Alien Rock From Mars Reveals Ancient Volcanic Secrets

A rare Martian meteorite has revealed complex volcanic processes and mantle heterogeneity on Mars, offering new clues to the planet’s magmatic evolution and thermal history.

In a groundbreaking discovery published in the inaugural issue of Planet, scientists at Chengdu University of Technology revealed how a newly identified Martian rock formed. This specimen—Northwest Africa (NWA) 16254—belongs to the gabbroic shergottite group and stands out as the first of its kind to show significant geochemical depletion. By studying its composition, the team has opened a new window onto Mars’s volcanic history and the way its mantle and crust have interacted over time.

Under the leadership of Dr. Jun-Feng Chen from the Research Center for Planetary Science, researchers used detailed mineral maps and chemical analyses to trace a two-stage cooling and crystallization sequence. At depths where pressure reached between 4.3 and 9.3 kbar, magnesium-rich pyroxene crystals took shape first, marking the rock’s earliest growth phase.

As the molten material rose to shallower levels (less than 4 kbar), it cooled more slowly, allowing iron-rich pyroxene rims and plagioclase to form. The resulting coarse-grained texture preserves a record of repeated melt extraction from an aged, depleted mantle source. These findings provide a key piece of the puzzle for reconstructing the planet’s magmatic evolution.

A Unique Geochemical Signature

The meteorite’s geochemical depletion, marked by light rare earth element (LREE) depleted (Fig. 2) and low oxygen fugacity (fO₂​=IW−1.0), aligns it with the rare QUE 94201 meteorite, hinting at a shared magma source. Its gabbroic texture, indicative of slow cooling in crustal chambers, distinguishes it as a unique archive of subsurface magmatism.

These findings challenge existing models of Martian volcanic evolution, as NWA 16254’s consistently low fO₂​, corroborated by Ti³⁺-bearing ilmenite assemblages, implies sustained reducing conditions during crystallization. This underscores the heterogeneity of Mars’ mantle and raises questions about the planet’s redox evolution over billions of years. Future geochronological studies could resolve whether this meteorite represents ancient mantle melting (~2.4 billion years ago) or younger magmatic activity, offering clues to Mars’ thermal history.

The study leverages state-of-the-art techniques, including TESCAN Integrated Mineral Analyzer (TIMA) mapping and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), to trace mineral zoning and trace element distributions. These methods revealed decoupled geochemical behaviors in pyroxene cores and rims—a phenomenon critical for reconstructing magma chamber dynamics. For researchers, NWA 16254’s well-preserved geochemical signatures present a prime target for isotopic analyses, potentially unlocking timelines of Martian mantle depletion and refining models of planetary differentiation.

Reference: “Petrography and geochemistry of a newly discovered Martian gabbroic shergottite NWA 16254” by Chen Jun-Feng, Tian Xinyi and Cao Fengke, 13 May 2025, Planet.
DOI: 10.15302/planet.2025.25002

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