A study finds zircon crystals in a Martian meteorite that could illuminate aspects of the planet's tectonic history. Although the mineral zircon is not expected to be a significant component of most rocky planets in the Solar System, some meteorites from Mars contain zircon crystals dating back to the origins of the planet. Martin Bizzarro and colleagues extracted zircon crystals from the NWA 7533 meteorite and analyzed the crystals' ages and isotopic compositions. The oldest zircons in the sample ranged in age from around 4.485 to 4.331 billion years, possibly representative of heavy bombardment on the planet's surface around the time of the early migration of gas giant planets. Another group of zircons returned ages of around 1.548 billion to 299 million years, and the authors suggest that the zircons likely formed as part of the Elysium and Tharsis volcanic provinces. These provinces are expressions of deep-seated plumes of material from the mantle, and the isotopic composition of the zircons suggest that their source is a previously unrecognized primitive mantle reservoir, with implications for the tectonic regime of Mars throughout its history. According to the authors, zircons may be ubiquitous on the surface of Mars, and the zircons in the meteorite sample may provide a record of the planet's volcanic activity.
Article #20-16326: "The internal structure and geodynamics of Mars inferred from a 4.2-Gyr zircon record," by Maria M. Costa et al.
MEDIA CONTACT: Martin Bizzarro, University of Copenhagen, DENMARK; e-mail: bizzarro@sund.ku.dk
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Proceedings of the National Academy of Sciences