Download Chapter 17 Plate Tectonics

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Chapter 17 Plate Tectonics
SECTION 17.1
190 points
Period
Draw the map of the world today and at Pangaea.
Drifting Continents (25 points)
In your textbook, read about continental drift.
1. What evidence suggested to early mapmakers that the continents might
have moved?
Illustrate and label all evidence from the left side of this paper.
2. What was Pangaea?
3. List and describe three sources of evidence used by Alfred Wegener to
support his hypothesis of continental drift.
4. Describe fossil evidence supported Wegener’s idea of continental drift.
5. What did fossils of aquatic reptiles found in freshwater rocks suggested to
Wegener?
6. Based on observations of fossils of Glossopteris, what did Wegener
concluded?
7. What did the coal beds in Antarctica indicated to Wegener about the
climate of Antarctica in the past?
8. What did Wegener argue based on the glacial deposits observed?
9. Why did most scientists at the time rejected Wegener’s hypothesis of
continental drift?
Standard 2: Students will understand Earth’s internal structure and the dynamic nature of the tectonic plates that form its surface.
Objective 2: Describe the development of the current theory of plate tectonics and the evidence that supports this theory.
Objective 3: Demonstrate how the motion of tectonic plates affects Earth and living things.
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SECTION 17.2
Seafloor Spreading (40 points)
In your textbook, read about seafloor spreading.
In the space at the left, write correct if the statement is correct; if the statement is
not correct, change the italicized word or phrase to make the statement correct.
_______1. Sonar uses sound waves to measure water depth.
_______2. Maps made from sonar and magnetometer data led to the
discovery of ocean ridges and deep-sea trenches.
_______3. Deep-sea trenches are vast, underwater mountain chains.
_______4. Rock samples taken near ocean ridges are older than rock
samples taken near deep-sea trenches.
_______5. The thickness of ocean-floor sediments decreases with distance
from an ocean ridge.
_______6. The oldest ocean floor rocks are about 3.8 billion years old.
_______7. The study of the magnetic record preserved in Earth’s rocks is
called paleomagnetism.
_______8. An isochron is a change in Earth’s magnetic field.
_______9. Earthquake activity and volcanism are common along ocean
ridges.
_______10. The magnetic patterns on either side of a deep-sea trench are
mirror images of each other.
_______11. The theory of continental drift states that new ocean crust is
formed at ocean ridges and destroyed at deep-sea trenches.
_______12. As new seafloor is carried away from an ocean ridge, it heats
up, expands, and becomes less dense than the material beneath it.
Period
In your textbook, read about magnetism. Complete the passage
Earth’s (17) __________________ has
changed over time. A field with the same orientation
as today’s field is said to have (18) __________
____________. A field that is opposite the
present field has (19) _____________
___________. Magnetometers have been used
to measure the ocean floor’s magnetic field. When
the ocean floor’s magnetic readings match the
present field, the two fields (20)
The statements below describe the steps involved in the process of seafloor
spreading. Number these steps in the order in which they occur.
_______14. Magma fills the gap that is created.
_______15. Magma hardens to form new ocean crust.
_______16. Magma is forced upward toward the crust.
_____________ . This produces
a(n) (21) ____________ than normal reading. When the magnetic
readings of the ocean floor are reversed compared to today’s field, the two
_____________________ to produce a(n)
(23) ______________ than normal reading. Magnetic data of the
ocean floor has been used to generate (24) _______________ maps,
which have shown that the ocean floor is (25) ________________
near ocean ridges and (26) ______________ near deep-sea trenches.
fields partially (22)
In your textbook, read about ocean rocks and sediments, magnetism, and
seafloor spreading. For each item write the word described.
_______________27. Device that can detect small changes in
magnetic fields
_______________28. Minerals containing this metal act like small
compass needles and record the orientation of
Earth’s magnetic field at the time of their
formation
_______13. The theory of seafloor spreading explains that Earth’s
continents move because they ride atop ocean crust as it moves
away from ocean ridges.
combine
stronger
isochron
lower
magnetic field
normal polarity
older
cancel
reversed polarity
younger
_______________29. This scale was constructed from data
gathered from continental basalt flows
_______________30. This type of line connects points on a map
that have the same age
_______________31. Each cycle of spreading and magma intrusion
along an ocean ridge results in the formation of
this
Standard 2: Students will understand Earth’s internal structure and the dynamic nature of the tectonic plates that form its surface.
Objective 2: Describe the development of the current theory of plate tectonics and the evidence that supports this theory.
Objective 3: Demonstrate how the motion of tectonic plates affects Earth and living things.
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d SECTION 17.3 Theory of Plate Tectonics (45 points)
Period
9. Which type of rock makes up most of the oceanic crust?
In your textbook, read about plate tectonics and plate boundaries.
