NASA's Curiosity rover detects boron on surface of Mars

The finding provides more clues about water habitability.

The findings were discussed in San Francisco during the American Geophysical Union conference

"No prior mission to Mars has found boron," said a postdoctoral researcher Patrick Gasda from Los Alamos National Laboratory.

"If the boron that we found in calcium sulfate mineral veins on Mars is similar to what we see on Earth, it would indicate that the groundwater of ancient Mars that formed these veins would have been 0-60 degrees Celsius [32-140 degrees Fahrenheit] and neutral-to-alkaline pH," Gasda added.

Boron is famously associated with arid sites, where much water has evaporated away--think of the borax that mule teams once hauled from Death Valley.

However, environmental implications of the boron was found by NASA's Curiosity rover science team is still open to debate.

The discovery of boron is only one of several recent findings related to the composition of Martian rocks.

Curiosity is climbing a layered Martian mountain and finding rock-composition evidence of how ancient lakes and wet underground environments changed, billions of years ago, in ways that affected their favorability for microbial life.

As the rover has progressed uphill, compositions trend toward more clay and more boron.

These and other variations can tell us about conditions under which sediments were initially deposited and about how later groundwater moving through the accumulated layers altered and transported ingredients.

Groundwater and chemicals dissolved in it that appeared later on Mars left its effects most clearly in mineral veins that filled cracks in older layered rock. But it also affected the composition of that rock matrix surrounding the veins, and the fluid was in turn affected by the rock.

"There is so much variability in the composition at different elevations, we've hit a jackpot," said John Grotzinger of the California Institute of Technology, Pasadena, California.

As the rover gets further uphill, researchers are impressed by the complexity of the lake environments when clay-bearing sediments were being deposited and also by the complexity of the groundwater interactions after the sediments were buried.

"A sedimentary basin such as this is a chemical reactor," Grotzinger said. "Elements get rearranged. New minerals form and old ones dissolve. Electrons get redistributed. On Earth, these reactions support life."

Whether Martian life has ever existed is still unknown. No compelling evidence for it has been found.

"The boron and clay underline the mobility of elements and electrons, and that is good for life," Grotzinger explained.