glaciation Flashcards
what causes an ice age?
- a change in the earths orbit around the sun
* change of angle in earths axis
what are the processes of erosion in a glaciated landscape?
- plucking
* abrasion
explain plucking
the bottoms of glaciers scraped along valley floors. this created friction which led to melting at the base of the glacier. the glacier then picks up rocks- the erosion and transport of rocks
explain abrasion
when rock fragments within the glacier scratch the surface and the sides and further erode rock picking it up and adding to the load of the glacier
what are the features of glacial erosion
- cirque
- pyramidal peak
- arête a
- glaciated u shaped valley
- hanging valley
- ribbon lake
- fjords
what is a cirque
a hollow in a mountain with three steep sides and often contains a lake.
what is a pyramidal peak
created when 3 or more cirques form back to back or side to side. what is left is a steep ridge or steep sided peak of the original mountain
what is an arête
a narrow ridge that forms when two cirques form side by side or back to back. the land between the cirques became narrower as a result of erosion.
what is a glaciated u-shaped valley
has a wide, flat floor with steep sides.
what is a hanging valley
a small tributary glaciated valley that hangs above the main valley. rivers in hanging valleys often enter the main glaciated valley as waterfalls.
what is a ribbon lake?
a long narrow lake found on the floor of a glaciated U-shaped valley.
what is a paternoster lake?
a number of ribbon lakes joined by a river stream
what is a fjord?
a drowned glaciated U-shaped valley. formed as a result of the melting of glaciers.
what is an ice age
a period of time when large parts of several continents were covered by ice sheets
what are the features of glacial deposition ?
- erratic
- boulder clay plain
- drumlin
- moraines
what is an erratic?
a huge boulder transported and deposited by a glacier. it is a different rock type to other rocks.
what is a boulder clay plain?
an area covered in boulder clay. formed when ice sheets melted and deposited their load.
what is a drumlin?
formed when the glacier that deposited the boulder clay moves forward and smoothens and rounds the boulder clay.
what is moraine?
deposited material found in the lowlands of glacial valleys.
what are the features of meltwater deposits
- esker
* outwash plain
what is an esker?
a long narrow ridge of sand and gravel that winds its way across lowland areas. formed because of friction between the bottom layer of the glacier and the ground over where it travelled melted.
what is an outwash plain ?
a low flat area of sand and gravel that is found at the front of terminal morraine. formed when a glacier melted it deposited its material over the low lying area
what are the advantages of glaciation ?
- tourism
- generation of HEP
- fertile land
- routeways
- resources for construction industry
- recreation
what are the disadvantages of glaciation ?
- unfertile land
- poor drainage
- flooding
