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

The direct analysis of ancient Martian crustal rock provides evidence of past water circulation, potentially indicating habitable environments within early Mars.

A Martian meteorite, Teghaza 001, discovered in Mali's Sahara Desert in 2022, has been analyzed and dated to at least 4.1 billion years old, providing a rare glimpse into Mars' ancient crust. This igneous rock, weighing under 800 grams, is one of only a few truly ancient Martian meteorites known on Earth, alongside Allan Hills 84001 and Black Beauty. Its composition, rich in feldspar and pyroxene, suggests slow cooling deep within the Martian crust. The rock's internal mineral alteration and its unusual oxygen isotope composition indicate interaction with hot, circulating water shortly after its formation, suggesting a dynamic early Martian hydrosphere. Trace element analysis also points to a mantle source deeper than previously understood for early Mars.

The discovery and analysis of Teghaza 001 challenge previous assumptions about the evolution of the Martian mantle in its early history. Trace element ratios indicate its magma originated from depths exceeding 160 kilometers, a source not identified in previous meteorite studies. This suggests a more complex mantle differentiation process in Mars' first few hundred million years than currently modeled.

The presence of substantial water circulation within the Martian crust 4.1 billion years ago, evidenced by mineral alteration and oxygen isotopes in Teghaza 001, implies that early Mars possessed a more active and dynamic hydrosphere than previously believed. This finding significantly bolsters the potential for early habitability within the Martian crust, prompting a reevaluation of planetary exploration strategies.