The Meteoritical Bulletin, No.
Northwest Africa 10783
2015 May 01
in the Almahbas region near the frontier between Morocco and Algeria.
characteristics: The stone is a breccia with
no visible fusion crust. The type specimen is mostly light colored with
metal specks, and there is a dark zone at one end.
(R. Hewins, S. Pont, B. Zanda, MNHNP)
Most of the prepared section is a poikilitic anorthosite resembling Apollo
77017. It consists of plagioclase phenocrysts up to 2 mm in length set in
pyroxene poikilitic to stubby tiny plagioclase laths (down to 20 μm)
and to olivine granules (~50 μm). Both pigeonite and augite are present,
but with no obvious exsolution. Minor minerals include chromite, ilmenite,
baddeleyite, taenite and kamacite. There is a dark sliver of breccia matrix
at the end of the section containing a huge variety of clast types, 1 mm or
smaller. These include crystal clasts (olivine, pigeonite, augite,
anorthite, chromite and a silica polymorph), breccia clasts, and lithic
clasts often with elongated plagioclase laths.
compositions and Geochemistry: (R. Hewins and S. Pont, MNHNP) The olivine composition is Fa34.1±1.5, with
FeO/MnO 119±14. Pyroxenes are pigeonite Fs25.4Wo11.1
and augite En49.6Fs19.2Wo31.2. Plagioclase
is An94.0±0.6Ab5.5±0.6Or0.5±0.2. Taenite
contains ~37% Ni. Mineral compositions are similar to those of Apollo
77017, but olivine is a little less ferroan.
(R. Hewins MNHN, L. Labenne Paris) Lunar poikilitic
The type specimen consists of 3.78 g and 0.63 g at MNHNP. The remaining 17.6 g minus sawdust has been sold in the
form of thin slices by Labenne.