Review weathering and erosions as well as the different types of each! Warm Up Review weathering and erosions as well as the different types of each! http://www.youtube.com/watch?v=lyysL02ZvQ8

WHAT HAPPENED HERE? Today we’re going to be investigative environmentalists working to find out what happened to the land.

This calls for an expert! We are about to explore some mysterious land changes, and I need your help determining what happened. We need three groups of experts: one for Erosion by Gravity, one for Erosion by Wind, and one for Erosion by Glaciers. In your groups, use your text book to review and record 5 key facts about your expertise. Pick some key vocabulary words to record as well. Work together, I need all the help I can get!

Share your knowledge Elect a speaker from your group of experts. Share your facts with the class. Let’s briefly discuss each of the categories of erosion before we begin our investigation. Let’s uncover the truth!

Erosion by GRAVITY Mass Movement: any type of erosion that happens as gravity moves material down-slope. This happens either very slowly or very rapidly (often by catastrophic event). SLUMP: when a mass of material slips down along a curved surface. This occurs when a slope becomes too steep to support the sediment above it. Rock and soil slips downward. CREEP: when sediments slows shift their position downhill. Common in areas of frequent freezing and thawing. ROCK FALLS: occurs when blocks of rock break loose from a steep slope tumble through the air. As they crash into other rocks, more sediment breaks loose and tumbles down MUDFLOWS: usually occurs in areas with thick layers of loose sediment, heavy rains causes it to turn thick and pasty while gravity causes it to slip down a slope.

Erosion by GLACIERS A large mass of ice and snow moving on land under its own weight is a glacier. Glaciers are agents of erosion. Plucking: when water fills the cracks in a rock but then freezes, it can lift out pieces of the rock in the ice. Scouring: as a glacier moves, hard rock can be dragged along, making striations and scarring rock. What is a MORAINE DEPOSIT? What is an OUTWASH DEPOSIT? What is an ESKER? Continental Glaciers: huge masses of ice, snow, and fragments where ice and snow are thick and abundant. Valley Glaciers: can occur where temperatures are warmer, these grow slowly and creep along, typically on mountain tops.

KEY VOCAB: Loess, dune, moving dune Erosion by WIND Deflation: when wind erodes by deflation, it blows across loose sediment, removing small particles such as silt, sand, and clay. Abrasion: when windblown material strikes rock, the surface of that rock gets scraped and worn away over time. *these two occur most commonly in deserts, beaches, and plowed fields. Sandstorms: forceful winds cause more and more grains to rise into the air and a low cloud of sandy particles can form. Duststorms: when soil dries out it can be eroded by wind. This soil is mostly clay or silt sized particles that are moved high into the air. KEY VOCAB: Loess, dune, moving dune

Are we ready to use scientific thought to infer what happened?

Case #2130 Location: Nachterstedt, Germany, Saturday, July 18, 2009. What evidence can we gather from these photos? What caused this damage?

Case #6210 Located in Montana What are some features we can identify before we decide what caused these formations?

Case #42j3 Located near the coast What are some observations we can make to determine what happened here?

Case #k810 located east of Valdez Alaska. What is the name of what we see? What caused it?

Case #50073 These deposits were found near the Yellow River in China. Notice that they are fine grained and unlayered! What is the name of this deposit? What was the mechanism that caused this?

Case #7310 Location: Southern Egypt What is this a picture of? What caused these sediments to pile up here? What direction did the movement occur? How can we tell?

Case #198 We were informed that these results formed very slowly. What force is causing these deformations? What is the name of the type of erosion happening here?