Intro to Meteorites

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Intro to Meteorites
2012-01-10 00:48:45
science meteorites Weisberg geology classification terminology

Information found in the Weisberg et. al. paper on terminology and classification of meteorites.
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  1. Who developed the current system used to classify meteorites?
    Prior (1920) and Mason (1967)
  2. Why do we classify meteorites?
    • To communicate their different attributes
    • To recognize the associated implications
  3. What is it called when a meteorite can be connected to an observed fall event?
  4. What is it called when a meteorite cannot be connected to an observed fall event?
  5. Which type of meteorite is more prone to chemical interaction with terrestrial environments: falls or finds?
  6. How is a meteorite named?
    • Location
    • Year found
    • Observation order
  7. What is a chondrite?
    An undifferentiated meteorite.
  8. What is an achondrite?
    A differentiated meteorite.
  9. Name 3 characteristics common to chondrites.
    • They contain small (1-2mm) chondrules.
    • They have a solar-like composition.
    • They are derived from asteroids or comets that did not undergo planetary differentiation.
  10. Name 2 commonly found achondrites.
    • Igneous rock melts
    • Breccias from differentiated origins
  11. What is a class?
    Two or more groups sharing primary whole-rock chemical and O-isotopic properties.
  12. What are the 3 primary classes of meteorites?
    • Carbonaceous (C)
    • Ordinary (O)
    • Enstatite (E)
  13. What are the 4 primary clans of meteorites?
    • CR
    • CM-CO
    • CV-CK
    • CI
  14. What is a group?
    A minimum of 5 unpaired chondrites of closely similar petrologic, whole-rock chemical, and O-isotopic characteristics.
  15. Name the 8 C-chondrite groups.
    • CI
    • CM
    • CO
    • CV
    • CK
    • CR
    • CB
    • CH
  16. Name the 3 O-chondrite groups in order from highest to lowest amount of iron (Fe).
    • H
    • L
    • LL
  17. Name the 2 E-chondrite groups in order from highest to lowest amount of iron (Fe).
    • EH
    • EL
  18. When is a subgroup defined?
    When there are lesser petrologic differences among members of the same group.
  19. What is a primitive achondrite?
    A meteorite that has a primitive chemical affinity to the chondrite that it was formed from, but with a texture suggesting differentiation (e.g. molten, melt residue, extreme recrystallization).
  20. What 4 processes do achondrite textures suggest?
    • Melting
    • Partial melting
    • Melt residue
    • Extreme recrystallization
  21. What are the 4 classic core groups of primitive achondrites?
    • Acapulcoites
    • Lodranites
    • Winonaites
    • Silicate-bearing IAB & IIICD irons
  22. Where do achondrites most often come from?
    Differentiated asteroids, Mars, and the Moon
  23. True or False: Achondrite group names are indicative of a common parent body.