Download Plate Tectonics - Earth Science Teachers` Association

GEOLOGY STUDY GUIDE
Module exam GL1 June 2005
PLATE TECTONICS AND
PALAEOMAGNETISM
Geology Department, Greenhead College, Huddersfield.
Thingvellir, Iceland
Your name .....…………………….................................................
Date .........……………...........
LEARNING TARGETS
margin notes
When you have completed this study guide, you will:
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Know about the distribution of lithospheric tectonic plates
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Understand the formation of different plate margins
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Know the characteristics of plate margin features using EMMIFF
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Be able to draw simple diagrams to show each plate margin and its features
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Understand the ideas behind palaeomagnetism
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Understand how palaeomagnetism gives geologists useful information
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Have tested your knowledge and learned the topic
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GEOLOGY STUDY GUIDE
Module exam GL1 June 2005
Resources
Here is a choice of resources to use. You do not need to look at them all but clearly the more you read the
better your knowledge of case studies will be. Tick the box once you have used the resource.
If you read a photocopied extract then highlight it to help you reread it for revision. If you make notes
from a video tape make sure that the notes are headed with the name of the tape so that you know the
source of your information.
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Understanding Geology David Webster p 139-146
PT1
Geoscience Edwards and King p 12-14
PT2
Geological Science by Andrew McLeish p 177-181
PT3
World map for locating plate margins
PT4
Video Earth Revealed- Plate Dynamics Tape 47 30mins
PT5
Christmas Lectures 1995 Tape 12 12mins and Tape 11 16 mins
PT6
Library video Earth Story Programme 2 The Deep 50mins and Tape 39
PT7
Crustal spreading calculations
PT8
PT10 CDRom Interactive Plate Tectonics
PT11 CD Rom Physical World
PT12 Library Hamblin, W.K. The Earth’s Dynamic Systems
PT13 Library Levin, H.L. Contemporary Physical Geology
PT14 Library Strahler, A.N. Principles of Physical Geology
PT15 Library Strahler A and Strahler A Introducing Physical Geography Chap 11
PT16 Library OU Science Units 7 and 8 Plate tectonics
PT17 Library Fifield, Richard The Making of the Earth
PT18 Library Kearey, P., and Vine, F.J., Global Tectonics
PT19 Library Scientific American Earthquakes and Volcanoes (difficult)
PT20 Library Paul R. Pinet Oceanography Chap 3
PT21 Library Bernard W. Pipkin Geology and the Environment Chap 3
PT22 Library Reed Wicander and Monroe, J.S. Historical Geology Chap 7
PT23 Library Skinner, B.J. and Porter, S.C., The Dynamic Earth Chap 15
PT24 Library Heather, D.C. Plate Tectonics
PT25 Summary Table on plate margins and their characteristics
PT26 Video Christmas lectures 1995 Tape 11 5mins
PT27 Video Magnetic Earth Tape 5 22mins
PT28 Handout on magnetic reversals
PT29 CD Rom Basic Skills for Earth Sciences. Magnetism
PT30 Library Rice, R.J. Fundamental of Geomorphology - Palaeomagnetism
PT31 Library M. Ozima Geohistory - Magnetism
PT32 Library Skinner, B.J. and Porter, S.C., The Dynamic Earth Chap 16
Websites
www.geolsoc.org.uk/ Go to Teaching Resources
www.ucmp.berkeley.edu/geology/tectonics.html
www.geolsoc.org.uk/template.cfm?name=tec_plates
www.geolsoc.org.uk/template.cfm?name=lithosphere
There are many other websites you could search.
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GEOLOGY STUDY GUIDE
Module exam GL1 June 2005
ACTIVITY ONE : PLATE TECTONICS
margin notes
TASK 1 WHAT ARE PLATES?
The processes that we call plate tectonics take place in the upper part of the mantle
and the crust, in the regions called the lithospheric plates (or plates, for short). In
the Earth Structure study guide you learnt about the crust, the mantle and the
asthenosphere. Revise this information.
There are two main types of lithospheric plates – continental lithosphere and
oceanic lithosphere. Draw a diagram to learn about the differences between them.
TASK 2 PLATE MARGINS
Look at PT 1 p 14-15 and answer these questions:
1.
2.
3.
Describe the distribution of earthquake zones throughout the world.
Now describe the distribution of volcanic areas.
The general idea is that the zones correspond with each other. To what
extent is this true?
Plate margins are the boundaries along which plates meet. Complete these
questions:
4.
5.
6.
7.
8.
9.
10.
On PT 4 add the plate margins and the names of each plate.
How many plates are there on the map on p 15?
If continental crust underlies continents and oceanic crust underlies oceans
which plates are purely continental?
Which plates are purely oceanic?
Which plates are moving apart?
Which plates are sliding past each other?
Which plates are moving together and colliding?
Now you need to find out more about the differences between each type of plate
margin.
TASK 3 CONSTRUCTIVE PLATE MARGINS
Constructive plate margins are the ones that pull apart from each other. These are
called constructive because material is added to the crust along these zones so that
each plate is having rocks added to its edge. Constructive plate margins occur
where there is tension resulting in pulling apart of the crust. The resulting
pressure release allows partial melting to take place in the mantle so that magma
is produced.
In class we will use PT 1 p 140 to draw a diagram to explain how this mechanism
works.
Name some constructive plate margins from the map you drew in Task 2.
