The origin of Martian meteorites revealed

Every year, thousands of tonnes of meteorites and micro-meteorites reach the Earth, mainly from the asteroid belt. Some of them have a much more exotic origin: the planet Mars. These rare samples, around 300 kg in all, are of vital importance in understanding the evolution of the red planet and its differences from Earth.

Until now, the precise sites from which these rocks came remained a mystery. An international team, including CNRS Terre & Univers researchers (see inset), has just lifted the veil on the origin of several groups of these precious meteorites.

To solve this enigma, the scientists developed an innovative approach combining artificial intelligence, satellite observations, numerical simulations of asteroid impacts and geochemical laboratory analyses. This method has enabled them to identify with precision the craters of origin of three groups of Martian meteorites, located in the volcanic provinces of Elysium and Tharsis.

This discovery goes far beyond mere localisation. It highlights fundamental geochemical differences between these two regions, revealing the existence of two distinct mantle domains on Mars. This new data opens up fascinating prospects for recalibrating the Martian chronology, particularly over the last two billion years. The researchers hope to refine our understanding of the duration and nature of the events that have shaped the history of the Red Planet. This major advance could have considerable implications for our knowledge of the evolution of Mars and, by extension, of the processes involved in the formation and evolution of rocky planets.