Current interpretations of water-borne mineral assemblages in the nakhlites suggest ground water infusion. Although the formation times of the carbonate formation episodes are unknown, their slightly different nature and the much older age of the host meteorite compared to other martian meteorites suggest that alteration may have occurred relatively early. Thus, martian meteorites suggest aqueous activity may have persisted throughout martian history. Because martian meteorites never spent substantial time at the very surface, more highly weathered surface materials are likely to contain greater species diversity and higher concentrations of water-bearing phases, which is consistent with Viking chemical analyses of martian soils. Binocular view shows carbonate grains 100 microns across in ALH84001.
Colored rings are due to variations in carbonate composition.
This drop of water extracted from a martian meteorite has the unique stable isotope composition of martian crust.