Theory of Continental Drift
Sea Floor Spreading
Plate Tectonics
Convection Currents
Surprise!
100
When looking at the continents as they appear today on a map, Alfred Wegener noticed that they...
Fit together like puzzle pieces
100
Where does sea-floor spreading occur
mid-ocean ridges
at the mid-atlantic ridge
100
plate boundary where two pieces of crust collide
convergent
100
What is the cause of plate tectonics?
Convection currents in the mantle
100
What is the difference between magma and lava?
magma=below the crust
lava=above the crust
200
How long ago did Pangea exist?
Around 200 million years ago
200
Crust forming near the center of a mid ocean ridge is ___________ in age while crust farther from the mid ocean ridge is ___________ in age.
younger, older
200
when oceanic crust and continental crust collide, what type of plate boundary do you get?
subduction zone
200
Which part of the mantle is liquid? Which part of the mantle is solid?
upper mantle is liquid, lower mantle is solid
200
What is the inner core made of?
Solid iron
300
What piece of evidence was Alfred Wegener missing to solidify the theory of Continental Drift?
Evidence of sea-floor spreading
300
Why does oceanic crust reverse polarity over time?
It has magnetite in it which changes direction when the Earth's magnetic field changes direction
300
What landforms do you find at divergent plate boundaries?
mid-ocean ridges
rift valleys
300
With your hand, show how you would draw the flow of arrows that convection currents make
300
Where is the mid-atlantic ridge?
In the middle of the Atlantic Ocean
400
List all 4 pieces of evidence of Alfred Wegener's origional theory of continental drift
1. fossils match
2. landforms match
3. glacial evidence
4. puzzle pieces
400
If sea floor spreading is occuring all the time, is the Earth getting bigger? Why or why not?
No, because eventually crust undergoes subduction on other places on earth
400
new crust is created at _____________ plate boundaries
divergent
400
What does it mean that the upper mantle is considered "plastic"
It can flow
400
What is the date of your plate tectonics quiz?
4/11 or 4/12
500
At what speed per year are the continents moving away from each other?
2-3 cm
500
What is happening in the mantle that causes magma to rise to the surface to create new crust
convection currents
500
what type of plate boundary does not involve magma?
transform
500
Use this picture to explane how convection currents move the crust above them
hot magma rises from the core, once it rises it cools and sinks, pulling on the crust above it before sinking
500
What type of rock makes up oceanic crust? What type of rock makes up continental crust? Which type of crust is more dense?
basalt, granite, oceanic is more dense