Northwest Africa 1195

Morocco

Purchased 2002 March/April

Martian meteorite (basaltic shergottite)

A. and G. Hupé (Hupé) purchased a 50 g fragment of a broken stone with a distinctive, thin weathering rind collected by nomads near Safsaf, Morocco in 2002 March, and subsequently purchased the remainder of the same elongated stone (total weight 315 g). Dimensions of the reassembled stone are 133 mm × 43 mm × 37 mm. Classification and mineralogy (A. Irving and S. Kuehner, UWS): olivine megacrysts (up to 4 mm) are set in a groundmass of low-Ca pyroxene and maskelynite (Ab₃₇Or_0.5 to Ab₄₁Or_0.7) with minor Ti-chromite, pyrrhotite, ilmenite and Mg-bearing merrillite. The euhedral to subhedral shapes of most of the olivine grains suggest that they are phenocrysts rather than xenocrysts. Olivine exhibits strong compositional zoning (cores Fa₁₉, FeO/MnO = 54; rims Fa₄₀, FeO/MnO = 62) and contains abundant inclusions of chromite, clinopyroxene, orthopyroxene, and pyrrhotite. The groundmass low-Ca pyroxenes are zoned from cores of pigeonite (Wo₇Fs₂₆, FeO/ MnO = 37.1) or, less commonly, orthopyroxene (Wo₄Fs₂₃, FeO/MnO = 37.0) to rims of more Fe-rich pigeonite (Wo₁₂Fs₃₃, FeO/MnO = 36.6). Occurring very rarely on groundmass pyroxene grains are patchy overgrowths of an Fe-rich mineral (possibly related to chamosite or chlorite, with 35 wt% FeO, 5 wt% Al₂O₃, 1.5 wt% MgO and a low oxide sum of 85 wt%, suggesting the presence of water or hydroxyl). Calcite occurs sparsely along grain boundaries and as thin veinlets. Texture and mineral compositions are similar to those in olivine-phyric basaltic shergottite DaG 476/670, but olivine is much more magnesian than in other olivine­phyric basaltic shergottites SaU 005/008 and NWA 1068/ 1110. Specimens: type specimen, 20 g, and two polished thin sections, UWS; main mass, xHupé.