Teghaza 001: NASA-Funded Study Dates One of the Oldest Mars Meteorites at 4.1 Billion Years

NASA says a meteorite named Teghaza 001, found in the Sahara in 2022, is one of the oldest Martian meteorites ever discovered. A study published in the journal Science on October 29, 2026 reports that it formed more than 4.1 billion years ago and carries clues to an early, active water cycle on Mars. This article summarizes NASA’s account of the rock, how it was dated and what the researchers say it shows.

What is Teghaza 001?

NASA reports that Teghaza 001 is named after a salt plain in Mali, where it was discovered in the Sahara Desert in 2022. It weighs nearly 2 pounds, or 800 grams. It is one of roughly 435 known meteorites from Mars. A Martian meteorite is a piece of rock blasted off Mars by an impact that eventually fell to Earth. That definition is general and is not a NASA quotation.

How old is it?

NASA says the rock formed more than 4.1 billion years ago. It also says water alteration occurred around 4.1 billion years ago, which suggests the rock itself formed even earlier. Caltech’s Francois Tissot used in-situ rubidium-strontium dating on single mineral grains from a sample smaller than a fingernail, which preserved the rare specimen. By our own arithmetic, 4.1 billion years is about 90% of Earth’s age of roughly 4.54 billion years, a general figure that is not from NASA’s article.

What does the rock show?

According to NASA, the rock’s igneous minerals record how Mars’s crust formed from cooling magma and was later altered by water below the surface. Clues in its oxygen isotopes, texture and chemistry point to a more dynamic early water cycle on Mars. An isotope is a form of an element with a different number of neutrons. NASA does not claim the study proves that surface oceans existed, and neither do we.

Where did it come from?

Scientists identified 13 locations on Mars that match the meteorite’s mineralogy and chemistry, but its exact source is unknown. NASA says its mineralogy matches terrain that NASA’s Mars Reconnaissance Orbiter observed in the cratered southern highlands. That makes the highlands a leading candidate region, though not a confirmed origin.

Who did the work?

The lead author is Yang Liu of NASA’s Jet Propulsion Laboratory. The main paper appeared in Science, and a separate paper in Science Advances in June covered the meteorite’s water content. NASA funded the study, according to the headline of its report. We have not read either paper, so we rely on NASA’s summary.

How to read the numbers

The meteorite is one of about 435, so by our own arithmetic it represents roughly 0.2% of known Martian meteorites. The figure of 13 candidate locations is a count of matches, not of confirmed sources. The age is a minimum for the rock, since the water alteration happened at about 4.1 billion years ago and the rock must be older. These readings are ours and follow from NASA’s numbers. Mass of about 800 grams equals about 1.8 pounds, consistent with NASA’s nearly 2 pounds.

Why study meteorites when rovers exist?

A rover can only carry a few instruments, while a meteorite in a laboratory can be examined with the most precise tools on Earth. The cost of that advantage is that a meteorite arrives without context, so scientists must infer where it came from. NASA’s report shows that problem, since the source is one of 13 matching spots. A mission that returns samples from a known place would remove the guesswork. This is a general comparison and is not stated in the NASA article.

Why is dating a meteorite hard?

Meteorites are small, and destroying one to measure its age would waste a rare specimen. NASA says Caltech’s team dated single mineral grains in place from a sample smaller than a fingernail, which avoids grinding up the rock. The method relies on the slow decay of rubidium into strontium, and the ratio of the two elements in a grain acts like a clock. The point of the technique is to get a precise age while using almost none of the material, a general feature of in-situ methods and not a detail NASA spells out.

What should readers keep in mind?

A single meteorite is one data point. It can show that Mars had water-altered rock more than 4.1 billion years ago, but it cannot show how widespread the water was or for how long. Scientists will compare Teghaza 001 with other meteorites and with rover data before drawing wide conclusions. NASA’s language is cautious, and the headline claim is that the rock is among the oldest Martian meteorites found, not that it settles the history of water on Mars.

How does it connect to other coverage?

Studies of Mars combine many sources of evidence. Our article on Perseverance and Martian dust covers what a rover learned about the planet’s dust, and our report on Japan’s MMX mission covers a launch toward Mars’s moons. Our summary of NASA’s simulated Mars crew describes ground work for human missions, and the article on the Psyche mission covers a spacecraft that flew past Mars. Together, they show that understanding Mars needs rocks, robots and models.

Glossary

• Meteorite: a rock from space that survives landing on Earth
• Igneous mineral: a mineral formed from cooled molten rock
• Isotope: a form of an element with a different number of neutrons
• Rubidium-strontium dating: a method that uses radioactive decay to find a rock’s age
• Highlands: the older, cratered regions of a planet

These definitions are general explanations and are not quoted from NASA.

What is not covered here?

NASA’s report does not give the meteorite’s full chemical makeup, the amount of water it once held or the precise age with uncertainty. We have not added those details. Readers who want them should read the Science paper.

Key facts at a glance

• Name: Teghaza 001, found in the Sahara in 2022
• Mass: nearly 2 pounds (800 grams)
• Age: formed more than 4.1 billion years ago
• Candidate source regions: 13 locations, southern highlands favored
• Journal: Science, October 29, 2026

Frequently asked questions

How do we know it came from Mars?

NASA classes it among roughly 435 known Martian meteorites, based on its composition.

Does it prove ancient oceans?

No. NASA says it points to a more dynamic early water cycle.

Where exactly did it form?

Unknown. Thirteen locations match, and the southern highlands are a leading candidate.