One of the most well known meteorites of Mars contains water in an amount of 0.6 percent a tiny amount, but it can be imagined as a sliver of a fingernail, yet it is one great sliver that can alter the way scientists read the earliest pages of Mars.
The meteorite is NWA 7034, or Black Beauty one dark and polished chunk of Mars weighing about 11 ounces (320 grams), discovered in 2011 in the Moroccan Sahara. It is very old even by the standards of the Martians, its ages are approximated at about 4.4 to 4.5 billion years, and it is commonly considered to be a rare physical record of a time when the surface and crust of the planet were still finding their long-term way.
Scientists were aware of the fact that Black Beauty carried the signatures of water over the years but there was a high price attached to finding out more. Conventional laboratory analysis involved de-chipping the rocks and cutting them to powder or solution, a technique that irreversibly destroys the internal structure of the rocks- the context in which the water may have been either a late contaminant or it may have been incorporated in the primordial crustal events. Such limitation is important, since the Black Beauty is not a uniform rock, he is a breccia, a patchwork of blow, with countless little pieces glued together into a specimen.
Another strategy in imaging is newer to avoid that trade. Scientists used a hybrid of computer tomography techniques whereby X-ray CT, best used with dense, metal-containing parts, was combined with neutron CT which is very sensitive to hydrogen. The most important was direct mapping of hydrogen-carrying regions within dense material with no need to cut the material in half, the neutron CT was used to focus on water-related chemistry hiding.
The scans surpassed the main part of the meteorite water onto minute clasts- small fragments that were situated in the bigger rock- of hydrogen rich iron oxyhydroxide (H-Fe-ox). This substance is chemically close to rust and it can be formed when iron is exposed to water at high pressure, like in the case of an impact. These H-Fe-ox clasts were found in approximately 0.4% of the sample space, but contained a large proportion of the total water content of that scanned piece of Black Beauty, suggesting that the hydration of Black Beauty is not homogeneous and is concentrated in certain micro-environment.
It is that internal patchiness which belongs to the scientific appeal. Water squeezed into separate clasts can leave a more readable record of its place of origin and the manner in which it was formed than in water smeared through a rock by subsequent processes. Independent studies on Black Beauty also suggested the existence of water-driven heat and chemistry on early Mars: small zircon grains of the meteorite have been cited to suggest that hot fluids existed in crustal rocks as early as 4.45 billion years ago.
The story of Black Beauty has taken its place next to a much alternative piece of evidence of Martian water: the “sounding” of the interior of the planet through marsquakes. Through the analysis of seismic waves by use of the InSight mission, scientists estimated the existence of reservoirs of liquid water 10 to 20 kilometers or so deep within the crust- well below the extent of the ice deposits on the surface and also well beneath the current methods of drilling. Combined with other water-carrying signs of antique meteorites and other deep crustal indicators characterize Mars as a planet, which did not lose water to space but accumulated it in rocks, both as bound hydrogen chemically in minerals and as ground water in porous formations.
Having no regular stream of the Mars returned samples, the meteorites such as Black Beauty provide a direct, physical path to a Martian water chemistry. Specifically, non-destructive scans allow scientists to re-examine irreplaceable specimens as technology advances, revealing an additional layer of information without destroying the evidence itself.
