Name ___________________________________
Period ____
Chapter 5 Study Guide
1. What Wegener’s hypothesis? Wegener hypothesized that the continents were moving and once
existed as one supercontinent.
2. Why was Wegener’s theory of continental drift rejected? He could not give a cause as to what
force could move the continents.
3. Why is old oceanic crust denser than new oceanic crust? It is saturated with water and is cooler
4. What is a rift valley and where does it form? A rift valley is an area where Earth’s crust is being
pulled apart. It is formed between two divergent boundaries.
5. What is stress? Stress is a force exerted on rocks through the movement of plates.
6. Name all three types of stress and what they do to rock.
 Compression – squeezes rocks until it folds or breaks.
 Tension – pulls crust apart and thins rock in the middle
 Shearing – stress that pushes a mass of rock in two opposite directions.
7. What provides the force that causes magma to erupt to the surface? Expanding gases in rising
magma.
8. What is Pangaea? Supercontinent
9. How did scientists discover that rocks farther away from the mid-ocean ridge were older than
those near it? Determined by the the age of rocks using uranium dating of zircon crystals.
10. Explain the process of subduction. The denser plate sinks beneath another plate at a convergent
boundary.
11. What are plates composed of? Crust and Lithosphere
12. What are plates doing at a divergent boundary? Name one example. Two plates moving apart.
Example: Atlantic mid-ocean ridge.
13. What are plates doing at a convergent boundary? Name one example. Two plates colliding.
Example: Indian and Eurasian plates colliding which continue to create the Himalayas mountains.
14. What are plates doing at a transform boundary? Name one example. Plates sliding past each
other. Example: San Andreas Fault in California
15. What is a fault and what causes faults? A fault is a break in the rock of the crust caused by
stress.
16. What kind of stress causes a normal fault? Tension
17. What kind of stress causes a reverse fault? Compression
18. What kind of stress causes a strike-slip fault? Shearing
19. What determines whether an eruption will be quiet or explosive? An eruption will be quiet or
explosive based on the amount of silica in the magma. Magma high silica will result in an explosive eruption since gases get trapped due to its high viscosity. Magma low in silica will result in a
quiet eruption since it has a low viscosity and the lava flows more like a fluid.
Low silica = low viscosity = fluid lava = quiet eruption
High silica = high viscosity = sticky lava = explosive eruption
20. There is no twenty.
.
21. Label the plate boundary that exist for each diagram below:
22. Label the type of fault for each diagram
below:
a) Divergent Boundary (tension stress)
b) Convergent Boundary (compression stress)
c) Transform Boundary (shearing stress)
23. Draw a diagram for each type of volcano.
Shield Volcano
Cinder-Cone Volcano
a) Normal Fault
b) Reverse Fault
c) Strike-Slip Fault
Stratovolcano
24. *Know how to identify the parts of a volcano (magma chamber, pipe, vents, lava flow, and
crater). Refer to notes!
Use the figure below to answer the following questions in the spaces provided.
25. What stress caused the rock layers to take on the shape shown in diagram B?
Compression caused the rock layers in diagram B to squeeze together which caused them to
fold.
26. Contrast the plate movements that cause the stresses in diagrams C and D.
Diagram C is under tension which pulls the rocks (divergent boundary) apart causing a rift valley. Diagram D is under shearing stress which causes a strike-slip fault due to plates sliding past
each other (transform boundary).
Use the figure below to answer the following questions in the spaces provided.
27. How do volcanoes form at B?
The subducting oceanic plate is saturated with water. The water lowers the melting point of the
mantle which creates magma. Magma rises to the surface, breaks through the crust, and eventually creates a volcano.
28. How do volcanoes form at A?
Fractures at the divergent boundary allow magma to rise to the surface, which eventually create
volcanoes at a mid-ocean ridge.
.