Magma, igneous rocks, and intrusive activity

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Magma, igneous rocks, and intrusive activity
2014-02-23 18:16:15

chapter 4
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  1. Pumice
    A volcanic rock that is extremely vesicular and glassy.
  2. Andesite
    The extrusive equivalent of diorite.
  3. Basalt
    The extrusive equivalent of gabbro.
  4. Rhyolite
    The extrusive equivalent of granite.
  5. Vesicle
    An open cavity in a volcanic rock that was filled by a gas bubble when the lava was still mainly liquid.
  6. Texture
    The sizes, shapes, and arrangements of mineral grains in an igneous rock.
  7. Granite
    Igneous rock with the highest silica content.
  8. Peridotite
    Igneous rock with the lowest silica content.
  9. Felsic or granitic composition
    High silica content
  10. Mafic or basaltic composition
    low silica content
  11. Aphanitic igneous rock texture
    • Fine grained texture
    • crystals can't be seen with the naked eye
  12. Phaneritic igneous texture
    • Coarse-grained
    • minerals can be seen with the naked eye.
  13. Porphyritic igneous texture
     Large phenocrysts embedded in ground mass
  14. Vesicular igneous texture
    Voids left by gas bubbles.
  15. Glassy igneous texture
    Molten rock ejected into the atmosphere that cools quickly and becomes solid without forming grains.
  16. Pyroclastic igneous texture
    • Consolidation of individual rock fragments ejected during explosive volcanic eruptions.
    •  tuff or welded tuff
  17. Pegmatitic igneous texture
    Exceptionally coarse grained igneous rock, which most of the crystals are more that 1 centimeter in diameter.
  18. granitic (felsic) igneous rocks
    • Granite(intrusive)/ rhyolite (extrusive)
    • obsidian (extrusive)
    • Pumice
  19. Andesitic (intermediate) rocks
  20. basaltic (mafic) rocks
  21. Pyroclastic rocks
    • tuff/welded tuff: small ash and glass particles
    • breccia: composed mainly of particles larger than ash