Plate Tectonics Flashcards
What are the three types of plate boundaries?
Convergent - collide
Divergent - separate
Transform - slide/slip
What is plate tectonics?
The theory that the Earth is divided into plates (pieces) that move around on the asthenosphere
At what plate boundaries can earthquakes occur?
All of them: Convergent, divergent, and transform
At which type(s) of plate boundaries can new sea floor is made?
Divergent
What happens at __________ boundary depends on the type of crust of plates.
Convergent
What are the three type of crust combinations at plate boundaries?
Continental - Oceanic
Continental - Continental
Oceanic - Oceanic
The most common divergent boundary is at ___-_____ _____.
Mid-ocean ridge
At what plate boundary. Do plates slide past each other? And what’s an example of a result of this?
Divergent
The San Andreas Fault
What is a divergent plate boundary?
Where plates move away from each other
What is a convergent plate boundary? What are two things that can happen at convergent boundaries?
When plates move toward each other
Collision and Subduction
What is a transform plate boundary?
When plates slide horizontally next to each other
Continental crust is less _____ than _______ crust so it doesn’t sink. It is never _________ and it is ________.
Dense
Oceanic
Destroyed
Permanent
Oceanic crust is heavier so it ____. It is constantly being ______ and _________ at ocean ridges and trenches.
Sinks
Formed
Destroyed
Some ___________ crust can carry on beyond the edges of land so it ends up _____ the sea. That explains why all the edges of continents don’t have deep trenches up against their coastlines.
Continental
Under
Plates usually NEVER _______. However one exception is the _____ _________. This means the plates must either _______ or both are ______ up. To form ________ or one of the plates muse be pushed down into the mantle and be _________.
Overlap Rocky Mountains Collide Pushed Mountains Destroyed
There are never gaps between the plates, so if two plates move apart — new ____ will be formed.
Rock
The earth IS NOT getting bigger …so the amount of new crust being formed must be the same as the amount being _________.
Destroyed
Plate movement is VERY SLOW. But when plates make sudden movements we call them ___________. This is the only time we are aware that the plates are moving.
Earthquakes
Why did many scientists reject Wegener’s hypothesis?
They didn’t think that the crust could move that way because of how strong rocks were.
On the process of sea-floor spreading, what happens when magma rises to Earth’s surface and solidifies?
It forms mid-ocean ridges, and if it gets above sea level, it forms land.
The theory that explains how continents reached their current locations
Continental drift
Area where sea-floor spreading takes place
Mid-ocean ridges
Process of forming new oceanic lithosphere as magma rises to the surface
Sea-floor spreading
What is Pangaea?
Super continent from about 200 million years ago
