*Nature Communications:Determining volcanic eruption styles on Earth and Mars from crystallinity measurementsWSU News:Undergrad helps develop method to detect water on Mars
PULLMAN, Wash. – A Washington State University undergraduate has helped develop a new method for detecting water on Mars. Her findings appear in Nature Communications *
Kellie Wall ... looked for evidence that water influenced crystal formation in basalt, the dark volcanic rock that covers most of eastern Washington and Oregon. She then compared this with volcanic rock observations made by the rover Curiosity on Mars’ Gale Crater.
...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 ...
Using an x-ray diffraction machine on the WSU campus, home to one of the most sophisticated basalt labs in the world, 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.”
Kellie T. Wall, Michael C. Rowe, Ben S. Ellis, Mariek E. Schmidt & Jennifer D. Eccles
Published 03 October 2014