Wind Erosion A Wind 1 Conditions Wind erosion

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Wind Erosion

Wind Erosion

A. Wind 1. Conditions -Wind erosion and weathering are most effective where sands, silts,

A. Wind 1. Conditions -Wind erosion and weathering are most effective where sands, silts, and clays lie loose and dry. • Ex. Great desert areas of the world Sahara in Africa and the Mohave SW USA. 2. Dust storms -Very destructive, strong steady winds lift great amounts of loose silt and clay. • Ex. Great Plains 1930 s

B. How Wind Causes Erosion 1. Abrasion -the particles must be light and hard.

B. How Wind Causes Erosion 1. Abrasion -the particles must be light and hard. a. Causes rounding of rocks 2. Deflation -The removal of loose rock particles by wind a. Stronger particles need stronger winds to move. b. Results: 1. ) Desert pavements- area of only heavy rocks 2. ) Blowouts- hollow areas

Abrasion

Abrasion

Desert Pavement

Desert Pavement

Blowout

Blowout

C. Wind Deposition Are hills deposited by winds. They form 1. Sand Dunes when

C. Wind Deposition Are hills deposited by winds. They form 1. Sand Dunes when sand piles up against shrubs, boulders or other obstacles. a. Windward- -Long gentle slope facing the direction the wind is blowing. b. Leeward -Steep slope facing away from the direction the wind is blowing. -Depends on the following: Supply of sand, c. Shape of Strength of wind, Steadiness and amount of the sand dune vegetation.

Barchan

Barchan

Transverse

Transverse

Longitudinal

Longitudinal

Star

Star

Star Dune

Star Dune

Dune Migration

Dune Migration

C. Wind Deposition 2. Loess - Wind deposited sediment a. Sediment is fine silt

C. Wind Deposition 2. Loess - Wind deposited sediment a. Sediment is fine silt & clay (creates fertile land)

Loess deposits of the world.

Loess deposits of the world.

Erosion Poster Guidelines • Bold Title. § Must be done on poster board •

Erosion Poster Guidelines • Bold Title. § Must be done on poster board • Catchy subtitle. paper no smaller than 12”x 18” • Include five topics about your type furnished by yourself. of erosion. Minimum of 3 sentences EACH. • Three diagrams illustrating agent Erosion Types: processes. • Mechanical vs. • Colored. Chemical • Sketch or create digitally. NO PRINTED PICTURES! Weathering • Rough draft must be done prior to • Stream Erosion final poster. This rough draft will be attached to the poster and is • Wind Erosion worth 20 percent of the total grade. It must be colored. • Glacier Erosion

Erosion Poster Project • Red Textbook – Streams: page 272 – Chemical vs. Mechanical

Erosion Poster Project • Red Textbook – Streams: page 272 – Chemical vs. Mechanical weathering: page 238 – Glaciers: page 291 – Wind: page 301