Download The Puzzling Plates Part I

The Puzzling Plates – Part I
Original Source: Dr. Leslie Sautter (Dept. of Geology, College of Charleston)
There are two parts to this activity, which is an expanded version of the activity “The Puzzling Plates”
that accompanies the 3-D Plate Tectonics Puzzle, developed by Dr. L. Sautter.
Part I does not require the 3-D Puzzle, but allows teachers to construct their own 2-layer version of the puzzle.
Grade Level:
SC Standards:
5th and 8th
National Standards:
Earth and Space Science Content Standard D
5th – IIIA2a,b,c
8th – IIIB4a
Focus Questions
What earth layers are included in the
different types of lithospheric plates?
What are the relationships between
lithospheric plates and seafloor features?
Objectives
Students will:
investigate the components of the
lithosphere and lithospheric plates.
identify the associations among various
seafloor features, continental features and
the edges of plates.
compare different types of plates (oceanic
plates, continental plates).
compare and contrast the difference
between the major ocean basins with
respect to the types of plates found in each.
Key Words
crust
upper mantle
lithosphere
lithospheric plate
exact-o knife
thin cardboard (preferably corrugated, as it
is less likely to warp over time). The amount
needed is the same size as the
physiographic map being used.
Posterboard or card-weight paper (optional).
globe
For each collaborative group of students:
a puzzle consisting of the cardboard and
map pieces.
Time Frame
One to two 50-minute class periods (after
puzzles pieces have been cut)
Suggested Learning Environment
This activity works well with a small (2-3
students) collaborative learning group. Each
group will require a set of the puzzle pieces.
Relevant pages in Of Sand and Sea
Chapter I, The Ocean Planet, pp. 1-16.
Teacher Preparation
continental plate
oceanic plate
Materials
For the teacher (to make one puzzle):
2 physiographic maps of the ocean floor
(recommended map: by TASA Graphic Arts,
Inc., available through Syzygy Arts, Inc.:
www.syzygy06.com)
scissors
This activity is designed to follow “Introduction
to the Seafloor” and “Quakes and Plates,” and
begins to explain our understanding of how the
earth’s outer surface is fractured into large
pieces of crust and upper mantle, referred to as
lithospheric plates.
Prior to conducting this activity the puzzle
pieces must be constructed. Instructions
follow.
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Puzzling Plates – Part I
TEACHER PAGES
d. Cut the cardboard pieces, following the
perforations, to create the upper mantle
portion of the tectonic plates.
Constructing the Cardboard Plate Puzzle
The cardboard will be cut into the shapes of the
tectonic plates to form one layer of the 3-D puzzle:
the upper mantle. The
physiographic map will also be cut into plate-size
pieces and will represent the crust that lies on top
of the upper mantle. The two layers are assembled
at different stages of the activity.
Before initiating the activity:
e.
Separate the puzzle into 2 piles: upper mantle
(cardboard pieces) and crust (map pieces).
f.
Hide the puzzle piece piles and physiographic
maps from view. Do not tell students about the
puzzle, or that the puzzle relates to the ocean
floor map.
To cut the puzzle, use the following directions:
(Time necessary is approximately 1 hour.)
a.
NOTE: the actual boundary between the North
American Plate and the Eurasian Plate (north of
the Pacific Ocean) is not well defined and is in
debate by scientists. This activity uses the
extension of the western end of the Aleutian
Islands through Siberia as the boundary.
Lay one physiographic map on top of the uncut
piece of cardboard. Tape the edges of the map
to the cardboard. Do not affix the map to the
cardboard permanently, as the map pieces
(crust) must remain separate from the
cardboard (upper mantle).
b. With Figure 1 as a guide and using the exact-o
knife, carefully puncture the map (piercing into
the cardboard) along the locations of plate
boundaries. Make many perforations so that the
plate boundaries will be identifiable on the
cardboard.
Procedure
The steps that follow are included in the STUDENT
PAGES. Additional information on the TEACHER
PAGES is included in blue italics.
1.
NOTE: At this stage, you will not actually cut
the pieces, but the knife will mark the plate
boundary locations on the cardboard, so that
the map and cardboard can be cut separately.
This method will allow the cardboard puzzle
layer (the upper mantle) to fit well with the
overlying crust (both continental and oceanic
crust).
c.
