http://www.spacedaily.com/2003/030123181812.5qkebuw8.html
Meteorite hints at Mars' watery past LONS-LE-SAUNIER, France AFP January 23, 2003 Analysis of a Martian meteorite that fell to Earth suggests that magma rocks beneath the surface of the "Red Planet" were rich in water, a scientific panel that carried out the study said here on Thursday. The meteorite, NWA 1669, which fell in the Western Sahara, is a basalt rock of a type called shergottite, the commonest signature among the 28 Martian rocks recovered on Earth. The Theodore Monod Consortium said the sample was remarkable -- and indicated the presence of water on Mars -- because of the crystallisation pattern that developed in two minerals called pyroxenes after the liquid magma cooled and became rock. One of the pyroxenes, augite, had crystallised before the other, pigeonite. "Experiments on the same liquids have shown that this kind of phenomenon can only happen if the liquid magma has a significant quantity of dissolved water, at least three percent, in high pressure conditions," it said. A member of the Monod group, Albert Jambon, a specialist in magmatology and geochemistry in the Paris-VI University, said: "This is the first sample of martian rock which enables us to confirm the theory that deep below Martian surface the rocks are more water-rich than is the case on Earth." The find is puzzling, however, because Mars has no oceans and the amount of surface water there "appears to be very small," he said. Martian meteorites are believed to have been knocked off the surface of the planet by an asteroid collision millions or billions of years ago. The chunks wandered in space until they were finally drawn into the Earth's gravity and made landfall, surviving a fiery plunge through the atmosphere. These meteorites have been identified as Martian because their chemical profile matches that of rocks analysed by US space probes. NWA 1669, a specimen weighing 38.85 grammes (1.1 ounces), was bought in Morocco in January 2001 by Bruno Fectay and Carine Bidaut, a well-known pair of meteorite hunters, who have a priceless collection of more than 400 meteorites, five of them martian. Basalt is a kind of igneous rock that, on Earth, is usually formed when volcanic lava cools after reaching the surface. Whether water, the stuff of life, exists or has existed on Mars has excited enormous debate since NASA's Mars Global Surveyor orbiter started sending back pictures in 2000 that showed valleys and gullies which some US analysts believe were dug out by ice flows, floods or even oceans. Where the water is now is another question, with speculation that it has either evaporated into space or is possibly lingering just below the surface. ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
