1. EARTH SCIENCE

2. An Idea Before Its Time Continental Drift  Wegener’s __________________ ________________________hypothesis stated that the continents had once been joined to form a single supercontinent. Wegener proposed that the supercontinent, ___________________, began to break apart 200 million years ago and form the present landmasses.

3. Breakup of Pangaea

4. An Idea Before Its Time Continental Drift  Evidence The Continental Puzzle Matching __________________ - Fossil evidence for continental drift includes several fossil organisms found on different ______________________.

5. An Idea Before Its Time Continental Drift  Evidence Ancient _____________ ________________Types and Structures - Rock evidence for continental exists in the form of several ______________belts that end at one coastline, only to reappear on a landmass across the ocean.

6. Matching Mountain Ranges

7. Glacier Evidence

8. Rejecting the Hypothesis 9.1 Continental Drift  A New Theory Emerges Wegener could not provide an explanation of exactly what made the continents move. News technology lead to findings which then lead to a new theory called ______________________ __________________.

9. Plate Tectonics  According to the plate tectonics theory, the uppermost ______________, along with the overlying ________________, behaves as a strong, rigid layer. This layer is known as the _____________________. A _____________________is one of numerous rigid sections of the lithosphere that move as a unit over the material of the __________________________.

10. Plate Tectonics  _____________boundaries (also called ______________centers) are the place where two plates move ______________.  ______________boundaries form where two plates move ______________.  _________________fault boundaries are margins where two plates ______________past each other without the production or destruction of the _______________________.

11. Three Types of Plate Boundaries

12. Actions at Plate Boundaries  Oceanic Ridges and Seafloor Spreading ________________ _________________are continuous elevated zones on the floor of all major ocean basins. The rifts at the crest of ridges represent divergent plate boundaries. ___________ ____________are deep faulted structures found along the axes of divergent plate boundaries. They can develop on the seafloor or on land. ______________ _____________produces new oceanic lithosphere. ________________Boundaries

13. Spreading Center

14. 9.3 Actions at Plate Boundaries  _________________ ________________ When spreading centers develop within a continent, the landmass may split into two or more smaller segments, forming a rift. Divergent Boundaries

15. Actions at Plate Boundaries  A ______________zone occurs when one oceanic plate is forced down into the mantle beneath a second plate. Denser oceanic slab sinks into the _______________.  ______________-______________ Pockets of magma develop and rise. ______________ ________________ ________form in part by volcanic activity caused by the subduction of oceanic lithosphere beneath a continent. Examples include the Andes, Cascades, and the Sierra Nevadas. ___________________Boundaries

16. Oceanic-Continental Convergent Boundary

17. Actions at Plate Boundaries Two oceanic slabs ___________and one descends beneath the other.  ______________-____________ This kind of boundary often forms ______________on the ocean floor. ______________________________form as volcanoes emerge from the sea. Examples include the Aleutian, Mariana, and Tonga islands. Convergent Boundaries

18. Oceanic-Oceanic Convergent Boundary

19. Actions at Plate Boundaries When _______________plates contain continental material, two continents collide.  _____________-_______________ This kind of boundary can produce __________ ________________ranges, such as the Himalayas. Convergent Boundaries

20. Continental-Continental Convergent Boundary

21. Collision of India and Asia

22. Actions at Plate Boundaries  At a transform fault boundary, plates _______past each other without destroying the _________________.  ______________ _______________ Most join two segments of a mid-ocean ridge. At the time of formation, they roughly parallel the direction of plate movement. They aid the movement of oceanic crustal material. ____________ ___________ Boundaries

23. Transform Fault Boundary

24. Evidence for Plate Tectonics Testing Plate Tectonics  ___________________________is the natural remnant magnetism in ____________bodies; this permanent magnetization acquired by rock can be used to determine the location of the magnetic poles at the time the rock became magnetized. ______________polarity—when rocks show the _____________magnetism as the present magnetism field ______________polarity—when rocks show the ____________magnetism as the present magnetism field

25. Evidence for Plate Tectonics Testing Plate Tectonics  The discovery of strips of __________________polarity, which lie as mirror images across the ocean ridges, is among the __________________evidence of seafloor spreading.

26. Polarity of the Ocean Crust

27. Testing Plate Tectonics  _______________Patterns Scientists found a close link between deep-focus earthquakes and ____________trenches. The absence of deep-focus earthquakes along the oceanic ridge system was shown to be consistent with the new theory.

28. Testing Plate Tectonics  Ocean ______________ The data on the ages of seafloor sediment confirmed what the seafloor spreading hypothesis predicted. The _________________oceanic crust is at the ridge crest, and the ______________________oceanic crust is at the continental margins.

29. Testing Plate Tectonics  Hot Spots A ___________ _____________is a concentration of heat in the ________________capable of producing ___________________, which rises to Earth’s surface; The Pacific plate moves over a hot spot, producing the _____________________Islands. Hot spot evidence supports that the plates move over the Earth’s surface.

30. Mechanisms of Plate Motion  Scientists generally agree that _________________occurring in the mantle is the basic driving force for plate movement. ______________ ______________is the motion of matter resulting from changes in _________________________. Causes of Plate Motion

31. Mechanisms of Plate Motion  Slab-Pull and Ridge-Push __________________________ causes oceanic lithosphere to slide down the sides of the oceanic ridge under the pull of gravity. It may contribute to plate motion. ______________________is a mechanism that contributes to plate motion in which cool, dense oceanic _________________sinks into the mantle and “pulls” the trailing lithosphere along. It is thought to be the primary downward arm of convective flow in the mantle.

32. Mechanisms of Plate Motion  Mantle Convection The ______________ ________________of heat within Earth causes the thermal convection in the mantle that ultimately drives plate motion. _______________________are masses of hotter-than-normal mantle material that ascend toward the surface, where they may lead to igneous activity.

33. Mantle Convection Models