Class Test - Igneous

Card Set Information

Author:
Anonymous
ID:
86530
Filename:
Class Test - Igneous
Updated:
2011-05-18 05:37:59
Tags:
geology
Folders:

Description:
Igneous Rock Characteristics
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user Anonymous on FreezingBlue Flashcards. What would you like to do?


  1. Composed wholly of crystals e.g. granite
    Holocrystalline
  2. Composed entirely of glass e.g. obsidian
    Holohyaline
  3. Composed of both glass and crystals e.g. lava, shallow obtrusive rocks
    Hypocrystalline
  4. If most constituents can't be seen by the naked eye, the rock has a _____ texture.
    Aphanitic
  5. Crystals can be distinguished by a microscope.
    Microcrystalline
  6. Crystals cannot be distinguished by a microscope.
    Cryptocrystalline
  7. If the crystals can be identified with a hand lens alone, the rock has a ______ texture.
    Phaneritic
  8. Fine-grained =
    Average diameter of individual grains is less than or equal to 1mm
  9. Medium-grained =
    Average diameter of individual grains is 1-5mm
  10. Coarse-grained =
    Average diameter of individual grains is 5mm-3cm
  11. Very coarse-grained =
    Average diameter of individual grains is more than 3cm
  12. Holocrystalline rocks of medium and coarse grain (e.g. granite) are typical of...
    Plutonic intrusions. They crystallised slowly from magmas intruded at 800-1000 degrees Celsius and then cooled slowly.
  13. Finely crystalline, aphanitic, and glassy textures are typical of...
    Rapid cooling
  14. Grains completely bound by rational (straight) crystal faces
    Euhedral
  15. Grains partly bounded by crystal faces
    Subhedral
  16. Grains devoid of crystal faces, often irregular shapes
    Anhedral
  17. Crystals all same size and shape
    Equigranular
  18. Some grains euhedral, some subhedral, and some anhedral crystals (granitic texture), mostly seen in granites.
    Subhedral granular
  19. Phenocrysts gathered in distinct clusters
    Glomeroporphyritic
  20. Intergrowth of crystals (e.g. feldspar and pyroxene)
    Ophitic
  21. Numerous minerals enclosed within crystals of different composition
    Poikilitic

What would you like to do?

Home > Flashcards > Print Preview