Download Review of Plate Tectonics Name

Review of Plate Tectonics
Name ________________________
Date ____________
1. Wegener’s hypothesis was that the continents had all once been ______________and had drifted apart.
2. Wegener named the supercontinent _____________ and his theory was called ___________________.
3. Use one sentence to explain the following evidences for his theory:
a. Evidence from landforms.
b. Evidence from fossils
c. Evidence from glaciers
4. Scientists rejected Wegener’s theory because he could not explain __________________________
5. Today we have new evidence that explains what is causing the “Continental Drift”. We now call the
theory that explains this ______________________________.
6. The process that powers plate tectonics are large circular currents called _______________. These
currents take place in the __________________ layer of the earth. _________________ boundaries
occur at places where there is an upcurrent. While ________________boundaries occur where there is a
down current.
7. At a mid-ocean ridge, molten material (circle one) rises from/sinks to the mantle and erupts, then
spreads out, pushing (circle one) together/apart rock to both sides of the ridge. This type of plate
boundary is called a _______________ boundary. ___________________ is an example of a country
that is located on an above-sea level portion of the mid-Atlantic Ridge.
8. Another example of a _____________ plate boundary that can found in the middle of a continent is in
East Africa and is called the Great Rift Valley. Along this crack, the rift may someday split the eastern
part of Africa away from the rest of the continent. As lava rises up and fills in the rift valley it is getting
(circle one) wider/more narrow, Eventually a new ______________ will form where the rift valley was.
9. The place where two plates come together is called a ____________________ boundary.
10. When two plates collide, the ________________ of the plates determines which one subducts. Oceanic
crust is ________________ dense than continental crust. The three types of convergent boundaries are
_________________________, __________________________, and _________________________.
11. When an oceanic plate edge collides with a continental plate edge, the more dense _________________
dives under the less dense _________________________. This process is known as _______________.
Lava that rises up through weakened cracks in the continent erupts to form explosive
__________________. Some of the deepest holes in the ground called __________________ are here.
12. Many subduction zones occur where the __________________ Ocean meets continents. A
ring of volcanoes all around this ocean is called the __________________________________.
13. When two continental plate edges collide, neither sinks into the mantle because both plate edges are not
__________________ enough. Instead the plates crash head-on and squeeze the crust into
___________________________. An example of this is where India on the Indo-australian Plate
crashed into Asia and is still forming the __________________________ mountains.
14. The Appalachian Mountains on the ____________ coast of the United States formed a long time ago in
the formation of _____________________. At one time they were mighty mountains like the
Himalayas, but over many years were ______________________ to their present day height.
15. Another type of plate boundary called a ________________ boundary occurs where two plates are
sliding past each other. At this type of site the plates get locked together with friction and store great
stress over a long time. When the boundary finally breaks apart, the sudden motion causes
____________________. An example of this type of plate boundary can be found in the state of
___________________________ at the ____________________ fault.
16. Additionally, there are places, such as Hawaii, with volcanoes that are not located on a plate boundary.
These are called _________________________. Hawaii is a chain of volcanoes caused when a hot
plume of ________________ keeps punching through a plate as it moves over it.