How to Detect Water on Mars: New Method Discovered with Volcanic Rocks

Finding water on Mars is an important part of the hunt for life on the Red Planet. Yet actually detecting it isn't easy. Now, researchers have developed a new method for finding water on Mars.

In this case, the scientists looked for evidence that water influenced crystal formation in basalt, the dark volcanic rock that covers most of eastern Washington and Oregon. Then, they compared this with volcanic rock observations made by NASA's Mars rover Curiosity on Mars' Gale Crater.

More specifically, the researchers established a method to quantify the texture of volcanic rock using an index called "groundmass crystallinity." This texture is similar to the texture of a chocolate chip cookie, which can vary according to how it's cooked and cooled. In this case, the scientists were interested in the "dough" part of the cookie.

Liquid volcanic rock cools rapidly as it hits water, flash-freezing to mostly form glass. When it doesn't hit water, though, it takes longer to cool and form crystals within the groundmass. The researchers analyzed rock samples in order to better understand how the crystallinity on Earth compared to that on Mars.

"The rocks that erupted and interacted with water, which we call phreatomagmatic, all had a groundmass crystallinity as low as 8 percent and ranging up to about 35 percent," said Kellie Wall, the lead author of the new study, in a news release. "The rocks that erupted without interaction with water had groundmass crystallinities from about 45 percent upwards to almost totally crystalline. The analyses we did on the Mars soil samples fell in the range of the magmetic type eruptions, which are the ones erupted without water interaction."

The findings reveal a possible way to detect water on Mars by examining rock formations. Since water is a key indicator for the potential of microbial life, it's possible that these new findings could allow scientists to pinpoint likely areas that should be studied.

The findings are published in the journal Nature Communications.