| A | B |
|---|
| The hypothesis that the continents were once joined together in a single landmass | continental drift |
| Name of the supercontinent that existed millions of years ago | Pangaea |
| Any trace of an ancient organism preserved in rock | fossil |
| Technology that scientists used in the mid-1900's to help map the ocean floor | sonar |
| Process where molten material rises from the mantle and erupts along mid ocean ridges | sea-floor spreading |
| Describe oceanic crust as it moves farther away from the mid-ocean ridge | it is older, cooler and more dense |
| Geologists think the movement of Earth's plates is caused by | convection currents in Mantle |
| Theory that states pieces of lithosphere are in constant, slow motion | Theory of plate tectonics |
| Boundary where two plates slip past each other, moving in opposite directions | transform boundary |
| How did scientists discover that rocks farther away from the mid-ocean ridge were older than those closer to it | determining age of rock samples obtained from drilling on ocean floor |
| When two pieces of continental crust collide it produces | a mountain ridge |
| True or False - Mid-ocean ridges are found in all of Earth's oceans | True |
| What is the process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle | subduction |
| At what type of boundary does a rift valley form | divergent boundary |
| The place where two plates come together is called | convergent boundary |
| What process continually adds new material to ocean floor along the mid-ocean ridge | sea-floor spreading |
| Pieces of the lithosphere that float on top of the athenosphere are called | plates |
| What is formed when continental plates pull apart at a divergent boundary on land | rift valley |
| What 3 types of evidence did Alfred Wegener provide to support his hypothesis | Evidence from landfeatures, fossils, and climate |
| The formation of volcanoes and mountain ridges can be explained by | Theory of Plate Tectonics |
| What 3 types of evidence support the occurrence of sea-floor spreading | Evidence from ocean material, magnetic stripes, and drilling samples |
| Describe oceanic crust closest to the mid-ocean ridge | it is younger, lighter, and hotter |
| What happens when 2 oceanic plates collide at a convergent boundary | The plate that is more dense sinks under the less dense plate as subduction occurs. A deep-ocean trench and/or volcanoes form |
| Describe what happens when an oceanic plate and continental plate collide at a convergent boundary | Mountains may form as the oceanic crust pushes up the continental crust. A deep-ocean trench forms and the oceanic crust will sink back into the mantle as subduction occurs |
| Describe what happens when 2 contiental plates collide at a convergent boundary | The crust is squeezed into high mountain ranges |
| A divergent boundary where new oceanic crust is added through sea-floor spreading occurs along | mid-ocean ridges |
