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Northwest Africa 11118
Basic information Name: Northwest Africa 11118
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 11118
Observed fall: No
Year found: 2016
Country: Western Sahara
Mass:help 222 g
Classification
  history:
Meteoritical Bulletin:  MB 106  (2018)  CM2
Recommended:  CM2    [explanation]

This is 1 of 532 approved meteorites classified as CM2.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 2), CM chondrites, and CM-CO clan chondrites
Comments: Approved 26 Feb 2017
Writeuphelp
Writeup from MB 106:

Northwest Africa 11118 (NWA 11118)

Western Sahara

Purchased: 2016

Classification: Carbonaceous chondrite (CM2)

History: The meteorite was bought in 2016 from a Moroccan meteorite dealer.

Physical characteristics: A single, black individual partly covered with fusion crust was recovered from the desert near Dakhla City, Western Sahara. The rock is unusually light and diffuses an organic smell.

Petrography: (A. Greshake, MNB) The meteorite appears to be a loosely consolidated aggregation of chondrules, chondrule and mineral fragments and rare CAIs virtually all surrounded by fine-grained dust rims of variable thickness. The different components seem to stick directly together at their respective rims forming a perfect accretionary texture. The meteorite lacks matrix-dominated areas but shows unusually high porosity. Often the fine-grained rims are found empty with the object they had previously surrounded missing. BSE imaging as well as µ-CT scanning of an 1 cm3 volume yield porosities ranging from 30 to up to 38%; the bulk density (volume determined by 3D-scanning) of the meteorite is 1.95 g/cm3. Chondrules are about 60-550 μm in diameter (mean: 171±93 μm, n=43) and dominantly of PO and POP types. Although olivine is highly unequilibrated in chondrules and mineral fragments with Fa0.3-75.8, low-Ca pyroxene is generally far less Fe-rich with Fs1.0-4.3. In several chondrules the glassy mesostasis is partly preserved attesting to a rather low degree of alteration. The latter is also confirmed by the low abundance of phyllosilicates and carbonates. Opaque phases include chromite, FeNi-metal (4-6 wt.% Ni), pentlandite and pyrrhotite.

Geochemistry: Oxygen isotopes (K. Ziegler, UNM): material analyzed by laser fluorination gave: δ18O=6.764; δ17O=0.670; Δ17O= -2.901 (all per mil).

Data from:
  MB106
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2016
Mass (g):222
Pieces:1
Class:CM2
Shock stage:S1
Weathering grade:W1
Fayalite (mol%):24.6±25.7 (0.3-76.1, n=69)
Ferrosilite (mol%):1.8±0.7 (1.0-4.3, n=22)
Wollastonite (mol%):1.3±0.7 (0.9-3.8, n=22)
Classifier:A. Greshake, MNB
Type spec mass (g):20
Type spec location:MNB
Main mass:anonymous
Comments:Submitted by Ansgar Greshake
Plots: O isotopes:  
Institutions
   and collections
MNB: Museum für Naturkunde, Invalidenstrasse 43, D-10115 Berlin, Germany (institutional address)
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
Catalogs:
References: Published in Gattacceca J., Bouvier A., Grossman J., Metzler K., and Uehara M. (2019) Meteoritical Bulletin, no. 106. Meteorit. Planet. Sci. 54 in press.
Find references in NASA ADS:
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Geography:

Western Sahara
Coordinates:Unknown.

Statistics:
     This is 1 of 206 approved meteorites from Western Sahara (plus 20 unapproved names)

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