1. What is the composition of soil?

2. Essential Question: How is soil formed?
Standard:
S6E5h. Describe soil as consisting of weathered rocks and decomposed organic material.

3. Composition of Soil Air Water Soil Particles
Weathered rock and mineral particles such as clay, sand, and silt
Decomposed organic matter

4. Composition of Soil

5. Label your diagram

6. The rock and mineral fragments come from rocks that have been weathered.
Most of these fragments are small particles of sediment such as clay, silt, and sand.

8. Organic matter is the remains of once living organisms.
Organic matter can come from plant leaves, stems, roots, animals, and microorganisms.

9. Organic Matter in Soil

10. After organic matter gets into soil, fungi and bacteria cause it to decay (decompose). The decayed organic matter turns into humus, a source of nutrients for plants.

11. Soil Layers (Horizons)
Organic Matter

12. Soil Layers (Horizons)
Top Soil (Horizon A)
The topsoil has more humus and fewer rock and mineral particles than the other layers.

13. The subsoil has less organic matter and is lighter in color because it has less humus. Therefore, it is less fertile.
Subsoil (Horizon B)

14. Parent Rock (Horizon C)
Horizon C consists of partially weathered rock that gave rise to the soil horizons above it (parent rock).
Parent Rock (Horizon C)

15. Soil Layers (Horizons)
Most Fertile
Least Fertile

16. Soil can take thousands of years to form and is different depending on where it is formed.

17. Activating Strategy: Watch Ice Age: Scrat Continental Crack Up video clip and have students either answer individually or with a partner the following questions:
(1) Which part(s) of Scrat’s adventure is accurate? (2) Which part(s) of Scrat’s adventure is not accurate?
Share and discuss with the class.

18. Essential Question: How does the constant movement of lithospheric plates cause major geological events on the earth’s surface?
Standard:
S6E5e. Recognize that lithospheric plates constantly move and cause major geological events on the earth’s surface.

19. One of the accurate events shown in Scrat’s Continental Crack Up is that the continents were once joined together but moved apart.
An inaccurate representation is that the break-up and moving of the continents occurred quickly.

20. In 1912, a man named Alfred Wegener proposed that at one time the continents were joined together, but over time have moved slowly to their current locations. His hypothesis is called Continental Drift.

21. Wegener called the once connected large landmass Pangaea.

22. Other than the “puzzlelike” fit of the separated continents, what evidence was used to support the theory of continental drift?

23. Rock, fossil, and climate clues were the main types of evidence for continental drift. Advances in technology have provided additional clues to help explain continental drift.

24. Continental Drift Video Continental Drift Song
Continental Drift Song

25. The theory of seafloor spreading explains the formation of the underwater mountain ranges.

26. Seafloor Spreading
Hot, less dense material below the Earth’s crust rises toward the surface at the mid-ocean ridges.
The seafloor spreads apart and magma is forced upward pushing the older seafloor away from the ridge in opposite directions.
The magma becomes solid as it cools and sinks forming new seafloor.

27. Seafloor Spreading

28. Seafloor Spreading Video Clip

29. A new theory that combined continental drift and seafloor spreading was developed known as the theory of Plate Tectonics.

30. The theory of Plate Tectonics states that the Earth’s crust and part of the Upper Mantle are broken into plates (sections) that move.

31. Lithosphere – Crust and Upper Layer of the Mantle
The “plates” of the lithosphere float and move around on the asthenosphere.
Inner Core Solid
Outer Core
Liquid
Mantle
Lithosphere – Crust and Upper Layer of the Mantle
Layer of the Mantle (asthenosphere) that consists of hot rock of tar-like consistency, which slowly moves

32. Plate Boundary Map

33. When plates move, they can interact in several ways:
They can move toward each other
They can pull apart from each other
They can slide alongside one another
The result of plate movement can be seen at plate boundaries.

34. Divergent Plate Boundary: two plates are moving apart and new crust is created

35. Divergent Plate Boundary: Continental Plate Continental Plate
When two continental plates spread apart rifts (cracks) begin. Magma can rise and squeeze between the cracks sometimes forming volcanoes.

