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Who developed the current system used to classify meteorites?
Prior (1920) and Mason (1967)
Why do we classify meteorites?
- To communicate their different attributes
- To recognize the associated implications
What is it called when a meteorite can be connected to an observed fall event?
What is it called when a meteorite cannot be connected to an observed fall event?
Which type of meteorite is more prone to chemical interaction with terrestrial environments: falls or finds?
How is a meteorite named?
- Year found
- Observation order
What is a chondrite?
An undifferentiated meteorite.
What is an achondrite?
A differentiated meteorite.
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.
Name 2 commonly found achondrites.
- Igneous rock melts
- Breccias from differentiated origins
What is a class?
Two or more groups sharing primary whole-rock chemical and O-isotopic properties.
What are the 3 primary classes of meteorites?
- Carbonaceous (C)
- Ordinary (O)
- Enstatite (E)
What are the 4 primary clans of meteorites?
What is a group?
A minimum of 5 unpaired chondrites of closely similar petrologic, whole-rock chemical, and O-isotopic characteristics.
Name the 8 C-chondrite groups.
Name the 3 O-chondrite groups in order from highest to lowest amount of iron (Fe).
Name the 2 E-chondrite groups in order from highest to lowest amount of iron (Fe).
When is a subgroup defined?
When there are lesser petrologic differences among members of the same group.
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).
What 4 processes do achondrite textures suggest?
- Partial melting
- Melt residue
- Extreme recrystallization
What are the 4 classic core groups of primitive achondrites?
- Silicate-bearing IAB & IIICD irons
Where do achondrites most often come from?
Differentiated asteroids, Mars, and the Moon
True or False: Achondrite group names are indicative of a common parent body.