More than 4.5 billion years ago, it’s possible that Mars, the Red Planet, had a crust comparable to Iceland today. This discovery, hidden in the oldest martian fragments found on Earth, could provide information about our planet that was lost over billions of years of geological movement and could help explain why the Earth developed into a planet that sustains a broad diversity of life and Mars did not.
The 4.48-billion-year-old meteorite, informally named Black Beauty, recorded the first stage of the evolution of Mars and, by extension, of all terrestrial planets, including the Earth. “As the Earth lost its old surface mainly due to plate tectonics, observing such settings in extremely ancient terrains on Mars is a rare window into the ancient Earth surface that we lost a long time ago,” says Valerie Payré, a Northern Arizona University researcher in a release.
The meteorite, the chemistry of which indicates that Mars had volcanic activity similar to that found on Earth, recorded the first stage of Mars’ evolution (Nature Communications). Although it was ejected from the surface of Mars 5-10 million years ago after an asteroid impact, its source region and geological context has remained a mystery.
This team studied the chemical and physical properties of Black Beauty to pinpoint where it came from; they determined it was from Terra Cimmeria-Sirenum, one of the most ancient regions of Mars. Planetary bodies like Mars have impact craters all over their surface, so finding the right one is challenging. They were able to isolate the most plausible ejection site — the Karratha crater that excavated ejecta of an older crater named Khujirt.
