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Northwest Africa 6023 | |||||||||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 6023 This is an OFFICIAL meteorite name. Abbreviation: NWA 6023 Observed fall: No Year found: 2009 Country: (Northwest Africa) Mass: ![]() | ||||||||||||||||||||||||||||||
Classification history: |
This is the only approved meteorite classified as Brachinite-an. Search for other: Brachinites, Primitive achondrites | ||||||||||||||||||||||||||||||
Comments: | Approved 7 Jun 2018 | ||||||||||||||||||||||||||||||
Writeup![]() |
Writeup from MB 107:
Northwest Africa 6023 (NWA 6023) (Northwest Africa) Purchased: 2009 Classification: Brachinite-an History: The meteorite was bought from a local meteorite dealer in Erfoud, Morocco. Physical characteristics: Dark brownish rock with patches of fusion crust. Petrography: A polished surface of the meteorite shows sub-mm sized shiny crystals. It displays an equilibrium texture of 200-300 μm sized olivine (about 90 vol.%), some Ca-pyroxene and chromite typically showing triple junctions between adjoining crystals. Nearly all olivine crystals are surrounded by fine-grained intergrowths of low-Ca pyroxene and metallic Fe. Strikingly, olivine shows pronounced reduced rims and the meteorite contains flaky graphite. No plagioclase has been detected. Geochemistry: olivine: Fa32.3±0.7 (Fa30.4-32.9, n=14, CaO=0.11±0.02, Cr2O3=0.03±0.01, FeO/MnO=70±5); reduced rims in olivine: Fa12.6-16.2; Ca-pyroxene: Fs11.4±0.2Wo43.3±0.3 (Fs11.1-11.8Wo42.6-43.8, n=13, FeO/MnO=35±3); Oxygen isotopes (K. Ziegler, UNM): material analyzed by laser fluorination gave: δ18O=5.162, 5.226, 4.838, 5.110; δ17O=2.445, 2.491, 2.269, 2.402; Δ17O= -0.281, -0.268, -0.285, -0.296 (all per mil) Classification: Brachinite-anomalous. Mineral chemistry, high abundance of olivine, equilibrium texture and oxygen isotopes are consistent with classification as brachinite, but reduced rims and high graphite-content are typical of ureilites. | ||||||||||||||||||||||||||||||
Data from: MB107 Table 0 Line 0: |
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Plots: | O isotopes: | ||||||||||||||||||||||||||||||
Institutions and collections |
MNB: Museum für Naturkunde, Invalidenstraße 43, D-10115 Berlin, Germany (institutional address; updated 24 Dec 2011) UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015) Ralew: Stefan Ralew, Kunibertstraße 29, 12524 Berlin, Germany; Website (private address) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462
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Geography: |
Statistics: This is 1 of 9305 approved meteorites from (Northwest Africa) (plus 1873 unapproved names) |