Transcript Wind Erosion

Wind Erosion
Erosion
Mechanical weathering breaks rocks
apart, erosion moves the broken pieces.
Water
Wind
Ice
Sediment types

Sand = larger

Silt= small

Clay=small…very small

Dust (silt and clay)= medium
Wind erosion
Sand is mostly transported by…
 Saltation

◦ Moves sediment by a series of jumps and
bounces
Wind erosion

Silt is mostly transported by
◦ Deflation: winds blow sediment into air *dust
storms
Why only sand and silt
Which Climates produce the most
deflation?
desert is a barren area of land where little precipitation occurs and
consequently living conditions are hostile for plant and animal life. The lack of
vegetation exposes the unprotected surface of the ground.
Farmers
Everything is going to end up
somewhere!
Sand dune formation

a dune is a hill of sand built by either wind
or water flow.

Formation
1. Wind blows sand
2. Wind is slowed by some type of barrier
3. Accumulation of sand can now occur
4. More sand is added buries original barrier
* Limited by angle of repose 30- 40 degrees
Loess deposits

predominantly silt-sized sediment, which
is formed by the accumulation of windblown dust.

Formation
1. Wind carries dust and silt
2. Silt is deposited in thin layers
3. Thick layers form from this accumulation
*Loess often stands in either steep or vertical
faces. loess will often stand in banks for many
years without slumping. (unlike sand dunes!)
Wave erosion
Wave formation
usually result from the wind blowing over a
vast enough stretch of fluid surface.
• wind or some force causes up and
down motion of water
• Transfers energy
Breakers

Some waves undergo a phenomenon
called "breaking". A breaking wave is one
whose base can no longer support its top,
causing it to collapse.
◦ Wave hits the bottom of the shore or sand
bar
◦ Collides with another
wave
Wave size
3 Factors affect wind wave size:
1.
Wind speed: wind must be moving faster
than the wave crest for energy transfer
2.
Wind duration: how long the wind
blows
3.
Fetch
Fetch

The uninterrupted distance of open water
over which the wind blows without
significant change in direction.
Partner time
Westerlies
Superior
Huron
Michigan
Erie
Ontario
Long shore current

Waves go at an angle to shoreline
◦ Water moves along shore
◦ Carries sediment with it
Shoreline erosion features
C
A
F
D
E
B
G
Mass movements

Also known as mass wasting, is the
process by which soil, sand, and rock
move downslope largely under the force
of gravity.
Triggers
◦
◦
◦
◦
◦
Saturation of water(heavy rain fall)
Spring melts
Earthquakes/tectonics
Wind
Humans
Mass movements

Rockfall/slide:
◦ Sudden movement of rocks, normally in mountain
regions

Landslide:
◦ Sudden movement of masses of loose rock and
soil, down hill/slope.

Mudflow:
◦ It is a rapid movement of a large mass of mud
formed from loose dirt and water.
Mass movements

Lahar:
◦ Volcanic mud flow from ash

Slump:
◦ Slow moving block of soil moves
Down hill

Creep:
◦ Very slow movement and very effective of all
mass movements
Mass movements

Solifluction:
◦ slow downslope movement of watersaturated sediment due to recurrent freezing
and thawing of the ground, affected by gravity.