The Martian meteorite NWA 7034, known as "Black Beauty" and considered one of the oldest Martian meteorites, has been found to contain significant amounts of ancient water locked within its structure. Utilizing advanced non-destructive scanning techniques, researchers identified hydrogen-rich compounds, further contributing to understanding Mars' early hydrological history and the potential for past habitability.
Black Beauty: An Ancient Martian Visitor
Discovered in 2011 by nomads in Morocco's Sahara Desert, the NWA 7034 meteorite weighs approximately 11 ounces (320 grams). Its age is estimated to be between 4.44 and 4.48 billion years, making it one of the oldest known pieces of Martian material. Scientists hypothesize it originated from the 6-mile-wide (10-kilometer) Karratha crater near Mars' equator and was ejected into space between 5 million and 10 million years ago.
Non-Destructive Analysis Unlocks Secrets
Previous studies of Black Beauty often involved destructive sampling, such as cutting or crushing portions of the meteorite. Recent research, detailed in a pre-print paper by Estrid Naver and co-authors from the Technical University of Denmark, employed non-destructive methods for analysis. These included:
- X-ray Computed Tomography (CT): This technique is effective for identifying dense materials, such as iron, within the meteorite.
- Neutron Computed Tomography (CT): This method utilizes neutrons to penetrate denser materials, proving particularly effective in detecting hydrogen, a key component of water.
This novel neutron scanning method allowed for the analysis of hydrogen atoms embedded within the dense rock without causing physical damage to the sample.
Significant Ancient Water Content Confirmed
The analyses confirmed a substantial presence of water within the meteorite:
- Water accounts for approximately 0.6% of Black Beauty's total mass, which corresponds to an estimated 6,000 parts-per-million (ppm) of water. This is considered a high concentration for Martian material.
- Most of this water is contained within tiny fragments identified as hydrogen-rich iron oxyhydroxide (FeHOâ‚‚ or H-Fe-ox) clasts. These clasts constituted approximately 0.4% of the volume of a small sample analyzed and contained up to 11% of that sample's total water content.
- This compound typically forms when iron reacts with water under high pressure, a process that can occur during events such as meteor impacts.
Unveiling Mars' Watery Past and Habitability Potential
The identification of ancient water in Black Beauty offers further evidence regarding Mars' early hydrological history. Traces of water in the meteorite were initially identified in 2013, with later analyses suggesting the water might have been partially heated. The new findings reinforce the theory that Mars once harbored significant liquid water, potentially including large, Earth-like oceans, which largely disappeared about 3 billion years ago.
This discovery complements observations of watery samples found by the Perseverance rover at Jezero crater, suggesting a widespread presence of liquid water on the surface of Mars billions of years ago.
As the oldest direct evidence of water on Mars, Black Beauty provides insights into how the planet might have initially acquired its water and conditions that could have supported early extraterrestrial life.
Remnants of Mars' water currently persist as ice slabs, frosty deposits, and subsurface reservoirs.
Paving the Way for Future Martian Sample Analysis
The non-destructive CT techniques used in this study were initially considered for analyzing samples from future Mars Sample Return missions, allowing for analysis within their titanium housing. While the cancellation of a specific program may impact these plans, a Chinese sample return mission remains scheduled, offering potential future opportunities for similar studies. Researchers also consider applying these non-destructive tests to other Martian meteorites to leverage current expertise and equipment.