The Meteoritical Bulletin, No.
Northwest Africa 10783
2015; Purchased: 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
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 anorthositic breccia.
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.