1 / 38

Changing Earth’s Surface

Changing Earth’s Surface. 8.1 Weathering. Changing Earth's Surface. Weathering The process that breaks down and changes rocks that are exposed at Earth’s surface. Erosion Moving weathered material from one place to another. Deposition Sediment is laid down at a new location. 2.

byron-pena
Download Presentation

Changing Earth’s Surface

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Changing Earth’s Surface

  2. 8.1 Weathering Changing Earth's Surface • Weathering • The process that breaks down and changes rocks that are exposed at Earth’s surface • Erosion • Moving weathered material from one place to another • Deposition • Sediment is laid down at a new location 2

  3. 2.1 Landforms Shaping the Earth with Water • Most erosion is done by water. • Rivers, ocean currents, and ice (p. 334, 342) 1

  4. Rivers

  5. Rivers • Streams and rivers are active systems that erode land, transport sediment, and deposit sediment. 2

  6. 8.2 Erosion and Deposition Deposition • Sediment and rock that are eroded and carried by river systems are transported and eventually deposited at a new location. • Oxbow lakes • Delta • Alluvial fans (Page 345) 1

  7. Flooding

  8. 8.2 Erosion and Deposition Flood • When the water level in a river rises above the usual height and overflows its banks • Floodplain: a wide, flat valley located along the sides of rivers and streams 2

  9. 8.2 Erosion and Deposition Levees • Protect area from flooding • Natural levees: long, low ridges formed by sediment carried by floodwaters and deposited along the floodplain • Artificial levees: human–made structures built to help control floodwaters (p. 348) 1

  10. Beaches

  11. 8.2 Erosion and Deposition Beaches • Landform consisting of loose sand and gravel • Dynamic, actively changing systems • Sand supplied by the continuous flow of rivers to oceans 4

  12. 8.2 Erosion and Deposition Erosion Features • Cliffs: formed by the cutting action of waves • Eroded cliffs move back from the shoreline and leave behind a flat area called a wave-cut platform • Sea caves, sea stacks, and sea arches can form when waves erode the softer portions of rocks. 3

  13. 8.2 Erosion and Deposition Longshore Current • Movement of the water that moves large amounts of sediment along coasts 2

  14. 8.2 Erosion and Deposition Erosion Prevention • Shoreline armoring: retaining walls, harbor channels, and groins • Changes natural shoreline processes but is necessary to prevent collapse of cliffs or the complete destruction of a beach. (p. 349) 1

  15. Glaciers

  16. 8.2 Erosion and Deposition Glaciers • Large masses of ice and snow • Form in areas where amount of annual snowfall is greater than the meltoff • Formation takes hundreds to thousands of years • Movement is about 2.5 cm/day 2

  17. 8.2 Erosion and Deposition Glaciers (cont.) • Valley glaciers (alpine glaciers): form in existing stream valleys high in the mountains • Continental glaciers (ice sheets): cover entire land areas, only located in Antarctica and Greenland • Video (Page 350) 1

  18. Glaciers shape the land

  19. 8.2 Erosion and Deposition Glaciers and Erosion • Glaciers erode surfaces as they pass over them. U-shaped valleys. • Trapped rocks and boulders at the bottom of the ice create grooves and scratches as the glacier moves. • Grooves and scratches show the direction the glacier was moving. (striations) 2

  20. 8.2 Erosion and Deposition Deposition and Glaciers • Till: sediment deposited by glacier. Often builds up along the sides and fronts of glaciers into long, high ridges called moraines • Outwash: sediment deposited by glacial river; consists mostly of sand and gravel (p.351) 1

  21. MassWasting

  22. 8.2 Erosion and Deposition Mass Wasting • Form of erosion caused by gravity • Downhill movement of rocks and/or soil in one large mass • Usually occurs when the ground is saturated with rainwater but can be triggered by vibrations from earthquakes, heavy machinery, and blasting • Steeper the slope of hillside, the more likely mass wasting will occur 2

  23. 8.2 Erosion and Deposition Mass Wasting (cont.) • Landslides:rapid, gravity-caused events that move soil, loose rock, and boulders • Mudslides: mixtures of soaked soil and rock • Rock falls: loosened rock falling from steep cliffs • Slumps: a block of rock and overlying soil slide down as one large mass • Creep: sediment moves slowly downhill • (p.343) 1

  24. Climate & Erosion

  25. 8.2 Erosion and Deposition Climate and Erosion • Climate determines amount of water a region receives • Regions with large amounts of rain more likely to experience mass wasting • Presence of thick vegetation on slopes tends to prevent landslides because the plants’ root systems hold sediment in place (p.344) 1

More Related