Mars Meteorite Teghaza 001 Formed More Than 4.1 Billion Years Ago, NASA-Funded Study Finds

A rose-colored Mars meteorite found in the Sahara Desert in 2022 formed more than 4.1 billion years ago, making it one of the oldest pieces of the Red Planet ever found on Earth, NASA-funded scientists reported Thursday, Oct. 29, in the journal Science. The rock, called Teghaza 001, offers a rare sample of Mars’ ancient crust.

The nearly 2-pound (800-gram) meteorite is named after the salt plain in Mali where it was discovered, according to NASA’s Jet Propulsion Laboratory in Southern California. It is one of roughly 435 known meteorites from Mars.

What makes Teghaza 001 different

NASA said Teghaza 001 is one of the three most ancient Martian meteorites found on Earth, and it stands out for its texture, its age and its unusual mix of igneous, or volcanic, minerals. That mix records how the planet’s crust formed from cooling magma before it was altered by subsurface water.

“It was only after we started looking closely that we realized this meteorite is really unique,” said the paper’s lead author, Yang Liu of JPL. “One of the paper’s reviewers called it a Rosetta Stone for Mars.”

The meteorite’s mineralogy matches what NASA’s Mars Reconnaissance Orbiter has observed in the planet’s heavily cratered southern highlands. The exact launch site can never be known, but the researchers identified 13 locations on Mars that match its mineralogy and chemistry, shown on the map above.

“This is really our first piece of Martian crust from a part of Mars we’ve never had a sample of before,” said second author Lee Saper, who did the research as a JPL postdoctoral scholar and now works at NASA’s Ames Research Center. “It records interactions of water and rock and maybe even an imprint of the Martian atmosphere as it was losing water.”

The data: how it compares with other ancient Mars rocks

NASA’s description of the three oldest known Martian meteorites shows why scientists value the new sample:

Researchers at the University of New Mexico had already identified the rock as Martian from its oxygen isotopes, which act as geochemical fingerprints for different planetary bodies. It first appeared to be a shergottite, the most common class of Martian meteorite. Liu, an expert in planetary samples, said she nearly passed on studying it, but its odd textures and unfamiliar minerals drew her in, NASA said.

How scientists dated the rock

Liu and her colleagues found zircon crystals in Teghaza 001. Zircons record clues to a rock’s formation and allow geologists to age-date a sample precisely. Caltech coauthor Francois Tissot’s team used an in-situ rubidium-strontium dating method on a piece smaller than a fingernail, analyzing single mineral grains on its surface rather than dissolving the whole sample, which preserves the rare material for future research. NASA said the technique is also extremely precise and fast.

“Right now, we are one of very few labs in the world able to perform this kind of age-dating, and the first to date such an ancient Martian meteorite,” Tissot said in NASA’s announcement. “Our hope is to pave the way for dating even more Martian meteorites, or samples returned from other planets, their moons, and asteroids.”

The results showed the rock had been altered by Martian water around 4.1 billion years ago, which suggests it formed even earlier. NASA said clues in the oxygen isotopes, texture and chemistry of its minerals point to a much more dynamic water cycle on early Mars. A separate paper published in Science Advances in June detailed the meteorite’s water content.

Why it matters for Mars science

Although Martian meteorites differ from one another, they share a common history. Every Martian meteorite on Earth was blasted off the planet’s surface by an impact before following a path that eventually brought it here. Collectors often find meteorites in deserts or snowy plains, where they stand out from the rest of the barren landscape, NASA said. Scientists confirm a meteorite’s Martian origin by matching its minerals and chemistry with data from NASA missions, including the Viking landers and the Curiosity and Perseverance rovers. Teghaza 001 gives researchers a sample from a part of the planet that, in Saper’s words, scientists had never had a sample of before.

“We’ve only scratched the surface,” Liu said.

The finding adds to a busy week for NASA science. Read our coverage of the Cat’s Head Nebula captured by Hubble and Webb and of this year’s Nobel Prize in physics.

Sources

• NASA: NASA-funded Study Details One of Oldest Mars Meteorites Ever Found
• Science: A Martian meteorite that formed ≳4.1 billion years ago samples Mars’ early crust and mantle
• Science (news): Oldest known Mars rock offers glimpse of planet’s watery youth
• NASA Photojournal: Slice of Martian Meteorite Teghaza 001