Chap. 4 Lesson 3

plate

a piece of the Earth's crust

divergent boundary

A plate boundary where two plates move away from each other.

convergent boundary

A plate boundary where two plates move toward each other.

transform boundary

boundary between two tectonic plates that SLIDE past each other horizontally

plate tectonics

The theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle.

fault

A break in the earth's crust

rift valley

a deep valley that forms when two plates move apart