Description
7.85g fragment of this rare ungrouped achondrite. Sold with label/certificate.
Northwest Africa 10503 (NWA 10503)
(Northwest Africa)
Purchased: 2015 May
Classification: Ungrouped achondrite
History: Purchased by Fabien Kuntz in May 2015 from a dealer in Zagora, Morocco.
Petrography: (A. Irving and S. Kuehner, UWS) Triple-grain-junction texture, grain size 0.1-0.7 mm. Very fresh assemblage of predominantly olivine with subordinate clinopyroxene (~20 vol.%), intermediate plagioclase (~10 vol.%), and accessory pyrrhotite, chromite, taenite and pentlandite.
Geochemistry: Olivine (Fa31.8-32.0, FeO/MnO = 79-96, N = 3), clinopyroxene (Fs11.4-11.6Wo42.5-42.6, FeO/MnO = 43-44, N = 2), plagioclase (An32.3-33.9Or3.2-3.0). Oxygen isotopes (K. Ziegler, UNM): analyses of nine acid-washed subsamples by laser fluorination gave, respectively, δ17O -3.757, -3.884, -3.950, -3.557, -3.569, -3.779, -3.674, -3.818, -3.968; δ18O -0.848, -1.162, -1.212, -0.555, -0.624, -0.873, -0.792, -0.893, -1.206; Δ17O -3.309, -3.270, -3.310, -3.264, -3.240, -3.318, -3.256, -3.346, -3.331 per mil.
Classification: Achondrite (ungrouped). Despite similarities in texture this meteorite has an oxygen isotopic composition far removed from those of any brachinites, winonaites, and acapulcoites.
Specimens: 26.3 g including one polished thin section at PSF; main mass with Kuntz.
