EOS 120 w/ Prof Walker
Terms
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- landform:
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recognizable feature on Earth's
surface with characteristic shape, produced
by natural processes - landscape:
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distinct association of landforms
operated on by natural processes - Geomorphology
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scientific study of Earth surface
landforms & processes
interpretation of pattern & process
over various spatial & temporal
scales - applications of geomorphology
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Reconstructing past climate & environments
Modelling modern processes & responses
Resource exploration & management⬦ e.g.?
Land use planning & development⬦ e.g.?
Simulating future scenarios⬦ e.g.? - theories of Earth surface evolution
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1. Catastrophism
‘creationism’, 18th century
2. Uniformitarianism
‘gradualism’, 19th century
3. Plate tectonics & continental drift
A. Wegener, 1915
4. Cycle of erosion
W.M. Davis, 1909
5. Earth surface systems
1960s – present - Catastrophism
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‘creationism’, 18th century
Earth created & shaped by catastrophic
events & remains unchanged otherwise
‘Great Flood’, volcanic eruptions, meteor impacts
extinctions in fossil record (Cuvier)
The Bible: created in 6 days, 6000 yrs old - Uniformitarianism
-
idea that laws of nature remain same through time &
change is gradual
present-day processes explain past Earth
surface evolution(*this is a key idea in geomorphology!):
- Hutton (1785): endless rock cycle, gradualism
- Playfair (1800): rivers carve their valleys
- Lyell (1830): Principles of Uniformity
countered Creationism⬦ heresy! -
How can the cycle of erosion date the Earth?
What are the stages that landscapes evolve by? -
- (Davis 1909)
- driven by uplift, degraded by fluvial action
1. <bold>youthful </bold>(high energy, steep slopes) to…
2. mature (max. relief) to…
3. old (low energy ‘peneplain’) - Difference between open and closed systems? examples?
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An open system exchanges energy and/or matter w/ surroundings
open syst - most geol systems; river, glacial, closed syst - cooling lava, Earth itself! (mostly) - What are 'process-response' systems? examples?
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-processes of M & E exchange produce morphological responses
-weathering, water/ice flow, sediment transport, mass movement - entropy
- tendancy to move to lower energy state
- Geomorphic work from 2 kinds of energy?
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1. Potential (position)
2. Kinetic (movement) - What factors control landform dynamics?
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1. climate
2. relief & tectonics
3. lithology
4. time
5. human action - Earth's sufaces systems: open or closed?
- open - exchange between different 'spheres' (litho, hydro, bio)