Constructive or Destructive?

1. Constructive or Destructive? Changing Earth’s Surface

2. Constructive? Destructive? • What do these two terms mean? • Constructive: • Destructive: • What, on Earth, would you consider to be constructive and destructive? • What causes the constructive and destructive events on Earth?

3. As you know, tectonic plate boundaries are responsible for many changes on Earth. What are some of those features and events? Which of these are Constructive? Destructive? Tectonic Plate Boundaries

4. Volcanoes • Are Volcanoes constructive or destructive? • Give an example of when they could be one or the other, or even both.

5. Ring of Fire • The Ring of Fire refers to the large amount of volcanoes that wrap around the Pacific Ocean. • That sounds like a lot of new land being formed. How long do you think it takes to develop life on those islands?

6. What is a fault? • We are still dealing with compression, tension, and shear stress. • Faults and animations • More faults and animations • Hanging and Foot walls

7. Caused by tension Caused by compression Caused by shear stress The Three Types of Faults

8. Mountains • How were mountains formed at tectonic plate boundaries? • How else do mountains form?

9. Mountains • By the end of this section you should have recorded information on • Fault-block mountains • Upwarped mountains • Volcanic mountains • Folded mountains

10. Aren’t All Mountains the Same? • Check out this little video about the types of mountains. • Mountains

11. The Four Types of Mountains • Fault Block Volcanic

12. The Four Types of Mountains • Folded Upwarped

13. Can You Make It? • Mount Everest Game

14. What Do You Know? • In your assigned groups, answer the four questions with as many good answers as possible. • You are competing for bonus points, so don’t discuss your answers too loudly!!

15. Weathering • Weathering, in general, is the breakdown of rock into smaller and smaller pieces. • You may also consider the movement of material due to weathering processes

16. Mechanical Weathering • Mechanical weathering is the breakdown of rock by PHYSICAL means, such as ice, wind, water, gravity, plants, and animals

17. Mechanical Weathering - Ice • When water seeps into rocks and freezes, it expands. • When it expands, it breaks up the rocks.

18. Mechanical Weathering - Wind • Wind causes abrasion when it blows smaller rocks and sand against other rocks, which wears them down. • This action is like sandpaper.

19. Moving water causes abrasion when it carries small rocks and particles with it, which rub against other rocks, wearing them down. This action is like sand paper. Mechanical Weathering - Water

20. Mechanical Weathering - Water • Underground water flow can also cause sink holes.

21. Mechanical Weathering - Gravity • Gravity causes rocks and smaller particles to fall or tumble, causing abrasion when they rub against other rocks and wear them down. • This action is like sandpaper.

22. Mechanical Weathering – Plants and Animals • Plant roots move into existing cracks and then continue to grow, breaking up the rock. • Plant roots (which usually help hold soil) can cause the soil to loosen and erode in some areas. • Animals create burrows and tunnels through the soil, such as ants, worms, and moles.

23. Chemical Weathering • Chemical weathering is the breakdown of rocks and minerals into new substances by CHEMICAL means such as water, acids, air, and soil.

24. Chemical Weathering - Water • Water, even though it may be a slow process, can dissolve minerals and rocks. • This process is similar to you dissolving sugar in a glass of water.

25. Chemical Weathering – Acid Precipitation • Precipitation naturally contains small amounts of acid (such as sulfuric and nitric acids) which break down materials they come in contact with. • This is worse in areas with lots of factories.

26. Chemical Weathering – Acids in Ground Water • Sometimes water in the ground contains weak acids (such as carbonic or sulfuric acids) which dissolve rocks like limestone. • This process is what creates caves and caverns.

27. Chemical Weathering – Acids in Living Things • Organisms such as lichens, which grow on rocks (and trees), produce acids as a waste product. • These acids slowly break down the rocks. • This is how soil starts to form from rocks.

28. Chemical Weathering - Air • Oxygen in the air reacts with iron to create iron oxide – rust, which can be seen in rocks that contain iron.

29. Differential Weathering • When softer, less weather resistant rocks wear away and expose harder, more weather resistant rocks. • This is Devil’s Tower, which is the remains of the inside of a volcano.

30. Weathering Rate by Size • The smaller a rock is, the faster it will erode • Consider: dissolving a sugar cube or regular sugar

31. KEEP IN MIND... • The next slides of wave erosion, wind erosion, glaciers, and mass movement are all examples of mechanical weathering!!

32. Wave Energy • Waves carry a lot of energy, which is capable of moving large amounts of material.

33. Wave Energy - Beaches • Beaches are any area of shoreline made up of materials deposited by waves.

34. Wave Energy - Sea Cliffs • Waves erode and cut into the rock, creating steep slopes.

35. Wave Energy - Sea Arches • Sea Arches form when waves continue to erode the rock and cut through

36. Sea stacks used to be connected to the mainland, but have been eroded. Wave Energy - Sea Stacks

37. Wind Erosion • Wind is powerful and can change the landscape. • The changes depend on the amount of wind and the material that makes up the land.

38. Dunes are mounds of wind deposited sand that continue to move around. Wind Erosion - Dunes

39. A glacier, in general, is a large mass of moving ice. Glaciers

40. Alpine Glaciers • Alpine glaciers form in mountainous areas. • These carve out rugged features in mountains.

41. Continental Glaciers • Continental Glaciers are large ice sheets that can cover millions of square kilometers. • Antarctica is covered by a glacier more than 1.5 X the size of the U.S. and that is even up to 4,000 meters thick in some places!

42. Glacial Deposits • Glacial deposits are all of the material that is carried and deposited by glaciers.

43. Glacial Deposits – Striated Drift • Striated Drift means that the rocks and material have been sorted out by size and are in layers.

44. Glacial Deposits – Till Deposits • Till deposits is unsorted material deposited by the glacier.

45. Mass Movement • Mass movement is the movement of any material down slope. • Gravity controls mass movement. • It can be a slow or fast process.

46. Mass Movement – Rock Fall • Loosened and exposed rock may fall in chunks or slide down a slope. • This happens quickly.

47. Mass Movement - Landslide • Large amounts of material move downward quickly.

48. Mass Movement - Mudflow • Mudflows are large amounts of flowing mud. • This happens when water combines with rocks and soil.

49. Mass Movement - Lahars • Lahars are mudflows made from water, soil, and volcanic ash. • This material is similar to concrete.

50. Mass Movement - Creep • Creep is a slow movement of areas of land.