AIM: How does Wind change the Landscape?

AIM: How does Wind change the Landscape?Do Now: We have all felt the wind blow against us outside. Based on your experiences, what size particle do you think the wind can and cannot move? Write your answer in your notebook.

Namib Desert of Namibia, Angola

I. Wind Erosion• Wind erosion is most effective in deserts.

A. Deflation: wind lifts and removes small loose particles. This creates blowouts and a lowers the land.

B. Abrasion: blown particles cuts and polishes exposed rock.

Double Arch, Arches National Park Utah

• Strong wind erodes great quantities of fine sediment leaving coarse sediment behind.

II. Wind Deposition- Wind creates deposits of sediments that are graded (sorted)

As energy is lost, larger particles are dropped first.

- Smaller particles are on top

- Larger particles are on the bottom

A. Sand Dunes: created as wind stops and small sediments are deposited.

- Sand dunes have a long gentle slope on the side the wind is coming from, windward side. The short steeper side is the sheltered side of the dune.

WIND

B. Crossbeding – layers of sand deposited on the sheltered side of a dune is lithified.

III. Wind erosion Problems

- Human activities that removenatural vegetation, such as farming, logging, and construction, have greatly accelerated wind erosion.

Dust Bowl

Closure •Obtain a worksheet on Wind. With the

person sitting next to you use the notes to answer the questions on the handout.

WIND

1. Wind pushes sediments up gently along the slope facing the wind. Sediment falls off the other side creating a steeper slope.

2. Deflation lowers the land removing necessary soils for farmers to grow their crops in.3. There is nothing to block the wind and there is an endless supply of sediments to move around.

4. How should the sediment look after it was transported by

the wind?