Review Questions to Plate Tectonics

If you could observe Earth's tectonic plates moving in real time, what would be the most accurate comparison for their speed?

• About the same speed as a flowing river
• As fast as a running cheetah
• About the same speed as your fingernails grow
• As fast as a walking person

Why do convection currents in the mantle act like a conveyor belt system for tectonic plates?

• Hot rock rises and cool rock sinks, creating circular motion that drags plates along
• Magnetic forces pull the plates in different directions
• Ocean currents push the plates from above
• The Earth's rotation spins the plates around the surface

A geologist discovers a location where new oceanic crust is forming and the seafloor is spreading apart. What type of plate boundary is this most likely to be?

• Divergent boundary
• Subduction zone
• Transform boundary
• Convergent boundary

The Himalayas mountain range formed when two continental plates collided. What can you infer about the density of continental plates compared to oceanic plates?

• Density has no effect on mountain formation
• Continental plates are less dense than oceanic plates
• Continental plates are much denser than oceanic plates
• Continental plates and oceanic plates have the same density

At the San Andreas Fault, why do earthquakes occur frequently even though no new crust is being created or destroyed?

• Volcanic activity is causing the ground to shake
• The plates are sliding past each other horizontally, creating friction
• The plates are moving apart and creating tension
• The plates are colliding and one is subducting under the other

Scientists found identical fossils of the same ancient reptile on both sides of the Atlantic Ocean. What does this evidence most strongly support?

• Ocean levels were much lower in the past
• The continents were once connected and have since moved apart
• The animals could swim across the ocean
• The same species evolved independently on different continents

Why is the Ring of Fire particularly dangerous for the countries located within it?

• It has the most transform boundaries in the world
• It experiences the fastest plate movement
• It contains 75% of the world's active volcanoes and frequent earthquakes
• It has the deepest ocean trenches

When an oceanic plate meets a continental plate at a convergent boundary, what happens and why?

• Both plates push upward to form mountains
• The oceanic plate subducts because it is denser
• The continental plate subducts because it is denser
• The plates slide past each other horizontally

If you were to examine the magnetic patterns in rocks on the ocean floor, what would you expect to find as evidence of seafloor spreading?

• Random magnetic orientations throughout the ocean floor
• Magnetic patterns that mirror each other on both sides of mid-ocean ridges
• Stronger magnetic fields near the continents
• No magnetic patterns because ocean rocks don't contain magnetic minerals

The East African Rift is an example of a divergent boundary on land. What will most likely happen to this region over millions of years?

• It will transform into a transform boundary
• It will close up and disappear
• It will create a new ocean as the rift continues to widen
• It will form a new mountain range