Northwest Africa 6713 (NWA 6713)

Morocco

Found: 2010

Classification: Mesosiderite

History: Single stone bought in October 2010. The stone was found the same year, close to Beni Taijjite, Morocco.

Physical characteristics: Single 277 g fusion crusted stone.

Petrography: (J. Gattacceca, CEREGE): Texture is equilibrated. Silicates are orthopyroxene and plagioclase. No olivine. Large orthopyroxene crystals (to 5 mm). A large (>2 cm) orthopyroxenite clast is present. Metal and sulfides grains typically 200 μm to 1 mm. Modal abundances: silicates 80% (pyroxene 78%, plagioclase 2%), metal (kamacite and rare taenite) 10%, troilite 3%, weathering products 5%. Merrillite and chromite present. Copper grains to 80 μm associated with metal and sulfides. Weathering is moderate (~25 vol% of metal and sulfides have been oxidized). Magnetic susceptibility log χ = 5.65 (χ in 10^-9 m³/kg).

Geochemistry: (J. Gattacceca, CEREGE) Orthopyroxene Fs_24.8±0.3Wo_2.3±0.4 (n=8). Plagioclase An_92.4Ab_1.5Or_0.1 (n=5). Kamacite Ni=5.2 wt%, taenite Ni=36.7 wt%. Chromite Cr/(Cr+Al)=0.84. The orthopyroxenite clast (Fs_17.2±0.4Wo_1.7±0.1) is not equilibrated with the orthopyroxenes in the bulk of the meteorite, but its oxygen isotopic composition (δ¹⁷O = 1.82, δ¹⁸O = 3.90, and Δ¹⁷O = -0.21 (all per mil), J. Gattacceca, C. Sonzogni, CEREGE) is within the mesosiderite range.

Classification: (J. Gattacceca, CEREGE) Mesosiderite (type 3C).

Specimens: A total of 25 g and one polished section are on deposit at CEREGE. P. Thomas holds the main mass.