| A | B |
|---|
| fossil | preserved remains or traces of an organism that lived in the past |
| continental drift | the hypothesis that the continents slowly move across Earth's surface |
| Pangaea | the name of the single landmass that began to break apart 200 million years ago and gave rise to today's continents |
| Alfred Wegener | thought that the continents were once joined together in a single landmass and have since drifted apart |
| evidence from land features | - Africa and South America line up - coal fields in Europe and North America line up |
| evidence from fossils | -Glossopteris - Mesosaurus & Lystrosaurus |
| evidence from climate | tropical plants were found on an island in the Arctic Ocean |
| Wegener's hypothesis was | rejected |
| deep-ocean trench | a deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle |
| mid-ocean ridge | undersea mountain chain where new ocean floor is porduced, divergent plate boundary- longest mountain range |
| sea-floor spreading | theprocess by which molten material adds new oceanic crust to the ocean floor |
| subduction | the process by which oceanic crust sinks beneath a deep ocean trench and back into the mantle as a convergent plate boundary |
| sonar | device that uses sound waves to measure the distance to an object |
| the farther away from the ridge the ________the rock is | older |
| rock closest to the ridge is the ____________ rock | youngest |
| Alvin | a small submarine that explored the ocean floor |
| plate | a section of the lithosphere that slowly moves over the asthenosphere, carrying peices of continental and oceanic crust |
| divergent boundary | plates move apart or diverge from each other |
| transform boundary | two plates move past each other in opposite directions |
| plate tectonics | the theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle |
| rift valley | when Earth's crust diverge (move apart) on land a deep valley will form |
| fault | a break in Earth's crust along which rocks move |
| convergent boundary | plates come together or converge |
| convection currents | drive Earth's plate |
