Northwest Africa 3221

Morocco

Find: 2002

Achondrite (ureilite, polymict)

History: B. Fectay purchased a single stone of 38.5 g in Rissani, Morocco in 2002.

Physical characteristics: A fragment with 45% fresh black fusion crust with a typical polymict ureilite texture.

Petrography: (H. Takeda, Chiba and A. Yamaguchi, NIPR). The sample is a fragmental breccia with lithic clasts and subrounded mineral fragments embedded in a cataclastic matrix of predominantly ureilitic material. One large clast is a fine-grained carbonaceus chondrite 2.3x1.5 mm in size and another is very heavily shocked ureilite. Mineral fragments include olivine up to 1.8x1.2 mm, pyroxene, Na-rich plagioclase, rare K, Na-rich glassy grain.

Mineral compositions: Pyroxene (Fs₈Wo₈ - Fs₄₄Wo₁₀ - Fs₁₃Wo₃₄; Cr₂O₃ of pigeonite = 0.8-1.2 wt%; augite = 1.8 - 2.0 wt%), olivine (Fo_74-90; CaO = 0.25- 0.47 wt %; Cr₂O₃ = 0.42- 0.83 wt% [cores]) and plagioclase (An_6-60). High K, Na-rich glassy materials (SiO₂ = 66.5, Al₂O₃ = 11.3, FeO = 8.5, Na₂O = 4.2, K₂O = 2.1 [all wt%] observed). Coexistence of unshocked olivine and a very heavily shocked ureilite clast 4.4 x 3.2 mm in size (PTS 090,8) as in Dar al Gani 1023 with granoblastic texture. Clast olivines (Fo_70-78[cores]).

Classification: Achondrite (ureilite, polymict).

Type specimen: A total of 7.7 g of sample and a thin section are on deposit at NIPR. Fectay hold the main mass.