Field Museum Scientist Discovers Signs of Water on Mars – Chemical Analysis of Six Martian Meteorites Indicates That Water was Once Abundant on the My

A chemical analysis of Martian meteorites
supports the controversial theory of water on Mars, according to Meenakshi
Wadhwa, PhD, associate curator of meteoritics at The Field Museum in Chicago.
Her research is scheduled to be published in the February 23rd issue of
Science.

Last year, an analysis of images of Mars taken by NASA’s Mars Global
Surveyor spacecraft revealed surprising evidence that the planet was once a
watery place.
On Earth, sedimentary rock is formed by deposition from water,
and the photographs of Mars show hundreds of layers of sedimentation.

It has generally been assumed that Mars is more oxidized than Earth,
partly because of its red surface, which is caused by the presence of iron
oxides.
But the new evidence indicates that only the outermost rind (i.e.,
crust) of Mars is moderately to heavily oxidized.

This leads to the question of just how did the crust of Mars become
oxidized?
“On Earth, the most common oxidizing agent is water, so my research
supports the idea that abundant water was present in the crust of Mars at one
time,” Dr. Wadhwa says.
Whether water was ever present on Mars is especially
intriguing because water is thought to be a necessary ingredient of life.

The fact that the crust of Mars is much more oxidized than its deep
interior reveals another new piece of information about the mysterious red
planet.
It means that the oxidized crust of Mars has not mixed extensively
with the planet’s mantle, a layer between the planet’s crust and its interior
core.
“Therefore, Earth-style plate tectonics is not likely to be taking
place on Mars,” Dr. Wadhwa says.

In contrast, the Earth’s mantle (especially the upper part nearest to the
crust) is oxidized by “crustal recycling,” the mixing of the planet’s
water-oxidized crust with mantle rocks due to plate tectonics.

Although NASA has plans to gather rocks from Mars, rare SNC
(Shergottite – Nakhlite – Chassigny) meteorites are the only Martian rock
samples scientists currently have to study.
Dr. Wadhwa determined the
oxidation condition of six of the meteorites by analyzing minute amounts of a
rare earth element (specifically, europium) in a mineral known as pyroxene,
which makes up a major portion of these rocks.
The meteorites are thought to
have been produced by volcanic processes on Mars 180-474 million years ago.

The Field Museum houses one of the best collections of meteorites in a
museum setting.
Founded in 1893, it is one of the world’s great museums and
research centers.
It is home to more than 70 scientists in geology,
anthropology, botany, culture, environmental studies, and zoology.