On the table is a pile of cardboard puzzle
pieces. Work with your team to assemble the
puzzle. The edges of the completed puzzle will
be straight.
2. Now, think back to the previous activity,
“Introduction to the Seafloor.” How do the
shapes of these puzzle pieces relate to the
seafloor?
a. Identify the puzzle piece that represents
the portion of the Pacific Ocean that you
traced previously on the ocean floor map.
Recall the seafloor features that nearly
encircled the Pacific Ocean (what are
they?). Hold up the puzzle piece so your
teacher knows you are ready to continue.
Remove the perforated map from the
cardboard. If you choose to, glue the map to
posterboard (or card weight paper). After the
glue has dried use scissors (or the exact-o knife
to cut along the plate boundary perforations to
create the crust portion of the lithospheric
plates.
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Puzzling Plates – Part I
TEACHER PAGES
3. Your teacher will now provide you with a
seafloor map that is the same size as the
puzzle. Lay the map next to your puzzle.
a. Lay the puzzle piece you selected in number
2 on the appropriate part of the seafloor
map. How do you know where to place it?
Confer with your team-mates and agree on
the location, using the knowledge you gained
from the previous activity.
Plates that do not include continents are called
oceanic plates. The Pacific Plate is the largest
oceanic plate on Earth. The other Pacific oceanic
plates you have in the puzzle are adjacent to
(border) the Pacific Plate:
Philippine Plate (to the west)
Nazca Plate (to the southeast)
Cocos Plate (to the east)
Juan de Fuca Plate (the small plate to
the northeast)
4. Find and place on the map other puzzle pieces
that lie completely within the Pacific Ocean and
contain no continents. Be sure you do not
include the puzzle pieces that would cover the
continent of Antarctica.
a. How many pieces are found in the Pacific?
Describe the seafloor and continental
features that surround each of these
plates.
 Students should select the puzzle pieces
5. The Pacific Plate…
1) is an enormous oceanic plate,
2) nearly covers the entire ocean basin, and
3) lies completely within the ocean basin.
Move now to the Atlantic Ocean. Using the
three criteria listed above, can you now find an
“Atlantic Plate”? If not, go to number 6.
that represent the following oceanic plates:
Philippine, Cocos, Nazca, Juan de Fuca.
 Each puzzle piece (plate) has at least one
trench associated with it, and several have
mid-ocean ridges (such as the East Pacific
Rise or the Juan de Fuca Ridge).
6. If you had difficulties finding a large oceanic
plate that fits entirely within the Atlantic
Ocean basin, don’t worry. There is no Atlantic
Plate! (Sorry, but you needed to discover that
for yourself. That’s the only trick question,
rest assured.)
Did you find any plates with no continent
included? There are only two small oceanic
plates in the Atlantic:
Caribbean Plate (south of N. America)
Scotia Plate (southeast of S. America)
Locate them and place them on the map.
b. The Pacific Ocean should now be almost
completely covered with puzzle pieces.
Relate the shapes of the pieces to the
distribution of earthquake epicenters
observed in the “Quakes and Plates”
activity.
 All the plates are ringed by earthquakes.
7. Since there is no Atlantic Plate, cover up the
Atlantic Ocean with the puzzle pieces (plates)
that contribute to its seafloor. Because each of
these plates has significant areas covered by
continents, we refer to them as continental
plates.
Again, omit the Antarctic Plate (the reason why
will soon be explained).
Note: Remember that the earth is a sphere, so
puzzle pieces may continue to the other side of
the puzzle.
This is how we first identified the motion
and fracturing of the outer Earth.
The largest puzzle piece you have placed on the map
can now be referred to as the
Pacific Plate.
(Note: Plate names will all be bulleted and in bold
font so you will be able to review them later.)
The cardboard piece, however, is only one layer of
the plate. It represents the uppermost portion of
the earth’s mantle, called the upper mantle.
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Puzzling Plates – Part I
TEACHER PAGES
 The Eurasian Plate and Indo-Australian
is surrounded by a ridge that connects the
three oceans.
Plates have pieces on both the east and
west sides of the puzzle.
a.
10. There should be only one small continental piece
remaining, the
Arabian Plate.
Place this piece on the map to complete the
puzzle! How many plates do you have?
These plates are named for the continents
included on them. With your group, be sure
to identify each of the following:
North American Plate
Eurasian Plate
African Plate
South American Plate.
