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Definition
| The motion of continents across ocean basins. |
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Definition
| Wegener's ancient supercontinent formed from the assembly of most of Earth's continental landmasses some 200-300 million years ago. |
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Definition
| A long and narrow portion of Earth's crust that has subsided deeply and filled with sediment. |
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Definition
| The spreading of the sea floor outward from long submarine mountain ranges--the spreading ridges. |
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Term
| apparent polar wander curves |
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Definition
| Changes in Earth's apparent poles through time; plotting the apparent north pole using paleomagnetic inclination and declination measurements in different ages of rocks form one location yeilds different positions for the magnetic pole. |
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Term
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Definition
| Huge outpourings of basalt that are believed to be a result of large-scale melting of the upper mantle due to rising mantle plumes immediately prior to continental break-up. |
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Definition
| A localized zone of upwelling hot mantle. These plumes give rist to hot spots, which are places of abnormally high heat flow. |
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Term
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Definition
| Regions of unusually high heat flow due to upwelling within the mantle. |
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Term
| active continental margin |
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Definition
| A continental margin that is also a plate margin, either represented by a subduction zone or a transform fault. |
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Term
| passive continental margin |
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Definition
| The edge of a continent, corresponding to the junction between continental and oceanic crust where it occurs in the interior of a plate rather than at a plate boundary. |
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Definition
| The junction between three plates. |
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Term
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Definition
| Motion along a fault that does not cause earthquakes. |
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