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L03: Slope Processes

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Def'n: The interactive physical, chemical, and biological processes which ... iv) Lobate form w/ distal rim. Slope Processes. f) Identification. v) Deposits ... – PowerPoint PPT presentation

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Title: L03: Slope Processes


1
L03 Slope Processes
Geography 2106 Geomorphology Department of
Geography Geology Nipissing University 2008
2
Review Driving Resisting Forces
  • a) Geomorphic Equilibrium
  • b) Endogenic Processes
  • c) Exogenic Processes
  • d) Geomorphology Climate

3
Introduction Slopes
  • Slopes Channels
  • Three main stages in geomorphic processes
  • i) Weathering
  • ii) Erosion
  • iii) Deposition

4
Introduction Slopes
  • A continuum
  • A System
  • i) Inputs of energy, water, sediment
  • ii) Transfers and transformations
  • iii) Outputs of energy and water sediment

5
Weathering
  • Defn The interactive physical, chemical, and
    biological processes which collectively work to
    break down rocks
  • Weathering
  • i) The first step in the geomorphic system
  • ii) Preparation step

6
Weathering
  • Products
  • i) New more stable minerals
  • ii) Unconsolidated rock material
  • iii) Smaller particles

7
Weathering
  • Driving Forces
  • i) Water
  • ii) Heat Energy
  • Types of Weathering
  • i) Chemical
  • ii) Physical
  • iii) Biological

8
  • Physical Weathering
  • Defn The disintegration of rock material
    through physically breaking the material down to
    produce smaller particles
  • Types
  • i) Thermal Expansion
  • (e.g. diurnal and seasonal)

9
  • Physical Weathering
  • Types
  • ii) Frost Action
  • iii) Unloading
  • iv) Wetting Drying
  • v) Salt Weathering

10
Chemical Weathering
  • Defn The decomposition of rock material through
    chemical reactions to produce new mineral types.
  • Types
  • i) Solution
  • (i.e. where minerals dissolve into water)

11
Chemical Weathering
  • Types
  • ii) Oxidation
  • (i.e. a reaction btwn oxygen and minerals)
  • iii) Carbonation
  • (i.e. a reaction btwn dissolved carbon dioxide
    and minerals)

12
Chemical Weathering
  • Types
  • iv) Hydrolysis
  • (i.e. a reaction btwn hydrogen and minerals)
  • v) Hydration
  • (i.e. water is absorbed by minerals)

13
Weathering Climate
  • Heat Energy Water
  • (see fig. 4.5)

14
Weathering Erosion
  • Weathering vs. erosion
  • i) Weathering-limited
  • ii) Transport-limited

15
Slope Processes
  • Transfer and Transformation of Energy, Sediment,
    and Water
  • Shear Stresses (Driving Forces)
  • i) Gravity
  • (see fig. 5.3)

16
Slope Processes
  • Shear Stresses (Driving Forces)
  • ii) Water
  • (e.g. weathering, cohesion, lubrication, mass,
    pore water pressure, erosion see fig. 5.1)

17
Slope Processes
  • Shear Strengths (Resisting Forces)
  • i) Gravity
  • (see fig 5.3)

18
Slope Processes
  • Shear Strengths (Resisting Forces)
  • ii) Friction
  • iii) Cohesion

19
Slope Processes
  • Movement depends on
  • i) Decreases in shear strength
  • ii) Increases in shear stresses
  • Factor of Safety
  • Fs Shear Strengths
  • Shear Stresses

20
Slope Processes
  • a) Importance
  • i) Geomorphic work
  • ii) Hazards
  • b) Slope Components

21
Slope Processes
  • c) Classifications
  • i) Varnes
  • (see table 5.1)

22
Slope Processes
  • c) Classifications
  • ii) Carson Kirkby
  • (see fig.)

23
Slope Processes
  • All Landslides?
  • e) Types of Slope Processes
  • i) Rockfalls
  • ii) Rockslides
  • iii) Rock Avalanches

24
Slope Processes
  • e) Types of Slope Processes
  • iv) Translational Landslides
  • v) Rotational Landslides
  • (see fig. 5.5)

25
Slope Processes
  • e) Types of Slope Processes
  • vi) Earth Flows
  • vii) Mudflows
  • viii) Debris Flows
  • (see fig. 5.8)

26
Slope Processes
  • e) Types of Slope Processes
  • ix) Lahars
  • x) Subsidence
  • xi) Creep
  • xii) Snow Avalanches

27
Slope Processes
  • f) Identification
  • i) Scars
  • ii) Irregular valley profile
  • iii) Irregular topography
  • iv) Lobate form w/ distal rim

28
Slope Processes
  • f) Identification
  • v) Deposits
  • vi) Disrupted/poorly developed drainage
  • vii) Vegetation (silent witnesses)
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