Plate Tectonics Theory

Front

Tectonic Plate

Back

A block of lithosphere that consists of the crust and the rigid, outermost part of the mantle that move by convection currents.

Front

Mid-ocean ridge

Back

An underwater mountain chain where new ocean floor is formed.

Front

Seafloor Spreading

Back

The movement of oceanic crust away from a Mid-Ocean Ridge.

Front

Ocean trench

Back

Deep valley in the ocean floor that forms along a subduction zone.

Front

Magnetic Reversals

Back

Reversals in the magnetic field of Earth shown in the rock of the seafloor.

Front

Convection Currents

Back

Circular currents in the mantle caused by the magma being heated by the core of the Earth.

Front

Subduction zone

Back

Place where two lithospheric plates come together, the denser one sinking below the other.