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Northwest Africa 11811
Basic information Name: Northwest Africa 11811
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 11811
Observed fall: No
Year found: 2017
Country: (Northwest Africa)
Mass:help 182.4 g
Meteoritical Bulletin:  MB 107  (2018)  LL5-an
Recommended:  LL5-an    [explanation]

This is the only approved meteorite classified as LL5-an.
Search for other: LL chondrites, Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 9 Nov 2018
Writeup from MB 107:

Northwest Africa 11811 (NWA 11811)

(Northwest Africa)

Purchased: 2017

Classification: LL5-an

Physical characteristics: Dark stone. Cut surface reveals a gray interior with chondritic texture.

Petrography: (J. Gattacceca, H. Pourkhorsandi, CEREGE) Chondrite with recrystallized texture. Main minerals are olivine, pyroxene, and interstitial plagioclase with typical size about 25 μm. Presence of merrilite. Opaque minerals are sulfides (including pentlandite), chromite, and rare FeNi metal.

Geochemistry: Olivine Fa33.5±0.9, PMD=3%, NiO 0.17 wt% (N=8). Orthopyroxene Fs26.4±0.2Ws1.6±0.1 (N=5). Ca-pyroxene Fs25.1Wo17.4 (N=1). Plagioclase An11.9Ab80.2Or7.9 (N=2). Chromite Cr# = 0.91, TiO2 3.6 wt% (N=1). FeNi metal Fe32.3±0.3Ni66.2±0.3Co1.35±0.06 (N=7). Magnetic susceptibility log χ (× 10-9 m3/kg) = 3.42. Oxygen isotopic composition (J. Gattacceca, C. Sonzogni, CEREGE) from analysis of one acid-washed 1.5 mg aliquot of a powdered 475 mg bulk sample is δ17O=4.38‰, δ18O=5.85‰ , Δ17O=1.31‰ (linearized, slope 0.5247, analytical uncertainties 0.08‰, 0.12‰, 0.03‰ respectively).

Classification: LL5-anomalous. The anomalous designation comes from the high Fa content of olivine compared to other equilibrated LL chondrites, and the presence of metal in the form of FeNi2 exclusively.

Specimens: Type specimen at CEREGE. Main mass with Kuntz.

Data from:
  Table 0
  Line 0:
Place of purchase:Erfoud
Date:P 2017
Mass (g):182.4
Weathering grade:moderate
Fayalite (mol%):33.5±0.9 (N=8)
Ferrosilite (mol%):26.4±0.2 (N=5)
Wollastonite (mol%):1.6±0.1
Magnetic suscept.:3.42
Classifier:J. Gattacceca, H. Pourkhorsandi, CEREGE
Type spec mass (g):20.07
Type spec location:CEREGE
Main mass:Kuntz
Comments:work name K331; submitted by J. Gattacceca
Plots: O isotopes:  
   and collections
CEREGE: CEREGE BP 80 Avenue Philibert, Technopole de l'Arbois 13545 Aix-en-Provence Cedex 4 France, France (institutional address; updated 10 Jun 2023)
Kuntz: Fabien Kuntz, France; Website (private address)
References: Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462
Find references in NASA ADS:
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Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Wojciech Moscinski   

     This is 1 of 9305 approved meteorites from (Northwest Africa) (plus 1873 unapproved names)

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