Glaciers Flashcards
what is a glacier
mass of ice originated ON LAND by the recrystallization of snow AND shows evidence of past and present MOVEMENT
______ exceeds ______ in glaciers (snow fall vs snow melt)
snow fall EXCEEDS snow melt
four environmental significances of glaciers
- powerful agent of geomorphologic change
- source of freshwater (77% of all freshwater)
- release nutrients locked up in rocks
- contribute to changes in sea level
two terms associated with changes in sea level
- isostatic sea-level changes (related to land position)
- eustatic sea-level changes (related to water volume)
how is the sea level affected by the formation of glaciers and ice sheets
- eustatic FALL in the sea level (water is being taken out of the ocean and moved to land)
how is the sea level affected by the further growth of sea sheets
isostatic depression of land (land is being pressed DOWN because of the pressure above it) and a rise in sea level
how is the sea level affected by the melting of ice sheets
the eustatic rise in sea level (mass of glaciers on land is melting INTO the sea = decrease of freshwater on land)
how is the sea level affected by the decline of ice sheets and glaciers
- isostatic uplift of the land
- decrease in sea level BUT at the same time there is an eustatic rise in the sea level
the first year of snow for the glacial ice formation can be described as
mostly aid (not very dense)
what happens to the snow over the years in the formation of glacial ice
it begins to become compacted and denser (becomes firn) until it becomes glacial ice
describe the colour of glacial ice and why it is so
blue hue - based on it allowing light to pass through it and ONLY being able to absorb short light wavelengths (like blue light)
three major Canadian glacier locations
- Coridllera
- Baffin island
- Queen Elizabeth Islands
2 main types of glacier
- continental
- alpine
continental glaciers AKA
ice sheets
describe the area covered by ice sheets
it is extensive
does the ice cover the topography in an ice sheet
YES
describe the flow of ice sheets
unconfined due to gravity
example of ice sheets
- Greenland
- Antartica
- Laurentide ice sheet
are ice caps constrained
NO
what is smaller: ice sheets or ice caps
ice caps (have to be smaller than 50 000 km2)
describe the appearance of ice caps
dome-like surface or circular
locations of ice caps
polar and sub-polar regions
(Yukon, Canadian Arctic…)
describe the appearance of ice fields
NO dome-like surface
do ice field show restraint
YES
what are often produced by ice fields
outlet glaciers
ice shelves
where glaciers float out onto oceans