Ch. 3 Plate Tectonics

Front

The lithosphere is broken into sections called _________, which float on top of the asthenosphere.

Back

plates

Front

The process of ___________ _________ continually adds new crust to the ocean floor along both sides of the mid-ocean ridge.

Back

sea-floor spreading

Front

When continental plates pull apart at a divergent boundary on land, a(n) _____ ____ forms.

Back

rift valley

Front

According to Wegener's hypothesis of continental drift, the continents were once joined together in a single landmass. What is this landmass called?

Back

Pangaea

Front

Oceanic crust near the mid-ocean ridge is __________ than oceanic crust farther away from the ridge.

Back

younger

Front

What is the name of the layer of the Earth that is semi-fluid and allows the lithosphere to float?

Back

asthenosphere

Front

What type of boundary occurs when two tectonic plates slide past each other?

Back

transform boundary

Front

What geological feature is formed at a convergent boundary where an oceanic plate meets a continental plate?

Back

subduction zone

Front

What is the term for the theory that explains the movement of the Earth's plates?

Back

plate tectonics

Front

What is the main driving force behind plate tectonics?

Back

convection currents in the mantle