Unit 4 Vocab

  1. Igneous rocks- Intrusive or extrusive rock formed from the cooling and crystallization of magma or rock.

  2. Lava- magma that flows out onto Earth’s surface.

  3. Partial melting- process in which different minerals melt into magma at different temperatures, changing its composition.

  4. Bowen’s reaction series- sequential, predictable, dual-branched pattern in which minerals crystallize from cooling magma.

  5. Fractional crystallization- process in which different minerals crystallize from magma at different temperatures, removing elements from magma.

  6. Intrusive rocks- coarse grained igneous rock that is formed when molten rock cools slowly and solidifies inside Earth’s crust.

  7. Extrusive rocks- fine grained igneous rock that is formed when molten rock cools quickly and solidifies on Earth’s surface.

  8. Basaltic rocks- rock that is dark colored, has lower silica contents, and is rick in ron and magnesium; contains mostly plagioclase and pyroxene.

  9. Granitic rocks- light colored, intrusive igneous rock that has high silica content.

  10. Texture- the size, shape, and distribution of the crystals or grains that make up a rock.

  11. Porphyritic texture- rock texture characterized by large, well-formed crystals surrounded by finer-grained crystals of the same or different mineral.

  12. Vesicular texture- characterized by containing vesicles, or holes, formed by gas bubbles.

  13. Pegmatites- igneous rock with extremely large-grained minerals that can contain rare ores such as lithium and beryllium.

  14. Kimberlites- rare, ultramafic rock that can contain diamonds and other minerals formed only under very high pressures.

  15. Sediments- small pieces of rock that are moved and deposited by water, wind, glaciers, and gravity.

  16. Lithification- the physical and chemical processes that transform sediments into sedimentary rock.

  17. Cementation- process of sedimentary rock formation that occurs when dissolved minerals precipitate out of groundwater and either a new mineral grows between the sediment grains, or the same mineral grows between and over the grains.

  18. Bedding- horizontal layering in sedimentary rock; layers that can range from a few millimeters to several meters thick.

  19. Graded bedding- type of bedding in which particle sizes become progressively heavier and coarser toward the bottom layers.

  20. Cross bedding- depositional feature of sedimentary rock that forms as inclined layers of sediment are carried forward across a horizontal surface.

  21. Clastic sedimentary rocks- most common type of sedimentary rock, formed from the abundant deposits of loose sediments that accumulate on earth’s surface; classified according to the size of their particles.

  22. Clastic- composed of rock and mineral fragments produced by weathering and erosion and classified according to particle size and shape.

  23. Porosity- percentage of open spaces between grains in a mineral.

  24. Evaporites- the layers of chemical sedimentary rocks that form when concentrations of dissolved minerals in a body of water reach saturation due to the evaporation of water; crystal grains precipitate out of solution and settle to the bottom.

  25. Foliated- describes metamorphic rock, such as schist or gneiss, whose minerals are squeezed under high pressure and arranged in wavy layers and bands.

  26. Nonfoliated- describes metamorphic rocks like quartzite and marble, composed mainly of minerals that form with blocky crystal shapes.

  27. Regional metamorphism- process that affects large areas of Earth’s crust, producing belts classified as low medium, or high grade, depending on pressure on the rocks, temperature, and depth below the surface.

  28. Contact metamorphism- local effect that occurs when molten rock meets solid rock.

  29. Hydrothermal metamorphism- occurs when very hot water reacts with rock, altering its mineralogy and chemistry.

  30. Rock cycle- continuous, dynamic set of processes by which rocks are changed into other types of rocks.