Restless earth- Plates Flashcards
What is the crust divided up into?
Tectonic plates
The structure of the earth from outside to inside layer?
Crust (solid)
Mantle (thick liquid)
Outer core (liquid)
Inner core (solid)
Features of continental crust?
Thicker and less dense than oceanic
Features of oceanic crust?
Thinner and more dense than continental
Why are the plates moving?
Convection currents in the earths mantle generated by radioactive decay in the core
What is the place where two plates meet called?
Plate margins
What is a destructive plate margin?
Two plates moving towards each other
The oceanic plate goes underneath the continental plate and is destroyed.
What does destructive plate margins cause?
Volcanos and ocean trenches
What is a ocean trench?
Very deep section of the ocean floor where the oceanic plate goes down
An example of a destructive plate margin?
East Coast of Japan
Nazca plate sub-ducting under South American plate.
What is a constructive plate margin?
Two plates are moving away from each other
Molton rock rises up and fills the gap and cools, forming new crust
An example of constructive plate margin?
At the mid-Atlantic ridge-Iceland
What is a conservative plate margin?
Two plates moving sideways past each other
No crust is created or destroyed
An example of a conservative plate margin?
The San-Andreas fault
Who came up with the theory of continental drift originally?
Alfred Wegener
