Ramlat Fasad 600 (RF 600)        19°17.123’N, 053°51.700’E

Zufar, Oman

Find: 2020 Feb 05

Classification: Lunar meteorite (melt breccia)

History: A broken individual stone was found during a search for meteorites.

Physical characteristics: One dark greenish brown stone lacking fusion crust with wind-ablated surface. The fractured surface on one side indicates the existence of other fragments.

Petrography: (A. Zappatini, B. Hofmann, E. Gnos) The sample has a uniform fine-grained texture. The typical grain size is 50-100 µm with few clasts of plagioclase up to 500 μm. The rock consists predominantly of poikilitic plagioclase with interstitial pyroxene and olivine. Approx. 20% of the plagioclase is transformed to maskelynite. The rock is crosscut by glassy melt veins and contains sparse metal grains and accessory ilmenite, apatite. The rounded metallic iron grains are rimmed by troilite. Metal and troilite are partially transformed to iron oxides and hydroxides. Other terrestrial alteration products present are celestite and carbonates. A small exterior part of the sample consists of large pyroxene clasts and spherules with radial pyroxene-plagioclase in a dark clastic matrix, probably representing attached lunar regolith. In thin section a small area of fusion crust is visible.

Geochemistry: Mineral composition and geochemistry: (A. Zappatini) Plagioclase An_96.4±0.7 (N = 54), Pyroxene (matrix): Fs_29±3 Wo_12±6, Cr₂O₃ 0.58±0.1 wt%, mean FeO/MgO 0.85±0.1, mean FeO/MnO 54.2±4.1 (N = 78), Pyroxene (small regolith part): Fs_40±13 Wo_19±9, Cr₂O₃ 0.43±0.22 wt%, mean FeO/MgO 2.5±2.5, mean FeO/MnO 55.9±8.1 (N = 27), Olivine (matrix): Fa_39±2 (N = 59), Olivine (regolith): Fa_51±16 (N = 8). Bulk chemistry (LA-ICP-MS of a sintered powder pellet, N = 30): MgO 4.9±0.2 wt%, CaO = 15.6±0.3 wt%, K₂O = 0.056±0.009 wt%, Al₂O₃ = 26.3±0.5 wt%, FeO = 5.2±0.4 wt%, TiO₂ = 0.22 wt%, Na₂O = 0.47 wt%, MnO = 690±30 mg/kg, K₂O = 560±90 mg/kg, P₂O₅ = 340±45 mg/kg, Cr₂O₃ = 898±46 mg/kg, Th = 0.56±0.15 mg/kg, Fe/Mn = 75, K/Th = 822, K/La (CI normalized) = 0.05

Classification: Lunar anorthositic impact melt breccia. Lunar origin based on mineral chemistry and bulk chemistry. The interpretation as impact melt breccia is based on the fine-grained texture with mineral clasts. Strong shock attributed due to partial conversion of plagioclase to maskelynite, melt veins present.

Specimens: 12.5 g and one polished thin section at NMBE. Main mass: MHTO