From: Jan Wee <jwee@mail.arc.nasa.gov>
Subject: Martian Meteorite/Dr. Romanek
Date: Sat, 07 Dec 1996 07:32:37 -0600
Discuss-lfm members, This Press Release from early August may be of interest to you -- it was sent to me by Erich Landstrom, planetarium director. <slandstrom@milkyway.ci.savannah.ga.us> Thanks Erich! Jan Wee @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ QUADNET, AUGUST 8, 1996 ROCK8-9UGA RELEASE: IMMEDIATE MEMBER OF TEAM THAT STUDIED MARTIAN METEORITE CONVINCED THAT CRUCIAL EVIDENCE IS CONSISTENT WITH FOSSIL BACTERIA ATHENS, Ga. -- A geochemist at the University of Georgia who worked on the meteorite which researchers say may contain signs of microscopic life on Mars says he has no doubts that a crucial link in the chain of evidence is scientifically sound. Dr. Christopher Romanek, now of UGA's Savannah River Ecology Laboratory in Aiken, S.C., said that he is convinced carbonates found inside the meteorite were formed at low enough temperatures for life to have flourished around it on Mars. Romanek, a co-author on the paper to be published in the Aug. 16 issue of the journal Science, performed much of the early isotope analysis of the meteorite. "I feel very confident about it because we have several lines of evidence for the origin of the material," said Romanek. "Comparing the isotopic composition of the carbonate 'globs' to the surrounding matrix material clearly points to a low-temperature origin." The evidence for low-temperature formation of the meteorite is vital to the theory, proposed by NASA scientists at a press conference in Washington on Aug. 7, that primitive microscopic life may have existed on Mars. The meteorite, known as Alan Hills 84001, was found in Antarctica some 13 years ago. It was formed on Mars 4.6 billion years ago and, according to the paper in Science, became covered with microorganisms between 3.6 billion and 4 billion years ago. The researchers believe that about 16 million years ago, a comet or asteroid struck the Martian surface and blasted pieces of rock into space, where they drifted for millions of years. The meteorite, found in Antarctica, in 1984 fell to Earth about 13,000 years ago. Romanek's involvement in the process occurred because of a chance encounter with the meteorite at the Johnson Space Center in Houston, where he was working on a two-year postdoctoral fellowship. His lab was near that of Lockheed-Martin researcher Dr. David Mittlefehldt, an expert on meteorites. Mittlefehldt had been working on the Alan Hills meteorite when he began to notice that it possessed some unusual characteristics. "He had been working on meteorites called diogenites, but he realized that this particular meteorite had more in common with other known Martian meteorites," said Romanek. "So he sent some of the material to Dr. Bob Clayton, a preeminent isotope geochemist at the University of Chicago for oxygen isotpe analysis." Clayton examined the rock and confirmed that it is consistent with a Martian origin. At that point, Mittlefehldt began to study the meteorite more in depth, using such techniques as electron-beam microprobe analysis. Realizing that the samples were truly unusual in nature, Mittlefehldt walked across the hall and asked Romanek if he would come take a look at what he was seeing. Romanek became involved with the project almost immediately, looking at unusual carbonate spheroids or "globs," as they came to be called. He was able to separate some of them from the meteorite and began to analyze them using conventional techniques to look for stable isotope ratios. The spheroids, as it turned out, are composed of magnesium, iron and calcium, but they all contain carbon and oxygen as well, and Romanek specifically wanted to look at their isotopic signatures. "What I found was that the samples were extremely enriched in carbon 13 compared to materials on Earth," said Romanek. "So it was clear it wasn't terrestrial; however the signature was nearly identical for the 'fingerprint' that has been proposed for the carbon dioxide of Mars. Using other models of the isotope record, I concluded that these spheroids must have formed between zero and 80 degrees Celsius." Armed with this information, Romanek went to NASA scientist Everett Gibson and said that an in-depth investigation of the meteorite was urgent because of what he and Mittlefehldt had found. Gibson, in turn, took the evidence to NASA microscopy expert David McKay, who found the samples fascinating. As the project accelerated in intensity, it changed its focus from being about geochemical processes to the search for evidence of life. In the meantime, Romanek wrote a paper about his findings which was published in a 1994 edition of issue of Nature, the prestigious British science journal. (Editors: Volume 372, p. 655.) "At this point, it was no longer an isotope problem but a microscope problem," said Romanek, who left NASA about two years ago to join the University of Georgia's Savannah River Ecology Laboratory. Still, he has stayed involved with the project, spending several weeks at a time at the Johnson Space Center in Houston. He has also talked nearly weekly on the phone with Gibson or Kathie Thomas-Keprta of Lockheed-Martin in Houston, also part of the team studying the meteorite. Did Romanek ever have a "eureka" moment when he realized the possible magnitude of the discovery? "Absolutely -- every time the team had a scanning electron microscope session," he said. "We were looking at this material at a resolution that not a lot of people have used before in this way. And we had to be so careful about what we were seeing. Were they artifacts that didn't originate on the rock? Were they dust grains? All of this had to be addressed in highly constrained experiments. This kind of checking is invaluable, but it takes a long time to do." Romanek praised the review process for the upcoming Science article, saying that it was intensely rigorous and done by influential scientists who sent many questions and suggestions for revision. The paper, in fact, was revised numerous times before it was finally accepted by Science for publication. Romanek was part of a news conference in Washington on Aug. 7 at which panel members strongly defended their conclusions in the Science paper. While the research was met with praise in many quarters, it was also met with caution, including that of UCLA's Dr. William Schopf, who had been invited to the session and called the findings "preliminary." Romanek will be included on future work with the meteorite. McKay said the team hopes to find evidence of membranes or cell walls in the sample, as well as the possible presence of amino acids, which are the building blocks of proteins. So far, 12 meteorites found on Earth have been determined to have originated on Mars. -30- WRITER: Phil Williams, 706/542-8501, philwpio@uga.cc.uga.edu -------------