11-8 From the Moon to Antarctica: Petrological Characterization of Meteorite Dominion Range (DOM) 18678 Provides Insights into Lunar Magmatism and Impact History

Session: Applications of Igneous Petrology, Geochemistry, and Geochronology to Understanding Earth and Other Planetary Systems (Posters)

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On the 2018-2019 expedition conducted by NASA’s Antarctic Search for Meteorites (ANSMET), eight lunar meteorites were collected from the Dominion Range (DOM), Antarctica. This study will be the first to conduct a petrological investigation of sample DOM 18678 (mass: 11.6g). Previous work has classified the 2018-2019 lunar DOM meteorite suite as basaltic breccias, specifically polymict regolith breccias, with exteriors characterized by a black to dark gray fusion crust with occasional white speckles up to 1mm and minor oxidation across most of the surface. Work to date on a single thin section of DOM 18678 (1.6cm x 2cm) has been conducted via SEM, including BSE and EDS analysis. This has enabled a detailed and systematic textural, mineralogical, and geochemical characterization at the sub-mm scale to be completed. Clasts within DOM 18678 are predominantly basaltic, ranging from 50μm-1mm, and composed mainly of calcium-rich plagioclase (anorthite), clinopyroxene, iron-rich olivine (fayalite), and minor Fe-Ti oxide (ilmenite), silica, and iron sulfide (troilite). These clasts are surrounded by a black to dark gray, fine-grained, glassy matrix. Other clasts present include impact melt breccias, microbreccias, and 3-phase symplectites (fayalite, clinopyroxene, silica) consistent with previous work on this lunar DOM suite. Within the brecciated matrix, mineral fragments are subhedral to anhedral and predominantly plagioclase and clinopyroxene with minor olivine and Fe-Ti oxides. Throughout the brecciated matrix, glass spherules are present and include both glass and crystalline varieties. Glass is also present as melt veins throughout the entire sample, and as a variably vesiculated fusion crust surrounding ~55% of the meteorite (thickness varies from 10μm to 50μm). The presence of glass spherules and abundant melt veins are evidence of high pressure-temperature processes on the lunar surface, likely including impact-related events (shock metamorphism) and rapid cooling. 

Future in-situ analysis via EPMA will quantify major element mineral chemistry to evaluate basalt petrogenesis and potential source regions on the Moon (e.g., Mg# vs. wt. % Cr₂O₃ in clinopyroxene). When possible, this will be supported by in-situ trace element data acquired via LA-ICP-MS. By establishing the petrogenetic relationships between the components, and comparing those to other basaltic lunar materials, this study seeks to advance our knowledge of basaltic breccia petrogenesis, the Moon’s crustal evolution, and the impact history of this recently recovered lunar DOM suite.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1, 2026

doi: 10.1130/abs/2026SE-12760

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