Rare meteorite from Mars gives us a view into its ancient crust

A Martian meteorite discovered in the Sahara Desert, named Teghaza 001, has revealed that Mars possesses rocks dating back to 4.1 billion years ago. This ancient meteorite, found in 2022, provides a glimpse into the planet's early history. The discovery challenges previous knowledge, as most Martian surface features are more than 3 billion years old, but the meteorites found on Earth are younger.

Three primary groups of Martian meteorites—shergottites, nakhlites, and chassignites—were previously known to be 2.4 billion years old or younger. Only two truly ancient Martian meteorites, Allan Hills 84001 and Black Beauty, had been identified until now. The newly discovered Teghaza 001, however, is notably older and similar to some of the earliest rocks on Earth.

Planetary scientist Yang Liu from NASA's Jet Propulsion Laboratory and his team attribute the rarity of ancient Martian rocks on Earth to the challenges of launching such relics from the planet. The process of a meteorite leaving Mars typically requires a significant impact, and not all rocks can survive this event. The force of the impact may cause the rock to break apart rather than becoming a solid piece that can escape Mars' gravity.

Consequently, weak rocks are naturally filtered out during this process, resulting in the scarcity of ancient Martian rocks discovered on Earth.