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Northwest Africa 13791
Basic information Name: Northwest Africa 13791
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13791
Observed fall: No
Year found: 2020
Country: (Northwest Africa)
Mass:help 142.6 g
Meteoritical Bulletin:  MB 110  (2022)  Achondrite-ung
Recommended:  Achondrite-ung    [explanation]

This is 1 of 151 approved meteorites classified as Achondrite-ung.   [show all]
Search for other: Achondrites, Ungrouped achondrites
Comments: Approved 8 Aug 2021
Writeup from MB 110:

Northwest Africa 13791 (NWA 13791)

(Northwest Africa)

Purchased: 2020

Classification: Ungrouped achondrite

Petrography: (K. Metzler, IfP) Equigranular igneous rock with some vesicles. It consists of ~85% mafic components (olivine and low-Ca pyroxene with Ca-rich pyroxene rims) and ~15 vol% fine-grained interstitial material. The typical grain size is ~300-1000 µm. Metal and sulfide beads up to 800 µm are completely oxidized by terrestrial weathering.

Geochemistry: Mineral compositions and geochemistry: Olivine grains show igneous chemical zoning, with increasing Fe concentrations from core to rim. Mean olivine composition is Fa20.5±3.2 (Fa16.4-29.5; n=17); Fe/Mn (at.): 50±12. Mean low-Ca pyroxene composition is Fs20.1±0.9Wo2.7±0.3 (Fs18.1-21.4Wo2.2-3.1; n=17); Fe/Mn (at.): 29±10. The mean composition of Ca-rich pyroxene is Fs18.6±2.1Wo28.1±3.9 (Fs15.0-22.3Wo21.7-34.1; n=8); Fe/Mn (at.): 28±7. Mean bulk composition of fine-grained interstitial material (EDX analyses; area ~50x100 µm; wt%): SiO2 64.2; Al2O3 17.1; Na2O 9.4; FeO 4.2; CaO 3.2; MgO 0.5; K2O 0.8; TiO2 0.7. Based on mineral chemistry, this sample has affinities to L or H ordinary chondrites.

Classification: Ungrouped achondrite: The combination of mineral compositions does not fit to any known achondrite group, although it exhibits affinities to H or L ordinary chondrites.

Data from:
  Table 0
  Line 0:
Place of purchase:Waran, Mauritania
Date:P 2020
Mass (g):142.6
Shock stage:M-S1
Weathering grade:high
Fayalite (mol%):20.5±3.2
Ferrosilite (mol%):20.1±0.9; 18.6±2.1
Wollastonite (mol%):2.7±0.3; 28.1±3.9
Classifier:K. Metzler, IfP
Type spec mass (g):20
Type spec location:IfP
Main mass:Mohamed Ali Loud
Comments:Submitted by K. Metzler, IfP
   and collections
IfP: Institut für Planetologie, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany (institutional address; updated 23 Jan 2012)
References: Published in Gattacceca J., McCubbin F.M., Grossman J., Bouvier A., Chabot N.L., D'Orazio M., Goodrich C., Greshake A., Gross J., Komatsu M., Miao B., and Schrader D. (2022) The Meteoritical Bulletin, No. 110. Meteorit. Planet. Sci. 1-4
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Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Domjan Svilkovic   
Public domain photographs:
Knut Metzler      

     This is 1 of 9699 approved meteorites from (Northwest Africa) (plus 1854 unapproved names)

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