plate tectonics-a theory explaining the structure of the earth's crust and many associated phenomena as resulting from the interaction of rigid lithospheric plates that move slowly over the underlying mantle
continental drift-the gradual movement of the continents across the earth's surface through geological time.
pangaea-(plate tectonics) a hypothetical continent including all the landmass of the earth prior to the Triassic period when it split into Laurasia and Gondwanaland
asthenosphere-the upper layer of the earth's mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.
linthosphere-the rigid outer part of the earth, consisting of the crust and upper mantle.