GL 7 Flashcards
Rapid Change:
Change occurring rapidly
Rockfall
Randa Rockslide, Switzerland 1991
Three rockslides in less then one day, totalling 33million m3 of rock falling.
33 buildings destroyed
Dead livestock
Water Dammed
Seasonal change:
Change due to seasons
Infilling of lakes, Varves
Varves
Nant Ffrancon Valley
Long term change:
Post Glacial landscapes modified by water
Alluvial Fans
Infilling of Lakes
Misfit stream
Alluvial fans formation
Streams flow downhill rapidly, carrying large amounts of sediment
Gradient changes, streams slow down and fan out, sediment is deposited in fan shape
Alluvial fans Apex vs Apron
Apex - narrow top point
Apron - Wide triangle
Alluvial fans - Example
Nant Ffrancon valley, streams exiting hanging valleys, Cwm Idwal
Infilling of lakes - Long term change
Stream enters ribbon lake, velocity drops, stream load is deposited, infilling lakes
Infilling of Lakes - Example
Nant Ffrancon Valley
Misfit stream
At base of glacial trough
Cause vertical erosion, meandering, embankments and some interlocking spurs
Misfit stream - Example
Afon Ogwen, Nant Ffrancon valley