1. Table of Contents Title: Wind Page #: 75 Date: 2/14/2013

2. Objective Students will be able to describe conditions that contribute to the likelihood that an area will experience wind erosion. Students will be able to identify wind-formed landscape features. Students will be able to describe how dunes form and migrate.

3. Word of the Day Velocity: The speed of an object and its direction of motion.

4. Wind Wind: The horizontal movement of air across Earth’s surface. Wind modifies landscapes in all areas of the world by transporting sediment.

5. Wind Wind Erosion and Transport: Wind can move smaller particles. – It can cause them to roll: “creep.” – It can pick them up and carry them long distances: “suspension” – It can cause large particles to bounce up and down: “saltation”

7. Wind Wind erosion happens in areas that are dry and that have little vegetation.

8. Wind Deflation: The lowering of land surfaces that results from winds’ removal of surface particles. – Occurs when vegetation is removed and surface soil dries out and gets blown away. – Dust Bowl of the 1930s created “deflation blowouts” in mid-western U.S. – Deflation is a problem in agricultural areas and in deserts. – Leaves behind coarse gravel and pebbles called: Desert Pavement.

9. Soil that is experiencing deflation.

10. Deflation blowouts in New Mexico

11. Oklahoma, 1930s Dust Bowl

12. Desert Pavement

13. Wind Abrasion: When particles of sand rub against the surface of rocks or other materials. – Sand contains quartz – a hard mineral that wears away rock. – Characteristics of wind abrasion: Rocks are pitted and grooved. Rocks become polished on windward side and develop smooth surfaces with sharp edges.

14. Wind Ventifacts: Rocks shaped by windblown sediments. – “Arches” – “Pillars”

15. Wind Wind Deposition: When wind velocity slows down, particles are deposited. Dunes: A pile of wind blown sand. – Dunes develop where an object – rock, landform, vegetation – blocks forward movement of particles. – Sand continues to be deposited as long as winds blow in one direction.

16. Wind Dune Profile: The side from which the wind is blowing will have a gentler slope: “Windward side.” – The steeper side is called the “Leeward side” and is protected from the wind. Windward Leeward

17. Wind Different Types of Dunes: Determined by wind direction, vegetation, wind velocity and the amount of sand. Dune Migration: Dunes move as long as wind blows sand hard enough to cause it to blow of the windward side and onto the leeward side.

18. Different Types of Sand Dunes

19. Wind Loess: Thick windward silt deposits. – Loess soils are very fertile because they contain abundant minerals and nutrients.