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Northwest Africa 13238
Basic information Name: Northwest Africa 13238
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13238
Observed fall: No
Year found: 2019
Country: (Northwest Africa)
Mass:help 162.1 g
Classification
  history:
Recommended:  LL4    [explanation]

This is 1 of 368 approved meteorites classified as LL4.   [show all]
Search for other: LL chondrites, LL chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 5 Apr 2020
Writeuphelp
Writeup from MB 109:

Northwest Africa 13238 (NWA 13238)

(Northwest Africa)

Purchased: 2019 Jun

Classification: Ordinary chondrite (LL4)

History: Purchased in June 2019 by two anonymous collectors from a Moroccan dealer at the Ensisheim Show.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Well-formed, relatively large equilibrated chondrules are set in a recrystallized matrix containing sodic plagioclase, relatively abundant sulfides (troilite and pentlandite), Ti-chromite, ilmenite and minor kamacite (as altered holly-leaf-shaped grains) and taenite. One unusual chromite-rich chondrule is composed predominantly of chromite with subordinate ilmenite, intermediate plagioclase (labradorite) and pentlandite.

Geochemistry: Olivine (Fa32.6±0.1, range Fa32.4-32.8, N = 6), low-Ca pyroxene (Fs25.9±0.3Wo1.6±0.2, range Fs25.5-26.2Wo1.2-1.7, N = 6), plagioclase in chondrule (An85.9Or0.2), chromite in chondrule (Mg = 0.403, Cr = 0.221). Magnetic susceptibility log χ (× 10-9 m3/kg) = 3.38. Oxygen isotopes (K. Ziegler, UNM): analyses of acid-washed subsamples by laser fluorination gave, respectively, δ17O 4.740, 4.523; δ18O 6.518, 6.151; Δ17O 1.298, 1.275 per mil.

Classification: Ordinary chondrite (LL4). This LL chondrite has some anomalous features, including the presence of calcic plagioclase in chondrules, almost complete absence of metal, unusually high abundance of sulfides, elevated δ18O relative to literature values for 43 LL chondrite specimens.

Specimens: 20.4 g including one polished thin section at UWB; remainder with anonymous owners.

Data from:
  MB109
  Table 0
  Line 0:
Place of purchase:Ensisheim
Date:P 2019 Jun
Mass (g):162.1
Pieces:1
Class:LL4
Shock stage:S2
Weathering grade:W1
Fayalite (mol%):32.6±0.1
Ferrosilite (mol%):25.9±0.3
Wollastonite (mol%):1.6±0.2
Magnetic suscept.:3.38
Classifier:A. Irving, UWS, and P. Carpenter, WUSTL
Type spec mass (g):20.4
Type spec location:UWB
Main mass:Anonymous
Comments:Submitted by A. Irving
Plots: O isotopes:  
Institutions
   and collections
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
WUSL: Washington Univ., One Brookings Drive, St. Louis, MO 63130, United States (institutional address; updated 17 Oct 2011)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
Catalogs:
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7354 approved meteorites from (Northwest Africa) (plus 1958 unapproved names)

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