Antarctica, 2006; the Graves Nunataks ice-field: a meteorite is found that is different to any found before.
Graves Nunataks 06129 is an ancient achondritic meteorite that originated in the upper crust of an asteroid. Its composition is dominated (>75%) by a silicate mineral called plagioclase. This mineral is seen in large quantities in the Earth’s continental crust and in the mountainous regions of the Moon (the lunar highlands) but is not often seen in asteroid samples and never in such large proportions. All other asteroidal meteorites found are classed as basaltic (basalt is the material that makes up the Earth’s ocean crust). This makes this meteorite the first non-basaltic asteroid meteorite recovered on Earth. It can therefore add a great deal to our knowledge of what asteroids are made of, how they formed and how they evolved.
A picture of GRA9. The outside of the meteorite is brown and rusty due to weathering processes that occurred during its time on Earth. People working with this meteorite have reported its smell as it contains large amounts of sulphur!
We are interested in the element xenon that is contained in the meteorite. Measuring the amount of xenon can tell us how old the meteorite is, the chemical makeup of the of material the asteroid formed from and what kind of processes occured on the asteroid (such as heating events or chemical reactions). All this information can all help to unravel the history of the GRA 06129 meteorite.
Image courtesy NASA/JPL-Caltech.
Inert gas isotopes is very important, but, if there is a large number of meteorites found in the natural gold, meteorites can provide supernova nucleosynthesis of specimens.