Teghaza 001 preserves evidence that water-bearing fluids altered ancient Martian rock. A study published online in Science on October 29, 2026, dates that alteration to about 4.1 billion years ago, shortly after the rock first crystallized. The zircon age is not a precise date for the original crystallization. The study describes a slowly cooled igneous rock that offers a record of early Martian crust and its interaction with fluids.
The meteorite was found in Mali in 2022. The official catalog lists eight stones with a combined mass of 798.5 grams and classifies Teghaza 001 as a Martian shergottite. The catalog entry records the find and classification.
What the age measurements actually date
The study’s strongest zircon result is a uranium-lead (U-Pb) weighted mean of 4,114 ± 17 million years, calculated from six concordant measurements; the uncertainty is two standard errors. The authors interpret the approximately 4.1-billion-year zircon age as hydrothermal alteration, when hot, water-bearing fluids changed the rock. They place that event shortly after the rock’s initial crystallization, which occurred earlier.
Other dating methods produced results in a similar range. The measurements and the study’s interpretation are set out below.
| Dating method | Material analyzed | Reported result | Study interpretation |
| Zircon U-Pb | Zircon | 4,114 ± 17 Ma; six concordant measurements, 2 standard errors | The approximately 4.1-billion-year age dates hydrothermal alteration shortly after crystallization. |
| Zircon lead-lead (Pb-Pb) | Zircon | 4,113 ± 14 Ma; 10 measurements, 2 standard errors | Consistent with the approximately 4.1-billion-year chronology. |
| Phosphate Pb-Pb | Phosphate | 4,124 ± 28 Ma | Consistent with the approximately 4.1-billion-year chronology. |
| In-situ rubidium-strontium (Rb-Sr) | A small sample analyzed in place | 4,238 ± 208 Ma; 2 standard errors | Considered alongside the other dating methods. |
The different methods do not turn the alteration age into a precise crystallization date. The study’s interpretation is that the rock formed earlier, then underwent fluid-driven alteration around 4.1 billion years ago.
Minerals and evidence of water
The study describes Teghaza 001 as a leuco-gabbro, a slowly cooled igneous rock with more plagioclase feldspar than pyroxene. In a polished section, plagioclase makes up 68% of the measured area and clinopyroxene 25.5%. Those percentages describe the section’s surface area, not the meteorite’s mass. Pyroxene structures also point to slow cooling, estimated at about 0.01°C per year.
The case for ancient fluids comes from both mineral features and oxygen isotopes. The researchers measured a bulk oxygen-isotope value, δ¹⁸O, of 6.35 ± 0.15‰, about 2‰ above the cited average for SNC Martian meteorites and Allan Hills 84001. Together with sodium-rich alteration features, that result supports reactions with fluids enriched in the heavier oxygen isotope, ¹⁸O. The study considers two possible routes: direct reaction with those fluids or assimilation of crust that had already been altered by them.
This record points to fluid-rock interaction in one part of ancient Mars. It does not by itself establish a global ocean or life; the study reports geological and isotopic evidence, not a biosignature.
How deep the magma source may have been
Trace-element models favor partial melting of a mantle source containing garnet. In the study’s best-fitting model, melting began at about 5%, and garnet stability points to a depth of approximately 160 kilometers or more. That depth is a model-based estimate, not a direct measurement of where the rock formed.
The rock’s mineral mix and slow cooling fit an intrusive origin, meaning magma cooled beneath the surface. The study therefore links the sample to both an ancient crustal alteration event and a deeper mantle source, while treating the latter as a result of geological modeling.
What the maps say about its possible source
Remote-sensing comparisons favor a region in Mars’s ancient southern highlands, northwest of Hellas crater. The analysis began with 13 candidate locations and used chemical comparisons to narrow them. This identifies a broad possible source region, not a specific crater.
The meteorite’s ejection date is also undetermined. A sufficiently energetic impact can launch Martian rock beyond the planet’s escape velocity; fragments then orbit the Sun, and some eventually cross Earth’s path. That is the general route for Martian meteorites, not a reconstruction of Teghaza 001’s own journey. A review of Martian meteorites discusses identification methods, including isotope signatures and, in some meteorites, trapped gases matching Mars’s atmosphere. For Teghaza 001, the study says oxygen-isotope measurements verified its Martian origin.
Where the pieces are held
The University of New Mexico’s Institute of Meteoritics holds a 22-gram classification sample. The Maine Mineral & Gem Museum holds the 442-gram main mass and additional stones; research access is evaluated case by case.
