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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
Classification
  history:
Recommended:  Achondrite-ung    [explanation]

This is 1 of 107 approved meteorites classified as Achondrite-ung.   [show all]
Search for other: Achondrites, Ungrouped achondrites
Comments: Approved 8 Aug 2021
Writeuphelp
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:
  MB110
  Table 0
  Line 0:
Place of purchase:Waran, Mauritania
Date:P 2020
Mass (g):142.6
Pieces:1
Class:Achondrite-ung
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
Institutions
   and collections
IfP: Institut für Planetologie, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany (institutional address; updated 23 Jan 2012)
Catalogs:
References: Published in Meteoritical Bulletin, no. 110, in preparation (2021)
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Public domain photographs:
Knut Metzler      
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7937 approved meteorites from (Northwest Africa) (plus 1960 unapproved names)

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