Mali Meteorite Found in 2022 Is Among the Oldest Martian Rocks, Study Says

Bir Chali, Mali. A meteorite recovered in 2022 from the Sahara in Mali originated in the crust of Mars at least 4.1 billion years ago, scientists report, which may make it the oldest of the 435 known Martian meteorites on Earth.

Evidence of water on early Mars

The research team said the makeup of the meteorite, named Teghaza 001, sheds light on conditions in the early history of Earth’s neighbour. It offers new evidence of liquid water at the surface, supporting the idea that Mars in its earliest era could have been favourable to microbial life.

Related: Zelenskiy Says Russia Holds No Current Frontline Advantage in Ukraine War

RelatedZelenskiy Says Russia Holds No Current Frontline Advantage in Ukraine War

Yang Liu, a planetary scientist at NASA’s Jet Propulsion Laboratory in California, which is managed by Caltech, described the rock as “a witness to a time when Mars was likely warmer and wetter than it has been for most of its history.”

Mars today is cold, dry and barren. Abundant evidence shows, however, that billions of years ago water ran across its surface in rivers and lakes, and an ocean covered part of the northern hemisphere.

Composition and origin of the rock

Teghaza 001 is a gabbro, a coarse-grained rock type. Its chemistry indicates that it interacted with water while cooling and crystallizing slowly beneath the Martian surface. The rock belonged to the crust, the outer layer of the planet, but it formed from magma that came from deeper in the Martian mantle.

The meteorite was found in eight pieces in the desert, about 21 miles (34 km) from the Malian village of Bir Chali. The biggest fragment is roughly fist-sized. Its principal minerals are feldspar and pyroxene, and it holds zircon crystals containing uranium. The team determined its age by measuring how uranium turns into lead over time.

Why Martian meteorites matter

Liu, the lead author of the study published in the journal Science, said meteorites from Mars are the only physical samples of the planet available. According to Liu, they underpin knowledge of how early Mars formed and differentiated, and they let researchers test in laboratories whether the ancient planet could have been habitable.

Liu added that the detailed data drawn from such samples complements and confirms findings from satellites, landers and rovers sent to Mars.

The information also gives hints about how Mars and Earth began to follow different paths in their infancy, when life was starting to emerge on Earth, Liu said. Earth, Mars and the other planets of the solar system formed about 4.5 billion years ago.

Among only three from the early period

Only three Martian meteorites, Teghaza 001 included, date back to the early history of the planet. One of the others was found in Antarctica in 1984. It was first estimated to be about 4.5 billion years old but was more recently judged to be of similar age to Teghaza 001. The new study says Teghaza 001 is probably the older of the two.