Download GIS Plate Tech

Evidence for Plate Movement
My World GIS Activity
Purpose
Investigate how earthquake and volcanic activity provide evidence for plate boundaries.
Prelab - Biozone Pages 16,7 will have been assigned for homework. Answer additional questions on the student answer sheet
Data Chart page before starting this activity
Geographic Clues
Plate tectonics is a relatively new scientific concept, introduced some 30 years ago, but it has revolutionized our understanding
of the dynamic planet upon which we live. It drew together many branches of the earth sciences, from paleontology (the study
of fossils) to seismology (earthquake study). It has provided explanations to questions why earthquakes and volcanic eruptions
occur in very specific areas around the world, and how and why great mountain ranges like the Alps and Himalayas formed.
The theory of plate tectonics states that the Earth's outermost layer is fragmented into a dozen or more large and small plates
that are moving relative to one another as they ride atop hotter, more mobile material. Before the advent of plate tectonics,
however, some people already believed that the present-day continents were the fragmented pieces of pre-existing larger
landmasses ("supercontinents").
The belief that continents have not always been fixed in their present positions was suggested in 1596 by the Dutch map maker
Abraham Ortelius. In 1912 that the idea of moving continents -- called Continental Drift -- introduced by German
meteorologist Alfred Wegener. He contended that, 200 million years ago, a supercontinent called Pangaea began to split apart.
Source: USGS http://pubs.usgs.gov/gip/dynamic/historical.html
1) Open My Documents, MyWorld GIS, plate tectonics.m3vz
Part 1: Geographic Evidence that Pangaea once existed
1) In 1596 Abraham Ortelius suggested the Americas were "torn away from Europe and Africa . . . by earthquakes and
floods.” What visual evidence from the map you are viewing supports this statement???
2) To see what Pangaea looked like, turn on the “Linked Images” layer. Click the EYE – right of the layer name.
Now click the link tool to show link flags. The image
of Pangaea is linked to the easternmost point in
Antarctica. Click the point below the flag to show the image
link, and then click the image link to open the image.
NOTE Use mya means Million Years Ago
The upper left figure is Pangaea, and the remaining figures show
transition to modern times. Examine the figures and answer
3) India broke away from Pangea approx ???
India crossed the equator approx ???
4) South America and Africa separated approx. ???
Close the image .
Part 2: Fossil Distribution
Wegener was also intrigued by geologic structures and plant and animal fossils found on the matching coastlines of South
America and Africa. He reasoned that it was physically impossible for these organisms to have swum or have been transported
across the vast oceans. The presence of identical fossil species along the coastal parts of Africa and South America was the
most compelling evidence that they were once joined.
This also explained the evidence of dramatic climate changes on some continents. For example, fossils of tropical plants (as
coal deposits) in Antarctica implied that this frozen land previously must have been closer to the equator. Other mismatches
included fossil ferns (Glossopteris) in now-polar regions, and glacial deposits in present-day arid Africa.
When Wegener introduced his theory, the scientific community firmly believed the continents and oceans to be permanent
features on the Earth's surface. Not surprisingly, his proposal was not well received.
1) Turn OFF the Linked Images” layer, turn on the “Fossil Distribution” layer. This shows fossils of the same type of
plants and animals found on different continents. The name of each organism is in the upper right corner of the screen, and
fossil type is color coded. The map represents the theoretical position of the plates soon after the breakup of Pangaea, and a
representation of each organism.
2) “Fossil Distribution” layer, click radio button Glossopteris to show only Glossopteris.
Change the view
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Click the pull down arrow next to “Map View:” and select “Stereographic.”
On the map mark the computer displayed positions of Glossopteris on the appropriate land mass with an “G.”
3) Study the maps - Glossopteris indicates prior connections of which continents ???
Change the projection back to Geographic before proceeding.
4) ON “Linked Images” layer - click the point next to the westernmost flag
in Antarctica. This will bring up an image showing “bands” corresponding
to fossil ranges.
Add the bands to the map (answer sheet) - USE colored pencils!
Which fossil is found in Africa, India and Antarctica ???
Close the image .
Part 3: Glacial Evidence
Glacial deposits also provide evidence for the existence of Pangaea.
1. OFF “Fossil Distribution” layer. Open the image of Pangaea again (the easternmost flag in Antarctica) - see above.
Click the point below the flag to show the image link, and then click the link to open the image
Which areas were in the South Polar area 225 mya????
2. ON “Glacial Deposits” layer and compare to your predictions (note: the glacial deposits in Antarctica not shown).
Close the image.
Part 4: Evidence of Plate Boundaries
Wegner’s theory of continental drift was hotly debated off and on before it was largely dismissed, but beginning in the 1950s, a
wealth of new evidence emerged. By 1968 a new theory replaced continental drift – plate tectonics.
A: Transform Plate
Boundaries
1) ON the “plate
boundaries” layer.
The transform type is
color ??? Select
“Transform” radio button
- transform boundaries are
now color ???
One of the best examples
of a transform plate
boundary is the San
Andreas Fault, which runs
the entire length of
California
2) Use the zoom in tool to
zoom into the west coast
of the United States - the
region around Oregon and
Washington.
3) ON “Linked Images”
layer click link tool.
Click under the
flag in North
America to
open the Transform Plate Boundary image.
4) With the image open, focus on the region around the Mendocino Fracture Zone, and think about
Will the earthquakes to be deep or relatively shallow? Will there be volcanoes?
5) Investigate these questions ON “Earthquakes medium m4.0-5.9 (2001-03)” layer.
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This dataset shows the epicenter of over 28,000 earthquakes around the world, and the points are color coded according to the
depth of the focus.
