from The Meteoritical Bulletin, No. 110
Ramlat Fasad 532
Lunar meteorite (gabbro)
History: A single fragment was found during a search for meteorites.
Physical characteristics: Irregular fragment, 8x4x5 cm, very coarse grained, strongly wind-ablated, no fusion crust.
Petrography: (J. Pape, E. Gnos, B. Hofmann) The sample exhibits a brecciated texture with large, coarse-grained (up to ~15 mm) clasts in a matrix of mineral fragments up to 0.6 mm in size. Large clasts and groundmass show the same mineralogy with dominant pigeonitic to augitic pyroxene of variable compositions and plagioclase partly transformed to maskelynite. Minor phases are ilmenite, fayalitic olivine, elongated grains of silica up to 1 mm with complex fracturing, recrystallization and irregular, undulatory extinction. Common symplectitic intergrowths of fayalitic olivine (Fa96), augitic pyroxene and silica. Accessory phases are troilite and ulvöspinel. Pyroxene grains are highly fractured and show undulatory extinctions and mosaicism. Interconnected brown glassy melt veins (exhibiting flow lines in some areas) are traversing the whole sample, containing mineral inclusions from the host rock and vesicles filled with secondary alteration products (calcite). Strongly shocked, low weathering.
Geochemistry: (J. Pape) Pyroxene (pigeonite to augite) has Fs47.0±9.3Wo25.3±6.9 (Fs30.7-65.0Wo15.8-38.6), mean FeO/MgO = 4.7±4.6, mean FeO/MnO = 58.4±7.3 (N = 20). Plagioclase/maskelynite has An92.4±1.8Or 0.2±0.1 (N = 15). Symplectitic olivine has Fa95.8±1.5 (N = 7). Oxygen isotopes: (R. Greenwood, OU) δ18O = 6.205 δ17O = 3.249 Δ17O = 0.022 (all ‰). Bulk chemical composition (Activation Laboratories, all wt%): FeO = 20.77, MgO = 6.13, Al2O3 = 9.58, CaO = 13.31, TiO2 = 1.95, Th = 0.49 ppm; FeO/MnO = 66.8, Mg number = 0.344.
Classification: Lunar gabbro, strong shock, low weathering. Texture, mineralogy, mineral chemistry and bulk composition are very similar to MIL 05035 and Asuka 881757, suggesting source-pairing. Paired with Ramlat Fasad 535 (found at a distance of 118 m).
Specimens: 69.2 g and one polished thin section at NMBE. Main mass: MHTO.
All the other stones of the “YAMM” launch-pair group were found in Antarctica (4 different places).
Meteoritical Bulletin Database
Ramlat Fasad 532