Ancient Martian meteorite reveals clues to Mars’ early crust

New research places Teghaza 001’s formation at least 4.1 billion years ago and examines how fluids later altered the rock.

An ancient piece of Mars recovered in Mali is giving scientists a rare sample of the planet’s earliest crust. A study published October 29 in Science identifies Teghaza 001 as a slowly cooled igneous rock that formed at least 4.1 billion years ago.

The roughly 800-gram meteorite was found in the Sahara Desert in 2022. The new paper, led by Yang Liu of NASA’s Jet Propulsion Laboratory, examines its origins and evidence that fluids subsequently changed its minerals.

Why this rock matters

Most known Martian meteorites are comparatively young. That leaves scientists with relatively few laboratory samples of the ancient rocks that dominate much of Mars’ surface.

Teghaza 001 has a distinctive combination of minerals, texture and chemistry. The research team links it to ancient crust and a chemically distinct source in the planet’s mantle. An igneous rock forms when molten rock cools; its minerals can retain clues to that process even after later geological changes.

Separating formation from alteration

Oxygen isotope measurements at the University of New Mexico helped establish the meteorite’s Martian origin. Other analyses, including dating individual mineral grains, constrained its ancient history.

NASA’s account of the research places water-driven alteration around 4.1 billion years ago, implying that the rock had already formed. The formation age is therefore a lower bound: at least 4.1 billion years, rather than a precise date for its original crystallization.

A rock can record both its formation and later encounters with water. Keeping those events separate is essential when reconstructing a planet’s history.

What the new paper adds

The October 29 paper provides a broad geological characterization of Teghaza 001. A separate study in Science Advances had already examined its water history in June. The meteorite’s discovery and these water results both predate this week’s publication.

Observations from NASA’s Mars Reconnaissance Orbiter identify possible matches in the southern highlands, but the exact source location remains unconfirmed. The findings offer evidence of ancient water–rock interactions; those reactions alone cannot establish that Mars once hosted life.