Thursday, March 11, 1999 Published at 01:20 GMT
New Martian meteorite found
Rocks from Mars may contain evidence of life
By BBC News Online Science Editor Dr David Whitehouse
A brown stone the size of a coconut has been identified as only the 14th known meteorite from Mars.
It was picked up in the Dar al Gani region of the Libyan Sahara desert last year by an anonymous meteorite hunter.
A 10-gramme section of the rock was supplied by the finder to Dr Luigi Folco, meteorite curator of the Museo Nazionale dell'Antartide of the University of Siena in Italy.
The meteorite was also investigated by Dr Ian Franchi of the UK's Open University, who, through an analysis of oxygen isotopes, identified a unique "Martian signature" in the rock.
Mineralogical and petrographic analyses were also carried out by studying thin slices of the rock with optical and more powerful electron microscopes.
"We're quite delighted," said Dr Folco. "It is definitely from Mars. It is quite a find."
The rock shows signs of having been subjected to great stress and intense shocks, probably from the explosion that tore it away from Mars and sent it on a path to Earth about a million years ago.
The announcement of the new find will appear soon in the Bulletin of The Meteoritical Society. It will be designated Dar al Gani 489.
Unfortunately, it is not a particularly good specimen. It is fairly weathered, has probably been contaminated by terrestrial bacteria and is not particularly suitable to search for evidence of past life.
Early data indicates that Dar al Gani 489 is very similar to the piece of rock that was classified as the 13th Martian meteorite - Dar al Gani 476. Indeed, the two specimens may have been fragments from the same fall.
Scientists think that there could be more Mars rocks in the Libyan desert.
Of 14 rocks now identified as coming from Mars, six have been picked up in the frozen wastes of Antarctica.