 | Term | Definition |
| |
Theory of Continental Drift |
The theory hypothesized by scientist Alfred Wegener stating that "the continents once formed part of a single supercontinent that began breaking up into smaller continents about 200 million years ago (during the Mesozoic Era) |
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Mid-Ocean Ridges |
Undersea mountain ranges through the center of which run steep, narrow valleys |
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Sea-floor spreading |
The process by which new ocean lithosphere(sea floor) forms as magma and rises to Earth's surface and solidifies at a mid-ocean ridge |
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Paleomagnetism |
The study of the magnetic properties inside rocks |
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Rift |
a crack |
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Magma |
Lava from within Earth |
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Theory of Plate Tectonics |
The theory that explains why and how continents move and is the study of the formation of features in Earth's crust |
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Divergent boundary |
The process in which two tectonic plates move away from each other |
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Convergent boundary |
The process in which two tectonic plates move towards each other/collide with each other |
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Transform boundary |
The process in which two tectonic plates slide towards each other horizontally |
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Fracture zones |
Short segments of mid-ocean ridge are connected with these |
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Convection |
The movement of heated material due to differences in density that are created by differences in temperatures |
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Convection cell |
An area created when cooler, denser water sinks and the warmer water rises to the surface |
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Ridge push |
A force exerted by the asthenosphere when it pushes on the rest of the plate |
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Slab pull |
A force exerted when the lithosphere becomes dense and subducts into the asthenosphere. The edge pulls the rest of the plate with it. |
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Cratons |
Large areas of stable rock |
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Shields |
Rocks within cratons |
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Rifting |
The process by which a continent breaks apart |
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Terrane |
A piece of lithosphere that has a unique geologic history that differs from the histories of surrounding lithosphere |
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Accretion |
The process in which a terrane becomes part of a continent |
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Sea-mounts |
Small volcanic islands sometimes formed from terranes |
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Atolls |
Small coral islands that may form terranes |
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Supercontinent cycle |
The process by which supercontinents form and break apart over time |
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Pangaea |
The supercontinent that existed about 300 million years ago (during the Paleozoic Era) |
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Panthalassa |
The giant ocean that surrounded Pangaea |
