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Name ____________________________________________________ Period _______ Score _________
Unit 2: Plate Tectonics
Unit Objectives
 Identify that the sources of Earth’s internal heat (radioactive decay and heat of formation)
 Trace the lines of scientific evidence that lead to the inference that Earth’s core, mantle and crust are each made
up of different materials
 Trace the lines of scientific evidence that lead to the inference that Earth’s lithosphere, asthenosphere,
mesosphere, outer core and inner core each have different physical properties
 Explain how convection currents help distribute heat within the mantle
 Explain Alfred Wegener’s continental drift hypothesis, his evidence, and why it was not accepted in his time
 Cite examples of how the geologic record preserves evidence of past changes
 Establish the importance of the discovery of mid-ocean ridges, oceanic trenches, and magnetic striping of the sea
floor to the development of the modern theory of plate tectonics
 Explain how mantle plumes provide evidence for the rate and direction of tectonic plate movement
 Organize and evaluate the evidence for the current theory of plate tectonics
Layers of the Earth
The Earth is composed of four different layers: ___________________________________________________
The Crust
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______________________________________________________________________________
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Continental Crust: ________________________________________________________________
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Oceanic Crust: __________________________________________________________________
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_______________________________________________________________________________
The Mantle
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______________________________________________________________________________
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______________________________________________________________________________
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Lithosphere: ____________________________________________________________________
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Asthenosphere: __________________________________________________________________
o ________________________________________________________________________
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Mesosphere: _____________________________________________________________________
o ________________________________________________________________________
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The Outer Core
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The Inner Core
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Why is the Earth’s core so hot? ________________________________________________________
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Heat of formation: __________________________________________________________________
__________________________________________________________________________________
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__________________________________________________________________________________
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Radioactive Decay: __________________________________________________________________
___________________________________________________________________________________
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___________________________________________________________________________________
Layer of
Earth
Lithosphere
Asthenosphere
Mesosphere
Outer Core
Inner Core
Thickness
Made out
of
State of
matter
Unique
Properties
How Do We Know All This?
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_________________________________________________________________________________
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Shadow Zones: ___________________________________________________________________
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S-wave: __________________________________________________________________________
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Color and label the following: continental crust (green), oceanic crust (black), lithosphere, asthenosphere
(brown), mesosphere (yellow), mantle, outer core (orange), inner core (red).
Convection Currents
Convection: _______________________________________________________________________________
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_________________________________________________________________________________
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_________________________________________________________________________________
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_________________________________________________________________________________
Draw convection currents in the Earth’s mantle
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Continental Drift
•
Create a TREE MAP of the evidence that helped you piece the puzzle together.
Writing: Explain how you reconstructed the supercontinent Pangaea and list least 3 piece of evidence
that led to your decision.

Writing should be in complete sentences (2 points)

and have at least three sentences. (6 points total)
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Continental Drift
Alfred Wegener: ___________________________________________________________________________
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Pangaea: _______________________________________________________________________
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Panthalassa: _____________________________________________________________________
Evidence
1. __________________________________________________________________________________
2. __________________________________________________________________________________
3. __________________________________________________________________________________
4. __________________________________________________________________________________
When where Alfred Wegener’s ideas about Continental Drift accepted?
________________________________________________________________________________________
Why weren’t his ideas about Continental Drift accepted until then?
_________________________________________________________________________________________
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New evidence to back up the Theory of Continental Drift: SEA FLOOR SPREADING
Harry Hess: _______________________________________________________________________________
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____________________________________________________________________________
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____________________________________________________________________________
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Mid-Ocean Ridge: ___________________________________________________________________
o ______________________________________________________________________
o ______________________________________________________________________
o ______________________________________________________________________
______________________________________________________________________
Seafloor Spreading Map Instructions and Questions
Part A: Color the map on the next page according to these directions

Label the two mid-ocean ridges (the dark black lines)
o The East Pacific Rise is in the Pacific Ocean
o The Mid-Atlantic Ridge is in the Atlantic Ocean
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Color the Seafloor Spreading Map as follows:
o 1.Red 2. Orange 3. Yellow 4. Green 5. Blue 6. Purple Continents: Brown
Part B: Answer these questions on this paper after you complete part A.
1. How does the age of the rock change as you move away from the mid-ocean ridge?
_________________________________________________________________________________
2. Where is the youngest rock found? ____________________________________________________
3. What is the age of the youngest rock? __________________________________________________
4. What is the age of the oldest seafloor? ____________________________________________________
5. Where do you find the oldest seafloor? ___________________________________________________
6. Which mid-ocean ridge is longer? ________________________________________________________
7. Would older fossils be found in the green section or the orange section? _________________________
8. Describe how sea-floor spreading creates new rock using your own words. _____________________
_________________________________________________________________________________
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Paleomagnetism
Review: __________________________________________________________________________________
___________________________________________________________________________________
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The magnetic field protects Earth from ____________________________________________
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If the outer core were to become _______________, there would be no ________________________
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____________________________________________________________________________________
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Magnetite: __________________________________________________________________________
o ___________________________________________________________________________
o ___________________________________________________________________________
___________________________________________________________________________
o ___________________________________________________________________________
Draw a diagram of earth’s magnetic reversals
Plate Tectonics
The Theory of Plate Tectonics: ________________________________________________________________
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__________________________________________________________________________
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___________________________________________________________________________
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What causes plate motion?
1. ________________________________________________________________________________
________________________________________________________________________________
2. ________________________________________________________________________________
________________________________________________________________________________
3. ________________________________________________________________________________
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