glaciated landscapes Flashcards
what is a Neve
the fresh snow that gradually becomes compact
what is a firn
when the snow become more and more compact over the years
what are some inputs for glaciated structures
Snow, kinetic energy from the wind, thermal energy from the sun and potential energy from the position it is on, on the slop
what is accumulation
the overall gain in mass for glaciers. For example more layers of ice squeezingg air out of the glacier occurs during colder months
Why is it important for glaciers to have rock fragment and where are they found?
found on the surface or under the ice. This adds mass to the glacier. It also allows erosion so that the glacier to create landforms like truncated spurs or glaciated valleys
Describe the input of snow to a glacier
Snow will gradually become compact. Then over years snow will become more and more compact forming ice adding weight to the glacier squeezing out the air making the glacier look blue
what does glaciers have
a very high albedos (a measurement of the reflectivity of a surface)
describe the input of thermal energy to a glacier
It can cause it to melt or evaporate or lose some of its mass
What is sublimation
When the ice becomes water vapour without melting due to the heat
what is ablation and how does it effect a glacier
It’s when ice melts and it becomes meltwater which helps the glacier move faster as it acts as a lubricant between the bedrock and the glacier
what does the term rock flour mean
when melt water transport materials left from melted glaciers it appears grey or brown because it has a high content of rock materials in it
Examples of output for glaciated structures
meltwater and ablation
Describe the movement of cold base glaciers
found in higher latitudes like Antarctica but since temps are low they dont have meltwater so they freeze onto the bedrock. they move by Internal flow
Describe the movement of hot base glaciers
found in lower and higher latitudes like the French alp. They have meltwater which will lubricate the ice helping slide down as they are in warmer temperatures and they usually have steep relief
What are the 2 internal processes and describe them
inter granular movement- ice crystals slip against each other and the movement can occur within crystals along a line of weakness
plastic flow- when ice is under pressure it folds and moulds on itself like plastic
what does basal slippage mean
when the meltwater acts like a lubricant helping the ice slide over the bedrock
what is regelation
as ice moves it can force itself over and obstacle which can cause melting due to the higher pressure. When the pressure is reduced it creeps then refreezes
what is extending flow
When the gradient is steep the ice accelerates therefore the ice becomes thinner
what is compressing flow
when the gradient is gentle the ice decelerates so the ice becomes thicker
what does glacial budget mean
when there is a balance between accumulation and ablation
(Positive regime) what happens when there is more amount of accumulation than ablation
the top part of the glacier will cause the glacier to move down quicker as there is more mass. mostly found in the winter
(Negative regime) what happens when there is more amount of ablation than accumulation
the Lower end of the glacier will cause the glacier to move more slower and it will melt faster than it can be replaced so it will retreat. mostly found in the summer
Describe the formation of a corrie
1) accumulation occurs in a hollow in the mountain. It becomes a firn. Due to the ice becoming more compact it increases pressure and melts the sole of the glacier. This moves the ice (rotational slip)
2) Above the glacier freeze-thaw is occurring. When the ice thaws and refreezes within cracks of the rock. Every time it happens a chunk of rock (spree) falls onto of the glacier. Eventually it will sink with other debris.
3) due to rotational slip the debris at the bottom of the glacier moves with it which cause abrasion
4) plucking occurs as the ice melts and then refreezes around a large rock. This steepens the bakcwall
What is the term for glacial material that has been deposited
Boulder clay or till
