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| This graphic shows results of the first analysis of Martian soil by the Chemistry and Mineralogy (CheMin) experiment on NASA's Curiosity rover. [IMAGE: NASA/JPL-Caltech/Ames] |
Pasadena, California: NASA's Mars rover Curiosity has completed initial
experiments showing the mineralogy of Martian soil is similar to weathered
basaltic soils of volcanic origin in Hawaii.
The minerals were
identified in the first sample of Martian soil ingested recently by the rover.
Curiosity used its Chemistry and Mineralogy instrument (CheMin) to obtain the
results, which are filling gaps and adding confidence to earlier estimates of
the mineralogical makeup of the dust and fine soil widespread on the Red Planet.
The identification of
minerals in rocks and soil is crucial for the mission's goal to assess past
environmental conditions. Each mineral records the conditions under which it
formed. The chemical composition of a rock provides only ambiguous
mineralogical information, as in the textbook example of the minerals diamond
and graphite, which have the same chemical composition, but strikingly
different structures and properties.
CheMin 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. X-ray diffraction reads
minerals' internal structure by recording how their crystals distinctively
interact with X-rays. Innovations from Ames led to an X-ray diffraction
instrument compact enough to fit inside the rover.
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.
"Our team is
elated with these first results from our instrument," said Blake.
"They heighten our anticipation for future CheMin analyses in the months
and miles ahead for Curiosity."
The specific sample
for CheMin's first analysis was soil Curiosity scooped up at a patch of dust
and sand that the team named Rocknest. The sample was processed through a sieve
to exclude particles larger than 0.006 inch (150 micrometers), 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. Unlike
conglomerate rocks Curiosity investigated a few weeks ago, which are several
billion years old and indicative of flowing water, the soil material CheMin has
analyzed is more representative of modern processes on Mars.
"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."
Bish said, "So
far, the materials Curiosity has analyzed are consistent with our initial ideas
of the deposits in Gale Crater recording a transition through time from a wet
to dry environment. The ancient rocks, such as the conglomerates, suggest
flowing water, while the minerals in the younger soil are consistent with limited
interaction with water."
During the two-year
prime mission of the Mars Science Laboratory Project, researchers are using
Curiosity's 10 instruments to investigate whether areas in Gale Crater ever
offered environmental conditions favorable for microbial life.