Name ______________________
Date _________
Period ________
Notes: Plate Tectonics
Alfred Wegener
Continental Drift
Wegener thought whole sections of the crust moved
–Evidence
1. __________________
2. __________________
–Same mountains on different continents
3. __________________
–Same fossils on different continents
–Africa and South America look like they fit together
1. Ancient Mountain Belts
2. Ancient Sand Dunes
3. Fossil Evidence
–Fossil Evidence
Same _______________found on different _____________.
1. ______________
2. ______________
3. ______________
4. ______________
What the hypothesis was missing was the ______________
–________________ proposed that the continents were moving on a more
_____________ under the __________ that could possibly be moving due to
__________________ . . .
–He had no way to prove it!!
He was right!
•He died before his _______________ was accepted as a _______________.
New technology allowed scientists to examine the ________________________.
–They found that the crust was moving due to Earth’s ______________________.
–This developed into the theory of ___________________________.
Notes: Evidence for Plate Tectonics
Evidence
– Continental Drift (continents fit, fossils, rocks)
– New Evidence
• _______________________________________
• Magnetism of the ocean floor (p174)
• _______________________________________
Earthquakes and Volcanoes:
Most earthquake and volcano activity happen along _____________________.
• Plates are moving apart, moving together, or sliding past one another.
– This creates ______________________
• Where plates move apart and come together _____________is brought to
the surface
– This creates _______________________
– See page 712 to view direction of plate movement
Magnetism of the Ocean Floor (see page 174):
– Mid-ocean Ridges are places where ___________ rock is forming.
– These rocks contain ______________________ (minerals with iron) they point to
the _____________________
– The north pole can __________with the south pole
– These minerals flip too. This is called a ________________________.
Age of the Ocean Floor:
– New rock is formed at a __________________ or spreading center
– These are formed in the ____________ of the ocean
– The rock gets _______________ as you move away from the ridge
– The ocean floor is not that old because it subducts under continents
– The oldest ocean floor is ~_____________________________
Earth’s Structure:
• Crust + ________________ = Lithosphere (________)
• ________________ “fluid” portion
• Mantle - _________
• Outer Core –_________
• Inner Core – _________
– Heat comes from _____________________ material in the core
Thick
_______________
High Silica
____________
Thin
____________
Low Silica
__________
3 Types of Plate Boundaries:
1. Divergent __________________
2. Convergent __________________
3. Transform __________________
Notes: Divergent Boundary
Sea floor spreading

Large continents begin to ________ and
__________ apart
 The gaps fill with _________
 Small seas become ___________
 The __________________________ continues
to produce new crust
Characteristics
•________________ are moving apart
•_____________ comes to the surface and cools
•___________ rock forms
•___________ and ____________ in color
•Creates a _______________________
–Rift valleys form in the center
•Examples: Mid Atlantic Ridge and East Pacific Rise
Using the Map on page 712-713, highlight the Divergent Boundaries
How?
• The plates are pulled apart by _____________________ in the mantle below
• Caused by heat released from natural ________________ processes
• At mid-ocean ridges _______________ rock from below rises up to fill the gap with
new ______________ rock
Let’s Draw a Divergent Boundary:
Notes: Convergent Boundary
2 Plates Are Moving Together
SUBDUCTION
 Ocean – Ocean
 Ocean – Continent
- Volcanoes Form
- __________ Earthquakes
COLLISION
 Continent – Continent
- Creates Mountain Belts
- NO ________________
- Earthquakes
(a) = Ocean Continent
(b) = Ocean – Ocean
(c) = Continent – Continent
Subduction Boundary
• Ocean-______________ or Ocean-________________
• The _____________ plate always ________________
Ocean – Continent Subduction
• The __________________ always subducts because it is more dense.
• ___________________________ or a mountain chain of volcanoes form on the
________________.
• Examples: _________________________
Andes of S. America
Ocean – Ocean Subduction
• The _______________ ocean plate always ___________ because it is more dense.
• _______________________ or chains of volcanic islands form on the continental plate.
• Examples: __________________________
Mt Pinatubo, Philippines
Fuji, Japan
Let’s Draw a Subduction Boundary:
Collision Boundary
• There is ____________________ because both plates are ____________ and have
_____________________.
• They __________________ forming mountains (not _____________)
• Examples: Himalayas, India/Asia
Highlight the major Convergent Boundaries
Notes: Transform Boundary
 2 plates are __________________ one another
– Ocean-__________________
– Ocean-__________________
– Continent-_______________
 No ________________________
 Examples:
– ________________________
– ________________________
Highlight the major Transform Boundaries
Let’s Draw a Transform Boundary: