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Unit 6EarthStructure
| Term | Definition |
|---|---|
| 1. Mineral | A natural usually inorganic solid that has a characteristic chemical composition and an orderly internal structure. |
| 2. Element | A substance that cannot be separated or broken down into similar substances by chemical means: All atoms of an element have the same atomic number. |
| 3. Atom | The smallest unit of an element that maintains the properties of that element. |
| 4. Compound | A substance made of atoms or ions of two or more different elements joined by chemical bonds. |
| 5. Matter | Anything that has mass and takes up space. |
| 6. Crystal | Natural solid substance that has a definite geometric shape. |
| 7. Streak | The color of a mineral in powered form. |
| 8. Luster | The way in which a mineral reflects light. |
| 9. Cleavage | In geology, the tendency of a mineral to split along specific planes of weakness to form smooth, flat, surfaces. |
| 10. Weathering | the natural process by which atmospheric and environmental agents, such as wind, rain, and temperature changes, disintegrate and decompose rocks. |
| 11. Erosion | the process by which wind, water, ice, or gravity transports soil and sediment from one location to another |
| 12. Deposition | the process in which material is laid down |
| 13. Igneous rock | rock that forms when magma cools and solidifies |
| 14. Sedimentary rock | a rock that forms from compressed or cemented layers of sediment |
| 15. Metamorphic rock | a rock that forms from other rocks as a result of intense heat, pressure, or chemical processes |
| 16. Rock cycle | the series of processes in which rock forms, changes from one type to another, is destroyed, and forms again by geologic processes |
| 17. Uplift | the rising of regions of the Earth's crust to higher elevations |
| 18. Subsidence | the sinking of regions of the Earth's crust to lower elevations |
| 19. rift zone | A area of deep cracks that forms between two tectonic plates that are pulling away from each other. |
| 20. Crust | The thin and solid outermost layer of Earth above the mantle |
| 21. Mantle | The layer of rock between the Earth's crust and core. |
| 22. Convection | The movement of matter due to differences in density;the transfer of energy due to the movement of matter. |
| 23. Core | the central part of Earth below the mantle |
| 24. Lithosphere | the solid, outer layer of Earth that consists of the crust and the rigid upper part of the mantle. |
| 25. Asthenosphere | the solid, plastic layer of the mantle beneath the lithosphere; made of mantle rock that flows very slowly, which allows tectonic plates to move on top of it. |
| 26. Mesospherre | the strong, lower part of the mantle between the asthenosphere and the outer core. |
| 27. Pangaea | the supercontinent that formed 300 million years ago and that began to break up 200 million years ago. |
| 28. Sea - floor spreading | the processes by which oceanic lithosphere sea floor forms when magma rises to Earth's surface at mid-ocean ridges and solidifies, as older, existingsea foor moves away from the ridge |
| 29. Plate tectonics | the theory that explains how large pieces of the lithosphere, called plates, move and change shape |
| 30. Tectonic plates | a block of lithosphere that consists of the crust and the rigid, outermost part of the mantle. |
| 31. Convergent boundary | the boundary between tectonic plates that are colliding |
| 32. Divergent boundary | the boundary between two tectonic plates that are moving away from each other |
| 33. Transform boundary | the boundary between tectonic plates that are sliding past each other horizontally |
| 34. Convection | The movement of matter due to differences in density;the transfer of energy due to the movement of matter. |
| 35. Deformation | the bending, tilting, and breaking of Earth's crust; the change in the shape of rock in response to stress |
| 36. Folding | the bending of rock layers due to stress |
| 37. Fault | a break in a body of rock along which one block moves relative to another |
| 38. Shear stress | stress that occurs when forces act in parrallel but in opposite directions, pushing parts of a solid in opposite directons |
| 39. Tension | stress that occurs when forces act to strech an object |
| 40. Compression | stress that occurs when forces act to squeeze an object |
| 41. Earthquake | a movement or trembling of the ground tat is caused by a sudden release of energy when rocks along a fault move |
| 42. Focus | the location within Earth along a fault at which the first motion o a earthquake occurs |
| 43. Epicenter | the point on Earth's surface directy above an earthquake's starting point, or focus |
| 44. Tectonic plate boundary | the edge between two or more plates classifed as divergent, converent |
| 45. Elastic rebound | the sudden return of elastically deformed rock to its undeformed shape |
| 46. Volcano | a vent of fissure in Earth's surfave through which magma and gases are expelled |
| 47. Magma | the molten or partially molten rock material containing trapped gases produced under the Earth's surface |
| 48. Lava | magma that that flows onto Earth's surface |
| 49. Vent | an opening at the surface of the Earth through which volcanic material passes |
| 50. Hot spot | a volcanically active area of Earth's surface, commonly far from a tectonic plate boundary |