Northwest Africa 10102 (NWA 10102)

Morocco

Find: 2010

Classification: Ordinary chondrite (L(LL)3)

History: A 6 kg meteorite was reportedly found near Temara in 2010 and purchased by Ruben Garcia at the 2013 Tucson Gem and Mineral show.

Physical characteristics: Sawn surface is dark greenish black with abundant lighter colored chondrules. Some lighter angular clasts to 4 cm. Slices criss-crossed with thin oxide veins.

Petrography: Abundant chondrules, ~80 area% set in dark black matrix. Large range of chondrules types present (PO, POP, RP, granular, PP, RP with olivine), some in the size range for LL chondrites. Many of the low-Ca pyroxene grains in PP and POP chondrules show polysynthetic twinning. Troilite is abundant, occurring as rims around chondrules, fine-grained in matrix, as a fine web within cracks in silicate grains, and as larger grains. The larger Fe-S grains show significant weathering, however, the fine-grained Fe-S and web-like network is largely unweathered. Three thin sections studied. One section contains three large clasts: 7 × 5 mm clast composed of radial and barred olivine fragments; 6 × 4 mm irregularly shaped clast of radial pyroxene; and, 3 × 2 mm dark achondrtic clast. No metal observed.

Geochemistry: (L. Garvie, ASU) Olivine Fa_23.4±4.2, range Fa_10.3-30.0, FeO/MnO=52.7±10.6, Cr₂O₃=0.04±0.02 wt%, n=19. Low Ca pyroxene Fs_14.4±7.6Wo_2.7±3.8, range Fs_4.4-26.1Wo_0.3-14.4, FeO/MnO=23.0±10.2, n=16; high Ca pyroxene Fe23.8Wo_35.3 and Fs_7.1Wo_43.0. (K. Ziegler, UNM): Analyses of three acid-washed subsamples by laser fluorination dual inlet mass spectrometry gave, respectively, δ¹⁷O 4.212, 4.251, 4.093; δ¹⁸O 6.486, 6.144, 6.212; Δ¹⁷O 0.787, 1.007, 0.813 per mil (reference TFL slope = 0.528, values are linearized).

Classification: Ordinary chondrite (L(LL)3, S3, W3). Although the oxygen isotopes plot at the heavy ¹⁸O end of the LL field, the mean Fa content is consistent with L, and mean low Ca pyroxene Fs content with H. No Fe-Ni metal found. Despite the weathering, the abundance of areas with thin spider-like veining of unweathered troilite suggests that metal would have been preserved, as least locally, had it been present. Estimation of subtype 3.6 based on Cr₂O₃ content in ferroan olivine and on histograms (Fig. 4) in Grossman and Brearley (2005).

Specimens: 606.8 g at ASU.