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Unit 2
Vocabulary Words
Term | Definition |
---|---|
Plate Tectonics | a theory explaining the structure of the earth's crust |
Alfred Wegener | German geophysicist who proposed the theory of continental drift |
Pangea | the hypothetical landmass that existed when all continents were joined, from about 300 to 200 million years ago |
Crust | the outermost layer of the planet |
Lithosphere | the rigid outer part of the earth |
Asthenosphere an area on Earth where two or more lithospheric plates collide | the upper layer of the earth's mantle, below the lithosphere |
Transform Boundary | places where plates slide sideways past each other |
Sea-floor spreading | the formation of new areas of oceanic crust |
Convergent Boundary | an area on Earth where two or more lithospheric plates collide |
Divergent Boundary | a linear feature that exists between two tectonic plates that are moving away from each other |
Rift Valley | a large elongated depression with steep walls formed by the downward displacement of a block of the earth's surface between nearly parallel faults or fault systems |
Subduction | the sideways and downward movement of the edge of a plate of the earth's crust into the mantle beneath another plate |
Convection Current | a current in a fluid that results from convection |
Continental Drift Theory | the theory that the Earth's continents have moved over geologic time relative to each other |
Trench | a long, narrow ditch |
Ocean Basin | areas found under the sea |
Hot Spot | places within the mantle where rocks melt to generate magma |
Mid-ocean Ridge | an underwater mountain range, formed by plate tectonics |
Ring of Fire | a major area in the basin of the Pacific Ocean where many earthquakes and volcanic eruptions occur |