Ch 7 Plate Tectonics

What is Pangaea?

• a large ice sheet

• a fern that lives close to the equator

• a supercontinent made up of the present-day continents

What evidence suggests that continents were once joined?

• topography of the seafloor

• convergent plate boundaries

• the puzzle-like fit of coast lines

Seafloor spreading is a process that

• destroys oceanic crust

• occurs at mid-ocean ridges

• causes continents to plow through the ocean floor

Magnetic stripes on the seafloor show that

• crust is destroyed at ridges.

• Earth's magnetic field has changed.

• earthquakes are common in the ocean.

What are tectonic plates?

• slabs of oceanic crust

• slabs of continental crust

• slabs of crust and upper mantle

What happens at a transform plate boundary?

• plates slide past each other

• plates move toward each other

• plates move away from each other

What causes tectonic plates to move?

• earthquakes in the crust

• convection in the mantle

• magnetism on the seafloor

In a divergent plate boundary,

• two plates separate.

• two continental plates colide.

• two plates slide past each other.

• an oceanic plate and a continental plate colide.

Many of California's earthquakes are caused by

• two continental plates colliding..

• two plates sliding past one another.

• two plates moving away from each other.

• on oceanic plate and a continental plate colliding

located at a divergent plate boundary

• slab pull

• subduction zone

• San Andreas Fault

• East African Rift