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Ch10: Plate tectonic
Holt McDougalnEarth Science
| Question | Answer |
|---|---|
| Continental drift | The hypothesis that a single large landmass broke up into smaller landmasses to form the continents, which then drifted to their present locations. |
| Mid-ocean ridge | Along, undersea mountain chain that has a steep, narrow valley at its center, that forms as magma rises from the asthenosphere, and that creates new oceanic lithosphere (sea floor) as tectonic plates move apart. |
| sea-floor spreading | The process by which new oceanic lithosphere (sea floor) forms when magma rises to Earth's surface at mid-ocean ridges and solidifies, as older, existing sea floor moves away from the ridge. |
| paleomagnetism | The study of the magnetic properties of rocks. |
| plate tectonics | The theory that explains how large pieces of the lithosphere, called plates, move and change shape. |
| lithosphere | The solid, outer layer of Earth that consists of the crust and the rigid upper part of the mantle. |
| asthenosphere | The solid, plastic layer of the mantle beneath the lithosphere. |
| divergent boundary | The boundary between tectonic plates that are moving away from each other. |
| convergent boundary | The boundary between tectonic plates that are colliding. |
| transform boundary | The boundary between tectonic plates that are sliding past each other horizontally. |
| rifting | The process by which Earth's crust breaks apart; can occur within continental crust or oceanic crust. |
| terrane | A piece of lithosphere that has a unique geological history and that may be part of a larger piece of lithosphere, such as a continent. |
| supercontinent cycle | The process by which supercontinents form and break apart over millions of years. |
| Pangaea | The supercontinent that formed 300 million years ago and that began to break up 200 million years ago. |
| Panthalassa | The single, large ocean that covered Earth's surface during the time the supercontinent Pangaea existed. |