The lunar rock fragment designated Northwest Africa (NWA) 16254, a 406-gram gabbroic shergottite, was unearthed in Algeria approximately two years prior.
The NWA 16254 specimen, subjected to scholarly examination by Chen and associates: (a) a backscattered electron (BSE) image captured by the TESCAN Integrated Mineral Analyzer (TIMA); (b) mineralogical cartography executed by TIMA; (c) a depiction of iron content distribution as determined by TIMA; (d) a visualization of calcium content distribution from TIMA. Kindly attributed to Chen et al., with the digital object identifier: 10.15302/planet.2025.25002.
Lead author Dr. Jun-Feng Chen and his collaborators at the Chengdu University of Technology stated, “Martian meteorites serve as the sole terrestrial samples available for laboratory analysis of Mars’ mantle composition and its evolutionary trajectory, predominantly owing to their igneous origins which preserve geochemical signatures of mantle processes.”
“Within this collection of extraterrestrial materials, shergottites, accounting for approximately 90% of all Martian meteorites, are particularly instrumental in unraveling the complexities of mantle dynamics, the interplay between crust and mantle, and the magmatic differentiation phenomena on Mars.”
“Shergottites are categorized into four distinct petrological subgroups, differentiated by their unique textural and mineralogical characteristics: these include basaltic, olivine-phyric, poikilitic, and gabbroic classifications.”
“These variations are indicative of diverse formation environments, spanning from subterranean crystallization at superficial depths to potential eruptive events on the surface. Notably, gabbroic shergottites exhibit coarse-grained textures, a telltale sign of slow cooling within magma chambers located in the Martian crust.”
In their recent investigation, the researchers employed sophisticated mineralogical mapping and geochemical assessment techniques to elucidate the developmental history of NWA 16254.
Their analysis identified a divergence in geochemical signatures between the core and the outer layering of pyroxene crystals, a crucial observation for reconstructing the internal dynamics of magma chambers.
The research team reported, “Our findings suggest that NWA 16254 initially originated under conditions of high pressure (ranging from 4.3 to 9.3 kbar) at the interface between Mars’ mantle and crust, where pyroxene crystals rich in magnesium began to form.”
“Subsequently, the molten rock migrated to shallower crustal regions (below 4 kbar), leading to the development of pyroxene rims enriched in iron, alongside plagioclase.”
“This extended period of cooling, evidenced by the meteorite’s coarse-grained texture, implies that melt was extracted intermittently from a long-standing, depleted mantle source – providing vital insights into the magmatic evolution of Mars.”
“The meteorite’s observed geochemical depletion, characterized by a deficiency in light rare earth elements and a low oxygen fugacity, closely parallels that of a meteorite known as QUE 94201, suggesting a common origin for their magmatic material.”
“Its gabbroic structure, which points to slow solidification within crustal reservoirs, positions it as a singular record of subsurface magmatic activity.”
“These discoveries present a challenge to current hypotheses regarding Martian volcanic development, as the uniformly low oxygen fugacity detected in NWA 16254, supported by the presence of Ti3+-bearing ilmenite mineral associations, indicates persistent reducing conditions throughout its crystallization phase.”
“This observation highlights the heterogeneity present within Mars’ mantle and prompts further inquiry into the planet’s redox environment over geological timescales spanning billions of years.”
“Future geochronological investigations may clarify whether this meteorite is a product of ancient mantle melting events (approximately 2.4 billion years ago) or a manifestation of more recent magmatic activity, thereby shedding light on the thermal history of Mars.”
The scientists’ academic paper was disseminated on May 13, 2025, within the esteemed journal Planet.
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Jun-Feng Chen et al. Petrography and geochemistry of a newly discovered Martian gabbroic shergottite NWA 16254. Planet, published online May 13, 2025; doi: 10.15302/planet.2025.25002
