Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity Copyright © Houghton Mifflin Harcourt Publishing Company 1

Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity Florida Benchmarks SC.6.N.3.4 Identify the role of models in the context of sixth grade science benchmarks. SC.6.E.6.1 Describe and give examples of ways in which Earth’s surface is built up and torn down by physical and chemical weathering, erosion, and deposition. SC.6.E.6.2 Recognize that there are a variety of different landforms on Earth’s surface such as coastlines, dunes, rivers, mountains, glaciers, deltas, and lakes and relate these landforms as they apply to Florida. Copyright © Houghton Mifflin Harcourt Publishing Company 2

Gone with the Wind How can wind shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity Gone with the Wind How can wind shape Earth? When wind moves soil, sand, and rock particles, it acts as an agent of erosion. The grinding and wearing down of rock surfaces by other rock or sand particles is abrasion. Rocks can become smooth and polished from abrasion. Copyright © Houghton Mifflin Harcourt Publishing Company 3

How can wind shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can wind shape Earth? The removal of fine sediment by wind is called deflation. Desert pavement results when wind carries soil and fine sediment away from an area, leaving only rocks behind. Copyright © Houghton Mifflin Harcourt Publishing Company 4

How can wind shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can wind shape Earth? How does desert pavement form? Copyright © Houghton Mifflin Harcourt Publishing Company 5

How can wind shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can wind shape Earth? Dunes are mounds of wind-deposited sand common in deserts and along the shores of lakes and oceans. Dunes usually move in the same direction the wind is blowing. Wind moves material up the slope and deposits materials on the other side. Copyright © Houghton Mifflin Harcourt Publishing Company 6

How can wind shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can wind shape Earth? Why is the slip face of a dune steeper than the windward slope? Copyright © Houghton Mifflin Harcourt Publishing Company 7

How can wind shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can wind shape Earth? Loess are thick deposits of windblown, fine-grained sediment. The fine-grained material in loess can be carried far away from the original source and is a valuable resource for forming good soils. Copyright © Houghton Mifflin Harcourt Publishing Company 8

Groovy Glaciers What kinds of ice shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity Groovy Glaciers What kinds of ice shape Earth? A glacier is a large mass of moving ice that forms by the compacting of snow by natural forces. Glaciers move downhill by gravity and cause erosion. As a glacier melts, it deposits the materials it carries. Glacial drift is the general term for all materials carried and deposited by a glacier. Copyright © Houghton Mifflin Harcourt Publishing Company 9

What kinds of ice shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity What kinds of ice shape Earth? An alpine glacier is a glacier that forms in a mountainous area. Glaciers can erode a V-shaped valley caused by a stream into a U-shaped glacial valley. Cirques, arêtes, horns, and hanging valleys are landforms caused by alpine glaciers. Copyright © Houghton Mifflin Harcourt Publishing Company 10

What kinds of ice shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity What kinds of ice shape Earth? Continental glaciers are thick sheets of ice that may spread over large areas, including across entire continents. Continental glaciers flatten and smooth land. Erratics and drumlins are landforms caused by continental glaciers. Copyright © Houghton Mifflin Harcourt Publishing Company 11

Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity Melting the Ice During the last Ice Age, an ice dam held back the water of Glacial Lake Missoula. The dam broke and emptied the entire lake at once, forming huge waterfalls, deep canyons, and tall ripple marks in the land. Lake Missoula reformed and flooded about 40 more times. Copyright © Houghton Mifflin Harcourt Publishing Company 12

Slippery Slopes How can gravity shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity Slippery Slopes How can gravity shape Earth? Gravity influences the movement of water and ice. Gravity also moves rocks and soils down slope. Mass movement is the shifting of materials due to gravity. Creep is the extremely slow movement of materials down slope. Copyright © Houghton Mifflin Harcourt Publishing Company 13

How can gravity shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can gravity shape Earth? Rapid mass movements usually happen on steep slopes and are the most destructive. A rockfall happens when loose rocks fall down a steep slope. A landslide is the sudden and rapid movement of a large amount of material down slope. Copyright © Houghton Mifflin Harcourt Publishing Company 14

How can gravity shape Earth? Unit 2 Lesson 3 Erosion and Deposition by Wind, Ice, and Gravity How can gravity shape Earth? A mudflow is a rapid movement of a large mass of mud. Mudflows happen when a large amount of water mixes with soil and rock. Deforestation, volcanic eruptions, and heavy rains can all create mudflows. Copyright © Houghton Mifflin Harcourt Publishing Company 15