The mineralogy of Martian soil is similar to weathered basaltic soils of volcanic origin in Hawaii, initial experiments by US space agency NASA’s Mars rover Curiosity suggest.
The minerals were identified in the first sample of Martian soil Curiosity collected recently at a patch of dust and sand by using its Chemistry and Mineralogy instrument (CheMin).
The sample was processed through a sieve to exclude particles larger than 0.006 inches, roughly the width of a human hair. The sample has at least two components: dust distributed globally in dust storms and fine sand originating more locally.
"Much of Mars is covered with dust, and we had an incomplete understanding of its mineralogy," said David Bish, CheMin co-investigator with Indiana University in Bloomington.
"We now know it is mineralogically similar to basaltic material, with significant amounts of feldspar, pyroxene and olivine, which was not unexpected. Roughly half the soil is non-crystalline material, such as volcanic glass or products from weathering of the glass."
The identification of minerals in rocks and soil is crucial for the mission’s goal to assess past environmental conditions, NASA said, as each mineral records the conditions under which it formed.
How the CheMin instrument works
The CheMin instrument uses X-ray diffraction, the standard practice for geologists on Earth using much larger laboratory instruments. This method provides more accurate identifications of minerals than any method previously used on Mars, said NASA.
X-ray diffraction reads minerals’ internal structure by recording how their crystals distinctively interact with X-rays.
These NASA technological advances have resulted in other applications on Earth, including compact and portable X-ray diffraction equipment for oil and gas exploration, analysis of archaeological objects and screening of counterfeit pharmaceuticals, among other uses.
Curiosity landed on Mars in August for a two-year mission. The rover is investigating whether a region inside the Gale Crater region of Mars has offered environmental conditions that could have supported microbial life. Curiosity is also seeking clues about whether life ever existed, or could exist, on the red planet.
A ‘bite mark’ where NASA’s Curiosity rover scooped up some Martian soil. Image by NASA/JPL-Caltech/MSSS