El Mrira 001 H4-melt breccia #1 – 21,7 g

El Mrira 001 28.467°N, 8.920°W

Morocco

Find: 2019 Jan

Classification: Ordinary chondrite (H4, melt breccia)

History: The specimens (total weight 6600 g) were found together in January 2019 in southern Morocco at 28.467°N, 8.920°W and purchased by Jesper Grønne in 2019 from a dealer in Agadir, Morocco.

Physical characteristics: A notable feature of these specimens is the presence of abundant spherical to ellipsoidal vesicles and larger vugs (up to 14 mm across) in the fine grained melt-textured matrix.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Very fresh specimen consisting of equilibrated Type 4 chondrite clasts in a very fine grained matrix with prominent vesicles (some ellipsoidal and preferentially aligned). Lithic clasts are shock-darkened and consist of well-formed chondrules in a relatively coarse grained, recrystallized matrix containing relatively abundant kamacite plus taenite, troilite, merrillite, chlorapatite and chromite. Clasts have shock stage S4. The vesicular matrix contains distributed small silicate mineral clasts set in a partly glassy, melt-textured groundmass with dispersed composite metal+troilite spherules (up to 1.5 mm in size).

Geochemistry: Olivine (Fa_18.5±0.3, range Fa_17.9-18.9, N = 6), low-Ca pyroxene (Fs_16.5±0.5Wo_1.2±0.2, range Fs_16.2-17.3Wo_1.0-1.4, N = 5), subcalcic augite (Fs_9.1Wo_36.3), augite (Fs_6.0±0.6Wo_46.1±0.3, range Fs_5.5-6.4Wo_46.3-45.9, N = 2), plagioclase (Ab_64.2An_34.7Or_1.1).

Classification: Ordinary chondrite (H4-melt breccia).

Specimens: 20.1 g including one polished thin section at UWB; remainder with Mr. J. Grønne.