Dynamic Earth

Front

Pangaea

Back

name given to a supercontinent that began to break apart approximately 200 million years ago.

Front

Continental drift

Back

Wegener’s hypothesis that all continents were once connected in a single large landmass that broke apart about 200 million years ago and drifted slowly to their current positions.

Front

mid-ocean ridge

Back

long, narrow mountain range on the ocean floor; formed by magma at divergent plate boundaries.

Front

ocean trench

Back

a deep, underwater trough created by one plate subducting under another plate at a convergent plate boundary.

Front

seafloor spreading

Back

the process by which new oceanic crust forms along a mid-ocean ridge and older oceanic crust moves away from the ridge.

Front

magma

Back

molten rock stored below Earth's surface.

Front

lava

Back

magma that erupts onto Earth's surface.

Front

plate tectonics

Back

theory that Earth’s surface is broken into large, rigid pieces that move with respect to each other.

Front

convergent boundary

Back

Front

divergent boundary

Back

the boundary between two plates that move away from each other.