Name:
Date:
Science 10: 12.2 Features of Plate Tectonics
Text: Chapter 12, pages 506-517
Part A: Earth’s Interior Introduction
-Less than 100 years ago scientists had
to use the features at Earth’s surface to
infer what existed in its interior.
-What features would you use to
support the idea that Earth’s interior is
not just a solid mass of rock?
________________________________
________________________________
________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
-We now know that as Earth cooled after its formation dense materials sunk to its interior and
less dense materials floated on top, creating different layers.
Part B: Earth Cross Section
-There are four distinct Earth layers:
1. Crust:
-Outermost and thinnest layer. Continental is
granite, oceanic is basalt.
2. Mantle:
-Thickest layer and accounts for 70% of Earth’s
volume.
-Upper Mantle, partly molten rock rich in iron
and magnesium. Is plastic (solid that can flow)
Science 10: 12.2 Features of Tectonic Plates
Page 1
-Lower Mantle: Solid, dense and rich in iron and
magnesium.
3. Outer Core:
-Liquid, made of iron and nickel.
4. Inner Core:
-Earth’s centre. Made of mostly iron and some nickel.
High pressure makes it solid despite hot temperatures
(5000 to 6000 °C).
Part C: Tectonic Plates
-There are about 12 tectonic plates and they can be
composed of two types of materials. What are they?
___________________________________________
___________________________________________
-The upper portions of the mantle and crust can
further be subdivided into two separate layers:
1. Asthenosphere:
___________________________________________
__________________________________________
__________________________________________
2. Lithosphere:
__________________________________________
_____________________________________________________________________________________
-Two which of the layers above do the tectonic plates belong?
_____________________________________________________________________________________
Science 10: 12.2 Features of Tectonic Plates
Page 2
Part D: Tectonic Plate Motion
-Where do you think the heat that
keeps the asthenosphere molten is
coming from?
______________________________
______________________________
-Explain how the addition of heat to
the asthenosphere generates convection currents.
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
-Convection currents are one of the driving forces behind the movement of tectonic plates. Other
contributing factors include:
1. Ridge Push:
_____________________________
_____________________________
_____________________________
_____________________________
_____________________________
_____________________________
2. Mantle Drag:
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
2. Slab Pull:
_____________________________________________________________________________________
_____________________________________________________________________________________
Science 10: 12.2 Features of Tectonic Plates
Page 3
Part E: Tectonic Plate Interactions
-Plate boundaries are where two tectonic
plates interact. There are three main types:
1. Divergent
-What type of plate movement is occurring here?
___________________________________________________
-Rift valleys become mid-ocean ridges given enough time.
-Mid-Atlantic Ridge is the longest mountain chain in the world.
Science 10: 12.2 Features of Tectonic Plates
Page 4
2. Convergent
What type of plate movement occurs here?
_____________________________________________________________________________________
-Type of convergent boundary depends on the composition of the colliding plates:
a) Oceanic-Continental Plate Convergences
-Which of the two plates colliding here would subduct? Why?
_____________________________________________________________________________________
-What features are formed by this type of plate interaction?
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
Science 10: 12.2 Features of Tectonic Plates
Page 5
b) Oceanic-Oceanic Plate Convergences
-If both plates are made of the same material (basalt), why does one subduct?
_____________________________________________________________________________________
-What type of features will be formed?
_____________________________________________________________________________________
_____________________________________________________________________________________
c) Continental-Continental Plate Convergences
-When two continents collide, why does one plate not subduct?
_______________________
_______________________
_______________________
_______________________
-What type of features form
from this collision?
_______________________
_______________________
_______________________
_______________________
Science 10: 12.2 Features of Tectonic Plates
Page 6
3. Transform
-How is this plate boundary different from
the others we have looked at?
__________________________________
__________________________________
__________________________________
__________________________________
-What features would be produced by this
type of interaction?
__________________________________
__________________________________
__________________________________
__________________________________
*Below is a summary of plate tectonic
interactions:
Science 10: 12.2 Features of Tectonic Plates
Page 7
Part F: Earthquakes
1. Earthquake Formation
-Friction between interacting plates can
create stress (the build-up of pressure).
-When the stress gets too great the
plates slip and release the stored energy.
-What is the difference between the
Focus (Hypocentre) and Epicentre?
________________________________
_______________________________
______________________________
______________________________
______________________________
______________________________
-Examine the map right. Where
would the deepest focus be found?
______________________________
______________________________
_______________________________
_______________________________
-What depth of Earthquake do you think will cause the most damage? Why?
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
Science 10: 12.2 Features of Tectonic Plates
Page 8
2. Seismic Waves
-Energy released from earthquakes travels outwards from the focus as waves. There are three types:
-Seismic waves have been very useful to scientists in revealing the nature of Earth’s interior. For
example, seismic waves speed up as they descend into the mantle, which indicates that the mantle’s
density is increasing with depth.
Science 10: 12.2 Features of Tectonic Plates
Page 9
3. Measuring Earthquakes
-Seismometers measure the amount of ground
motion, the time of earthquake and how long it
lasted.
-Earthquakes are measured by magnitude, with a
10x increase in magnitude between numbers on
the Richter Scale.
-How much stronger is a magnitude 9
earthquake than a magnitude 5?
__________________________________
__________________________________
__________________________________
__________________________________
*Try 12-2C: Interpreting Seismograms
Science 10: 12.2 Features of Tectonic Plates
Page 10
Part G: Volcanoes
-The movement of tectonic plates cause three main types of volcanoes: Composite, Shield and Rift.
-With a partner, you will select one volcano type and research a specific volcano of that type (You will
need to get this approved by Mr. Fox). You will create a small presentation that must cover the following
points:
1. Name and location of your volcano.
2. Type of tectonic plate boundary your volcano is associated with. You should discuss the nature of this
boundary.
3. Discuss your volcanoes distinguishing features.
4. Relate the type of plate boundary and magma/lava created to the shape/characteristics of your volcano
(if applicable).
*Make sure that you take your own notes on all three volcano types from the text!
Science 10: 12.2 Features of Tectonic Plates
Page 11