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