Prentice Hall EARTH SCIENCE

1. PrenticeHallEARTH SCIENCE TarbuckLutgens 

2. Unit2 Rock Cycle, Composition of Earth, and Plate Tectonics

3. Rocks 3.1 The Rock Cycle  Rocks solid mass of mineral-like matter occurring naturally.  Types of Rocks 1. Igneous rock formed by crystallization of magma.

4. Rocks 3.1 The Rock Cycle  Types of Rocks 2. Sedimentary rock formed from weathered, transported, deposited, compacted, and cemented rock. 3. Metamorphicrockrock transformed by heat, pressure, and/or chemically active fluids.

5. The Rock Cycle 3.1 The Rock Cycle  The relationship between the three rock types(igneous, sedimentary, and metamorphic) Magma molten material from Earth’s interior. Lava magma reaching the surface. Weathering rocks broken down by water, air, and living things. Sediment weathered pieces of rock

6. The Rock Cycle

7. Energy That Drives the Rock Cycle 3.1 The Rock Cycle  Heat from Earth’s interior forms igneous and metamorphic rock.  Weathering, transporting, and depositing rock are external sedimentary processes powered by the sun.

8. Layers Defined by Composition 8.4 Earth’s Layered Structure  Earth’s interior consists of three zones —the crust, mantle, and core.  Crust • Thin, rocky outer layer • Varies in thickness - Roughly 7 km in oceanic regions - Continental crust averages 8–40 km - Exceeds 70 km in mountainous regions

9. Layers Defined by Composition 8.4 Earth’s Layered Structure  Crust • Continental crust - Upper crust – mostly granitic rocks - Lower crust – mostly basalt rocks - Average density = 2.7 g/cm3 - Up to 4 billion years old

10. Layers Defined by Composition 8.4 Earth’s Layered Structure  Crust • Oceanic crust - Basaltic composition - Density about 3.0 g/cm3 - Younger (180 million years or less) than the continental crust

11. Layers Defined by Composition 8.4 Earth’s Layered Structure  Mantle • Below crust to a depth of 2900 kilometers • Uppermost mantle is the igneous rock peridotite (changes at greater depths).

12. Layers Defined by Composition 8.4 Earth’s Layered Structure  Core • Below mantle • Sphere with a radius of 3486 kilometers • Composed of an iron-nickel alloy • Average density of nearly 11 g/cm3

13. Layers Defined by Physical Properties 8.4 Earth’s Layered Structure  Lithosphere • Crust and uppermost mantle (about 100 km thick) • Cool, rigid, solid  Asthenosphere • Beneath the lithosphere • Upper mantle • To a depth of about 660 kilometers • Soft, weak layer that is easily deformed

14. Layers Defined by Physical Properties 8.4 Earth’s Layered Structure  Lower Mantle • 660–2900 km • More rigid layer • Rocks are very hot and capable of gradual flow.

15. Layers Defined by Physical Properties 8.4 Earth’s Layered Structure  Inner Core • Sphere with a radius of 1216 km • Behaves like a solid  Outer Core • Liquid layer • 2270 km thick • Convective flow of metallic iron within generates Earth’s magnetic field

16. Earth’s Layered Structure

17. An Idea Before Its Time 9.1 Continental Drift  Wegener’s - continental drift- the continents were once joined to form a supercontinent. • Pangaea, broke apart 200 million years ago and formed the present landmasses.

18. Breakup of Pangaea

19. An Idea Before Its Time 9.1 Continental Drift  Evidence • The Continental Puzzle • Matching Fossils - Fossil evidence (the same fossil organisms found on different landmasses)

20. An Idea Before Its Time 9.1 Continental Drift  Evidence • Rock Types and Structures - Several mountain belts end at one coastline, ant reappear across the ocean. • Ancient Climates

21. Matching Mountain Ranges

22. Glacier Evidence

23. Rejecting the Hypothesis 9.1 Continental Drift  A New Theory Emerges • Wegener could not explain exactly what made the continents move. New technology lead to led to a new theory called plate tectonics that explained the mechanism of the movement.

