Metal Tech News - January 9, 2023
Martian opals discovered in a lakebed traversed by NASA's Mars Curiosity rover may be much more precious than their counterparts found on Earth. This is not due to the opals found on the Red Planet being more opalescent, dazzling, or exotic – though a pendant adorned with Martian opals would truly be out of this world – but because they may be a key to understanding past life and enabling future survival on our celestial neighbor.
Martian opals were first discovered in 2008 by the Mars Reconnaissance Orbiter.
"We see numerous outcrops of opal-like minerals, commonly in thin layers extending for very long distances around the rim of Valles Marineris and sometimes within the canyon system itself," Ralph Milliken of NASA's Jet Propulsion Laboratory said at the time.
Curiosity has since found an abundance of opals in Gale Crater, a large impact basin the rover was sent to explore in 2012.
A paper authored by an international research team led by Travis Gabriel, an astrogeologist with the U.S. Geological Survey, concludes that opals within Gale Crater are more prevalent than previously known and offers evidence that the window for past life habitation on Mars was longer than realized.
Opals such as those found in Gale Crater are formed when silica is dissolved into water and then deposited into cracks and other voids. As water evaporates out, silica-rich opals are formed.
Evidence suggests that the opal "halos" found by Curiosity were formed underground long after the surface was too cold and dry. This means that conditions conducive to microbial life may have extended for at least an extra 1 billion years under the Martian surface.
"This water-rich subsurface network was shielded from modern harsh surface conditions, allowing for a potentially habitable environment on Mars in a more recent era," the research team penned in a summary of their findings. "These light-toned features are also ideal for follow-up investigation or sample return as similar opal-rich deposits on Earth are known to preserve traces of microbial life."
Aside from adorning spacesuits with some opalescent splendor, how could this discovery help future Martian settlers?
As it turns out, during the opal-making process, not all of the water evaporates out of the semiprecious gemstones.
Studies show the opal deposits within Gale Crater are made up of somewhere between 3 and 6% water. Given that this crater is far from the ice-covered polar regions, the watery opal deposits could be a readily available source of the single most precious resource for future human settlements.
The research team says "the features themselves contain a considerable amount of readily released water, making them an ideal resource at the otherwise dry Martian equator."
The finding of the Gabriel-led research team can be read at On an Extensive Late Hydrologic Event in Gale Crater as Indicated by Water-Rich Fracture Halos in the Journal of Geophysical Research: Planets, Volume 127, Issue 12 published on Dec. 19, 2022.