1. Which theory states that Earth’s crust and rigid upper mantle move in
different directions and at different rates over Earth’s surface?
10. Name the feature that forms when two oceanic plates converge.
2. Tectonic plates interact at places called plate
11. What can happen when two oceanic plates converge and one is
subducted into the mantle?
3. Places where tectonic plates move apart are called
12. Which landform results from divergence of continental crust?
4. Where are most divergent boundaries found?
5. What happens along a divergent boundary?
6. What kind of boundary is the Mid-Atlantic Ridge an example of?
13. What happens when an oceanic plate converges with a continental plate?
14. Which feature is associated with a continental-continental plate
boundary?
7. Which boundary is where tectonic plates come together?
8. Illustrate three types of convergent boundaries. Label the types of crust.
15. At which tectonic plate boundary do plates slide horizontally past each
other?
16. Illustrate transform boundaries. Label the following: long faults,
shallow earthquakes, deformed and fractured crust.
Standard 2: Students will understand Earth’s internal structure and the dynamic nature of the tectonic plates that form its surface.
Objective 2: Describe the development of the current theory of plate tectonics and the evidence that supports this theory.
Objective 3: Demonstrate how the motion of tectonic plates affects Earth and living things.
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SECTION 17.4
Date
Causes of Plate Motion
(30 points)
In your textbook, read about mantle convection, ridge push, and slab pull.
Answer the following questions.
1. Explain the process of convection.
Convection is the transfer of thermal energy by the movement of
heated Heating matter causes it to expand and decrease in density.
This warmed is forced upward as a result of buoyancy. The cooler f
gravity. This up-and-down flow creates a pattern
of motion called a convection current.
2. Describe the formation of convection currents in the mantle.
Even though it is a solid, the upper mantle can flow like a soft plastic.
Convection
currents are set in motion by the transfer of energy between Earth’s
hot and cooler exterior. Regions of hot mantle are less dense than
areas of cooler
mantle and are slowly forced toward the crust. Cooler parts core. The
convection currents that result are probably set motion by.
3. Explain how the parts of a convection current in the mantle are related to
plate motions.
The rising part of a convection current spreads out as it reaches the
upper and causes lateral and upward forces. These forces lift and split
the lithosphere a divergent boundary. The downward part of the
current occurs where a force pulls plates downward at convergent
boundaries.
4. Compare and contrast ridge push and slab pull.
Both are processes associated with plate movements. Ridge push is a
process
in which the uplifted ridge is thought to push the oceanic plate toward
the
zone.
5. What is one hypothesis regarding the formation of a divergent boundary
on a continent?
Period
Reviewing Vocabulary Write the term that best completes the statement.
1.
S______ p_________ is a process that occurs at convergent
boundaries.
2. Wegener’s hypothesis of
_______________ ________
stated that Earth’s continents had once been joined as a single landmass.
3. The study of Earth’s magnetic record is known as
p__________________
.
4. A map line connecting points that have the same age is an
5. The
________.
__________________ states that Earth’s crust and rigid
upper mantle are broken into enormous slabs called plates that move slowly
over Earth’s surface.
6.
________________ _______________ are places
where plates slide horizontally past each other.
R___________ p_______
is a process whereby the weight of
an uplifted ocean ridge pushes an oceanic plate toward a subduction zone.
8. The transfer of thermal energy by the movement of heated matter is
7.
c__________________
.
9. Places where plates move apart are
10.
__________________
_________ __________.
occurs when one tectonic plate
descends beneath another.
11. Earth’s continents were once joined as a single landmass called
__________________.
12. A(n) __________________ detects small changes in Earth’s
magnetic field.
__________________ explains how new ocean
crust is created at ocean ridges and destroyed in deep-sea trenches.
13. The theory of
____________ _____________
14. Plates come together at
15. A long, narrow, fault-bounded, continental depression is a(n)
r________ v__________
.
16. A change in Earth’s magnetic field is called a
m___________
r______________.
Standard 2: Students will understand Earth’s internal structure and the dynamic nature of the tectonic plates that form its surface.
Objective 2: Describe the development of the current theory of plate tectonics and the evidence that supports this theory.
Objective 3: Demonstrate how the motion of tectonic plates affects Earth and living things.
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Understanding Main Ideas (30 points)
Circle the letter of the choice that best completes the statement or answers the question.
1. Many early mapmakers thought Earth’s continents had moved based on
a. plate boundary locations.
c. climatic data.
b. fossil evidence.
d. matching coastlines.
2. Why was Continental drift not widely accepted when it was first proposed?
a. Wegener couldn’t explain why or how the continents moved.
b. continental landmasses were too big to move slowly over Earth’s surface.
c. magnetic and sonar data proved that Wegener’s hypothesis was incorrect.
d. mantle convection currents weren’t in motion at that time.
