Boston College scientists dated meteorite Northwest Africa 13441, found in Algeria, to a period with no other dated shergottites, and found its chemistry points to a pristine reservoir deep in Mars.
No one has yet brought rocks back from Mars. But pieces of the planet have been arriving on Earth for millions of years. When asteroids slam into Mars, they can blast fragments into space, and a few eventually fall to Earth as meteorites. About 400 Martian meteorites have been found so far, and they are among the only samples scientists have of the red planet.
A newly studied one is helping fill a large hole in that record. Researchers at Boston College report in Geochimica et Cosmochimica Acta that the meteorite Northwest Africa 13441, found in Algeria in 2019, is about 1.27 billion years old, an age that falls in a long stretch of Martian history with no other samples of its kind.
“The characteristics of this meteorite were entirely surprising,” said Ethan Baxter, a professor of Earth and environmental sciences at Boston College. “No other martian meteorite like this has an age of 1.27 billion years old.”
A gap in the record
NWA 13441 is a shergottite, the most common group of Martian meteorites. Shergottites are igneous rocks, formed when molten rock from the planet’s interior cooled and solidified, so they record the history of Martian magmatism and volcanism.
Until now, dated shergottites fell into two groups. “Martian meteorites of this type are either younger than 600 million years old, or approximately 2.4 billion years old,” said Dylan M. Seal, a doctoral candidate at Boston College. That leaves a gap of roughly 1.8 billion years with no dated samples of this type.
Using high-precision techniques, the team dated NWA 13441 to about 1.273 billion years ago, placing it squarely within that gap. Seal noted that the result fills a large void in the timeline of Martian volcanic activity.
Two other rare classes of Martian meteorites, nakhlites and chassignites, date to about 1.3 to 1.4 billion years ago. But their chemistry differs from that of NWA 13441, indicating that they came from different sources within the planet.
Shergottites take their name from Shergotty, a town in India where the first known example fell in 1865. Nakhlites are named for El-Nakhla in Egypt, where a meteorite fell in 1911, and chassignites for Chassigny in France, where one fell in 1815. Together the three groups, sometimes called SNC meteorites, were recognized as Martian in the 1980s after gas trapped inside them was found to match the atmosphere measured by NASA’s Viking landers.
A pristine reservoir
The meteorite’s chemistry held another surprise. The team measured its initial neodymium isotope composition, a kind of chemical fingerprint that reflects the history of the rocks from which its magma formed. The value matches that of the early solar system, a composition geologists call chondritic, after the primitive meteorites known as chondrites.
No other shergottite has shown this signature. The result suggests that part of Mars’ deep interior remained chemically unaltered for billions of years, preserving material similar to the building blocks from which the planet formed.
That is notable because Mars formed very early, less than about 5 million years after the solar system began about 4.56 billion years ago, and its interior went through dramatic processes, including the separation of a core and the formation of a crust. Finding a region that escaped much of that processing could help scientists reconstruct the planet’s original composition.
On Earth, comparable evidence of ancient, unmixed mantle is rare, because plate tectonics continually recycles crust back into the interior and stirs the mantle. Mars has no plate tectonics today, which may have allowed distinct reservoirs in its interior to survive largely untouched for much longer.
How the team did it
Dating a rock this old with high precision relies on radioactive isotopes, which decay at known rates into other elements. By measuring the ratios of parent and daughter isotopes in the minerals of the meteorite, researchers can calculate when the rock crystallized.
Determining when a Martian meteorite crystallized is different from determining when it left Mars. Meteorites also record how long they spent drifting through space, because cosmic rays create distinctive isotopes in their surfaces, and how long they have sat on Earth. Martian meteorites typically spent a few million years or less in space before landing, so their crystallization ages reflect events on Mars itself.
The study was led by Baxter and Seal with Melody Z. Chen, an undergraduate researcher at Boston College, and Robert W. Nicklas, a former postdoctoral scholar now at the Lunar and Planetary Institute, along with colleagues from the Scripps Institution of Oceanography and The Open University. The work was supported by the U.S. National Science Foundation.
Next steps
Baxter said the team plans to analyze additional isotope systems to understand how NWA 13441 relates to other early Martian meteorites, including the nakhlites and chassignites that formed around the same time.
The findings also have implications for understanding how long Mars remained volcanically active. A planet’s volcanic activity is linked to the heat in its interior, and that heat influences everything from the release of gases into the atmosphere to the potential for environments that could have supported life.
Meteorites have one significant limitation: scientists usually do not know exactly where on Mars they came from. Samples collected by NASA’s Perseverance rover in Jezero Crater, which are intended for eventual return to Earth, would come with that geological context, although the future of the Mars Sample Return effort remains uncertain. Until then, rare finds such as NWA 13441 offer one of the few ways to read the planet’s deep history.
Notes
- “Implications for martian mantle reservoirs from petrogenesis of the 1.27 Ga olivine-phyric shergottite Northwest Africa 13441.” Geochimica et Cosmochimica Acta, 2026. DOI: 10.1016/j.gca.2026.06.035.
- Boston College. “Martian meteorite helps to bridge a 1.8-billion-year data gap in magmatic and volcanic activity on the Red Planet.” EurekAlert!, 1 August 2026. https://www.eurekalert.org/news-releases/1139166.
Scripps Institution of Oceanography at UC San Diego