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Wind Erosion . Erosion. Mechanical weathering breaks rocks apart, erosion moves the broken pieces. Water Wind Ice. Sediment types. Sand = larger Dust (silt and clay)= medium Silt= small Clay=small. Wind erosion . Saltation Moves sediment by a series of jumps and bounces. - PowerPoint PPT Presentation
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Wind Erosion
Erosion
Mechanical weathering breaks rocks apart, erosion moves the broken pieces.
WaterWindIce
Sediment typesSand = 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 erosionSilt 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 formationa dune is a hill of sand built by
either wind or water flow.
Formation 1. Wind blows sand2. Wind is slowed by some type of
barrier3. Accumulation of sand can now
occur4. 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 wind-blown dust.
Formation1. Wind carries dust and silt2. Silt is deposited in thin layers3. 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 size3 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
FetchThe uninterrupted distance of
open water over which the wind blows without significant change in direction.
Partner time
MichiganErie
Huron
Superior
Ontario
Wes
terli
es
Long shore current Waves go at an angle to
shoreline
◦Water moves along shore
◦Carries sediment with it
Shoreline erosion features
A
B
CDE
F
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 movementsRockfall/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 movementsLahar:
◦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 movementsSolifluction:
◦slow downslope movement of water-saturated sediment due to recurrent freezing and thawing of the ground, affected by gravity.