Plate Tectonics

What does the theory of continental drift state?

• The continents were once joined in a super-continent and have moved over time
• Continents are stationary and do not move
• The Earth is broken into lithospheric plates that move due to convection currents
• none of the above

What are the two types of crust

• continental and oceanic
• ocean and upper
• lower and upper
• pizza and subway

The type of plate boundary where two plates come together is a .....

• Convergent Boundary

• Divergent Boundary

• Transform Boundary

• Plate Boundary

Most geologists think that the movement of Earth’s plates is caused by _______

• convection.

• continental drift.

• subduction.

• conduction.

Ocean Ridges are formed by _______ plate boundaries

• Convergent Oceanic / Continental

• Convergent Continental / Continental

• Convergent Oceanic / Oceanic

• Divergent

Observe this diagram of a plate boundary. One statement BEST describes what is happening. It is that

• the oceanic crust is melting.

• the denser ceanic crust is subducting under the less dense oceanic crust

• volcanic islands are forming.

• the tectonic plates are moving away from each other.

How is it possible for new crust to be formed without increasing the surface area of the Earth?

• Crust is destroyed at the same time it is created

• New crust is underwater where it sinks

• New crust breaks more easily than old crust

Below is a picture of sea-floor spreading. How are the ocean crusts moving?

• Converging

• Diverging

• Sliding

• No movement

A fault is formed by the movement of a __________ plate boundary

• Transform
• Convergent
• Divergent

Why does oceanic crust subduct under continental crust?

• Oceanic crust is thin

• Oceanic crust is dense

• Continental crust is thin

• Continental crust is dense