A meteorite found in the Sahara in 2022 has been identified as a 4.1-billion-year-old piece of Mars, offering scientists an unusually detailed glimpse of the planet’s early crust.
The rose-coloured rock, discovered in Mali, weighs nearly two pounds and has been named Teghaza 001 after the salt plain where it was found. NASA said it is one of roughly 435 meteorites known to have come from Mars.
Scientists can establish a Martian origin by comparing a meteorite’s chemical and mineral composition with samples and data gathered by missions to the planet.
Age analysis placed Teghaza 001 among the three oldest Martian meteorites discovered on Earth. Its composition provides what NASA described as “a rare snapshot” of how the planet’s crust formed.
Yang Liu, the lead author of a paper detailing the dating process, said the rock’s importance only became clear after close examination. “One of the paper’s reviewers called it a Rosetta Stone for Mars,” said Liu, who is part of NASA’s Jet Propulsion Laboratory in Southern California.
The meteorite contains a distinctive combination of volcanic minerals, including zircon crystals. Researchers said those minerals match samples observed by NASA’s Mars Reconnaissance Orbiter in the planet’s southern highlands.
Using a pioneering technique, scientists analysed a fragment smaller than a fingernail and were able to examine individual mineral grains. The work showed that the rock had been altered by water on Mars about 4.1 billion years ago, although the rock itself may have formed earlier.
The findings suggest that early Mars may have had a more active water cycle than previously thought. Lee Saper, one of the paper’s authors, said the meteorite records “interactions of water and rock and maybe even an imprint of the Martian atmosphere as it was losing water”.
A separate study of Teghaza 001 examined its water content and considered how water may have shaped the early surface of Mars.
Lee, a scientist at NASA’s Ames Research Center, said: “This is really our first piece of Martian crust from a part of Mars we’ve never had a sample of before.”
Further research is expected. “We’ve only scratched the surface,” Liu said.
