Washington, Oct 5 :
A new method to quantify the texture of volcanic rocks using an index called “groundmass crystallinity” could help detect water on Mars, said a study.
“I think this quantification of volcanic textures is a new facet of the water story that has not yet been explored,” said Kellie Wall, an undergraduate student at Washington State University.
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, Wall analysed rock samples from New Zealand and Italy’s Mount Etna. She then compared them to rocks analysed by NASA’s Mars rover 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 eight 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 to almost totally crystalline.
“The analyses we did on the Mars soil samples fell in the range of the magmatic type eruptions, which erupted without water interaction,” Wall pointed out.
Water is a key indicator for the potential of microbial life on Mars.
While Wall and her colleagues did not see evidence of water from the two sites they studied, their method could look for water elsewhere.
Most of the studies searching for water have focused on either looking for sedimentary structures for evidence of water, or looking for rocks like limestone that would have formed in a water-rich environment.
The study appeared in the journal Nature Communications.