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Earth Science
E.S. Chapter 9 Sections 1-4
| Term | Definition |
|---|---|
| Wegner's; Pangaea | According to ________ hypothesis of continental drift, the continents had once been joined to form a single supercontinent. He called it _______ meaning all land. |
| Mesosaurus | a reptile whose fossil remains are limited to eastern South America and Southern Africa |
| Glossopteris | a small plant that are found today in South America, Southern Africa, and India |
| Sonar | _____ is a system that uses sound waves to calculate the distance to an object |
| deep- ocean trenches | As scientists mapped in the ocean floor, they found long, curved valleys along the edges of some ocean basins ____- _____ ________ |
| mid- ocean ridges | the ___- ______ ______ is a continuous elevated zone on the floor of all the major ocean basins and varying in the width from 1000 to 4000 kilometers; the rifts at the crests of ridges represent divergent plate boundaries |
| rift valley | A ____ ______ is a deep faulted structure found along the axes of divergent plate boundaries; rift valleys can develop on the seafloor or on land |
| volcanic activity | Scientist found evidence that the mid- ocean ridges formed as the result ________ _______ |
| 5 | The rates of sea- floor spreading averages about _ centimeters per year |
| subduction | in the process of __________ ocean floor returns to the mantle as it sins beneath a deep ocean trench. |
| paleomagnetism | _____________ is the study of changes in Earth's magnetic field, as shown by patterns of magnetism in rocks that have formed over time |
| youngest | The ocean floor is _________ along the central valley of the mid- ocean ridge. |
| plate | A _____ is one of numerous rigid sections of the lithosphere that moves as a over the material of the asthenosphere. |
| divergent boundaries | _________ _________ are found where two of Earth's plates move apart |
| divergent plate boundary | The Great Rift valley of Africa is an example of a _________ _____ ________ |
| convergent boundaries | __________ _________ form where two plates move together |
| transform fault boundaries | __________ _____ __________ occur where two plates grind past each other |
| transform fault boundary | The San Andreas fault in California is a ________ _____ _______ |
| continental; oceanic | When the leading edge of ___________ lithosphere converges with _______ lithosphere, |
| less; remains | the ____ dense continental lithosphere _______ floating |
| denser; sinks | the ______ oceanic slab _____ into the asthenosphere |
| convection current | _________ _______ is the continuous flow that occurs in a fluid because of differences in density |
| warm; less; rises | ____ material is ____ dense, so it _____. |
| cooler; sinks | ______ material is denser, so it _____. |
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