3. Wind Erosion. Common in Dry Climates (deserts) and along shorelines.
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Transcript of 3. Wind Erosion. Common in Dry Climates (deserts) and along shorelines.
3. Wind Erosion
• Common in Dry Climates (deserts) and along shorelines
Dunes
• Dunes – gentle slopes faces the wind
• Wind only pick up and carry clay, silt and sand
WIND
desert wind erosion
pitted
Sand Blasted and Pitted Rock
• Sand can only be picked up, up to 3 feet so lower parts get eroded away
• also get pitted rocks
Cross bedded deposits
• deposits from ripples and dunes
• indicate that the depositional environment was either water or wind
4. WAVES
ABRASION
Longshore Current
• Movement of sediment parallel to the shore as waves strike shoreline at an angle
Waves hit at an angle, water washes back
• http://www.youtube.com/watch?v=U9EhVa4MmEs
• http://www.youtube.com/watch?v=zEpfjyto8r0&list=PLB177833E87DA5C20
Mass Movement
Mass Movements–The downslope movement of
large masses of earth materials due to _______gravity
Three Main TypesCreep
Landslides
Mudflows
Creep
• Gradual downhill movement of soil
• Slow process
• Evidence: (tilted fences, utility pole, bent trees)
Landslides
• Sudden and rapid downhill movement• Likely to occur on steep slopes• Caused by high precipitation which “lubricates”
sediment (deceases friction)
• http://www.youtube.com/watch?v=ZVYGJYnJTi0• http://www.youtube.com/watch?v=S1Pi64I2wTU
Slump
La Conchita, CA
Spring 1995
RockslidePorteau Cove, B.C
July 30, 2008
Tully Landslide
April 27, 1993
Mudflow
• Cause - Fine-grained sediment becomes saturated with water and begins to flow
• Likely to occur on steep slopes
• Fast and destructive
Mt. Saint Helen’s, WA, LaharMarch 21, 1982