Weighing just under 800 grams and discovered in Mali’s Sahara Desert in 2022, the rose-colored meteorite Teghaza 001 has been confirmed as a 4.1-billion-year-old fragment of Martian crust. Researchers published the findings in Science, marking it as one of the oldest and most intact samples of the Red Planet ever recovered on Earth.
Nomadic meteorite hunters first came across the strange, fist-sized reddish rock on a salt plain roughly 21 miles from the village of Bir Chali in the Sahara Desert of Mali. The specimen made its way through the desert meteorite trade before a private collector sent a fragment to the University of New Mexico for initial classification.
The specimen was split into eight pieces weighing just under 800 grams in total.
Planetary scientists Carl Agee and Karen Ziegler measured the stone’s oxygen isotopes, which serve as geochemical fingerprints for planetary bodies. The values matched those of other Martian meteorites, leading to an initial classification as a shergottite, the most common class of rock ejected from the Red Planet. Oddities in the texture prompted a closer look.
Dating Teghaza 001
When Yang Liu of NASA’s Jet Propulsion Laboratory was first asked to examine the sample, she almost passed on the opportunity, having studied plenty of standard shergottites over her career as a planetary sample expert.
Upon inspection, however, she noticed unusual textures and minerals that set the rock apart from typical collections.
It was only after we started looking closely that we realized this meteorite is really unique. One of the paper’s reviewers called it a Rosetta Stone for Mars.
Yang Liu, lead author and planetary scientist at NASA’s Jet Propulsion Laboratory
Unlike younger Martian meteorites, Teghaza 001 is a single, intact chunk of ancient igneous crust composed mostly of pale feldspar and darker pyroxene crystals. The crystals grow up to a millimeter across, indicating the rock cooled slowly at a rate of roughly 0.01 degrees Celsius per year from magma that solidified underground rather than erupting onto the surface.
Tracing Water on Ancient Mars
To pinpoint the meteorite’s age, researchers relied on zircon crystals containing uranium.
Francois Tissot of Caltech helped the team utilize a rubidium-strontium age-dating method that analyzed single mineral grains on a surface smaller than a fingernail, preserving the rare specimen while achieving extreme precision.
The results stunned researchers, revealing that the rock formed at least 4.1 billion years ago and experienced aqueous alteration from Martian water around the same time. Remnant hydrogen and oxygen isotopes trapped within the minerals showed that liquid water percolated down into the deeper crust while the material was cooling, pointing to a dynamic and active water cycle on early Mars.
Multiple lines of evidence in Teghaza 001 suggest Mars’ surface had water at more than 4.1 billion years ago. This is reflected by hydrogen isotopes in phosphate and oxygen isotopes in minerals and bulk samples.
Yang Liu, lead author and planetary scientist at NASA’s Jet Propulsion Laboratory
At the same time, the deuterium-to-hydrogen ratio found in the reservoir indicated that the planet was already losing its atmosphere and water to space more than four billion years ago.
Lee Saper conducted the research at the Jet Propulsion Laboratory as a postdoctoral scholar. He is a scientist at NASA’s Ames Research Center and the BAER Institute, and he noted that the rock records interactions of water and rock and preserves an imprint of the escaping atmosphere.
Comparing Martian Specimens
Teghaza 001 joins an extremely elite group of specimens. Out of roughly 435 catalogued meteorites originating from Mars, only three date back to the planet’s early history.
| Meteorite Name | Discovery Location | Estimated Age | Key Characteristics |
|---|---|---|---|
| Teghaza 001 | Mali, Sahara Desert (2022) | At least 4.1 billion years | Intact gabbro crust, zircon crystals, extensive water alteration |
| ALH84001 | Antarctica (1984) | Similar age to Teghaza 001 | Composed almost entirely of a single mineral, limiting compositional comparisons |
| Black Beauty (NWA 7034) | Northwest Africa | Fragments dated at more than 4.3 billion years | A fragmented breccia mix rather than a single intact crustal sample |
While Allan Hills 84001 and Black Beauty provide historical glimpses, their restricted mineral compositions or fragmented structures limit what scientists can infer about planetary formation. By contrast, the mineralogy of Teghaza 001 closely matches data collected by the Mars Reconnaissance Orbiter in the planet’s cratered southern highlands, near potential locations like the Hellas Basin.
Early Mars Had Conditions to Support Life
The study, published in the journal Science, bears directly on whether early Martian conditions could support life. Researchers emphasize that while the rock does not prove biological organisms existed, it confirms that the necessary watery ingredients and surface conditions were present when life was just beginning on Earth.
The findings lend support to the idea that early Mars had the necessary ingredients and conditions to harbor life, but do not directly answer the question of whether there was life on Mars.
Lee Saper, scientist at NASA’s Ames Research Center and the BAER Institute
Because meteorites cannot carry a return address, scientists still do not know the exact launch crater on Mars where the impact blast originated. Yang Liu noted that while the meteorite is extraordinary, answering remaining questions about the planet requires dedicated sample-return missions directly to the Martian surface.