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New method to detect water on Mars

Jenny Winder, News Writer
Oct 7, 2014, 15:02 UTC

Sen—An undergraduate has helped develop a new method for detecting water on Mars.

Kellie Wall, 21 from Washington State University (WSU), is the lead author of research published in the journal Nature Communications. She and her team looked for evidence that water influenced crystal formation in basalt, the dark volcanic rock that covers most of eastern Washington and Oregon, and compared this with volcanic rock observations made by NASA's Curiosity rover on Mars’ Gale Crater.

The researchers established a method to quantify the texture of volcanic rock using an index called “groundmass crystallinity.” Wall compares it to the texture of a chocolate chip cookie, which can vary according to how it is cooked and cooled.

“We were interested in the cookie dough part of the cookie,” she said.

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Kellie Wall has an article in Nature Communications detailing a new method for finding water on Mars. Image credit Robert Hubner, WSU Photo Services

Liquid volcanic rock cools rapidly as it hits water, flash-freezing to form mostly glass. Without water, it takes longer to cool and forms crystals within the groundmass, the cookie dough part.

Using an x-ray diffraction machine, Wall analyzed rock samples from the Northwest, New Zealand and Italy’s Mount Etna and compared them to rocks analyzed by Curiosity’s x-ray diffractometer.

“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,” she said. “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 magmatic type eruptions, which are the ones erupted without water interaction,” she said.

Water is a key indicator for the potential of microbial life on the red planet. While Wall and her colleagues didn’t see evidence of it from two sites they studied, their method could look for water elsewhere.

“I think this quantification of volcanic textures is a new facet of the water story that hasn’t yet been explored,” Wall said. “Most of the studies searching for water have focused on either looking for sedimentary structures, large- and small-scale, for evidence of water, or looking for rocks like limestones that actually would have formed in a water-rich environment.

“But being able to determine the environment through the texture of a volcanic rock is something pretty cool and different,” she said. “I think it’s an interesting avenue for future research.”

WSU undergrad helps develop method for detecting water on Mars. Credit: Washington State Universty