GLACIERS Flashcards
define glaciers
slowly moving mass of ice formed by the compaction of snow
name three glacial erosional processes
- freeze thaw weathering
melt water enters crack of rock, freezes at night and expands by 9%, wideing the crack. In the morning the ice water melts and seeps deeper into the crack, process repeats - abrasion
small, sharp rocks embedded in the bas of glacier sandpaper along the bedrock underneath, resulting in striations - plucking
blocks of loosened bedrock freeze to the bas of the glacier and gets pulled out as the glacier moves down the valley
2 types of glacial deposition
- till deposits (materials deposited directly by ice)
- fluvioglacial material (materials deposited by streams of meltwater)
2 types of glaical transport
- basal sliding
meltwater at the base of glacier acts as lubricant
-internal flow
ice crystals within glacier slides over one another
2 post-glacial processes
–> freeze thaw weathering produces scree slops
–> mass movement forms steep glaciated slopes to valley floor
what and when was the last glacial period?
Pleistocene// 12000 years ago
when does a glacier advance and when does it retreat?
ACCUMULATION// ABLATION
name seven erosional glacial landforms
- corries and tarns
- aretes
3.pyramidal peaks - roches mountonees
- glacial trough
- truncated spur
- hanging valley
explain how corries and tarns form
1/ snow accumulates in hollow and is compressed into ice
2/plucking steepens back wall, abrasion deepens hollow, moraine left at end of glacier
3/ melt water forms tarn, moraine act as natural dam
explain how aretes form
-knife edge ridge formed when 2 corries for back to back
-freeze-thaw weathering continues to make ridge steeper
what are pyramidal peaks?
high point formed by 3 corries back to back
what are roche mountonnees and how do they form?
-band of rock that undergoes erosion
-abrasion smoothens stoss sside and plucking roughens lee side
what are glacial troughs?
v-shaped valley eroded into a ushaped glacial valley as plucking steepened the sides
how do truncated spurs form?
formed when morraine erodes lower sections of inter-locking spurs
how do hanging valleys form?
formed when a tributary glacier eordes a less deep trough (brough plucking and abrasion) which ‘hangs’ above the main valley, connected by waterfall
name 3 transport and depositional landforms
moraines
drumlins
crag and tail
state 2 types of glacial moraines
-terminal moraine (material built up at the end of glacier)
-ground moraine (material deposited on the valley floor)
explain what is a drumlin and how it is formed
-entirely till
stoss side is blunt as large material is deposited first as glacier looses energy
lee side is tapered as small material is deposited next
explain what is a crag and tail and how it is formed
crag= rock, steepend by abrasion and plucking
tail=till, deposition from large material to small material, forming a tapering edge
geographial information about glacial case study, ARRAN.
- Island off the SE coast of Scotland
northern Arran= mountainous with granite
southern arran= gently sloping with forest and farmland
name and explain with evidence 3 human activities in Arran
- settlements in glacial valleys (7 golf-courses)–> removal of trees/ soil erosion
- farming (over grazing by over 2000 deer)–> loss of native habitat and flora+ removal of trees for hill farming leads to soil erosion
- forestry (25% oand covered with non-native coniferous plants)–> this prevents soil erosion but unbalances the ecosystem, forcing some species out
*development in glaciated landscapes
- water storage and supply in KIELDER WATER
-u shaped valleys eroded by glaciers are used to create resevoirs
:) increased water supply to NE England
:( construction destroys plants and habitats (1.5 million trees removed to create reservoir!!) - renewable energy in KIELDER WATER
-U shape valley dams provide HEP
:) decreased reliance on fossil fuels decrease pollution (2 HEP plants produce power to light 11,000 homes)
:( visual pollution
3.tourism in SNOWDONIA
:) jobs, 8300 people employed
:( 1500 miles of artificial footpath causes visual pollution
4: conservation in SNOWDONIA
:) strict planning of laws to conserve local environment, protecting vulnerable, rare wildlife
:( $$$$$$$$
