NASA-funded study identifies 4.1-billion-year-old Mars meteorite showing early water activity

What was announced

NASA's Jet Propulsion Laboratory announced details of Teghaza 001, a meteorite found in Mali in 2022. Research published in Science on October 29, 2026, confirmed that the rock originated from Mars and was altered by water more than 4.1 billion years ago.

University of New Mexico researchers first identified the stone as Martian by studying its oxygen isotopes, which act as chemical signatures for different planets. While early assessments grouped it with common Martian meteorites known as shergottites, closer inspection by JPL lead author Yang Liu revealed zircon crystals and unfamiliar mineral patterns.

Caltech co-author Francois Tissot applied an in-situ rubidium-strontium dating method. Rather than dissolving the rock in acid, the team tested individual mineral grains on a chip smaller than a fingernail. This confirmed the rock is volcanic crust altered by water roughly 4.1 billion years ago.

What it means

Teghaza 001 is only the third ancient Martian meteorite discovered on Earth. Other known ancient samples, like ALH84001 and "Black Beauty," offer more narrow windows into Martian geology. One consists mainly of a single mineral, while the other formed about 2.1 billion years ago from broken rock fragments.

This meteorite holds a mixture of volcanic minerals matching spectral measurements collected from orbit by NASA's Mars Reconnaissance Orbiter. The data aligns with the cratered southern highlands of Mars, giving researchers physical material from a Martian region never sampled directly before.

Chemical signatures show that water was actively moving beneath the surface and altering crustal rock during the planet's infancy. Scientists can now study these minerals to examine how early Martian water reacted with rock and how the atmosphere may have begun losing water.

What the announcement does not tell us

Scientists will never know the exact spot on Mars where the rock came from, according to the paper. Orbital comparisons identified 13 potential source areas, but the specific impact crater remains unknown.

Researchers also did not determine how long the rock drifted in space before landing on Earth. While the paper describes water alteration around 4.1 billion years ago, the findings do not establish the exact date the magma originally hardened into rock. Finally, the announcement does not specify which laboratories will receive pieces of the sample for the next rounds of testing.