The plates included in this puzzle are only the
larger of Earth’s plates. There are several minor
plates that are too small to illustrate using this
model. These 14 plates (or 15 if you break apart
the Indo-Australian Plate) are considered to be the
major plates of the Earth. Many of these major
plates include much smaller “micro-plates.”
b. What seafloor feature is related to the
four major pieces that cover the Atlantic
Ocean?
 The Mid-Atlantic Ridge divides these 4
plates.
11. On a sheet of paper, make a table (or chart)
that lists the four major ocean basins, and the
oceanic plates and continental plates that are
part of each. If a plate contributes to more
than one ocean basin, be sure to include it
wherever is necessary.
8. Move now to the Indian Ocean. Place the puzzle
pieces (plates) that comprise the Indian Ocean.
Once again, omit Antarctica. One piece includes
India, and also stretches eastward to include
Australia. This plate has several names and
most geologists agree that it is currently
breaking apart into two plates. Here we will
simply refer to it as the
Indo-Australian Plate.
The layer of Earth that you have assembled is the
upper mantle portion of the lithosphere. The
lithosphere is comprised of the upper mantle and
the overlying crust. All of the lithosphere is
relatively cold rock, as compared to the deeper
mantle and core.
9. The oceans on your map should almost be
covered except for the southern portions of
the Pacific, Atlantic, and Indian Oceans. Finally,
you may add Antarctica to the map! This
continental plate is called the
Antarctic Plate.
This plate was saved until the end because it
only appears to be an enormous plate. Because
you are looking at a 2-dimensional map view of a
3-dimensional planet, the polar regions are
grossly exaggerated.
a.
So, now you have a map of the earth’s upper mantle.
The earth’s surface layer is still missing – the crust.
Your teacher will now provide you with the crust
layer puzzle pieces. The crust is represented by
cut pieces of another copy of the same map you
used earlier (which is now under your puzzle!).
12. Place all the crust pieces in their appropriate
locations on the puzzle to complete the
lithosphere. Each lithospheric plate (another
term for plate) is now accurately made of upper
mantle (cardboard layer) and crust (top map
layer).
Examine the classroom globe to see
approximately how large the Antarctic Plate
is relative to the Pacific Plate.
This plate is mostly continental (not all of
the continent is shown on the puzzle) and it
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Puzzling Plates – Part I
TEACHER PAGES
Remember that a plate is comprised of the
crust and upper mantle. A plate is a broken
piece of the lithosphere.
Lithosphere = Crust + Upper Mantle
14. Explore the various plates individually by
removing them (both crust and mantle) one by
one from the puzzle and examining the seafloor
features along the plate’s edges.
a. Make a table (or chart) that lists all of the
seafloor features found along the edges of
the following five plates:
Pacific Plate
Nazca Plate
South American Plate
African Plate
Indo-Australian Plate
13. Using your previous observations from steps 212, write the name of each plate on a label (or
Post-It Note) and affix it to the appropriate
plate. If a plate extends to the east-west
edges of the puzzle and map, remember to label
the plate piece on the other side of the world!
Summarize your observations and discoveries by
answering the questions that follow.
Questions
Use the students’ completed puzzles and science notebooks to assess the following:
Were all plates labeled correctly, including the plates that continue to the other side of the puzzle
(Eurasian Plate, Indo-Australian Plate, and Antarctic Plate)?
Were tables or charts complete (from Steps 11 and 14)?
Examine the student responses to questions 1-7. Key points to look for are shown in blue italics:
1) What are the layers included in the lithosphere? What is a lithospheric plate?
 Lithosphere is made of the upper mantle and crust. It is a layer of the Earth that breaks into
piece called plates, or lithospheric plates.
2) Explain what is meant by the terms oceanic plate and continental plate.
 An oceanic plate is a lithospheric plate that has little or no continental crust on it.
Continental plates have a large amount of continental crust. Most continental plates also have
oceanic crust. Only one of the major plates, the Arabian Plate has crust that is nearly all
continental crust.
3) In terms of the types of plates found (oceanic plate vs. continental plate), compare the Pacific
Ocean basin and the Atlantic Ocean basin.
 The Pacific Ocean basin is comprised of 5 oceanic plates. Together these plates make up
most of the basin. In contrast, the Atlantic Ocean includes only two small oceanic plates. It
is dominated by four large continental plates.
