Dhofar 287

Oman

Found 2001 January 14

Lunar meteorite (Low-Ti, olivine-pyroxene mare basalt breccia)

A dark gray, 154 g black stone without fusion crust was found in the Dhofar region of Oman, 400 m from Dhofar 025. Classification and mineralogy (M. Nazarov, Vernad; L. Taylor, UTenn): contains two adjacent lithologies, mare basalt (95 vol%) and regolith breccia (5 vol%). Basaltic portion consists of olivine (Fo_70–45) and minor augite (Wo_30–40 En_38–45) phenocrysts (up to 1 mm) set in a subophitic, fine-grained (50–100 µm) groundmass composed of plagioclase (An_85–75) and pyroxene (Wo_10–25En_2–50), with accessory pyroxferroite, K-Ba feldspar, apatite, ilmenite, Ti-rich chromite, ulvöspinel, baddeleyite, silica, tranquillityite, troilite, Fe-Ni metal, and a fayalite + K-rich glass mesostasis; shock veins and impact melt pockets are present; plagioclase is totally converted to maskelynite; mineral modes (vol%) are pyroxene = 49, maskelynite = 26, olivine = 18, opaques = 4, impact melt = 2; whole-rock TiO₂ content = 2.8 wt%; Fe/Mn = 75 g/g; a prominent negative Eu anomaly is present; similar in composition to Apollo 12 mare basalts, but distinctly higher in Na and incompatible elements. Regolith breccia portion: clast-rich, with numerous lithic and mineral grains (up to 1 mm) cemented by fine­grained mineral fragments (<100 µm) and minor impact melt; dominated by low-Ti and VLT mare basalt lithologies; minor highland material is probably present; lithic clasts are fine-grained, vitrophyric, granular to ophitic, basaltic rocks and impact melt breccias; mineral fragments are dominated by pyroxene, olivine, and plagioclase; glass fragments and spherules also occur; plagioclase, An_98–66; olivine, Fo_80–25; pyroxenes are highly variable, Wo_5–40En_2–80; main accessories are silica, fayalite, pyroxferroite, K-rich glass, apatite, ilmenite, Ti-rich chromite, ulvöspinel, troilite, and FeNi metal. Specimens: 32 g and two thin sections, Vernad; main mass with anonymous finder.