MOUNTAIN BUILDING
Introduction:
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First of set of classes considering Geomorphology - processes creating the shape of the Earth's surface (i.e. creating "landforms") Today: processes creating major (large area) features of the surface primarily looking towards how mountains are built next few classes - we wear away the mountains to get our current landforms
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Today's Class Structure:
1- Brief lecture introduction (review of material in Chapters 11 & 12):
an expanded version is given below (there will be no detailed class discussion):
it is recommended that you read this (and the text) before class -
- it will help you get the most out of the video
- it provides a guide for the material you should know for the next quiz
2- Video: The Living Machine
a set of comments and questions to help you as you view this are given below.
you do not have to hand in a set of answers, but:
the next quiz will assume that you have the answers!
N.B. This will be the only showing of this video - it is NOT available in the library.
1 - Mountain Building - Lecture Introduction
a - The Rock Cycle
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Rock cycle indicates basic processes going on - within earth & on surface 3 main rock types: igneous, sedimentary, metamorphic for landform creation - different resistance to erosion vital for soil development - different chemical composition of concern
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b - Geologic Time
Exact times rarely important for our present purposes, BUT
processes are going on continuously, so that:
large-scale changes take millions (even billions) of years
e.g. building Appalachian Mountains, depositing Coastal Plain
current landscape detail is superimposed on these slow large-scale changes,
often the result of last few tens or hundreds of thousands of years
e.g. 'cliffs' produced by sea level changes
much action is slow, continuous, almost imperceptible
e.g. brownish rivers of Coastal Plain indicate removal of material
other actions are almost instantaneous events
e.g. landslides in mountains, changes by hurricanes on coast
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c - Plate Tectonics
Plate movements continuous:
collisions produce mountains (e.g. Appalachians) and subduction zones
plates moving apart give depressions (e.g. Durham Basin)
Plate tectonics commonly considered on large spatial & long time scales
Look at more detail with:
d - Mountain Building Processes
More detailed view of plate collisions and resulting uplift
Folds and faults of various kinds occur
Earthquakes common as this occurs
Commonly associated with volcanic action
For North Carolina:
Several collisions and separations associated with NC Mountains and Piedmont
mainly involved (what are now) North American & African plates
Rock cycle active:
i.e. after uplift, erosion removed material
2 - Video - The Living Machine
The video was made in 1996 - computer technology has changed considerably since then, but the progress in geology/geophysics has not been as rapid. Probably the major change, encountered near the end of the video, has been the increasing acceptance of the theory of 'micro plate tectonics' and 'exotic terrains' now expressed in the term 'terranes'.
While watching, look out for answers to the following questions. Note that some answers may require only one word, others several sentences. Note also they are not necessarily in the same order as the video presentation.
1. What causes the chain of Hawaiian Islands?
2. Why are the Hawaiian Islands unusual?
3. What is happening to Mt. Everest?
4. Why is this happening to Mt. Everest?
5. What is the link between sea-floor spreading and the frozen lava compass?
6. How long will it take for Los Angeles to become a suburb of San Francisco?
7. Why will Los Angeles become a suburb of San Francisco?
8. Approximately how many tectonic plates are there?
9. Who was called the 'Father of Geology'?
10. The central part of the North American plate began tearing apart how many million years ago?
11. What is happening in central North America now?