Northwest Africa 15514 (NWA 15514)

Morocco

Find: 2014

Classification: HED achondrite (Eucrite, melt breccia)

History: This meteorite was purchased by Luc Labenne in Laâyoune, Morocco, from an anonymous Moroccan dealer.

Physical characteristics: (T. Shisseh, R. Hewins, FSAC, MNHNP) a flat slice with rock fragments embedded in a dark and vesicular matrix.

Petrography: (T. Shisseh, R. Hewins, B. Zanda, E. Jacquet, H. Chennaoui Aoudjehane, S. Pont, FSAC, MNHNP) This specimen is an impact melt breccia that contains rounded basaltic clasts and fragments set in a matrix of glass and devitrified glass. The clasts are predominately subophitic, and range from 1 to 4 mm in diameter. The major mineral phases are pyroxene and plagioclase. Minor mineral phases include silica, ilmenite, spinels (chromite and ulvöspinel) and zircon. Plagioclase within the clasts ranges from 30 to 200 µm in width. Schlieren of melted plagioclase with vesicles is present in the matrix. Pyroxene contains exsolution lamellae of augite with a wide range of thicknesses. Glassy shock veins crossing the clasts are abundant, and often contain entrained pyroxene and plagioclase fragments.

Geochemistry: (T. Shisseh, R. Hewins, FSAC, MNHNP) Low-Ca pyroxene is En_35±0.3Fs_58.5±0.4Wo_6.5±0.2 (Fe/Mn=32; Mg# =38; n=6). High-Ca pyroxene is En_29.6±0.4Fs_29.7±1.5Wo_40.7±2 (n=7). Plagioclase is An_87.5-89 (n=4). Average TiO₂ and FeO contents in ilmenite are 53 wt% and 44 wt%, respectively (with <1.4 wt% MgO, MnO and Cr₂O₃ contents; n=4).

Classification: (T. Shisseh, R. Hewins, FSAC, MNHNP) Eucrite melt breccia. This meteorite contains anorthite, and pyroxene with Fe/Mn ratios matching those of eucrites, plus typical brecciated eucritic textures.