Unit 7 Notes Flashcards
What are the different time scales measuring change of glacial landforms?
Rapid, Seasonal, Long Term.
What does rapid change involve?
Rapid, free falling rocks from a steep cliff face. Rock fragments fall from the side of a cliff due to gravity.
What are the case studies of Rapid change?
Nant Ffrancon Valley - Scree slopes. Randa rockslide - Switzerland.
What are the statistics of the Randa Rockslide?
Occured in 1991, 33 million metres cubed of rock fell to the valley floor, in under a day. 33 buildings were destroyed.
Why do fluvioglacial streams vary?
They are fed by meltwater, so when discharge is high, erosion of sediment is high as well, and lots of sediment is transported.
What happens when discharge falls?
Erosion of sediment is low.
What are the examples of seasonal variations?
The infilling of lakes such as kettle hole lakes and proglacial lakes.
What are varves made up of?
Layers of silt, or rock flour, and coarse gravel.
What happens if varves continuously form?
Kettle hole lakes and proglacial lakes fill up.
What are the examples of long term change landforms?
Alluvial fans, Misfit streams.
What happens as streams flow down from mountain areas?
They have a lot of energy, because of a steep gradient, allowing them to carry large amounts of sediment.
What happens as mountain areas emerge at lower altitudes?
Velocity of the stream is reduced, leading to a loss of energy. Much of the sediment is reduced, leading to a loss of energy. Much of sediment is deposited.
What is the narrow point of the fan called?
Apex.
What is the wide point of the fan called?
Apron.
How wide are fans in the Nant Ffrancon valley?
A few hundred metres across, on the floor of the valley.
