Image nwa 4478 1
Image nwa 4478 2
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History: G. Hupé purchased the sample in September 2006 in Zagora, Morocco.
Physical characteristics: Two dense, brown stones (298 g and 146 g) lacking fusion crust.
Petrography: (A. Irving and S. Kuehner, UWS) This specimen is composed of large mineral
and polycrystalline lithologies (up to 8 mm across) with interstitial fine-grained material of the
same phases.The large minerals consist of either olivine or orthopyroxene (with clinopyroxene
exsolution lamellae associated with blebs of Ni-free iron metal). The polycrystalline lithology
consists mainly of interlocking olivine grains (up to 3 mm across) and sparse large chromite
grains with interstitial clinopyroxene, orthopyroxene, kamacite, pyrrhotite, pentlandite and
troilite. The modal abundance of metal (+ limonite after primary metal) is 5 vol%. Plagioclase is
absent. Olivine grains contain numerous blebby to worm-like polycrystalline inclusions, and
clinopyroxene grains contain similar inclusions; some examples exhibit symplectitic
intergrowths of these various phases. Some olivine grains contain multiple blade-like lamellae
of olivine of a different composition. Narrow elongate zones or discontinuous veinlets of metal
are present within clinopyroxene, and adjacent to such metal the pyroxene has a more
Mineral compositions and geochemistry: Olivine (Fa10.6-10.9; FeO/MnO = 22.1-23.9),
clinopyroxene (Fs3.9Wo41.9; FeO/MnO = 10.2), orthopyroxene lamella in clinopyroxene (Fs9.
1Wo1.3; FeO/MnO = 11.9) and chromite (Cr/(Cr+Al) = 0.822-0.825; Mg/(Mg+Fe) = 0.506 -
0.520, TiO2 = 0.31-0.37 wt%). Oxygen Isotopes: (D. Rumble, CIW) Quadruplicate analyses by
laser fluorination gave, respectively, δ18O = 2.23, 2.43, 2.23, 2.40; δ17O = 0.14, 0.30, 0.07,
0.11; Δ17O = -1.034, -0.984, -1.107, -1.147 (all ‰).
Classification: Achondrite (lodranite).
||Found 2006, Algeria
||1 double polished covered thin section