Download es1 and accel plate boundaries lab

Investigating Features of Plate Boundaries
Name:
Earthquake and volcanic activity have revealed a map of the world of many plates. These plates consist
of continental crust, oceanic crust or a combination of both. Places in the ocean tend to be made of
oceanic crust, continental crust makes up the continents (including continental shelves)
1. List the names of the major plates that have continental crust (or both continental and oceanic
crust) making them up.
2. Name three oceanic plates (made primarily of oceanic crust):
3. Color the entire North American Plate red. The list here the names of plates that border it:
4. Color the Pacific Plate blue.
The plates are in motion and interact with one another. There are three types of plate boundaries:
divergent, convergent and transform. ______________________________ are where two plates pull
apart from one another. These places form new oceanic crust and are sometimes referred to as
spreading centers. Since the plates move apart from one another they are sometimes called rift zones.
Beneath divergent boundaries the process of ____________________ in the mantle is causing less
dense material in the mantle to rise up. As a result, alongside a divergent boundary under sea
mountains may form a mid ocean ridge.
5. Color all the divergent boundaries on your map in purple
6. List the names of two plates that are pulling away from each other:
7. Based on the boundary between the Eurasian plate and the North American plate in the Atlantic
ocean, is the Atlantic getting bigger or is it getting smaller?
8. The east coast of the United States does not have a plate boundary along it. It is referred to as a
passive continental boundary because it does not experience much tectonic activity (earthquakes or
volcanoes). Name two other passive boundaries by naming the continent and the coastline that is
passive.
When two plates move towards one another they form convergent plate boundaries. Beneath convergent
boundaries material in the mantle has cooled and is sinking back into the mantle. There are three types
of convergent boundaries. When oceanic crust meets continental, the denser oceanic crust sinks under
the continental. This is referred to as a _______________________ zone where one of the plates
subducts or sinks underneath the other. As the sinking crust melts, some molten material rises to the
surface forming a volcanic arc (chain of volcanoes) on the overriding continental crust. The place
where one plate first sinks under the other can form a deep ocean trench. The oldest material on the sea
floor is found here before melting back into the mantle.
When oceanic crust collides with oceanic crust, a subduction zone and trench will form as well. Again
molten material will rise up forming a chain of volcanoes but as they are in the ocean they are called an
.
When continental and continental crust collide, neither will sink. This is because they are too buoyant.
Instead they fold and buckle and form mountains.
9. Color in the convergent boundaries on your map in yellow
10. Name three plates with which the Pacific Plate is colliding
11. In general in which direction is the Pacific plate moving?
12. Draw 3 circles on your map to indicate places where island arcs would be found (remember to
consider the type of crust involved in the collision)
13. Draw 3 triangles to indicate where you would expect to find a volcanic arc
14. What kind of convergent boundary was likely involved in forming the Appalachian mountains?
15. Find the Nazca plate. Where would the oldest ocean floor be found?
Transform boundaries are where two plates slide past each other. These often occur at perpendicular
angles to rifting plates. Mostly they form because we have very rigid, lithospheric plates moving on a
surface that is round. The result is cracks called faults along which plates move past one another.
16 Find a transform fault on the West coast of the US. Which 2 plates are involved and in which
direction is each moving
17. Color transform boundaries green
Putting it all together
First decide which boundary is responsible for the following features (divergent, convergent,
transform)? Then if it is a convergent, be specific whether it is continental-continental, oceanic-oceanic,
or oceanic-continental. Use your notes, the map, and the information in the italicized paragraphs above
to help you decide.
Mount Saint Helens, Washington
East African Rift Valley
Himalaya Mountains
Mid Indian Ridge
Andes Mountains, west coast of S. America
Aleutian Islands (along Aleutian Trench)
New Zealand
Alps
San Andreas Fault
Caribbean islands
Below is a side view of each of the features you read about in the italicized paragraphs above. Find each
feature in the diagram and then write the letter of the feature next to each matching arrow on the
diagram. a. trench b. rift zone
c. island arc d. asthenosphere
e. volcanic arc
f. mountain range
g. subduction zone
Continental
oceanic
oceanic
Continental
oceanic
UPPER
MANTLE
19. Why isn’t the Earth getting larger even though new sea floor is created at divergent boundaries?
20. Look at the diagram above and compare the motions in the mantle to the types of plate
boundaries and direction of movement at plate boundaries. Explain how convection in the mantle
leads to the plate motion what boundaries form where the currents rise, where the currents sink and
why?