Northwest Africa 3146

Morocco or Algeria

Purchased 2003 December

Rumuruti chondrite (R4)

Several brown stones (total weight 304 g) were purchased from a Moroccan dealer in Erfoud by A. and G. Hupé (Hupé) in 2003 December.  Classification and mineralogy (A. Irving and S. Kuehner, UWS):  Complex genomict to polymict breccia composed of sparse clasts in a matrix of similar lithologies.  All components consist of relatively well-formed chondrules of various types and some angular (possibly xenocrystic) mineral clasts in a finer grained matrix.  Most chondrules contain relatively ferroan, Ni-bearing olivine (Fa_40.3-40.5, NiO = 0.23-0.26 wt.%) typical of R chondrites, but some chondrules contain more magnesian olivine (~Fa₂₀ and ~Fa_2-5) or magnesian orthopyroxene (~Fs₁₀).  Other phases include Ti-bearing chromite, Cr-bearing clinopyroxene (Fs_9.7Wo_47.1 to Fs_11.4Wo_45.3, Cr₂O₃ = 0.57 wt.%), relatively sodic plagioclase (An_12.2Or_3.6 to An_27.7Or_0.9; some as large, angular grains), Cr-rich orthopyroxene laths, iron sulfide, probable xenocrysts of olivine (~Fa₁₅) and orthopyroxene (Fs_12.5Wo_0.3), and interstitial feldspathic glass.  Specimens: type specimen, 20 g, and one polished thin section, UWS; main mass, xHupé.