4) Is the Indian Ocean basin more like the Pacific Ocean basin or the Atlantic Ocean basin? Justify
your answer, using your answer to the previous question.
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Puzzling Plates – Part I
TEACHER PAGES
 The Indian Ocean basin includes three continental plates and, therefore is more like the
Atlantic Ocean basin.
5) What is the dominant type of seafloor feature associated with the plates that are included in the
Atlantic Ocean basin? What type of plate (oceanic or continental) is found along this seafloor
feature? List the four major plates.
 The Mid-Atlantic Ridge is the major seafloor feature that accounts for the edge of four
large continental plates: North American Plate, Eurasian Plate, South American Plate, African
Plate.
6) What kind of plate is the Antarctic Plate? What is the dominant seafloor feature that surrounds
this plate?
 The Antarctic Plate is a continental plate that is almost completely surrounded by a mid-ocean
ridge. This ridge connects the Pacific, Atlantic, and Indian Ocean basins.
7) What is the dominant type of seafloor feature associated with the northern and western edges of
the Pacific Plate? Examine the edges of the adjacent plates - those that touch the Pacific Plate.
Is there oceanic crust or continental crust bordering the Pacific Plate? Write a short paragraph,
comparing this area with the eastern edge of the Nazca Plate.
 The western and northern edges of the Pacific Plate are rimmed with trenches. The adjacent
plates have oceanic crust at the boundary (even though the Eurasian Plate is a continental
plate, at the edge where it meets the Pacific Plate, there is oceanic crust).
 The Nazca Plate’s eastern edge has a trench, but the adjacent plate, the South American
Plate has continental crust at the boundary and therefore it is very different from the
western Pacific trenches. Students should make this observation. They might also observe
how the western Pacific trenches are very arcuate, whereas the southern Peru-Chile Trench
is very linear. These are observations made in the first activity, “Investigating the Seafloor”.
In future activities they will see how the trenches are formed.
8) Select one of the 4 plates listed below from the puzzle. Write a story that takes the reader on a
tour around the perimeter of the selected plate. Imagine that you are operating a submersible (a
manned underwater vehicle with viewing capabilities) just above the seafloor. Describe the
features you encounter along the way. Use the World Wide Web and other resources available to
find pictures of different seafloor images of mid-ocean ridges, trenches, fracture zones and
seamounts to aid with your descriptions.
(Nazca Plate, Cocos Plate, Juan de Fuca Plate, Indo-Australian Plate, Caribbean Plate)
 These plates were chosen because each has a trench, mid-ocean ridge and fracture zones.
Seamount are found on each as well, but may not be a dominant feature. Students may be
encouraged to present their tour, create a powerpoint presentation, or brochure.
Source: Dr. Leslie Sautter, Project Oceanica, Dept. of Geology and Environmental Geosciences, College of Charleston, SC.
Contributions to this activity were made by Arla Jessen.
website: http://oceanica.cofc.edu email: [email protected] phone: 843-953-5586
Funding for the COASTeam Program was provided by the South Carolina Sea Grant Consortium. http://oceanica.cofc.edu/coasteam/
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Puzzling Plates – Part I
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Figure 1 – Tectonic Plates of the Earth
Figure 1. The major lithospheric plates of the earth.
The earth is broken into many plates. The boundaries of these plates are well-defined
and can be identified by examining the locations of shallow focus earthquakes. Many
seafloor features are formed at these plate boundaries, such as trenches and mid-ocean
ridges. There are at least 14 major plates on the earth, as well as many smaller plates
(micro-plates).
Plates are numbered: (1) North American Plate; (2) Philippine Plate; (3) Pacific Plate;
(4) Cocos Plate; (5) Nazca Plate; (6) Caribbean Plate; (7) South American Plate;
(8) African Plate; (9) Arabian Plate; (10) Eurasian Plate; (11) Antarctic Plate;
(12) India-Australian Plate; (13) Scotia Plate; (14) Juan de Fuca Plate.
(Figure revised from Of Sand and Sea, by P. Keener-Chavis and L. Sautter, p. 9)
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Figure 2 – Cross-section View of the Lithosphere
Figure 2. The layers and textures of the lithosphere, both oceanic lithosphere and continental
lithosphere, are indicated. (Figure from Of Sand and Sea, by P. Keener-Chavis and L. Sautter, p. 8)
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