NASA's Curiosity rover has detected a substantial amount of silica deposits in the Martian rock formations it had investigated in the past seven months. Scientists believe this discovery provides evidence that water activity could likely have existed on the Red Planet in the past.
In a press conference held during the meeting of the American Geophysical Union (AGU) in San Francisco, researchers involved in the Mars mission reported that the rover found higher silica concentrations in some of the areas it had surveyed in the past few months than in any of the sites it had visited before.
The team discovered that as much as nine-tenths of the rocks the rover had examined were composed of silica.
Jens Frydenvang, a researcher from the Los Alamos National Laboratory and one of those analyzing the Curiosity's findings, said that while they are still trying to determine how the rocks were enriched with silica, many of their hypotheses point to the possibility that Mars experienced considerable water activity in the past.
He explained that areas with high silica deposits on Earth typically make suitable environments for sustaining microbial life-forms.
Frydenvang added that the discovery of silica in the Martian rocks has led the scientists to make a rare backtrack in their research in order to investigate the new findings further.
Traces of silica were first spotted while the Curiosity rover was approaching the region called "Marias Pass". The area is known to have a lower geological unit that makes contact with an overlying one.
Curiosity's laser-firing instrument known as ChemCam detected high amounts of silica in a number of targets the probe had passed on its way to the designated contact zone.
The rover continued to detect silica readings during its succeeding missions, which the scientists combined with elemental composition data from Curiosity's Alpha Particle X-Ray Spectrometer (APXS) and mineral data from its Chemistry and Mineralogy (CheMin) instrument.
"What we're seeing on Mount Sharp is dramatically different from what we saw in the first two years of the mission," Ashwin Vasavada, a researcher from NASA's Jet Propulsion Laboratory, said. "There's so much variability within relatively short distances."
"The silica is one indicator of how the chemistry changed. It's such a multifaceted and curious discovery, we're going to take a while figuring it out."
Two Hypotheses Involving Water
The researchers are following two primary hypotheses to figure out recent findings made on Mount Sharp, both of which have water playing a crucial role.
One of the hypotheses involves having acidic water carry away other elements from the rocks and leaving only the silica deposits behind. The other hypothesis features neutral or alkaline water dissolving silica and depositing them on the rocks through the resulting solution.
The latest findings made by the Curiosity have interesting threads associated with data collected by NASA's earlier Spirit rover in another part of Mars. The probe detected traces of sulfuric acidity in the region.
"Buckskin" is one of the Martian rocks analyzed by the Curiosity rover that contained evidence of the rare mineral tridymite.
On Earth, tridymite is formed when metamorphic or igneous rocks are exposed to high temperatures. The fine layers of sedimentary rocks the rover detected the mineral on, however, showed evidence that they may have been part of lakebed deposits. This proves that a magmatic evolution could likely have occurred on Mars.