Glaciation Flashcards
Explain the formation of a glacier
Snow collects in a north facing hollow. It compacts and compresses to form neve, eventually forming glacial ice.
Explain the movement of a glacier
Glaciers move under their own weight and gravity.
Glaciers also move by baisal sliding where a melt water layer is created due to friction between the glacier and land. This melts the bottom layer of the glacier allowing it to slide over land.
Explain the 3 erosional processes
Plucking - ice melts onto a piece of rock and pulls it out as the ice continues to move downhill.
Abrasion - ice already has fragments of rock embedded in its base and these scrape at the rocks surface.
Freeze thaw - water enters cracks in the rock. It freezes and expands to form ice. This forces the cracks wider. The water thaws and refreezes, again and again, further widening the cracks eventually loosening fragments of rock.
State the 4 stages involved in the formation of a Corrie.
Stage 1 - formation of a glacier
Stage 2 - movement of a glacier
Stage 3 - 3 erosional processes
Stage 4 - formation of a Corrie
Explain the formation of a Corrie
Back wall is steepened by plucking. Overtime, the hollow is deepened by abrasion. Ice may deposit material called a rock lip. When the ice melts, a Corrie loch is left behind.
Give an example of a Corrie
Red tarn
State the 5 stages involved in the formation of an arête
Stage 1 - formation of a glacier Stage 2 - movement of a glacier Stage 3 - 3 erosional processes Stage 4 - formation of a Corrie Stage 5 - formation of an arête
Explain the formation of an arête
An arête if formed when 2 Corries form back to back, creating a sharp ridge.
State the 6 stages involved in the formation of a pyramidal peak
Stage 1 - formation of a glacier Stage 2 - movement of a glacier Stage 3 - 3 erosional processes Stage 4 - formation of a Corrie Stage 5 - formation of an arête Stage 6 - formation of a pyramidal peak
Explain the formation of a pyramidal peak
A pyramidal peak is formed when 3 corries form back to back, creating a jagged peak
Give an example of an arête
Striding edge
State the 5 stages involved in the formation of a u-shape valley
Stage 1 - formation of a v-shape valley Stage 2 - formation of a glacier Stage 3 - movement of a glacier Stage 4 - 3 erosional processes Stage 5 - formation of a u-shape valley
Explain the formation of a v-shape valley
A v-shape valley is formed by verticals erosion of a river
Explain the formation of a glacier(v-shape valley)
Snow collects in a v-shape valley. It compacts and compresses to form neve, eventually forming glacial ice
Explain the formation of a u-shape valley
Plucking steepens the valley sides. Abrasion deepens the valley floor. The river left behind is called a misfit stream
State the stages involved in the formation of a hanging valley
Stage 1 - formation of a v-shape valley Stage 2 - formation of a glacier Stage 3 - movement of a glacier Stage 4 - 3 erosional processes Stage 5 - formation of a u-shape valley Stage 6 - formation of a hanging valley
Explain the formation of a hanging valley
A hanging valley is a small v or u shape valley that forms high up on the side of the main valley. Sometimes a waterfall is created
State the 6 stages involved in the formation of a ribbon lake
Stage 1 - formation of a v-shape valley Stage 2 - formation of a glacier Stage 3 - movement of a glacier Stage 4 - 3 erosional processes Stage 5 - formation of a u-shape valley Stage 6 - formation of a ribbon lake
Explain the formation of a ribbon lake
Ribbon lakes can form where softer bedrock is eroded more deeply than the surrounded area. Ribbon lakes can form where a terminal of recessional morraine creates a dam.
Give an example of a ribbon lake
Lake Windermere
Explain the 3 methods of transportation use for glacial debris
Supraglacial - material carried on the surface of the glacier
Englacial - material carried within the body of the glacier
Subglacial - material carried at the base of the glacier
State the 5 stages involved in the formation of a drumlin
Stage 1 - formation of a glacier Stage 2 - movement of a glacier Stage 3 - 3 erosional processes Stage 4 - transportation Stage 5 - formation of a drumlin
Explain the formation of a drumlin
Drumlin’s are oval hills made of till. Drumlins often appear in groups called swarms. The unsorted material is moulded by the base of the glacier to form a steep upstream end, with a more streamlined downstream gentler ice slope showing the direction in which the glacier was moving
State the 5 stages involved in the formation of an erratic
Stage 1 - formation of a glacier Stage 2 - movement of a glacier Stage 3 - 3 erosional processes Stage 4 - transportation Stage 5 - formation of an erratic
Explain the formation of an erratic
Erratics are boulders carried by ice by supraglacial transportation, often for many kilometres, which have been deposited in areas ofcompletely different rock type
State the 5 stages involved in the formation of a terminal moraine
Stage 1 - formation of a glacier Stage 2 - movement of a glacier Stage 3 - 3 erosional processes Stage 4 - transportation Stage 5 - formation of a terminal moraine
Explain the formation of a terminal moraine
As glaciers advance, material is bulldozed at the front of the glacier. When the glacier retreats, this mound of material is left and this is what is known as a terminal moraine. It shows the furthest extent that the glacier reached
State the 5 stages involved in the formation of an esker
Stage 1 - formation of a glacier Stage 2 - movement of a glacier Stage 3 - 3 erosional processes Stage 4 - transportation Stage 5 - formation of an esker
Explain the formation of an esker
Eskers are long, narrow, steep sided, winding ridges of sand and gravel. They are formed inside the ice, in tunnels in which melt water streams flowed and when the glacier melts are deposited perfectly in lines
