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Lunar Meteorite: Northwest Africa (NWA) 5000Morocco |
NWA 5000. Lower right image: 19 cm across (Photos Courtesy of Adam Hupé and Tony Irving) |
from The Meteoritical Bulletin, No. 9X, Meteoritics & Planetary
Science XX, Axxx-Axxx (200X) Northwest Africa 5000MoroccoFind: July 2007 Achondrite (lunar, feldspathic breccia) History: Found in July 2007 in southern Morocco and provided to Adam Hupé in October 2007 by a Moroccan dealer. Physical characteristics: A single, large cuboidal stone (11.528 Kg) with approximate dimensions 27 cm by 24 cm by 20 cm. One side has preserved regmaglypts and is partially covered by translucent, pale greenish fusion crust with fine contraction cracks. Abundant large beige to white, coarse grained clasts up to 8 cm across and sparse black, vitreous clasts up to 2 cm across (containing irregular small white inclusions) are set in a dark gray to black, partially glassy breccia matrix. One partially eroded clast exposed on an exterior surface contains both the coarse grained beige lithology and the more resistant black, vitreous lithology in sharp contact. Petrography: (A. Irving and S. Kuehner, UWS) Fragmental breccia dominated by Mg-suite olivine gabbro clasts consisting predominantly of coarse grained (0.5 - 2 mm) calcic plagioclase, pigeonite and olivine with accessory merrillite, Mg-bearing ilmenite, Ti-bearing chromite, baddeleyite, rare zirconolite, silica polymorph, K-feldspar, kamacite and troilite. Some gabbro clasts have shock injection veins composed mostly of glass containing myriad fine troilite blebs and engulfed mineral fragments. Black, vitreous impact melt clasts consist of sporadic, small angular fragments of gabbro and related mineral phases in a very fine grained, non-vesicular, ophitic-textured matrix of pigeonite laths (up to 20 microns long by 2 microns wide) and interstitial plagioclase with tiny spherical grains of kamacite, irregular grains of schreibersite and rare troilite. Mineral composition and geochemistry: Gabbro clasts: plagioclase (An96.1-98.0Or<0.1), pigeonite (Fs32.0-64.5Wo6.7-13.1, FeO/MnO = 51.1-62.0), olivine composition varies among the different clasts with the following values: Fa23.9-24.2, Fa40.4 and Fa58.8 (with FeO/MnO = 81-100), chromite (Cr/(Cr+Al) = 0.737, Mg/(Mg+Fe) = 0.231, TiO2 = 5.9 wt.%), ilmenite (4.1 wt.% MgO). Bulk composition (R. Korotev, WUSL): INAA of 6 subsamples gave mean values of 5.3 wt.% FeO and 0.4 ppm Th. Oxygen Isotopes: (D. Rumble, CIW) Replicate analyses of a gabbro clast by laser fluorination gave δ17O = 2.601, 2.684‰; δ18O = 5.014, 5.033‰; Δ17O = -0.036, +0.037‰. Classification: Achondrite (lunar, feldspathic breccia). Specimens: A total of 40.2 g of sample, two polished mounts and one large polished thin section are on deposit at UWS. Mr. A. Hupé holds the main mass. |
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