Prelab 1: Plate tectonics
Due at the beginning of Lab 1
name ___________________________________
Directions and Rules for Prelabs:
 Prelabs are due at the beginning of the class, BEFORE the quiz (your instructor will designate a place for
you to place your prelab after walking in the classroom).
 NO late assignments will be accepted unless the absence is excused. That means if you are late to
class it will not be accepted, and if you are on time but turn it in late it will not be accepted.
 You have will need to PRINT and COMPLETE the exercises listed below:
 Illegible answers will be marked incorrect; write neatly!
Refer to Chapter 2 in your lab manual. Turn to the pages listed below and complete the following questions.
Figure 2.1 (page 26)
Recognizing Plates and Plate Boundaries
Exercise. 2.1 (p.28) Using Figure 2.1 above as a reference to answer the questions below.
a. What is the name of the plate on which the United States resides?
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b. Does this plate consist of continental lithosphere? Oceanic lithosphere? Or both?
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c. Where does the lithosphere of the Atlantic Ocean form?
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d. What kind of plate boundary occurs along the west coast of South America?
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e. Is the west coast of Africa a plate boundary? _______________________________
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Figure 2.4 (page 31)
Figure 2.5 (page 32)
Putting the Early Evidence Together
Exercise 2.3 (page 32) Refer to Figures 2.4 and 2.5 (shown above) to answer the following questions
a. Look at the volcanic and earthquake activity that occurred on the west coast of North America. How
do these compare? __________________________________________________________________
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Examine the earthquake and volcanic material in the center of North America. How do these
compare? _____________________________________________________________________
b. Examine the chain of volcanoes and line of earthquakes in the middle of the Atlantic Ocean in
Figures 2.4 and 2.5. From reading the sections on pages 28 – 32, describe what you believe is
causing these.
______________________________________________________________________________
______________________________________________________________________________
c. Geologists have found rocks and fossils of species native to Africa in South America and rocks
and fossils native to South America in Africa. Considering your response in part b above,
explain what they theorize had happened.
______________________________________________________________________________
______________________________________________________________________________
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Estimating the Amount and Rate of Motion in a Continental Transform Fault
Exercise 2.10 (pages 44-45) Refer to the figure below to answer the following questions
Field geologists have mapped an active continental transform fault (red line in the figure below) for several
hundred kilometers. A 50 million-year-old (50-Ma) body of granite and a 30-Ma vertical layer of marble have
been offset by the fault as shown.
a. Draw arrows to indicate the direction in which the plate on the northeast side of the fault has
moved relative to the plate on the southwest side.
b. Measure the amount of offset of the 50-Ma granite body ______________ km
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Geologic markers displaced by a continental transform fault. (Ex. 2.10 (p.44-45) a-b)
Plate Direction: Footprints of a moving plate
Exercise.2.11 (p.48) a-b. Refer to the figure below to answer the following questions.
The Hawaiian Islands, located in the Pacific Ocean far from the nearest oceanic ridge, are an excellent example
of hotspot volcanic islands (see figure below). Volcanoes Kauai, Oahu, and Maui haven’t erupted for millions of
years, but the island of Hawaii hosts five huge volcanoes, one of which (Kilauea) has been active for over 30
years. In addition, a new volcano, Loihi, is growing on the Pacific Ocean floor just southeast of Kilauea. As the
Pacific plate moves, Kilauea will become extinct and Loihi will be the primary active volcano.
a. Where is the Hawaiian hot-spot plume located relative to the Hawaiian Islands? Explain your
reasoning.
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_________________________________________________________________________________
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b. Draw a line connecting the volcanic center (highlighted in red) on Maui to the spot between Kilauea
and Loihi (the volcanic center for Hawaii). Connect the volcanic centers of Maui to Molokai,
Molokai to Oahu, and Ohau to Kaui as well.
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