1. Objectives
- Students will be able to label and describe the layers of the Earth and their physcial characteristics.
- Students will demonstrate understanding of Continental Drift, and the evidence for Continental Drift.
- Students will demonstrate understanding of how the Continental Drift evolves into the Theory of Plate Tectonics.
- Students will demonstrate understanding of how convection currents in the Mantle cause Tectonic plate movement.
- Students will demonstrate understanding of the different types of crustal material (oceanic and continental) and how their interactions shape the Earths surface.
- Students will demonstrate understanding of the causes and geographic features of Tectonic Plate Boundaries: convergent, divergent, transform.

2. Section 17.1 Study Guide
Section 17.1 Main Ideas
Theory of Continental drift - Earth’s continents were joined as a single landmass that have drifted apart.

3. Section 17.1 Study Guide
Section 17.1 Main Ideas
Idea of moving continents Alfred Wegener
Wegener supported his hypothesis of continental drift with:
Rock types
Fossils
Ancient climate data
Theory rejected
It didn’t answer:
how continents moved
what caused their motion.

4. Section 17.2 Study Guide
Section 17.2 Main Ideas
1940s and 1950s - Sonar and magnetic studies of ocean rocks and sediments led to theory of seafloor spreading.
Magnetic patterns on the seafloor are symmetric in relation to ocean ridges
Age of ocean crust increases with distance from a ridge.
Sediment thickness increases with distance from a ridge.

5. Section 17.2 Main Ideas Seafloor spreading
Section 17.2 Study Guide
Section 17.2 Main Ideas
Seafloor spreading
magma rises and hardens to form new crust / ocean floor
The previous section of crust is forced slowly away from the ridge.

6. Section 17.3 Study Guide
Section 17.3 Main Ideas
Plate tectonics states that Earth’s crust and upper mantle are broken into plates
Plates move in different directions and at different rates.
Divergent plate boundaries, plates move apart.
Convergent boundaries, plates come together.
Transform boundaries, plates slide horizontally past each other

7. Section 17.3 Main Ideas Effects of Boundaries
Section 17.3 Study Guide
Section 17.3 Main Ideas
Effects of Boundaries
Divergent - High heat flow, volcanism, and earthquakes
Convergent - trenches and folded mountains
Transform - faults and earthquakes

8. Section 17.4 Main Ideas What is Convection?
Section 17.4 Study Guide
Section 17.4 Main Ideas
What is Convection?
transfer of energy via the movement of heated matter.
Convection currents in the mantle caused by energy transfer between Earth’s hot interior and cooler exterior.

9. Section 17.4 Study Guide
Section 17.4 Main Ideas
Ridge Push - the elevation of a ridge pushes a plate toward a subduction zone.
Slab Pull - weight of the subducting plate pulls a plate into a subduction zone.

10. Multiple Choice 1. Pangaea begin to break apart ____ years ago?
Chapter Assessment
Multiple Choice
1. Pangaea begin to break apart ____ years ago?
a. 65 million c. 200 million
b. 135 million. d. 400 million
Alfred Wegener hypothesized that Pangaea began to break apart 200 million years ago based on geologic evidence.

11. Chapter Assessment
Multiple Choice
2. The oldest oceanic crust is generally located near what feature?
a. ridge c. abyssal plain
b. trench d. rift
Subduction occurs in a trench, meaning that oceanic crust at a trench is older than any crust closer to a ridge. A rift is a valley that forms along the axis of a ridge. It is in the rift that new seafloor is created.

12. Chapter Assessment
Multiple Choice
3. The San Andreas Fault is an example of what kind of boundary?
a. divergent c. transform
b. convergent d. rift
Two plates sliding past each other form the San Andreas Fault. The San Andreas Fault is a rare example of a transform boundary that occurs on a continent.

13. Chapter Assessment
Multiple Choice
4. Which device was instrumental in determining the age of the ocean floor?
a. magnetometer c. sonar
b. isochron d. seismometer
A magnetometer allowed scientists to match patterns magnetic patterns in the seafloor with known patterns and ages of land-based material. From this they could determine the age of the ocean floor.

14. Chapter Assessment
Multiple Choice
5. The oldest part of the seafloor is approximately ____ years old.
a. 70 million c. 260 million
b. 180 million d. 430 million
The discovery that the seafloor is geologically young was one of the major factors in proposing the theory of seafloor spreading. There are examples, for comparison, of continental rocks that are 3.8 billion years old.

15. Chapter Assessment
Short Answer
6. Why are there more volcanoes around the rim of the Pacific Ocean than the Atlantic Ocean?
There are subduction zones located around the periphery of the Pacific Ocean. In the Atlantic Ocean, the seafloor is spreading, but with the exception of Caribbean, there are no subduction zones.

16. Chapter Assessment
Short Answer
7. Why was Wegener’s hypothesis of continental drift rejected when it was first proposed?
Two unanswered questions—what forces could move continents and how continents could move without shattering—were the main reasons that the hypothesis of continental drift was rejected when it was first proposed.

17. Chapter Assessment
True or False
8. Identify whether the following statements are true or false.
______ Wegener called his hypothesis Pangaea.
______ Magnetic reversal events are longer in duration than epochs.
______ There are around a dozen major plates.
______ Slab push is a process that is associated with an ocean ridge.
______ Folded mountain ranges are the result of a convergent boundary involving oceanic crust and continental crust.
false
true

18. Image Bank
Chapter 17 Images

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23. Image Bank
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