Leftovers from Ancient Lunar Impactors

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Leftovers from Ancient Lunar Impactors

• Lunar basins mark a time of intense bombardment
• Impact breccias contain fragments of debris from
  the impact events, why not relics of the
  impactors themselves?
• Meteorite fragments have now been identified in
  ancient lunar regolith breccias (3.83.4 billion
  years old)

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Leftovers from Ancient Lunar Impactors
The meteorite fragments have distinctive
compositions compared to Moon rocks but are
similar to chondritic meteorites.
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Leftovers from Ancient Lunar Impactors
Three-oxygen isotope compositions of most
meteorite fragments from the ancient lunar
breccias (blue) compared with olivines in two
younger lunar breccias (red green) suggest a
change in impactors from 3.8 billion years ago
to now.