Scientists Thought This Was an Ordinary Mars Meteorite. It’s Actually One of the Oldest Ever Found

In 2022, meteorite hunters discovered scattered fragments of an unusual rock in the Sahara Desert in northern Mali. The fragments would later be identified as Martian in origin, but their age remained another mystery. Now, scientists have dated the meteorite, known as Teghaza 001, to approximately 4.1 billion years ago, making it a valuable window into the Red Planet’s ancient history. The recent findings, published in Science, suggest that Teghaza 001 is one of the oldest Martian meteorites ever found on Earth, offering a rare glimpse of the planet less than 500 million years after it formed. “It was only after we started looking closely that we realized this meteorite is really unique,” Yang Liu, a geologist at NASA’s Jet Propulsion Laboratory and lead author of the paper, said in a statement. “One of the paper’s reviewers called it a Rosetta Stone for Mars.” Time capsule Scientists have identified more than 400 Martian meteorites that were flung from the Red Planet by some sort of impact and landed here on Earth. Most Martian meteorites scientists have studied are relatively young, giving us a limited picture of the planet’s earliest geological history. Teghaza 001 belongs to an exclusive group of Martian meteorites that preserve a record of the Red Planet’s earliest history, alongside famous specimens such as ALH 84001 and Black Beauty (NWA 7034). But Teghaza 001 stands out for its unusual mineral composition, which sets it apart from other ancient Martian rocks. Teghaza 001 was initially classified as a shergottite, the most common type of Martian meteorite. As an expert in planetary samples, Liu had seen plenty of them and almost passed up on the opportunity to take a closer peek at the rose-colored stone. By analyzing the rock, however, Liu and her team discovered zircon crystals, which can be used to precisely age-date a sample, in Teghaza 001. The team of researchers also used a new age-dating method, analyzing single mineral grains on a piece of Teghaza 001 that was smaller than a fingernail. The results revealed that the meteorite had been altered by Martian water sometime around 4.1 billion years ago, suggesting it originally formed even earlier. Clues to ancient Mars Teghaza 001’s age isn’t the only thing that makes it special. Unlike that of its ancient peers, this meteorite’s composition of volcanic minerals reveals clues as to how Mars’ crust formed from cooling magma before it was altered by subsurface water. “This is really our first piece of Martian crust from a part of Mars we’ve never had a sample of before,” Lee Saper, a scientist at NASA’s Ames Research Center in Silicon Valley and co-author of the study, said in a statement. “It records interactions of water and rock and maybe even an imprint of the Martian atmosphere as it was losing water.” The meteorite’s composition reveals evidence of its past interactions with water, suggesting a much more dynamic water cycle on early Mars. The findings also provide further evidence that Mars may have had the necessary ingredients to support life during its early history. The researchers are hoping that Teghaza 001 will help them answer more questions about the Red Planet’s ancient past. “We’ve only scratched the surface,” Liu said.