1. Class 1: Plate Tectonics Review Today’s topics:  Earth’s compositional layers  Plate tectonics: theory & actions

2. Earth’s Compositional Layers Atmosphere & Hydrosphere Crust Mantle Core

3. Earth’s Atmosphere & Hydrosphere

4. Earth’s Crust more dense relatively light CRUST

5. Earth’s Mantle MANTLE more dense than crust CRUST

6. Earth’s Core highest density CRUST MANTLE CORE

7. Earth’s Magnetic Field rocky core Earth Requirements for magnetic field: 1. rotation 2. heat flow, convecting fluid 3. a mobile conductor (iron or metallic hydrogen)

8. Global Earthquake Locations

9. Global Volcano Locations

10. Linking Observations

11. Continental Drift

12. Continental Drift (movie)

13. Ages of the Ocean Floor Ma = Million years ago 1 billion years = 1 Gyr 1 million years = 1 Myr 1 thousand years = 1 kyr

14. Fig.4.11a Heat Flow Warm colors = higher heat flow Cool colors = lower heat flow high at ocean ridges

15. Global Topography and Bathymetry ocean ridges

16. The Puzzle Solved….. earthquake locations volcano locations sea floor age sea floor bathymetry + heat flow too!

17. Earth’s Tectonic Plates

18. Earth’s Tectonic Plates (movie)

19. Lithosphere & Asthenosphere

20. Plate Boundaries

21. Divergent Plate Boundaries

22. Seafloor Spreading (movie)

23. Convergent Plate Boundaries 1 2 3

24. Seafloor Subduction (movie)

25. Transform Plate Boundary strike-slip faulting

26. Transform Faulting (movie)

27. Plate Boundaries Hotspots

28. Fig.4.20 Hot Spots hot spot trail

29. Fig.4.22a Hot (not molten) rising plume lithosphere Direction of plate motion Formation of Island Chains V1 melting at base of crust V1

30. Fig.4.22a Formation of Island Chains (movie)

31. Fig.4.22b Example: The Hawaiian Chain Fixed hot spot

32. Earth’s crust is divided into plates Plates move relative to one another at 1-15 cm/yr Plate interiors are largely undisturbed Deformation is concentrated at plate boundaries Consequences: Plate tectonics constantly change Earth’s surface Earthquakes occur mostly at plate boundaries Volcanoes occur mostly at plate boundaries Basic Premise of Plate Tectonics

33. 1.Examine volcanic rocks Q: what was the source for magma? How do we explore Earth’s interior? 2. Observe seismic waves from earthquakes Q: where are the layers, what are their densities? 3. Examine meteorites Q: what are they made of? like the core? 4. Existence and behavior of geomagnetic field Q: what is the core doing?

34. Satellites1 (Moon) Size (radius)6378 km Bulk density5.5 g/cm 3 (4.1 g/cm 3 uncompressed) Surface gravity 9.8 m/s 2 Tectonism, volcanismyes (today) Rotation 1 day Orbit365.25 days Atmosphere 78% N 2, 21% O 2 Surface pressure1 atm Surface temperature 20°C (diurnal, seasonal changes) Plate tectonicsyes Wateryes Earth