A rose-colored rock discovered in the Sahara Desert may hold some clues to Mars' ancient geological history.
The meteorite, named Teghaza 001 after the salt plain in Mali where it was discovered in 2022, weighs roughly 1.8 pounds (800 grams) and formed more than 4.1 billion years ago. Blasted off Mars by an impact before eventually landing on Earth, it is one of the three oldest Martian meteorites ever found. The extraordinary age and unusual mineral composition of Teghaza 001 offer a rare glimpse into the formation of Mars' early crust and how volcanic materials may have been altered by water, according to a statement from NASA’s Jet Propulsion Laboratory in Southern California.
"It was only after we started looking closely that we realized this meteorite is really unique,” research leader Yang Liu of NASA’s Jet Propulsion Laboratory in Southern California said in the statement. "One of the paper’s reviewers called it a Rosetta Stone for Mars."
A Rosetta Stone for Mars
Unlike many Martian meteorites, Teghaza 001 contains a distinctive combination of igneous minerals and textures that preserve evidence of its complex history. Its mineral composition resembles materials observed in Mars' southern highlands by NASA's Mars Reconnaissance Orbiter.
Although researchers can’t pinpoint exactly where the meteorite originated on Mars, they have identified 13 potential locations on the planet where it may have formed.
"This is really our first piece of Martian crust from a part of Mars we’ve never had a sample of before," team member Lee Saper, NASA’s Ames Research Center in Silicon Valley, said. "It records interactions of water and rock and maybe even an imprint of the Martian atmosphere as it was losing water." The meteorite was initially identified as Martian based on its oxygen isotopes. To determine its age, scientists then examined tiny zircon crystals embedded in the rock. Using a specialized rubidium-strontium dating technique, researchers analyzed individual mineral grains on its surface, preserving it for future analysis.
The results revealed that Teghaza 001 was altered by water around 4.1 billion years ago, suggesting the rock itself formed even earlier. The mineral and chemical evidence points to a dynamic water cycle on ancient Mars, when liquid water interacted with the planet's crust and potentially left traces of its atmosphere as it gradually lost water.
Scientists believe further analysis of Teghaza 001 could reveal more about how water shaped the Martian surface and influenced the planet's evolution. The study also marks the first time researchers have used rubidium-strontium dating to analyze an ancient Martian meteorite, opening the door for the technique to be applied to other samples in the future.
"We've only scratched the surface," Liu concluded.
Their findings were published on Thursday (Oct. 29) in the journal Science. A separate study examining the meteorite's water content was published on June 10 in the journal Science Advances, offering additional insight into early Mars.
