Mreïra        25°57.550’N, 10°57.615’W

Tiris Zemmour, Mauritania

Found:  Dec 2012

Classification: Ordinary chondrite (L6)

History: According to Ait Hiba Abdelhad, a fireball was seen in the afternoon sky on December 16, 2012, several school children saw the fireball explode and detonations were heard near the village of Mehaires, Western Sahara. Pieces were recovered approximately 40 miles south of Mehaires, near Mreïra, Mauritania, only a few days after the event. The strewn field is in the area called "Stailt Omgrain", which is a local nomadic name. This is south of Mehaires and north of the mountain "Galbe lahmar". Therefore this is a possible fall associated with the fireball of December 16, 2012.

Physical characteristics: The largest single piece weighed 602 grams and was completely covered with fresh fusion crust. A total of approximately 6 kg of freshly crusted stones were recovered.

Petrography: (C. Agee, UNM) Microprobe examination of two polished surfaces shows brecciation and numerous fractured silicate grains, scattered equilibrated chondrules, shock-melt pockets, kamacite, troilite, and merrillite. Fresh, vesiculated fusion crust ~200 μm thick.

Geochemistry: (C. Agee and L. Burkemper, UNM) Olivine Fa_24.4±0.2, Fe/Mn= 47±3, n=8; low-Ca pyroxene Fs_20.3±0.1Wo_1.5±0.1, Fe/Mn= 28±1, n=7; plagioclase Ab_82.7±2.0An_10.4±0.6Or_6.8±1.4, n=4.

Classification: Ordinary chondrite (L6), weathering grade (W0), shock grade (S6)

Specimens: 91.2 g including a fusion-crusted complete stone and a microprobe mount on deposit at UNM, MtMorgan holds the 602 g main mass and another 400 g of complete stones, Gary Fujihara holds 335 g of fusion crusted individuals, the largest being 104 g.