Martian meteorites 4 bn years younger than earlier believed

Washington: A team of geologists has proved that the most common group of meteorites from Mars is almost 4 billion years younger than many scientists had believed.

The team from Western University has resolved a long-standing puzzle in Martian science, painting a much clearer picture of the Red Planet`s evolution that can now be compared to that of habitable Earth. Lead author Desmond Moser, an Earth Sciences professor from Western`s Faculty of Science, Kim Tait, Curator, Mineralogy, Royal Ontario Museum, and a team of Canadian, US, and British collaborators show that a representative meteorite from the Royal Ontario Museum (ROM)`s growing Martian meteorite collection, started as a 200 million-year-old lava flow on Mars, and contains an ancient chemical signature indicating a hidden layer deep beneath the surface that is almost as old as the solar system. The team, comprised of scientists from ROM, the University of Wyoming, UCLA, and the University of Portsmouth, also discovered crystals that grew while the meteorite was launched from Mars towards Earth, allowing them to narrow down the timing to less than 20 million years ago while also identifying possible launch locations on the flanks of the supervolcanoes at the Martian equator. Moser and his group at Western`s Zircon and Accessory Phase Laboratory (ZAPLab), one of the few electron nanobeam dating facilities in the world, determined the growth history of crystals on a polished surface of the meteorite. The researchers combined a long-established dating method (measuring radioactive uranium/lead isotopes) with a recently developed gently-destructive, mineral grain-scale technique at UCLA that liberates atoms from the crystal surface using a focused beam of oxygen ions. Moser estimates that there are roughly 60 Mars rocks dislodged by meteorite impacts that are now on Earth and available for study, and that his group`s approach can be used on these and a much wider range of heavenly bodies. The study is published in the journal Nature. ANI