Lithosphere
What two parts of Earth make up the lithosphere?
Crust and uppermost mantle
Where is the asthenosphere located?
Below the lithosphere
What was Pangaea?
A supercontinent where all the continents were joined together
Who proposed the theory of seafloor spreading?
Harry Hess
Which type of plate boundary occurs when two plates move toward each other?
Convergent
How would you describe tectonic plates?
As large pieces that move slowly and fit together like puzzle pieces
What is the asthenosphere made of?
Partially melted rock
About how long ago did Pangaea exist?
300 million years ago
Where does new oceanic crust form according to seafloor spreading?
Mid-ocean ridges
What type of plate boundary is formed when two plates move away from each other?
Divergent
What does it mean when we say the lithosphere is "brittle"?
It can break or crack under stress
How does the asthenosphere move?
It flows slowly like thick plastic
Who proposed the Continental Drift Theory?
Alfred Wegener
What happens to older oceanic crust as new crust forms at mid-ocean ridges?
It moves away from the ridge
Which boundary is characterized by plates sliding past each other horizontally?
Transform
What layer does the lithosphere “float” on top of?
Asthenosphere
Why is the asthenosphere important for plate movement?
It allows tectonic plates above it to move
What evidence supports the idea of Pangaea?
Matching fossils and similar rock layers on different continents
What evidence from the ocean floor shows that new crust is constantly forming?
Magnetic striping
What often forms at a convergent boundary where an oceanic plate collides with a continental plate?
Volcanoes and mountain ranges
Why the lithosphere is important for plate tectonics?
It’s made of tectonic plates that move and cause earthquakes, volcanoes, and mountain building.
Describe one key difference between the lithosphere and the asthenosphere.
The lithosphere is rigid and brittle, while the asthenosphere is soft and can flow.
How does the “puzzle piece” idea support the theory of Pangaea?
The continents look like they could fit together, showing they were once connected.
Which process directly creates new oceanic crust at mid-ocean ridges?
Magma rising and cooling
Which type of plate boundary is commonly associated with earthquakes but not the creation of new crust?
Transform