3. Compared to ocean crust near deep-sea trenches, crust near ocean ridges is
a. younger. b. older.
c. the same age.
d. magnetically reversed.
4. The magnetic pattern of ocean-floor rocks on one side of an ocean ridge is
a. a mirror image of that of the other side.
b. younger than on the other side.
c. much different from the magnetic pattern found in rocks on land.
d. at right angles to the ocean ridge.
5. Isochron maps of the seafloor indicate that ocean crust is
a. oldest near ocean ridges.
c. youngest near ocean ridges.
b. youngest at deep-sea trenches. d. thinnest in subduction zones.
6. Each cycle of spreading and intrusion of magma during seafloor spreading
results in
a. magnetic reversals.
c. subduction.
b. new ocean crust.
d. plates colliding.
7. Features found at divergent boundaries include
a. ocean ridges.
c. crumpled mountains.
b. deep-sea trenches.
d. island arc volcanoes.
8. Subduction results in the formation of
a. a deep-sea trench.
c. a rift valley.
b. a magnetic reversal.
d. new continental crust.
9. Continental-continental plate collisions produce
a. island arcs.
c. deep-sea trenches.
b. rift valleys.
d. very tall mountain ranges.
10. Crust is neither destroyed nor formed along which of the following
boundaries?
a. convergent
b. divergent
`c. transform
d. magnetic
11. The driving forces of tectonic plates are related to convection currents in
Earth’s
a. crust.
b. mantle.
c. inner core.
d. outer core.ng
Period
Label each feature in the diagram below.
1. Subduction zone
2. Rift valley
3. Volcanoes
4. Highly-folded mountains
5. Divergent boundary.
6. Convergent plate boundaries
7. Ridge push
8. Slab pull
9. Draw arrows to show the
direction of flow of
convection currents
beneath the plates.
Video Study Guide: Earth Revealed Episode 4: The Seafloor
View online at http://www.learner.org/resources/series78.html?pop=yes&pid=315
Scroll down to see full video. Choose the correct episode. Click the VoD link.
1. What is the main type of igneous rock found on the seafloor?
2. What are terrigenous and pelagic sediments?
3. What do oceanic ridge systems represent?
4. What is found at the crest of the oceanic ridges?
5. Discuss the age of the ocean floor as it relates to the oceanic ridge systems.
6. What conditions limit exploration and development of resources from the
seafloor?
7. Discuss pros and cons of the study, exploration, and development of the
seafloor.
magneter
Standard 2: Students will understand Earth’s internal structure and the dynamic nature of the tectonic plates that form its surface.
Objective 2: Describe the development of the current theory of plate tectonics and the evidence that supports this theory.
Objective 3: Demonstrate how the motion of tectonic plates affects Earth and living things.
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Applying Scientific Methods (20 points)
Scientists have studied the motions of Earth’s tectonic plates and recorded
many of their findings as maps. Based on the assumption that the direction
and rate of plate movement taking place today will continue for the next 50
million years, researchers have made predictions about the world’s future
geography. The results of those predictions are presented in the diagram
below, which shows the configuration of the continents 50 million years
from the present. The shaded areas of the diagram represent the present
positions of the continents.
Period
6. Describe the geographic position of Europe on the map in relation to its
present position.
7. What might happen if Africa collides with Europe?
8. Locate the small strip of land off the northwestern coast of the North
American plate. Describe where you think this land came from and how it
got there.
Thinking Critically
Answer the following questions.
1. Even Alfred Wegener acknowledged that the apparent fit of continents or
“matching” of continental coastlines was crude at best. Propose an
explanation for this inexact fit.
Answer the following questions.
1. In which compass direction have North and South America moved in
relation to Africa?
2. Evolution is adaptation, or change, of organisms in response to
environmental changes. The theory of evolution states that similar
organisms evolved from a common ancestor. Scientists hypothesize that
marsupials like koalas and kangaroos, which are native only to Australia,
evolved from the same ancestor as the marsupials known as opossums,
which are native to North and South America. Does the theory of plate
tectonics support the theory of evolution in this case? Explain your answer.
2. How does the size of the future Atlantic Ocean compare with its present
size?
3. What will probably happen to Australia if the plate upon which it sits
continues to move in the direction shown?
4. Describe the changes taking place in East Africa.
3. About 200 million years ago, extensive tropical swamps existed in North
America. At the same time, glaciers covered southern Africa, southeastern
South America, much of India, portions of Australia, and nearly all of
Antarctica. How does this information support Wegener’s idea of
continental drift?
5. How does the size of the Pacific Ocean on this map compare with its
present size?
Standard 2: Students will understand Earth’s internal structure and the dynamic nature of the tectonic plates that form its surface.
Objective 2: Describe the development of the current theory of plate tectonics and the evidence that supports this theory.
Objective 3: Demonstrate how the motion of tectonic plates affects Earth and living things.
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