Younger Age for Oldest Martian Meteorite

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Younger Age for Oldest Martian Meteorite
Long Geologic History
Formation by crystal accumulation in a magma
chamber
Aqueous alteration and deposition of carbonate
globules
Isotopic systems, hence ages, affected by shock
and alteration
Shocked and crushed by impact
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Younger Age for Oldest Martian Meteorite
Igneous formation age of ALH84001 is 4.09 Ga,
much younger than the previously-reported Sm-Nd
age of 4.50 Ga.
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Younger Age for Oldest Martian Meteorite
Next step Reconcile igneous, impact, and
alteration events recorded in ALH84001 with ages
of impact basins on Mars.