Toggle between the pre-selected depths to verify the depths of the earthquakes around the transform plate boundary.
Record the results in your Data Chart
6) ON the “Volcanoes” layer and record the results in your Data Chart
B: Divergent Plate
Boundaries
OFF Volcanoes and
Earthquakes layers.
ON “Linked Images” and
“Plate Boundary Types”
layers.
Click radio button in
“Plate Boundary Types” layer
to highlight the divergent
plate boundaries.
1) Zoom into the region
around the Mid-Atlantic Ridge
with Iceland in the view
2) ON “Linked Images” layer
and click the link tool. Click
the point under the flag in the
Atlantic Ocean to open the
divergent plate boundary
image. Check the cross
section you drew for HW
3) ON “Earthquakes medium m4.0-5.9 (2001-03)” layer.
Use the pre-selected depths to verify the depths of earthquakes around the
plate boundary.
Toggle between deep and shallow earthquakes and record the results
4) ON “Volcanoes” layer enter results in data table
5) ON the “Sea-floor age (m.y.)” layer. This layer shows the age of the
sea-floor in millions of years before present and age ranges are color
coded. Toggle the different pre-selected age ranges ANSWER
1. Sea floor age closest to N. America and Africa???
2. Sea floor age closest to Greenland???
3. How does the age change between the Mid Atlantic ridge and the continents???
6) OFF “Sea-floor age (m.y.)”
ON “4' World Shaded Relief” “Elevation & Bathymetry” layers. These
layers will give you a sense of the change in elevation along the sea-floor.
Click the vertical profile tool draw a vertical profile.
Change the “Sample Every:” box from 60 to 10 to
increase the resolution. Click “OK”
The vertical profile function works by clicking and
drawing a line across the area you want to profile.
Click once to start the line, double click to stop the
line.
It will draw the profile across the ridge at
approximately a right angle.
Explain what is happening at the highest point on your profile ?????
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C: Convergent Plate Boundaries
OFF the layers from the previous activity
ON countries, linked images, Plate
Boundary types
“Zoom To All” tool button to zoom out to the full
extent.
Click convergent button in the plate boundaries
layer to highlight
Zoom to the region west of South America.
2) On the “Linked Images” layer
and click the link tool Click the point
under the flag in South America to
open the convergent plate boundary image.
The process where one plate goes UNDER another
is called SUBDUCTION
Check the cross section in your data sheet
3) As for divergent boundaries investigate
earthquake depth
volcanoes
and complete your Data Chart
4) Use profile method - check your cross section drawing - make sure the trench is accurately labeled.
Get Teacher sig
The trench depth is ??? m below sea level; the mountain peaks are ??? m above sea level..The mountains range is called ???
Where are the earthquakes located relative to the mountain range
a) Shallow quakes ???
b) Deeper quakes ???
D. Investigate
a) Find the Himalayas, -Investigate boundary type This is a ?????? boundary
But without subduction. Since both plates are continents they are approximately equal density so neither sinks
Investigate Earthquakes , volcanoes and profile . Complete your data chart
Note the Alps in Europe are similar
E. Extra - Investigate
a) African Rift Valley Divergent
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b) Japan or Indonesia
Evidence for Plate Movement
My World GIS Activity Questions
Names ___________________________________
Part 1
1) What visual evidence from the map you are viewing supports that the Americas were "torn away from Europe and Africa?
________________________________________________________________________
3) India broke away from Pangea approx _________________, crossed the equator approx ___________________
4) . South America and Africa
separated approx. ____________
Part 2
Glossopteris indicates prior
connections of which continents
__________________________
__________________________
_____________________
Add the bands to the map
- USE colored pencils!
Which fossil is found in Africa,
India and Antarctica ONLY?
________________________
Part 3
Which areas were in the South
Polar area 225 mya?
______________________
_______________________
Part 4 A.
1) The transform type starts as color____________ ;
Transform radio button clicked - transform boundaries now highlighted - change to ____________
Complete data table earthquake and volcano details for transform faults
Part 4 B
Record earthquake and volcano data in table
1. Sea floor age closest to N. America and Africa?
____________
2. Sea floor age closest to Greenland?
__________________
3. How does the age change between the Mid Atlantic ridge and the continents? ___________________________________
Check the profile on your chart. What is happening at the highest point on your profile ?
__________________________________________________________________________________
Part 4 C
4. Using the profile method check your cross section drawing - make sure the trench is accurately labeled.
Teach sig ______
The trench depth is ________________ m below sea level; the mountain peaks are ___________ m above sea level.
The mountains range is called
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Where are the different earthquakes located relative to the mountain range ?
a) Shallow quakes
b) Deeper quakes
Part 4 D Find the Himalayas, -Investigate boundary type This is a ______________________ boundary
Summary Questions - use the activity and HW (Biozone) to answer
1. According to the theory of plate tectonics, the lithosphere is broken into large segments called plates. These plates “float”
on a more fluid layer called the ___________________ ,. The plates continuously move and gradually change shape and size.
2. Briefly explain two evidences of plate tectonics.
3. Explain why deep ocean trenches are close to continents and not in the middle of oceans.
4. What is occurring in the ocean region between North America and Europe?
5. How do you account for mid-plate volcanoes such as Hawaii ?
6. Why are volcanoes not common at a transform plate boundary?
7. Explain the differences and similarities between the Andes in S.America and the Himalayas
8. How did using GIS help you to understand plate tectonics ?
This activity is modified from the free plate tectonics activities provided by Northwestern University and Pasco .
http://myworldgis.org/myworld/activities/
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