Mantle

Turner Burwick 12/2/2009 Period 7 Vocabulary Continental drift - the lateral movement of continents resulting from the motion of crustal plates. Pangaea - The landmass that existed when all continents were joined, from about 300 to 200 million years ago. Seafloor spreading - a process in which new ocean floor is created as molten material from the earth's mantle rises in margins between plates or ridges and spreads out. Plate tectonics - a theory of global tectonics in which the lithosphere is divided into a number of crustal plates, each of which moves on the plastic asthenosphere more or less independently to collide with, slide under, or move past adjacent plates.