Writeup from MB 97:

Direct Link:

http://tin.er.usgs.gov/meteor/metbull.php?code=50846

Northwest Africa 5960

Mali

Find (August 2009)

Achondrite (Martian, olivine-phyric shergottite)

History: A pale colored stone found near Guirat Laghnam in northern Mali in August 2009 was purchased by Ali and Mohammed Hmani.

Physical characteristics: A very fine grained, partly fusion-crusted stone (147 g) displaying fluted abrasion features on several sides. The fresh interior is pale gray with evenly-distributed, larger, pale tan grains.

Petrography: (A. Irving and S. Kuehner, UWS): Porphyritic texture, with small (0.15 to 0.35 mm) olivine phenocrysts in a finer grained groundmass composed mainly of prismatic pigeonite and maskelynite with accessory olivine, chromite, titanomagnetite, ilmenite, merrillite and pyrrhotite.

Geochemistry: Olivine (core Fa25.4, rim Fa39.2; FeO/MnO = 47.0-52.1), pigeonite (Fs31.2-38.7Wo5.1-12.5, FeO/MnO = 26.2-31.3), plagioclase (An55.9-56.6Or2.1-1.8).

Classification: Achondrite (Martian, olivine-phyric shergottite). This specimen has essentially the same external appearance, grainsize, texture and mineral compositions as NWA 2990, and may be paired with it.

Specimens: A total of 20.0 g of type material and one polished thin section are on deposit at UWS. The remaining material is held by an anonymous collector.