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Northwest Africa 6023
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:help 72 g
Meteoritical Bulletin:  MB 107  (2018)  Brachinite-an
Recommended:  Brachinite-an    [explanation]

This is the only approved meteorite classified as Brachinite-an.
Search for other: Brachinites, Primitive achondrites
Comments: Approved 7 Jun 2018
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:
  Table 0
  Line 0:
Place of purchase:Erfoud, Morocco
Date:P 2009
Mass (g):72
Shock stage:low
Weathering grade:moderate
Fayalite (mol%):32.3
Ferrosilite (mol%):11.4
Wollastonite (mol%):43.3
Classifier:A. Greshake, MNB
Type spec mass (g):14.4
Type spec location:MNB
Main mass:Stefan Ralew
Comments:Submitted by Ansgar Greshake
Plots: O isotopes:  
   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)
References: Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462
Find references in NASA ADS:
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     This is 1 of 9746 approved meteorites from (Northwest Africa) (plus 1855 unapproved names)

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