Relief, Weathering and Erosion

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Relief, Weathering and Erosion
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Crustal Orders of Relief

• First Order Relief
• Continental Platforms
• Ocean Basins

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Global First Order Relief
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Crustal Orders of Relief

• First Order Relief
• Continental Platforms
• Ocean Basins
• Second Order Relief Features
• Mountain Masses
• Plains
• Lowlands

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US Elevation Map
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Crustal Orders of Relief

• Third Order Relief Features
• Individual mountains
• Cliffs
• Valleys
• Hills
• Other features identifiable in local landscapes

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Earth Hypsometry
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Plate Motions

• Plate tectonics movie
• Plate movements result in stresses and strains at
  surface
• Folding
• Broad Warping
• Anticlines
• Synclines

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Surface Expression of Stress/Strain
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Plate Motions

• Plate tectonics movie
• Plate movements result in stresses and strains at
  surface
• Folding
• Faulting
• Tension
• Compression
• Shear

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Surface Expression of Stress/Strain
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Folded Landscapes
Figure 12-8
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Domes and Basins
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Orogenesis (Mountain Building)

• O-C Collision
• O-O Collision
• C-C Collision

Figure 12-14
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Our Neighborhood
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What Happened to the ReallyBig Mountains We
Used to Have?
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Landmass Denudation

• Weathering
• Mass Movement
• Erosion
• Transportation
• Deposition

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Dynamic Equilibrium

• Landscapes in dynamic equilibrium
• Ongoing adaptations to ever-changing conditions
• rock structure
• climate
• local relief
• elevation

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Slope Mechanics and Form
Fig 13-3
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Weathering

• Factors Influencing Weathering
• Jointing
• Slope aspect
• Vegetation
• Two basic flavors of weathering
• Physical
• Chemical

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Physical Weathering

• Frost Action
• Crystalization
• Hydration
• Pressure-Release Jointing

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Chemical Weathering Processes

• Hydrolysis
• Feldspar (K, Al, Si, O) H2O and Carbonic Acid gt
• residual clays dissolved minerals silica
• Oxidation
• Fe O gt iron oxide
• Carbonation and Solution
• CaCO3 Carbonic acid H20 gt
• Calcium bicarbonate

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Mass Movement
Figure 13-21
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Erosion

• Removal of weathered material
• Requires a fluid medium
• Air
• Liquid Water
• Ice