El Médano 444 (EM 444)        24°44.75’S, 70°21.49’ W

Antofagasta, Chile

Find: 14 Nov. 2017

Classification: Enstatite chondrite (EL6)

Petrography (E. Jacquet, B. Doisneau, MNHNP): The meteorite shows a granular texture of enstatite (58 vol%), plagioclase (11 vol%), silica (2 vol%), with no olivine, with irregularly shaped (few 100 µm) grains of Fe-Ni metal (24 vol%) associated with subordinate (<1 vol%) schreibersite, troilite, daubreelite (as exsolution lamellae in the former) and rare alabandite. Some trails of micron-sized metal and sulfide occur within silicates. Locally, metal may form symplectic intergrowths with plagioclase (10s of µm). Graphite grains (4 vol%), sometimes euhedral, often in sheaves showing pressure lamellae such as Fig. 4 of Ramdohr (1963), up to 1 mm occur mostly associated with the metal. Only one relict radial pyroxene chondrule was recognized in the section studied.

Geochemistry: Enstatite Fs_0.39±0.15Wo_1.53±0.07 (N=16); plagioclase An_16.1±0.3Ab_80.1±0.4Or_3.7±0.4 (N=9); silica 1.3±0.5 wt% Al₂O₃, 0.6±0.3 wt% FeO (N=9); Fe,Ni metal 5.8±0.4 wt% Ni, 1.1±0.05 wt% Si (N=32); troilite 0.45±0.05 wt% Ti, 0.87±0.11 wt% Cr (N=9).

Classification: Enstatite chondrite (EL6). Chondritic nature is indicated by the abundance of metal and tentative evidence of relict chondrules. The reduced mineralogy, and in particular the presence of alabandite and the Si content of kamacite, indicates affiliation to EL, with the abundance of metal on the high end of the range. A petrographic type 6 despite the paucity of chondrules seems consistent with enstatite chondrite usage.

Specimens: 135 g with MNHNP (type specimen), 32 g at CEREGE.