Northwest Africa 2352

Northwest Africa

Found 2003

Achondrite (Ureilite)

A complete, dark brown and partially crusted stone of 389 g was purchased in Erfoud, Morocco.  Description and classification (T. Bunch and J. Wittke, NAU): high amounts of large, laminated graphite grains (up to 1.9 mm in length) occur interstitially to olivine and pigeonite; only small amounts of carbonaceous-metal-silicate masses are present. Very limited olivine rim reduction or smelting, R1 level with less that 0.02 mm of olivine margins affected. Olivine cores, Fa_11.9, FeO/MnO = 21 and rims are Fa_10.7, FeO/MnO = 19; pigeonite. Fs_11.4Wo_9.4, FeO/MnO = 13.7. Oxygen isotopes (D. Rumble, CIW): replicate analyses by laser fluorination gave δ¹⁷O = 2.86 and 2.89, δ¹⁸O = 7.16 and 7.37 and Δ¹⁷O = -0.913 and  -1.002 per mil. Very lightly weathered in the interior with low-level shock. Specimens: type sample, 21.1 g, NAU: main mass, Regelman.