Содержание
- 2. 4- Deformation of Rocks A force causes stress on rocks Rocks near surface are elastic and
- 3. Three Types of Stress 4- Compression – pushes on rocks from opposite directions; shortens rocks Tension
- 4. 4- Earth’s Interior Internal heat source is energy causing metamorphism, uplift of crust (rock cycle) Seismic
- 5. 4- Earth’s Structure
- 6. 4- Earth’s Structure Crust – Less dense layer Lithosphere Mantle ~2,900 km (1,800 mi) thick Rocky,
- 7. Earth’s Interior Scientists hypothesize inner and outer core are iron-nickel alloy Outer core Metallic liquid Inner
- 8. 4- Earth’s Magnetic Field Inner core is solid, rotates faster than planet Electrically charged metallic ions
- 9. 4- Earth’s Magnetic Field
- 10. 4- Earth’s Internal Heat Geothermal gradient 25°C/km – temperature increases with depth Heat from radioactive decay
- 11. Earth’s Internal Heat 4-
- 12. 4- Continental Drift Idea that continents were once joined first proposed in 1596 by Dutch mapmaker
- 13. Continental Drift Alfred Wegener 1922 book on theory of continental drift More evidence than Taylor –
- 14. 4- Developing Theory of Plate Tectonics
- 15. 4- Developing Theory of Plate Tectonics Mapping ocean floor began in 1855 by U.S. Navy WW1
- 16. Mapping the Ocean Floor 4-
- 17. Magnetic Studies Igneous basalts contain iron mineral magnetite (Fe3O4) Magnetite is naturally magnetic Atoms orient parallel
- 18. Magnetic Reversal Figure 4.11 Page 101
- 19. Sea Floor Spreading Figure 4.12, Page 101 Mid oceanic ridges – magma erupts forming new ocean
- 20. Earthquakes Earthquake – release of energy that occurs when rocks are deformed past their elastic limit
- 21. Earthquake Locations Figure 4.13, Page 102
- 22. Earthquake Locations Epicenters along Mid Atlantic Ridge – magma rises up, buckles crust forming ridge Epicenters
- 23. Last Piece of Evidence for Continental Drift Magnetite rocks form/cool, atoms orient to magnetic north pole
- 24. Polar Wandering 4-
- 25. 4- Plate Tectonics and Earth’s Systems By 1960, 50 years of data proved sea floor spreading
- 26. Plate Tectonics and Earth’s Systems Plate Boundaries defined by epicenters Plates move over asthenosphere Slide past
- 27. 4- Plates
- 28. Plate Boundaries Movement generates compression, tension or shear 3 Types of Boundaries Divergent Convergent Transform See
- 29. 4- Plate Boundaries
- 30. 4- Movement of Plates Figure 4.17, Page 106
- 31. Surface Features & Plate Boundaries Convergent Oceanic-oceanic island arc; one plates undergoes subduction; may produce an
- 32. 4- Surface Features & Plate Boundaries Divergent Ocean ridges Rift valleys; may fill in with water
- 33. Divergent Plate Boundaries 4-
- 34. Convergent Plate Boundaries 4-
- 35. Transform Plate Boundary 4-
- 36. East African Rift Valley 4-
- 37. East African Rift Valley 4-
- 38. Future of African Continent? 4- http://www.pmfias.com/wp-content/uploads/2015/12/East-African-Rift-Valley-break-up.jpg
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