegrates the rock due to stress.
Pressure release
When the weight of overlying ice in a glacier is lost to melting, the underlying rock expands parallel to the surface.
Chemical weathering
The decay of rock.
What are the processes of chemical weathering?
Oxidation, carbonation, solution, hydrolysis and hydration.
Oxidation
Minerals in rock react with oxygen, either in the air or in water. The rock becomes soluble under acidic conditions and the original structure is destroyed.
Carbonation
Rainwater with dissolved carbon dioxide produces a weak carbonic acid. Then reacts with calcium carbonate in rocks to produce calcium bicarbonate with is soluble.
Solution
Some salts are soluble in water so minerals such as iron dissolves.
What is Biological weathering?
It may consist of physical actions such as the growth of plant roots.
What are the processes of biological weathering?
Tree roots and organic acids.
Tree roots
Grown into cracks in rocks and exert outward pressure.
Organic acids
Produced during decomposition of plant and animal litter which causes soil water to become more acidic and react with some minerals.
What is geomorphic?
Related to the form of the landscape
Geomorphology
The study of landscapes/ landforms and how they form.
What is Erosion?
The wearing away and removal of soil, rock or dissolved material.
Where does material carried by glaciers come from?
Rockfall
Avalanches
Volcanoes
Debris flows
Abrasion
Plucking
Aeolian deposits
Material deposited by lactation is known as what?
Drift
What are the two types of glaciation drift?
1) Till- directly deposited by the ice
2) Outwash- deposited by meltwater
What are the two types of glacial Till?
Lodgement till and ablation till
Lodgement till
Deposited at the base of advancing glacier due to melting
Ablation till
This is the more common glacial till. Material is deposited as the ice melts away from retreating or stagnant glacier.