Download Chapter 1—Plate Tectonics and California

Geology 125
Homework Ch 1—Plate Tectonics
Answer the following questions, in complete sentences where appropriate. The multiple
choice questions may appear on Quiz #1 and any of the questions may appear on
Midterm #1.
1. What are the names of the three compositional layers of Earth? What is the name of
the rock that each layer is made of?
2. What are the names of the two structural layers of Earth? What does it mean when we
say “structural layer”?
3. What is a plate? How fast do plates move?
4. Draw a sketch of a convergent plate boundary where subduction is occurring. On the
sketch, label the following: oceanic trench, volcanic arc, where magma is forming, a
batholith and the accretionary wedge. Describe what each one is. Use several
“X’s” to show where earthquakes would occur. Use arrows to show how the plates
are moving with respect to one another.
5. Draw a sketch of a divergent boundary where sea floor spreading is occurring. On the
sketch, label the following: pillow basalt, where magma is forming, and volcanoes.
Use “X’s” to show where earthquakes would occur. Use arrows to show how the
plates are moving with respect to one another.
6. What is a transform plate boundary? What geologic features and processes occur
there? Name the most accessible, best-studied transform boundary in the world (!).
7. What is an accreted terrane? What, specifically, could accreted terrane be composed
of?
8. Which two types of plate boundaries are found in California?
a. convergent and divergent
b. convergent and transform
c. divergent and transform
d. CA doesn’t have plate boundaries
9. A deep, linear, relatively narrow depression in the Earth’s surface that develops
where oceanic plates subduct is a(n):
a. ocean trench b. forearc basin c. volcanic arc d. backarc basin
e. island arc
10. Sea floor spreading occurs at:
a. subduction zones b. ocean trenches
c. island arcs d. mid-oceanic ridges
e. island arcs
11. New oceanic crust is formed where plates move apart from one another. This
new crust is composed primarily of:
a. basalt
b. granite c. marble d. sandstone e. limestone
12. Before 250 million years ago, most of CA did not exist.
a. true b. false
13. All plate boundaries are characterized by:
a. volcanic activity b. earthquakes c. subduction
e. all of the previous
d. mountain ranges
14. What is the name of the most significant plate boundary in CA?
a. the Hayward Fault
b. the San Andreas Fault
c. the Sierra Nevada Mountains
d. the Mt. Diablo Thrust Fault
15. The continental crust is formed primarily of:
a. a volcanic rock called basalt
b. a sedimentary rock called sandstone
c. a plutonic rock called granite
d. a metamorphic rock called blueschist
16. What is meant by compressional stress?
a. forces are squeezing inward
b. forces are uniform around an object
c. forces are pulling apart
d. forces are moving sideways