Northwest Africa 15509 (NWA 15509)

Morocco

Find: 2014

Classification: HED achondrite (Eucrite, polymict)

History: This meteorite was purchased by Luc Labenne in Agadir, Morocco, from a Moroccan dealer.

Physical characteristics: (T. Shisseh, R. Hewins, FSAC, MNHNP) A single stone that consists of a dark matrix enclosing clasts and mineral fragments.

Petrography: (T. Shisseh, R. Hewins, B. Zanda, E. Jacquet, H. Chennaoui Aoudjehane, S. Pont, FSAC, MNHNP) Brecciated rock with angular, subrounded and rounded clasts and mineral fragments embedded in a glassy and vesicular matrix. Clasts are up to 4 mm in diameter, and exhibit granoblastic, subophitic, ophitic and granular textures. Plagioclase reaches up to 0.7 mm in width, and contains inclusions of pyroxene, silica and oxides. Blobs and schlieren of melted plagioclase are present within the matrix. The predominant pyroxene phase is pigeonite, with augite lamellae ranging from <1 µm to 30 µm in thickness. Pigeonite lamellae in augite is also present. The majority of lamellae are bended and faulted. Minor mineral phases include silica, chromite, ulvöspinel, ilmenite, late-stage olivine and troilite.

Geochemistry: (T. Shisseh, R. Hewins, FSAC, MNHNP) Low-Ca pyroxenes are En_47±0.75Fs_51±1Wo_2±0.4 (Fe/Mn=31; Mg# =48; n=14), and En_37±7Fs_60±2Wo_3±1.5 (Fe/Mn=30; Mg# =38; n=8). Augite lamellae in magnesian pigeonite are En_37±2Fs_21±2Wo_42±3.9 (n=11), and in ferroan pigeonite are En_30±0.9Fs_27±1Wo_43±1.3 (n=9). Plagioclase is An_89-94 (n=7). Late-stage olivine is Fa_69.5±0.7Fo_30.3±0.7 (n=16). Chromite is Chr62.6±1.5Usp18±3Spl18±0.9 (n=3).

Classification: T. Shisseh, R. Hewins, FSAC, MNHNP) Polymict eucrite. This meteorite contains cumulate and basaltic fragments, and pyroxene with Fe/Mn ratios matching those of eucrites, plus typical eucritic textures.