Wind Erosion

1. Wind Erosion

2. Erosion • Mechanical weathering breaks rocks apart, erosion moves the broken pieces. • Water • Wind • Ice

3. Sediment types • Sand = larger • Dust (silt and clay)= medium • Silt= small • Clay=small

4. Wind erosion • Saltation • Moves sediment by a series of jumps and bounces

5. Wind erosion • Strong winds lift dust into the atmosphere • Dust storms

6. Why only sand and silt

7. Which Climates produce the most deflation?

8. Farmers

9. Everything is going to end up somewhere!

10. Sand dune formation • a dune is a hill of sand built by either wind or water flow. • Formation • Wind blows sand • Wind is slowed by some type of barrier • Accumulation of sand can now occur • More sand is added buries original barrier * Limited by angle of repose 30- 40 degrees

11. Loess deposits • predominantly silt-sized sediment, which is formed by the accumulation of wind-blown dust. • Formation • Wind carries dust and silt • Silt is deposited in thin layers • 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!)

12. Wave erosion

13. Clicker • The fine-grained, sediment that is soft, easily eroded, and deposited by the wind in steep cliffs is called: • Loess • Sand dune • Desert pavement • Dust storms Times up! Timer

15. 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

16. 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

17. Wave size 3 Factors affect wind wave size: • Wind speed: wind must be moving faster than the wave crest for energy transfer • Wind duration: how long the wind blows • Fetch

18. Fetch • The uninterrupted distance of open water over which the wind blows without significant change in direction.

19. Partner time Superior Ontario Westerlies Huron Michigan Erie

20. Long shore current • Waves go at an angle to shoreline • Water moves along shore • Carries sediment with it

21. Shoreline erosion features F C D A E B G

22. 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

23. 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.

24. 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

25. Clicker • What is the most common trigger for mass movements? • Water/precipitation • Wind • Earthquakes • Humans Times up! Timer

26. Mass movements • Solifluction: • slow downslope movement of water-saturated sediment due to recurrent freezing and thawing of the ground, affected by gravity.