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Name __________________
Looking at the world map, what do you notice about the
shape of the continents?
The thing is…the world didn’t always
look like this! It used to look like this:
How is this possible?!?!?
Plate Tectonics Theory
o
The lithosphere is ____________ into a number of
large and small _____________ and the plates are
floating on the ______________
Lithosphere = the Earth’s ______________ plus the upper
portion of the _____________ layer
Plate Boundaries
Divergent Boundary:
o
o
Plates are moving ___________ from each other
Midocean ridges are ____________ and ___________ ocean floor plates are created
Convergent Boundary:
o
Plates are moving __________ each other and are colliding (3 types)
1. When Ocean Plates collide with Contintental Plates
 _____________________________, trenches
 Create near coast volcanoes
 ______________ __________ zones (a pattern of earthquakes as an ocean plate grinds down
the underneath side of a continent)
2. When ocean plates collide with other ocean plates
 ___________________ are created
 (a pattern of volcanic islands created from a subduction zone
that is located off the coast)
3. When a continental plate collides with another continental plate
 ______________________ are created (example:
Himalayan Mountains)
Transform Fault Boundary
o
o
o
o
Plates are neither moving toward nor away from each other, they are
moving ______________________.
The plates may move in _____________ directions or in the
_________ directions but at different rates and frequent
_____________ are created (example: San Andreas Fault)
Plates are destroyed as fast as they are created (2 ways)
Plates may be subducted and ____________ or may push be pushed upward to form
______________
How can Oreos model the plate boundaries?



Very carefully, take just the top cookie off the Oreo.
Break the top cookie into 2 equal halves.
Replace the cookie halves back on the Oreo
Using the cookie,
 Demonstrate a transform fault boundary
 Demonstrate a divergent plate boundary
 Demonstrate a convergent plate boundary
Seafloor Spreading Theory:


Ocean floors are moving like broad ______________________
New ocean floor crust is being created at the
_______________________________
What causes this?
___________________________________ within the mantle
 The up-welling leg of the current creates a _____________ boundary which produces
_______________________________
 The down-welling leg of the current creates one type of
________________ boundary that results in
________________ and a ________________ zone
What evidence do we have to support this idea?






Midocean ridges are ________________ than surrounding ocean
floors
____________________________ on ridges, earthquakes on ridges
Midocean ridge rocks are _____________ than surrounding ocean floor rocks
Midocean ridge volcanoes are _________________ than volcanoes further away
Ocean floor sediments are _______ on the ridges and get ____________ as the distance from
the ridges increase
Polar reversal magnetism proves that the ocean floor is moving away from the ridges
Speed of Spreading


Atlantic Ocean – _________ cm/year
South Pacific Ocean – __________ cm/year
Continental Drift Theory
The __________________ have shifted their position over geologic time and at one time all land
masses were ____________ into one piece called _________________
o
Pangaea began to split apart 200 million years ago
o Diagram
Laurasia
Pangaea
Gondwanaland
North America
Greenland
Eurasia
West G.
East G.
Africa
S. America
Antarctica
Australia
India
The continents are like packages on the seafloor conveyor belt.
What evidence do we have to support this idea?
o
o
o
o
High percentage __________ of continents at the 500 fathom level
Minerals, fossils, and mountains on now ______________ continents ___________ if the
continents were together
Glaciation patterns indicate a ___________ ice cap at the South Pole
________________________ (magnetism of old rocks) indicate a common pole if the
continents were all connected