Use this box for notes
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GEOLOGY STUDY GUIDE
Margin notes
Module exam GL1 June 2005
TASK 4 FEATURES OF MID-OCEANIC RIDGES
Transform faults break up mid-oceanic ridges as shown in Fig.13.4. Draw a
simple version of that diagram and label it in your own words.
Watch video PT 7 to see what constructive plate margins in the deep sea are really
like.
TASK 5 EMMIFF
Make a list of features found associated with constructive plate margins. Use the
formula EMMIFF - earthquakes, mountains, metamorphism, igneous activity,
folds and faults. For each explain why the feature occurs (or does not occur) and
say something about its nature and scale.
TASK 6 RATES OF CRUSTAL SPREADING
Complete PT 8 to find out how fast sea-floor spreading takes place.
TASK 7 DESTRUCTIVE PLATE MARGINS
Research the three types of destructive plate margins;
1. Continental-continental crust collisions (like the Himalayas)
2. Continental-oceanic (subduction) crust collisions (like the Andes)
3. Oceanic-oceanic crust (subduction) collisions (like the west side of the
Pacific Ocean)
Read PT 1 p 142-145 first of all as the basis of your understanding. If necessary
make some notes to remind you of the major processes that take place.
Then read and use PT 10 – 24 which range from library books to CD Roms and
websites to help learn about destructive plate margins.
Make notes, draw diagrams and keep the EMMIFF list in your mind so that you
can learn the features found at each margin.
You can divide this work between you as there are many resources.
In groups, decide which type of research suits you best. Plan on having a session to
get together to discuss what you have found out about each plate margin. Then
decide how you will share out the information about each plate margin so that you
all have notes and diagrams on each one.
Use this box for notes
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GEOLOGY STUDY GUIDE
Margin notes
Module exam GL1 June 2005
TASK 8 CONSERVATIVE PLATE MARGINS
Conservative plate margins are those where two plates slide past each other,
without subduction occuring. The best known example is the San Andreas Fault
on the west coast of North America, passing through San Francisco and Los
Angeles, where earthquakes can be destructive. Draw a sketch of PT 1 p 146
Fig.13.12 and explain in your own words which plates are moving past each other
and at what rate they move.
Make notes on EMMIFF for conservative plate margins. Watch PT5 to help you
understand plate margins.
TASK 9 HOT SPOTS
Hot spots are rising plumes of hot rock which originate at the core/mantle
boundary and are unrelated to mantle convection cells. There are many around the
world at present. Iceland and Hawaii are the best known examples.
Learn Hawaii as an example to show that hot spots remain stationery for millions
of years.
TASK 10 SHALLOW AND DEEP FOCUS EARTHQUAKES
Look at the maps of earthquake foci PT 3 p 120. Answer these questions:
1. Describe the distribution of shallow focus earthquakes using names of
continents, oceans, mountains and countries where appropriate.
2. Compare it with the distribution of intermediate and deep focus earthquakes.
3. Explain, in terms of what you have learned about plate tectonics, why the
distribution of each is so different.
TASK 11 HOW DO LITHOSPHERIC PLATES MOVE?
There are several theories which change and develop as more is discovered about
the seismic and chemical nature of the mantle.
Watch PT 5 and discuss these theories, making brief notes.
TASK 12 SUMMARY OF PLATE MARGINS
Now fill in the table PT 25, which summarises the nature and effects of the
activities at each of the five plate margins. Use all the notes and diagrams you
have collected so far.
TASK 13
EXERCISE
PT 1 p.150 qs.1-8
Deadline: ………………………………..
Use this box for notes
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GEOLOGY STUDY GUIDE
Module exam GL1 June 2005
ACTIVITY TWO : PALAEOMAGNETISM
TASK 14 PALAEOMAGNETISM
Some rocks contain a record of the direction of the Earth’s magnetic field at the
time of their formation. This is called Palaeomagnetism.
Explain how rocks are able to take up the magnetism of the earth’s magnetic field
at the time at which they were formed, considering the different rock types,
sedimentary, igneous (know about Curie point) and metamorphic.
Remnant magnetism is what geologists call the magnetism of the rock at the time
it was formed, which may be quite different from the earth’s present magnetism.
Make notes in class on these ideas.
TASK 15 EVIDENCE FOR SEAFLOOR SPREADING
Read PT 1 p140-141, which gives an excellent account of the three main types of
evidence that geologists needed to show that sea floor spreading is taking place.
Make bullet point notes to explain the evidence in your own words using these
headings:
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Ages of oceanic floor sediments and basalts
Magnetic anomalies
Matching continents.
TASK 16 INCLINATION
Watch PT 27 so that you have a visual picture of how the earth’s magnetic field
develops and how it produces the effects it has. PT 3 p131-136 has much more
detail about earth’s magnetism so read it if you want to find out more.
Use the hand-out PT 28 in class on magnetic reversals and examples of
palaeomagmetic time scales to see how geologists have used the idea of
palaeomagnetism.
TASK 17 APPARENT POLAR WANDERING CURVES
Apparent Polar Wandering Curves (APW curves) are a specific use for which
palaeomagnetism has been valuable.
Look at the APW curve map PT 2 p 213 and explain how this shows the movement
of one part of the crust over the last 550my. How does this evidence help with the
understanding of continental drift?
If you want to know more about palaeomagnetism read and use PT 28-31.
TASK 18
PERSONAL RECORD SHEET
Complete a personal record sheet so that you can record how you have got on with
this large study guide.
Deadline: ……………………………….
TASK 19 SUMMARY NOTES
You need to learn this topic now.
Review notes deadline: ......…….................................
Use this box for notes
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