Chapter 5 - Glaciation Flashcards
Ice age
A period when large parts of several continents were covered by ice sheets
What could cause an ice age?
○A change in the earth’s orbit around the sun
○ A change in the angle of the earth’s axis
What are the processes of glacial erosion?
Plucking
Abrasion
Define plucking
Glacial erosion where rock fragments are pulled out of the valley floor by moving ice
Define abrasion glacial
Rock fragments carried by a glacier scraped the rock surface as the glacier advanced
The scratches created by glacial abrasion are called…
Striae
Glacier
Large river of ice. Move downhill and change the shape of the landscape by erosion and deposition
What is a cirque/corrie? Give an example
Large, deep hollow with a steep back wall found high up on a mountainside in an area affected by ice. e.g. Coomshingaun
What is a pyramidal peak? Give an example
A peak formed when three or more cirques formed back to back. e.g. Matterhorn, Switzerland
What is an arête? Give an example
A knife-edged ridge formed when two cirques formed back-to-back or side-by-side
What is a U-shaped valley? Give an example
A steep-sided and flat floored valley (U-shaped) formed by the action of a glacier. e.g Glendalough
What is a hanging valley? Give an example
Small tributary glaciated valley that hangs above the main valley. e.g Polanass Waterfall, Glendalough
What is a ribbon lake? Give an example
Long, narrow lake found on the floor of a glaciated U-shaped valley. e.g. Glendalough
Sometimes a group of ribbon lakes are joined together by a river or stream. These are called…
Paternoster lakes
What is a fjord? Give an example
Drowned glaciated U-shaped valley. e.g. Killary Harbour, Co. Mayo
Moraine
Deposited material found in lowlands of glaciated valleys
What is an erratic? Give an example
Huge boulders that have been transported and deposited by a glacier some distance from their source region. e.g. Granite found in the limestone region of the Burren & Scottish granite found in the Wicklow Mts
What is boulder clay?
Deposits of sand,gravel and stone from a melting glacier
What is a drumlin? Give an example
An oval shaped hill consisting of boulder clay. e.g. Clew Bay Co.Mayo to Strangford Lough, Co.Down
Lateral moraine
Material deposited either side of a glacier. Consists of unsorted material that fell from upland slopes and gathered at the side of the glacier
Medial moraine
Some lateral moraines join to form medial moraine as two glaciers meet. Consists of a low ridge of material that runs along the centre of a glaciated valley
Ground moraine
Irregular covering of boulder clay in a lowland area
Terminal moraine
Ridge of material marking the end point of a glaciers journey. Consists of a high bank of soil and stone
What are the four types of moraine
○Lateral
○Medial
○Ground
○Terminal
Name the features of glacial erosion
Cirques/corries Pyramidal peaks Arêtes U-shaped valleys Hanging valleys Ribbon lakes Fjords
Name the features of glacial deposition
Erratics Boulder clay plains Drumlins Moraine Eskers Outwash plains
What is an esker? Give an example
Long, narrow ridge of sand and gravel that winds its way across lowland areas. e.g. Eiscir Riada, Dublin to Galway
What is an outwash plain? Give an example
Low-lying areas of sand and gravel found in front of a terminal moraine. e.g. Curragh, Co.Kildare
How does glaciation have a positive affect on human activity?
☺Tourism ☺HEP ☺Fertile agricultural land ☺Routeways ☺Resources for construction ☺Recreation
How does glaciation have a negative affect on human activity?
◘Infertile lands
◘Poor drainage
◘Flooding
