1.  How does the distribution of fossils provide evidence for continental drift?  How does the location of mountain chains provide evidence of continental drift?  Why was wegener’s hypothesis rejected?  What is plate tectonics?

2. 1. Describe the difference between divergent, convergent, and transform fault boundaries. 2. Which one of the following was NOT used as a support of Wegener’s continental drift hypothesis? a. Fossil evidence b. Paleomagnetism c. The fit of South America and Africa d. Ancient climates 3. At what type of plate boundary do plates move apart, resulting in the upwelling of material from the mantle to create new seafloor? a. Divergent b. Convergent c. Transform fault d. subduction

3. 1. Cracks in rocks widen as water in them freezes and thaws. How does this affect the surface of the Earth? a. It reduces the rates of soil formation. b. It changes the chemical composition of rocks. c. It exposes rocks to increased rates of erosion and weathering. d. It limits the exposure of rocks to acid precipitation. 2. Which storm most likely develops as air masses interact with the warm water in the northwest Pacific Ocean? a. Typhoon b. Tornado c. Blizzard d. Monsoon 3. Which will most likely form when movement along a plate boundary forces a landmass to be pulled apart? a. Volcanic island arc b. Continental mountains c. Continental rift d. Ocean trench 4. What evidence suggest that mountain ranges existed across continents during Pangaea? a. Age and type b. Size and shape c. Color and texture d. Height

4. Today, you will be able to: Explain seafloor spreading and continental rifting Describe the process takes place at subduction zones. Differentiate among subduction at oceanic-continental, oceanic-oceanic, and continental-continental convergent boundaries.

5.  Divergent Boundaries  Oceanic Ridges and Seafloor Spreading Oceanic ridges are continuous elevated zones on the floor of all major ocean basins. The rifts at the crest of ridges represent divergent plate boundaries. Rift valleys are deep faulted structures found along the axes of divergent plate boundaries. They can develop on the seafloor or on land. Seafloor spreading produces new oceanic lithosphere.

7.  Divergent Boundaries  Continental Rifts When spreading centers develop within a continent, the landmass may split into two or more smaller segments, forming a rift.

9.  Convergent Boundaries  A subduction zone occurs when one oceanic plate is forced down into the mantle beneath a second plate.  Oceanic-Continental Denser oceanic slab sinks into the asthenosphere. Pockets of magma develop and rise. Continental volcanic arcs 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.

11.  Convergent Boundaries  Oceanic-Oceanic Two oceanic slabs converge and one descends beneath the other. This kind of boundary often forms volcanoes on the ocean floor. Volcanic island arcs form as volcanoes emerge from the sea. Examples include the Aleutian, Mariana, and Tonga islands.

13.  Convergent Boundaries  Continental-Continental When subducting plates contain continental material, two continents collide. This kind of boundary can produce new mountain ranges, such as the Himalayas.

16.  Transform Fault Boundaries  At a transform fault boundary, plates grind past each other without destroying the lithosphere.  Transform faults 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.

18. 1. What is seafloor spreading? 2. What is a Subduction zone? What types of plate boundaries have Subduction zones? 3. What actions of plate boundaries cause the destruction of the lithosphere?

19. Plate Boundaries (page 69)