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Meteorite Study Shows Glimpse of Red Planet's Ancestry

Purdue News

CONTACT: Lipschutz, (765) 494-5326, e-mail rnapuml@vm.cc.purdue.edu
Purdue News Service: (765) 494-2096; e-mail, purduenews@uns.purdue.edu

March 18, 1997

Meteorite study shows glimpse of Red Planet's ancestry

WEST LAFAYETTE, Ind. -- While the controversy continues over whether a
Martian meteorite bears evidence of ancient life on Mars, a Purdue
University scientist says the rocky fragments can tell us something about
the early life of the planet itself.

Michael Lipschutz, professor of chemistry who has analyzed trace elements in
11 of the 12 known Martian meteorites, says the samples contain a different
mix of volatile elements than do rock samples from Earth, indicating that
the Red Planet was created from a different nebular womb.

"It looks like the cloud of gas and dust from which Mars was born contained
more volatile elements such as thallium, bismuth and cadmium than did the
cloud from which Earth was formed," Lipschutz says.

Prior studies of the oxygen isotopes in the Martian meteorites indicated
that they all came from the same planet. But other studies, using
nonvolatile chemical markers, had revealed differences in their composition,
indicating that the samples had encountered different experiences as the
planet formed and evolved.

"Our study is the first to show that the characteristics revealed by the
nonvolatile elements are also present in the volatile elements," Lipschutz
says. "That is to say that these meteorites share some common
characteristics, but due to differences in their composition, they belong to
the three separate categories that are commonly used to distinguish these

He presented his findings today (3/18) at the 28th Lunar and Planetary
Science Conference in Houston.

Lipschutz, who has studied the solar system and meteorites for more than 30
years, based his findings on studies of 15 trace elements in 11 of the 12
meteorites identified as originating from the planet Mars. He will complete
studies of the 12th meteorite this spring.

His studies of the Martian meteorites focused on the volatile trace
elements, the chemical elements that were most likely to condense last as
the planet solidified from a cloud of dust and gas.

Trace elements and ultratrace elements -- especially volatile ones found in
parts per million or parts per billion -- can yield important information
about a meteorite because the composition levels are so low that even the
smallest change induced by a physical or chemical transformation is
magnified into a relatively large change.

In addition, the samples from Mars show that the planet has experienced at
least two fractionation events -- events that separate the volatile trace
elements from the non-volatile elements, Lipschutz says.

"The amazing thing is that whatever chemical fractionation events Mars
experienced, all of the elements -- volatile or not -- were able to remain
and record the events," he says. "This is unlike the situation in other
extraterrestrial bodies where late heating, caused for example by the shock
of an impact, can vaporize the volatile elements and destroy evidence of
past events. In the case of some of the meteorites from the moon, chemical
elements were introduced by events such as volcanism, which also clouded the
historical record."