24. Earth’s Major Roles 9.2 Plate Tectonics  Plate tectonicsstates that the uppermost mantle and overlying crust, behave as a strong, rigid layer known as the lithosphere. • A plate - rigid section of the lithosphere that moves as a unit over the material of the asthenosphere. http://science.discovery.com/videos/100-greatest-discoveries-shorts-plate-tectonics.html

25. Types of Plate Boundaries 9.2 Plate Tectonics  Divergent boundaries(spreading centers) where two plates move apart.  Convergent boundarieswhere two plates move together.  Transform fault boundarieswhere two plates grind past each other without production/destruction of the lithosphere.

26. Three Types of Plate Boundaries http://uccpbank.k12hsn.org/courses/APEnvironmentalScience/course%20files/multimedia/lesson14/animations/2c_convergent_plates.html

27. Divergent Boundaries 9.3 Actions at Plate Boundaries  Oceanic Ridges and Seafloor Spreading • Oceanic ridges- elevated zones on the oceanfloor. The rifts at the crest of ridges represent divergent plate boundaries. Seafloor spreading produces new oceaniclithosphere. • Rift valleys are deep faulted structures found along divergent plate boundaries. They can develop on the seafloor or on land.

28. Spreading Center

29. Divergent Boundaries 9.3 Actions at Plate Boundaries  Continental Rifts • Spreading centers within a continent, land splits into two segments, forming a rift.

30. Convergent Boundaries 9.3 Actions at Plate Boundaries  subduction zone when an oceanic plate is pushed into the mantle beneath a second plate.  Oceanic-Continental • Denser oceanic slab sinks. • Pockets of magma rise. • Continental volcanic arcs caused by melting of subducted oceanic plate under a continent. • Examples include the Andes, Cascades, and the Sierra Nevadas.

31. Oceanic-Continental Convergent Boundary

32. Convergent Boundaries 9.3 Actions at Plate Boundaries  Oceanic-Oceanic • 2 oceanic plates converge, 1 descends under the other, this can forms volcanoes on the ocean floor. • Volcanic island arcs form as volcanoes emerge from the sea. • Examples include the Aleutian, Mariana, and Tonga islands.

33. Oceanic-Oceanic Convergent Boundary

34. Convergent Boundaries 9.3 Actions at Plate Boundaries  Continental-Continental • two continents collide, forming mountains. • Example - Himalayas.

35. Continental-Continental Convergent Boundary

36. Collision of India and Asia

37. Transform Fault Boundaries 9.3 Actions at Plate Boundaries  plates grind past each other without destroying the lithosphere.  Transform faults • the faults are parallel to the direction of plate movement.

38. Transform Fault Boundary

39. Evidence for Plate Tectonics 9.4 Testing Plate Tectonics  Hot Spots • A concentration of heat in the mantle capable of producing rising magma. • The Pacific plate moves over a hot spot, producing the Hawaiian Islands. • Hot spot evidence supports plate tectonic theory.

40. Hot Spot

41. Causes of Plate Motion 9.5 Mechanisms of Plate Motion  Convection in the mantle drives plate movement. • Convective flow - motion of matter resulting from changes in temperature.

42. Causes of Plate Motion 9.5 Mechanisms of Plate Motion  Slab-Pull and Ridge-Push • Slab-pull - plate motion in which cool, dense oceanic crust sinks and pulls lithosphere with it. It aids in convective. • Ridge-push – gravity aids the oceanic lithosphere in sliding down the ridge, contributing to plate motion. • http://earthguide.ucsd.edu/eoc/middle_school_t/t_tectonics/p_seafloor_spreading_2.html

43. Causes of Plate Motion 9.5 Mechanisms of Plate Motion  Mantle Convection • Mantle plumes - masses of super-hot mantle material that moves toward the surface. • Unequal distribution of heat causes convection in the mantle driving plate motion. • http://stemie.mcgraw-hill.com/submission/show/4155 or • http://www.youtube.com/watch?v=wjKjfs_a3xU

44. Mantle Convection Models