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| Alfred Wagener hypothesized that all continents were once part of a single supercontinent, Pangea, parts of which drifted apart to form the smaller modern continents. Now widely accepted as a theory. |
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| Transform plate boundaries |
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Definition
| Plates slide past one another, and they are neither formed nor destroyed. |
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Definition
| Compacts a block or rock and squeezes it into less space. |
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Definition
| Pulls a block apart and increases its length. |
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Definition
| Smears a block or rock from side to side and may eventually tear it apart into two blocks that slide past each other along a lateral (strike-slip) fault. |
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Definition
| When heating a rock comprised of several different minerals (each mineral with different melting points) these parts of the rock will melt at different temperatures. Meaning that not all of the rock will melt at once. |
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Definition
| The gradient of increasing temperature with pressure (and therefore depth). |
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Definition
| Pressure as the depth at which the rocks are located increases. |
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Definition
Reducing the confining pressure of a mineral lowers it's melting point.
Therefore, taking pressure off causes decompression melting. This happens at divergent boundaries. |
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Term
| Pressure-Temperature (P-T) Diagram |
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Definition
| Rock melting is related to both temperature and pressure. A P-T diagrams show multiple combinations of pressure and temperature and how the melting of a particular rock reacts to these combinations. |
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Definition
| At P-T points below (to the left of) the solidus, all mineral crystals in the rock remain solid. |
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Definition
| At P-T points above (to the right of) the liquidus, all mineral crystals in the rock melt to liquid. |
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