IU geologist helps analyze composition of Mars

BLOOMINGTON, Ind. (AP) - Mars, the planet closest to Earth, is rocky and red, photos have shown. But what minerals make up the planet?

The answer to that question has been just conjecture — until now. David Bish, an Indiana University geological sciences department professor, is researching the answer.

Bish is on a NASA team to analyze the surface of Mars using the Curiosity rover. Ultimately, the Mars Science Laboratory Project hopes to find out whether the planet at one time may have been favorable for microbial life.

Earlier this week, NASA hosted a media teleconference on preliminary research results, and Bish was one of the presenters.

The scientists are using a device they call CheMin, short for chemical and mineral instrument, attached to Curiosity.

At a site called Rocknest, Curiosity has scooped up some windblown dust and deposited it into CheMin, where X-ray diffraction determines its mineral composition.

X-ray diffraction is "the gold standard" for analyzing mineral composition, said Bish's colleague David Blake of NASA's Ames Research Center, the principal investigator for CheMin.

It can identify materials with a crystalline structure, and determine how much of each mineral is present. It's used on Earth in the oil and mining industries and by archaeologists studying ancient artifacts.

The first definitive mineralogy of Martian dust showed it contains feldspar and olivine, two minerals found on Earth, and similar to the weathered basaltic soil found near Mauna Kea volcano in Hawaii. Those minerals contain silicate, iron and magnesium.

Half of the dust was "amorphous material," the equivalent of weathered glass, without a crystalline structure and impossible for X-ray diffraction to identify. Further analysis will reveal the composition of that, Bish said.

The sample the researchers analyzed was from the thin surface of one spot on a planet that is subject to global dust storms, so its composition contains material blown from elsewhere. That can help reveal the history of Martian surface geology, including weather and possibly even historic climate change. Minerals reveal a record of how they were formed, and how they were worn down, Blake said.

The research on Mars is continuing right now, with dozens more samples to come. Curiosity and CheMin will continue to analyze Martian soil at other locations, digging deeper and looking for evidence of the remains of water. Additional results are expected in about a month.