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.