A Martian meteorite found in Algeria, NWA 13441, has filled an important gap in the geological history of the Red Planet. Its age — 1.27 billion years — makes it one of the most unusual samples ever to have reached Earth.

Why this rock is special

As Space.com reports, the meteorite was discovered in 2019 in Northwest Africa, but its precise age was only confirmed recently. It belongs to the shergottite group — the most common type of Martian meteorites. However, until now, no shergottite was known from the vast time window between roughly 600 million and 2.4 billion years ago. Known samples from that period belonged to rarer types — chassignites and nakhlites.

"The characteristics of this meteorite turned out to be completely unexpected. No other Martian meteorite of this age — 1.27 billion years — is known to us," noted study co‑author Ethan Baxter, Professor of Earth and Environmental Sciences at Boston College.

The work was published on 1 August in the journal Geochimica et Cosmochimica Acta.

Two surprises in its composition

The first peculiarity is its mixed composition. Although the meteorite is a shergottite (i.e., solidified magma), it contains isotopes of the rare‑earth metal neodymium that are typically found in chondrites — more "primitive" meteorites preserved from the early stages of the Solar System's formation 4.56 billion years ago.

This combination suggests that the deeper layers of Mars have remained relatively undisturbed since the planet's formation. This is consistent with the fact that Mars lacks plate tectonics, which on Earth constantly mixes and recycles the crust.

The second surprise relates to its isotopic composition. It helps refine the boundaries of processes that occurred in the very early Solar System during Mars's formation. The researchers suggest that the meteorite may have originated from a previously unstudied reservoir on the Red Planet — a kind of "intermediate" zone between enriched and depleted sources of shergottites.

What's next

Scientists hope that further analysis of the meteorite will shed light on Mars's magmatic and volcanic activity during that period. The next step will be to study isotopes to understand the relationship between NWA 13441 and other ancient Martian meteorites.

In brief

The 1.27‑billion‑year‑old meteorite NWA 13441 is the first known shergottite from a large gap in Mars's geological history. Its unusual composition, combining characteristics of both shergottites and chondrites, points to the existence of a previously unstudied reservoir in the planet's interior and helps us understand early Solar System formation processes. The study was published in the journal Geochimica et Cosmochimica Acta.