(See related pages)
Below you will find key words and concepts that you should remember from this chapter.
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| asthenosphere | A region of Earth’s outer shell beneath the lithosphere. The asthenosphere is of indeterminate thickness and behaves plastically. (See page(s) 470) |
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| continental drift | A concept suggesting that continents move over Earth’s surface. (See page(s) 462) |
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| convection | A very slow circulation of a substance driven by differences in temperature and density within that substance. (See page(s) 468) |
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| convergent plate boundary | A boundary between two plates that are moving toward each other. (See page(s) 470) |
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| divergent plate boundary | Boundary separating two plates moving away from each other. (See page(s) 470) |
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| island arc | A curved line of islands. (See page(s) 479) |
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| lithosphere | The rigid outer shell of Earth, 70 to 125 or more kilometers thick. (See page(s) 470) |
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| magmatic arc | A line of batholiths or volcanoes. Generally the line, as seen from above, is curved. (See page(s) 480) |
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| mantle plume | Narrow column of hot mantle rock that rises and spreads radially outward. (See page(s) 488) |
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| plate | A large, mobile slab of rock making up part of Earth’s surface. (See page(s) 470) |
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| plate tectonics | A theory that Earth’s surface is divided into a few large, thick plates that are slowly moving and changing in size. Intense geologic activity occurs at the plate boundaries. (See page(s) 462) |
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| polar wandering | An apparent movement of the earth’s poles. (See page(s) 465) |
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| sea-floor spreading | The concept that the ocean floor is moving away from the midoceanic ridge and across the deep ocean basin, to disappear beneath continents and island arcs. (See page(s) 462) |
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| subduction | The sliding of the sea floor beneath a continent or island arc. (See page(s) 468) |
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| transform fault | The portion of a fracture zone between two offset segments of a midoceanic ridge crest. (See page(s) 474) |
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| transform plate boundary | Boundary between two plates that are sliding past each other. (See page(s) 471) |