36. Divergent Boundary in Iceland

37. Divergent Boundary in Africa

38. Divergent Plate Boundary: Continental Plate Continental Plate
Continental Crust
Continental
Crust
Ridge

39. Divergent Plate Boundary: Oceanic Plate Oceanic Plate
When two oceanic plates spread apart magma is forced upward pushing the older seafloor away in opposite directions forming a ridge.

40. Divergent Plate Boundary: Oceanic Plate Oceanic Plate

41. Divergent Boundary: Mid-Atlantic Ridge

42. Divergent Plate Boundary: Oceanic Plate Oceanic Plate
Oceanic Crust
Oceanic
Crust
Mid-Ocean Ridge

43. Convergent Plate Boundary: two plates collide

44. Convergent Plate Boundary: Oceanic Continental

45. Convergent Plate Boundary: Oceanic Continental
The denser oceanic plate subducts (goes down), under the continental plate into the mantle.
A deep sea trench is created where one plate bends and sinks.
High temperatures cause rock to melt around the subducting plate as it goes under the other plate
Newly formed magma is forced upward along these plate boundaries, forming volcanoes.

46. Convergent Plate Boundary: Oceanic Continental

47. Convergent Boundary
Andes Mountains

48. Convergent Plate Boundary: Oceanic Continental
Volcano
Oceanic Crust
Continental Crust
Trench

49. Convergent Plate Boundary: Continental Plate Continental Plate the crust buckles and pushes upward forming mountains

50. Convergent Plate Boundary Continental Continental

51. Convergent Plate Boundary Continental Continental
Earthquakes are common at these convergent boundaries, but volcanoes do not form because there is no, or little, subduction.

52. Convergent Plate Boundary Continental Continental
Himalayan Mountains

53. Convergent Plate Boundary Continental Continental
Continental Crust
Continental Crust
Mountains
Volcanoes do not form because there is no subduction when continental plates collide; therefore, no melting of the crust
Why no volcanoes?

54. Convergent Plate Boundary: Oceanic Oceanic

55. Convergent Plate Boundary: Oceanic Oceanic
A colder, older, denser oceanic plate subducts (goes down), under another oceanic plate into the mantle.
A deep sea trench is created where one plate bends and sinks.
High temperatures cause rock to melt around the subducting plate as it goes under the other plate
Newly formed magma is forced upward along these plate boundaries, forming volcanoes.
Over millions of years, erupted lava piles up until it rises above sea level to form volcanic islands.

56. Convergent Plate Boundary: Oceanic Oceanic

57. Convergent Plate Boundary: Oceanic Oceanic
Underwater Volcanoes and Volcanic Islands
Oceanic Crust
Oceanic Crust
Trench

58. Transform Plate Boundary: Plates Slide Past Each Other

59. Transform Boundary
Plates move in opposite directions or in the same direction at different rates
When one plate slips past another plate suddenly, earthquakes occur
These plate boundaries do not destroy or build up Earth’s crust.

60. Transform Boundary

61. Transform Boundary: San Andreas Fault in California

62. Transform Boundary
Earthquakes

63. Volcano

64. Volcano
A volcano is a mountain that forms when layers of lava and ash erupt and build up
Volcanoes form where plates are moving apart, moving together, and at locations called hot spots.

65. Volcano
When the pressure from the rising magma in a volcano becomes too much, it erupts gases, ash, and lava

66. Ring of Fire Eruption Song:

67. Earthquakes are sudden breaks in crust continuously stressed by plate movement.

68. Along plate boundaries, the Earth’s lithosphere fractures along faults
Along plate boundaries, the Earth’s lithosphere fractures along faults. As plates move, blocks of crust shift along the faults. There are different kinds of faults.

69. Tsunamis are ocean waves caused by earthquakes and landslides that occur near or under the ocean in oceanic crust.

70. The lowest point of a tsunami wave hits inland first and creates a vacuum that sucks up the coastal water near the shoreline away from the land, exposing the sea floor. This is the first indicator that the destructive part of the wave is on its way.

71. As a tsunami’s waves travel across deep water they may be only a foot or so high and hard to detect. Once it reaches inland the surge can reach heights of 100 feet or more.
It is a massive wall of water that reaches land and can cause incredible destruction and loss of life.