A research team using new methods to analyze data from NASA’s Curiosity, a rover that has operated on Mars since 2012, was able to independently verify that they contained fracture halos. opalon Earth a precious stone formed by the alteration of silica by water.
The study finds that the vast subsurface fracture networks would have provided conditions that were potentially more habitable than those on the surface.
In 2012, NASA sent the Curiosity rover to Mars to explore Gale Crater, a large impact basin with a huge layered mountain in the middle. As Curiosity has traversed the surface of Mars, researchers have discovered light-hued rocks surrounding fractures that crisscross certain parts of the Martian landscape, sometimes extending as far as the horizon in the rover’s images. Recent work finds that these widespread halo networks served as one of the last, if not the last, water-rich environments in a modern era for Gale Crater. This subsurface water-rich environment would also have provided more habitable conditions when conditions on the surface were likely much harsher.
as part of a new study published in Geophysical Research Journal: Planets, led by former Arizona State University NewSpace Postdoctoral Fellow Travis Gabriel, now a US Government Research Physicist, examined archival data from several instruments and showed significant anomalies near light-hued rocks at beginning of the journey. By chance, the Curiosity rover passed just over one of these fracture halos many years ago, long before Gabriel and ASU graduate student and co-author Sean Czarnecki joined the rover team.
Looking at the old images, they saw a large expanse of fracture halos stretching into the distance. By applying new methods to analyze instrument data, the research team found something curious. Not only did these halos look like halos found much later in the mission, in completely different rock units, but they were similar in composition: lots of silica and water.
“Our new analysis of archival data showed striking similarity between all the fracture halos that we have observed much later in the mission,” Gabriel said. “Seeing that these fracture networks were so widespread and probably chock full of opal was amazing.”
By looking at drill cores taken from the Buckskin and Greenhorn drill sites many years after the mission, the scientists confirmed that these light-hued rocks were unique compared to anything the team had seen before.
In addition to reviewing archival data, Gabriel and his team looked for opportunities to study these light-hued rocks again. Once they reached the Lubango drill site, a brilliantly-hued fracture halo, Gabriel led a dedicated measurement campaign using the rover’s instruments, confirming the opal-rich composition.
The opal discovery is noteworthy, as it can form in settings where silica is in solution with water, a process similar to dissolving sugar or salt in water. If there is too much salt, or if conditions change, it begins to settle to the bottom. On Earth, silica falls out of solution in places like the bottoms of lakes and oceans and can form in hot springs and geysers, somewhat similar to the environments in Yellowstone National Park.
Since scientists expect this opal in Gale Crater to have formed in a modern era on Mars, these subsurface fracture networks could have been much more habitable than today’s harsh conditions on the surface.
“Given the extensive fracture networks discovered in Gale Crater, it is reasonable to expect that these potentially habitable subterranean conditions would extend to many other regions of Gale Crater as well, and perhaps to other regions on Mars,” Gabriel said. “These environments would have formed long after the ancient Gale Crater Lakes dried up.”
The importance of finding opal on Mars will hold advantages for future astronauts, and exploration efforts could take advantage of these widespread water resources. Opal itself is predominantly composed of two components: silica and water, with water content ranging from 3 to 21 percent by weight, with minor amounts of impurities such as iron. This means that if you grind it and apply heat to it, the opal releases its water. In a previous study, Gabriel and other scientists from the Curiosity rover demonstrated this exact process. Combined with growing evidence from satellite data showing the presence of opal on other parts of Mars, these strong materials can be a great resource for future exploration activities on other parts of Mars.
material provided by the arizona state university.