 ASTHENOSPHERE: An area of earth’s upper mantle that has a low density and partially melted rock material

 LITHOSPHERE: The outer portion of earth that includes the crust and upper mantle

 Continental Drift: A theory that states that the continents have drifted from one location to another over time  Wegner: The scientist who came up with this hypothesis.

 Wegener’s support to his hypothesis: a. Coasts of continents fit like puzzle pieces b. Fossil remains found on two separate continents c. Rock formations found on different continents would match up d. Climate change evidence.

 Earth’s lithosphere is broken into plates that move on the asthenosphere  Plate Tectonics: A theory that describes the formation, movements and interactions of these plates

 Support: Data about earthquakes, magnetism, the age of rocks on the ocean floor, some of Wegner’s findings  As the plates move, the continents move.

 Most locations of earthquakes and volcanoes = Location of plate boundaries

 Magnetic minerals in magma orient themselves to face the magnetic pole as the magma solidifies  Magnetic pole has reversed several times in the geologic past  We have a record of age and pole switches

 Mid-Ocean Ridge: long chain of volcanic mountains on the ocean floor  As new rocks rise in the middle as magma, it forces older rocks out to the side