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Boulder, boulder, big and round, Tell me something, real profound. - Johnny Hart (B.C.) Glacial erosion . Lecture 16. Webpage for course (daytime). Webpage for course (nighttime). Lab midterm scores. 65 4 64 2 63 62 2 61 3 60 4 59 58 4 57 55 2 54 2
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Boulder, boulder, big and round,Tell me something, real profound. - Johnny Hart (B.C.)Glacial erosion Lecture 16 Webpage for course (daytime) Webpage for course (nighttime)
Lab midterm scores 65 4 64 2 63 62 2 61 3 60 4 59 58 4 57 55 2 54 2 53 52 49 47 45 40 39 31 26 2 17 3 11 2
http://www.learner.org/courses/essential/earthspace/images/show6_ice_age.jpg&imgrefurlhttp://www.learner.org/courses/essential/earthspace/images/show6_ice_age.jpg&imgrefurl
Geologic processes are usually slow Mountains come up, worn down Over millions of years Streams take a long time to Erode transport and deposit their grains The grains transported are small
Glaciers Can erode larger portions of mtns Transport and deposit the material Over 10,000s years Grains can be the size of trucks
Water Ice Flows slowly – bulldozer effect High viscosity – flows around obstructions
Two general kinds (scales) of glaciation Alpine Continental
Snow Accumulates in mtns colder weather – advances warmer weather - retreats Flows to lowlands
In mountains – erosion on large scale Glacial quarrying (plucking) Abrasion Avalanching
Cirques http://www.goldengatephoto.com/westus/greatbasin.html&usg
In valleys – transportation on large scale Glacial vs. Stream U-shape Less sinuous HUGE Hanging waterfalls