The 4.1-Billion-Year-Old Red Planet Visitor
A reddish igneous rock discovered in the Sahara desert of Mali in September 2022 has been confirmed as one of the oldest Martian meteorites ever identified on Earth. Designated as Teghaza 001, the specimen formed at least 4,100 million years ago, according to a study published in Science. The rare find consists of eight fragments with a combined weight of approximately 798.5 grams, with the largest single piece tipping the scales at 442 grams.
Deep Magma Chambers and Slow Cooling
Classified as a coarse-grained gabbro, the rock is composed primarily of pyroxene and feldspar, alongside zircon crystals containing uranium. Scientists calculated its age by measuring the radioactive decay of uranium into lead. The mineral grains cooled at a sluggish rate of just 0.01 degrees Celsius per year. This gradual temperature drop reveals that the magma solidified deep beneath the Martian surface rather than in a fast-moving surface flow. Furthermore, the specimen bears high-pressure minerals including maskelynita and reidita, forged by the violent impact of an asteroid that blasted the rock out into space.
Clues to an Ancient Martian Water Cycle
Hydrogen and oxygen isotopes trapped inside the sample tell a story of an infant planet shaped by fluids. Water filtered down into the deep crust, mixing directly with molten rock more than 4,100 million years ago. Yang Liu, a planetary scientist at NASA and lead author of the research, noted that the object acts as a witness to an era when the planet was likely warmer and wetter than during most of its subsequent history. Researchers believe the specimen originated in the southern highlands near the Hellas impact basin.
Rarity Among Extraterrestrial Samples
Out of more than 400 Martian meteorites recovered on Earth, only three known samples date back to this primordial chapter of planetary history. This places Teghaza 001 in an exclusive group alongside ALH84001, which consists of a single mineral. By contrast, another famous sample known as Black Beauty formed roughly 2,100 million years later from volcanic fragments. Unlike Earth, which constantly recycles its crust through plate tectonics, Mars has preserved vast stretches of ancient crust—leaving these rare meteorites as critical physical archives for studying primitive habitability.
