Study Reveals Details Of One Of The Oldest Mars Meteorites Ever Found On Earth

A rose-coloured rock discovered in the Sahara Desert in 2022 has turned out to be a piece of Mars that formed more than 4.1 billion years ago. Scientists studied the minerals in the nearly 800-gram rock and found that it is one of the oldest Martian meteorites ever discovered on Earth, according to NASA.

Named Teghaza 001 after the salt plain in Mali where it was found, the meteorite may help scientists understand how the surface of Mars formed and how water interacted with rocks on the planet billions of years ago.

Researchers presented their initial study of Teghaza 001 in a paper published in Science on Thursday. The study offers a rare look at the ancient crust of Mars and the planet's early formation.

Yang Liu, the lead author of the paper from NASA's Jet Propulsion Laboratory in Southern California, said the meteorite's unique features became clear only after scientists examined it closely. One of the paper's reviewers described it as a Rosetta Stone for Mars.

What Makes Teghaza 001 Special

Teghaza 001 stands out because of its age, texture and volcanic minerals. It is among the three oldest Martian meteorites found on Earth.

The other two include ALH84001, which is made almost entirely of one mineral and is similar in age to Teghaza 001. The second, known as Black Beauty, formed about 2.1 billion years ago and contains small pieces of volcanic rock.

Unlike these meteorites, Teghaza 001 contains a mixture of volcanic minerals. These minerals provide clues about how Mars' crust formed as magma cooled and how underground water later changed the rock.

Its mineral composition also matches features observed in the cratered southern highlands of Mars by NASA's Mars Reconnaissance Orbiter. Although scientists cannot identify the exact location where the meteorite originated, the study points to several possible locations that match its minerals and chemical composition.

Meteorite Offers Clues About Water on Mars

Lee Saper, the second author of the study, said Teghaza 001 provides a sample of Martian crust from a region that scientists have not previously studied through a meteorite sample.

He explained that the rock records how water interacted with rocks and may also preserve signs of the Martian atmosphere from a time when the planet was losing water.

A separate paper published in Science Advances in June examined the meteorite's water content and provided further information about how water shaped the early surface of Mars.

Scientists Determine The Meteorite's Age

Researchers at the University of New Mexico had already identified Teghaza 001 as a Martian meteorite by studying its oxygen isotopes. These act as chemical fingerprints that help scientists identify where a rock came from.

However, the rock's unusual textures and minerals caught Liu's attention. Her team discovered zircon crystals, which preserve information about how rocks formed and help scientists determine their age.

The researchers then used a method developed by a team led by Caltech scientist Francois Tissot. Instead of dissolving and analysing an entire sample, the method examines individual mineral grains on the rock's surface using a very small piece of the meteorite.

Tissot said the technique allows scientists to determine the age of ancient Martian meteorites with high precision while preserving rare samples for future research.

Findings Point To Ancient Water Activity

The age-dating results surprised Liu. Scientists found that water had altered the meteorite around 4.1 billion years ago, meaning the rock itself had formed even earlier.

The oxygen isotopes, texture and chemical composition of its minerals also suggest that early Mars had a more active water cycle than scientists may have previously understood.