Meteorites from Mars

Scientists using mass spectrometry to measure the isotopic composition of a meteorite.

Some achondrites are basalts and related igneous rocks similar in mineralogy and bulk composition to other achondrites, but much younger (less than 1.3 billion years) than other meteorites.

Scientists use mass spectrometry to measure the age and isotopic composition of meteorites and other rocks. When scientists measured young ages for several of these meteorites they argued that it made more sense if the meteorites came from a large body like a planet rather than a small one like an asteroid. The clincher was measurement of the noble gas isotopic composition of gases in dark glass in EETA79001. They were the same composition as those measured in the Mars atmosphere by the Viking lander spacecraft, and distinct from gases on Earth and in other meteorites.

EETA79001, martian meteorite having trapped martian atmosphere.

An origin on Mars is thus very likely, and indeed widely believed, for this group of 32 igneous achondrite meteorites. However, this martian origin is not as certain as the Moon origin for lunar meteorites because we don't have documented martian rocks for comparison. These probable martian meteorites give us valuable information about the surface of Mars to supplement remote sensing photos and data, and are useful in planning science experiments for space probes to Mars.

Meteorites, from chondrites, through achondrites, irons, and stony irons, to lunar and martian meteorites, are indeed valuable assests in exploring the origin and history of the solar system.