Identification of a very rare type of Martian meteorite

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PARIS (AFP) - a Martian rock of an "exceptional" type has been just identified by an international team of researchers, reported Thursday by French scientists. "It seems to be a black, fist-shaped rock, broken in several pieces, which had been found in Morocco about four years ago by two well known hunters of meteorites, Bruno Fectay and Carine Bidaut", geochemist Jean-Alix Barrat, of the University of Brest explained to AFP. Only last summer was a fragment entrusted to scientists and the true nature of the sample was recognized. This work was undertaken by researchers of Université of Brittany Occidentale, Higher Teacher training school of Lyon, Open University (England), of Field Museum in Chicago (the United States), University of Tokyo (Japan) and NASA Johnson Space Center in Houston (the United States).

Called "Diderot" in homage to the famous encyclopedist from Langres, this meteorite is now officially identified as Northwest Africa 2737 (NWA2737), according to international nomenclature. Among the 25,000 meteorites known to date, only 33 were ejected from the surface of Mars by violent impacts. Although the surface of Mars is being studied by the NASA rovers Spirit and Opportunity, these 33 meteorites are the only samples return of the red planet at the disposal of researchers. Indeed, with the Martian sample return programme being quasi-abandoned, these meteorites offer priceless data to understand the evolution of our solar system.

The majority of these meteorites are recent magmatic rocks, formed less than 500 million years ago. Diderot, which is today in the course of dating, is of a type which was previously represented by one specimen: a meteorite fallen in France near Chassigny, on the plain of Langres (Haute-Marne) in 1815. This rock -more than one billion years old - carries important information on the ancient history of Mars, which can be checked and confirmed thanks to this new discovery, according to Jean-Alix Barrat. NWA 2737 is being studied today by European, American and Japanese teams. The first results will be presented in March in Houston at the time of Lunar and Planetary Science Conference, the annual worldwide meeting of planetologists.

Translation by Babelfish and Nick Hoffman