1 Wegner s evidence a Continent shapes matched b Fossils from different animals found in other places c Rock types found on various continents 2 Wegner had no name for his theory 3 Continents move across the asthenosphere a Behaves like a soft plastic even though it s a solid 4 Convection currents rising from the outer core of the Earth and make a circular motion As they move outward they cool down and move back down a Causes the plates to move 5 Mantle hotspots are where the convection currents begin 6 Convection currents occur along Mid Ocean Ridges Convection Currents 1 Arthur Holmes thought that the earth generated from convection currents 2 Harry Hess was a captain in the U S Navy a They were constructing sonar images of the ocean floor so that they could hide submarines b Found underwater mountain ranges Earth s Magnetic Field 1 Paleo magnetism all magnetism 2 True North and Magnetic North are not the same thing a Compasses don t point to True North 3 The magnetic pole of the Earth reverses 4 Oceanic crust is denser than continental crust a It s forced into a subduction zone 5 Mid Ocean Ridges are where the oceanic plates are rifting 6 Great Rift Valley in Africa 7 Divergent Plate boundaries mid ocean ridges where new ocean floor is being created 8 Convergent Plate boundaries located where one plate is being forced under the other Associated with volcanoes and deep ocean trenches 9 Transform boundaries plates move laterally past one another 10 Plates move very slowly Convergent Boundaries 1 Ocean to Continent convergent boundary is the area where plates collide 2 Oceanic crust is denser than continental crust 3 Oceanic crust contains water 4 No older than 180 200 million years 5 Ocean to ocean convergent boundary is where two oceanic plates collide a Get a volcanic island arc 6 Continent to continent convergent boundary is where two continental plates collide a Where the mountains form i e the Himalayan Mountains 7 Transform boundaries are where plates slide past each other laterally a San Andreas Fault 8 Yellowstone Hot Spot is found under the asthenosphere and the plates move over it Eventually it will be located somewhere else 9 Hawaii is located over a hot spot