The Gradual movement of the continents across earth's surface 

A supercontinent that consisted of all continents today, but together

The theory that Earth's crust is divided into SEPARATE plates that glide over the Mantle 

sheets of Earth's crust that float independently over Earth's Mantle

 feature that is between 2 tectonic plates that are moving away from each other 

Where 2 tectonic plates move toward each other and collide  

Where the tectonic plates move horizontally instead of colliding

An elevated area w/ a valley on an ocean floor between 2 diverging plates

a large depression with steep walls formed by the displacement of some of the earth's surface between nearly parallel faults

ion of new areas of oceanic crust that occurs through the upwelling of magma at midocean ridges

The crash site of tectonic plates

A long narrow ditch 

A curved chain of volcanic islands bounded on the convex side by an oceanic trench

The study of magnetism in rocks during the time that they were formed 

volcanic regions thought to be fed by underlying mantle that is unusually hot compared to the surrounding mantle.

when a hotter liquid rises because it is less dense than the cooler liquid

the pull of gravity on a plate that is being subducted 

a proposed mechanism for plate motion in plate tectonics

upper layer of the earth's mantle, below the lithosphere, in which there is low resistance to plastic flow and convection is to occur.

The region of the interior of the Earth between the core and the crust