Dhofar 305

Oman

Found 2001 June 28

Lunar meteorite (anorthositic impact melt breccia)

A light-grey stone weighing 34.11 g was found in the Dhofar region of Oman. Mineralogy and classification (M. Nazarov, Vernad; L. Taylor, UTenn): fusion crust is absent; the meteorite is an impact melt breccia consisting of mineral fragments and lithic clasts set within fine-grained, well-crystallized impact-melt matrix; clasts of impact melt breccias are most common; granulites and possible igneous rocks are rare and have mainly anorthositic and troctolitic compositions; orthopyroxenite clasts are present; feldspar, An_87–98; orthopyroxene, Wo_1–5En_40–88; clinopyroxene; Wo_{6– 48}En_30–70; olivine, Fo_44–90 (Fe/Mn = 94 at); accessory minerals are Ti-rich chromite, Cr-pleonaste, ilmenite (1–8 wt% MgO), armalcolite, troilite, and FeNi metal (17–32 wt% Ni; 1.3–2.3 wt% Co); composition of the impact-melt matrix is (wt%) SiO₂ = 43.9, TiO₂ = 0.16, Al₂O₃ = 28.5, Cr₂O₃ = 0.10, FeO = 3.69, MnO = 0.07, MgO = 6.08, CaO = 15.9, Na₂O = 0.36, K₂O = 0.02, P₂O₅ = 0.04; the stone is moderately weathered; calcite, celestite, gypsum, and Fe hydroxides are present. Dhofar 305 is close to Dhofar 303, which was found nearby, in degree of weathering, mineral chemistry, and matrix composition. The meteorites may be paired, but they are very different in texture. Pairing with Dhofar 081, 280, 302, 306, and 307 is also possible. Specimens: type specimens of 7 g, and a thin section, Vernad; main mass with anonymous finder.