Do Now: - In your review books, answer questions # 1-4 on page 213. We will go over the answers in 5 minutes. Answers: Hand in your Chemical Weathering Labs

Erosion: Deposition: AIM: Erosional and Depositional systems Do Now: In your notebooks… 1) Define the two terms below in your own words. 2) Explain how the two terms work together. The movement/transport of material from one place to another (picking material up) The dropping/placement/leaving behind of material (putting material down)

Why do materials (rocks, sediment or soil) on Earth start to erode (picked up)? - erosion occurs when an agent such as gravity, water, wind, waves or ice push on the material. Why can these agents of erosion move the material? - these agents have energy which allows them to move materials. More energy = Larger materials move

What causes materials to be deposited (put down)? -Deposition occurs when the agents energy decreases (slows down or stops moving). -If the agent slows down or stops moving, the material stops moving. Erosion picks up materials on Earth moving them to a new place. When the agent of erosion stops, the materials are deposited in this new area.

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 cut and polish exposed rock. Double Arch, Arches National Park Utah Why? Nothing to block the wind and there is a lot of small sediment

II. Wind Depositional Features - Wind grades (sorts) the sediment as it is deposited. As wind looses energy, larger particles are dropped first. - Smaller particles are on top - Larger particles are on the bottom

A. Sand Dunes are a depositional feature created by wind. - Sand dunes have a long gentle slope and a short steeper slope. Wind smooth's out the gentle sided, called the windward side. As sediment is pushed to the top of the dune, it falls over creating the steeper short side, sheltered side. WIND Long gentle slope

B. Crossbeding – lithified (compacted and cemented) sand on the sheltered side of a sand dune.

III. Wind erosion Problems -Human activities that remove natural vegetation, such as farming, logging, and construction, have greatly accelerated wind erosion as seen in the 1930’s dust bowl. 1930’sDust Bowl Why would removing plants help wind erode more materials? Plan roots hold together the soil keeping it anchored and safe from erosion

Closure Obtain a worksheet on Wind (back top bin). 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 removed necessary soils that farmers needed to grow their crops. Without these crops, there was nothing to help the soil together and more erosion occurred. 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? The sediment should look graded or sorted. Smaller Larger

Answers from the back: Closure: In your review books, Read pages and the answer questions 1-7 on pages Answers: