New Martian Meteorite NWA 16254 Sheds Light on Ancient Volcanic Activity

A recently analyzed Martian meteorite, designated Northwest Africa (NWA) 16254, has provided significant insights into the volcanic processes that occurred on ancient Mars. Weighing 406 grams, this gabbroic shergottite was found in Algeria two years ago, and its study, led by Dr. Jun-Feng Chen at Chengdu University of Technology, was published on May 13, 2025, in the journal Planet.

Martian meteorites are crucial for understanding the composition and evolution of Mars since they are the only direct samples available for laboratory analysis. According to Dr. Chen and his colleagues, shergottites comprise about 90% of the Martian meteorite collection and are vital for deciphering mantle dynamics, crust-mantle interactions, and magmatic differentiation on Mars.

Shergottites are categorized into four petrological subtypes, including basaltic, olivine-phyric, poikilitic, and gabbroic, based on their unique textural and mineralogical properties. These variations reflect differing formation environments, from shallow subsurface crystallization to potential surface eruptions. Gabbroic shergottites, like NWA 16254, exhibit coarse-grained textures indicative of slow cooling processes in crustal magma chambers.

In their research, the team employed advanced mineralogical mapping and geochemical analyses to unravel the history of NWA 16254. They identified distinct geochemical behaviors in pyroxene cores and rims, offering critical insights into magma chamber dynamics. "Our findings indicate that NWA 16254 initially formed under high-pressure conditions at the Martian mantle-crust boundary, where magnesium-rich pyroxene cores crystallized before the magma ascended to shallower depths," Dr. Chen stated.

This cooling process, evident in the meteorite’s coarse-grained texture, suggests episodic melt extraction from a long-lived, depleted mantle reservoir—a key aspect for reconstructing the magmatic evolution of Mars. The meteorite's geochemical profile, characterized by light rare earth element depletion and low oxygen fugacity, aligns with another meteorite known as QUE 94201, suggesting a shared magma source.

NWA 16254 stands out due to its gabbroic texture, which underscores it as a unique archive of subsurface magmatism. The study challenges existing models of Martian volcanic evolution, as the meteorite's consistently low oxygen fugacity, verified by the presence of Ti3+-bearing ilmenite assemblages, indicates sustained reducing conditions during its crystallization.

Dr. Chen emphasized that this research highlights the heterogeneity of Mars’ mantle and raises important questions about the planet’s redox evolution over billions of years. Future geochronological studies may determine whether NWA 16254 represents ancient mantle melting, approximately 2.4 billion years ago, or more recent magmatic activity, thereby offering further insights into Mars’ thermal history.

The implications of this research extend beyond academic interest; understanding the volcanic history of Mars is critical for future exploration and potential colonization efforts. By piecing together Mars’ geological past, scientists can better assess its habitability and the potential for past life on the planet. As exploration missions continue, findings like those from NWA 16254 are vital for unraveling the mysteries of our neighboring planet.