NASA’s Curiosity rover has uncovered new evidence suggesting that not only did Mars have a wet past but that hydrothermal activity might have been prominent too. This discovery expands the range of potential conditions that made the young Red Planet a suitable candidate for life.
As reported in the Journal of Geophysical Research, researchers have discovered germanium and zinc to be 10 to 100 times more abundant in the Gale Crater part of Mars that it's studying than in Martian crust studied from meteorites. On Earth, these chemical are usually found together in high-temperature fluids, like those coming out of hydrothermal vents.
This is not the first evidence for hydrothermal activity on Mars, other rovers have previously seen indications. Mars used to have active volcanoes and large water bodies, so underwater geothermal activity has always been considered plausible. The impact of this research is for the future of Curiosity’s research. Gale Crater seems even more likely to have hosted life in the past.
"You have heat and chemical gradients, conditions favorable for the genesis and persistence life," lead author Jeff Berger, from the University of Western Ontario, said in a statement.
Gale Crater was created between 3.8 and 3.5 billion years ago by a meteor impact. The 154-kilometer-wide (96 miles) region was then flooded and over several hundred million years it filled with a few kilometers of sediments. The sediments were then eroded away thanks to the wind. These characteristics made the Gale Crater an ideal study location.
The possibility of hydrothermal activities in Gale Crater makes Curiosity’s mission even more exciting. The possibility of hot water might not be a certainty for life on Mars, but it definitely contributes to a habitable picture of the Red Planet. If an extensive hydrothermal system is confirmed, it might change the history of the region significantly.
The study was possible thanks to the Mars Science Laboratory APXS mounted on top of Curiosity’s robotic arm. The instrument is designed to measure the abundance of the 16 most common elements as well as detecting some minor ones. The team was surprised when they looked at the less common chemical species and discovered an over-abundance of germanium.
Germanium is usually found in a predictable proportion to silicon on Mars, so its unusually high abundance clearly indicates that something different went on in this region.