A rare meteorite found in the Sahara Desert has turned out to be a fragment of Mars’ primordial crust, formed at least 4.1 billion years ago — giving scientists an unprecedented look at the red planet’s earliest geological history.
The rock, named Teghaza 001, is described in a paper published online on 29 October 2026 in the journal Science by Yang Liu of NASA’s Jet Propulsion Laboratory and colleagues. It is not a newly fallen meteorite: the fragments were recovered from the Sahara in Mali about four years ago, and the new study is the analysis that identifies what they are.
What Teghaza 001 is
Teghaza 001 consists of eight fragments with a total mass of 798.5 grams. The largest fragment weighs 442 grams and is roughly 10 centimetres across. It is named after an ancient, abandoned salt-mining settlement in Mali close to where the fragments were found.
The rock is a coarse-grained igneous rock, a plagioclase-rich gabbro, whose internal structure shows it cooled slowly, probably underground. Unusually, it is a single, unadulterated rock type — not a mixture of fragments cemented together, as many ancient Martian samples are.
How old it is — and why that matters
The researchers dated its zircon crystals using uranium-lead methods and arrived at an age of about 4.11 billion years. A separate rubidium-strontium analysis gave a consistent, though less precise, date of about 4.24 billion years. That second date may record a period of hot, mineral-laden water circulating through the rock soon after it crystallised, rather than the moment it solidified.
Either way, the rock formed no later than about 4.1 billion years ago, during the earliest geological period of Mars — a few hundred million years after the planet itself formed.
That age makes it exceptional. Of the roughly 300 to 400 known Martian meteorites, nearly all are far younger: the three main classes, shergottites, nakhlites and chassignites, formed 2.4 billion years ago or later. Only two older specimens had previously been identified — Allan Hills 84001, which crystallised about 4.1 billion years ago, and Northwest Africa 7034, known as Black Beauty, some of whose pieces are older than 4.3 billion years. The study authors say Teghaza 001 is the oldest Martian igneous rock ever found by a large margin.
Evidence of water — not evidence of life
Teghaza 001 carries evidence that it interacted with water or other hot, mineral-rich fluids on Mars, well before an impact flung it into space. Its oxygen isotopes are heavier than those of other Martian meteorites, which the researchers attribute to interaction with fluids enriched in oxygen-18, either in the crust or directly with magma.
Domains within the rock contain high levels of manganese oxide, a compound Mars rovers look for as an indicator of environments conducive to life. Water molecules bound within the mineral apatite appear to have come from two sources: some from magma rising from the Martian mantle, and some from the surface and atmosphere percolating through the crust.
At the same time, the study shows Mars had already lost much of its water by then. Ultraviolet light broke water molecules apart, hydrogen floated away into space, and the remaining water carries a higher concentration of deuterium, the heavier version of hydrogen — a ratio similar to that found in Allan Hills 84001.
To be clear: manganese oxide and water-altered minerals are indicators of an environment that could have supported life, not proof that life existed. The paper makes no claim of fossil or microbial evidence.
Where on Mars it may come from
By comparing the rock’s chemistry with orbital measurements of Mars, the scientists identify the southern Martian highlands, particularly the region northwest of the Hellas impact basin, as the most likely source area. Identifying a source region could help determine where future landers, rovers or sample-return missions should investigate the planet’s ancient crust.
Carl Agee, director and curator at the University of New Mexico’s Institute of Meteoritics, who examined the samples with colleague Karen Ziegler using electron-microprobe and oxygen-isotope analysis, said the find’s age plus its alteration indicated an Earth-like environment, with fluids coursing over the surface and volcanoes creating hydrothermal systems.
What remains unknown
It is not certain when the rock was knocked into space or when it landed in the Sahara. The study also cannot say exactly when Mars lost most of its surface water — only that much of it was already gone when Teghaza 001’s water record was set.
Related coverage on Emadan: NASA marks 100th US spacewalk with seventh iROSA array and China plans first crewed lunar mission with three astronauts.
Frequently asked questions
What is Teghaza 001? A Martian meteorite of eight fragments (798.5 grams total) found in Mali’s Sahara Desert about four years ago, identified in a Science paper published 29 October 2026.
How old is it? At least 4.1 billion years old — about 4.11 billion years by uranium-lead dating of its zircon crystals.
Does it prove life on Mars? No. It shows Mars had water-rich, hydrothermal environments early in its history. That is a condition that could have supported life, not evidence of life itself.
Sources
- Phys.org / University of New Mexico: Rare 4.1-billion-year-old Martian meteorite reveals clues to planet’s ancient past (29 October 2026)
- Sci.News: Meteorite Found in Sahara is Piece of Mars at Least 4.1 Billion Years Old (October 2026)
- Business Standard / Reuters: Meteorite found in Sahara turns out to be 4.1 bn year old piece of Mars (31 October 2026)
- Yang Liu et al., A Martian meteorite that formed ≳4.1 billion years ago samples Mars’ early crust and mantle, Science (2026), DOI: 10.1126/science.adz5646
