Glacier Landforms Flashcards
What are crevasses?
Cracks in the ice, extremely dangerous
What is a Corrie and give an example of one in N.I.
Steep sided hollow at head of a valley/mountainside
E.g SPERRINS
How is a Corrie formed?
Snow accumulates in north/east facing hollows
Snow is compacted into ice + moves downhill
Frost shattering and plucking creates steep sided backwall
Abrasion deepens hollow to form a rock basin
Rock lip is left where rate of erosion has decreased
What is an arête?
‘Knife edged’ ridges formed between two corries
How is an arête formed?
When two corries form back to back, they both erode backwards until they create a narrow ‘knife edge’ between them.
What is a pyramidal peak?
Formed when 3 or more corries cut backwards into the same mountain eg matterhorn (located in Switzerland/Italy)
What is a u-shaped valley/glacial trough? give an example in ni.
A type of valley with a broad floor and steep walls produced by glacial erosion.
E.g MOURNES, NEWCASTLE
What is a moraine? Give an example in ni.
Material (till), that an advancing glacier pulls out of the mountain & deposits. Deposited at end of snout and sides of a glacier. Made up of unsorted angular rocks.
E.g ANNALONG
How many different types of moraine are there? Name them.
Lateral, Medial, Ground, Recessional, Terminal
what is lateral moraine?
Produced from frost shattering of valley sides. Carried to sides of a glacier.
What is medial moraine?
Found in centre of glacier
What is ground moraine?
Dragged beneath a glacier. Forms a part of the valley floor.
What is recessional moraine?
Marks interruptions from retreat of a glacier.
What is terminal moraine?
Found at snout. (Maximum advance of a glacier)
What are drumlins? Give an example in Northern Ireland.
Formed of till (eroded material). Elongated (stretched) features that can reach a km or more in length, 500m or so in width and over 50m in height. Common to find several together.
E.g COUNTY DOWN
What is a collection of drumlins called?
Swarm
What are erratics? Give an example in ni.
Large boulders that have been carried by the glacier and then deposited in an area of different rock type, so that they look completely out of place. Erratics can have originated from hundreds of miles away.
E.g ROSTREVOR
How are u-shaped valleys formed?
Start off as v-shaped valleys
Glacier is strong enough to go straight down valley, so erodes the valley making it a ‘u’ shape.
What are depositional landforms?
Sediment and rock debris deposited at snout. From the snout, this material can be placed directly from the ice onto the land. (Forms depositional landforms)
