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Northwest Africa 12738
Basic information Name: Northwest Africa 12738
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12738
Observed fall: No
Year found: 2019
Country: (Northwest Africa)
Mass:help 2.99 kg
Recommended:  Achondrite-ung    [explanation]

This is 1 of 156 approved meteorites classified as Achondrite-ung.   [show all]
Search for other: Achondrites, Ungrouped achondrites
Comments: Approved 26 Mar 2024
Writeup from MB 113:

Northwest Africa 12738 (NWA 12738)

(Northwest Africa)

Purchased: 2019 Feb

Classification: Ungrouped achondrite

History: Found in the El Hank region of Mauritania in late 2018 and purchased in February 2019 by Darryl Pitt from a Mauritanian dealer.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Vesicular, igneous-textured assemblage of zoned, subhedral olivine and twinned, prismatic low-Ca pyroxene plus interstitial feldspathic glass and minor accessory chromite, troilite and Ni-poor metal.

Geochemistry: Olivine (core Fa15.2; predominantly Fa21.4±1.8 (range Fa20.3-23.5), N = 4), low-Ca pyroxene (Fs21.2±0.3Wo2.8±0.1 (range Fs20.8-21.3Wo 2.7-2.9), N = 3), subcalcic augite (Fs20.0±1.3Wo27.8±2.1 (range Fs18.5-20.8Wo25.7-29.8), N = 3). Oxygen isotopes (K. Ziegler, UNM): analyses of acid-washed subsamples by laser fluorination gave, respectively, δ17O 3.759, 3.731, 3.830; δ18O 5.100, 5.044, 5.250; Δ17O 1.066, 1.068, 1.058 per mil. Magnetic susceptibility, log χ (× 10-9 m3/kg) = 3.44.

Classification: Achondrite (ungrouped, igneous with L chondrite affinities, metal-poor). Likely paired with NWA 13272, NWA 13351, NWA 14843, NWA 14849, NWA 14963, and NWA 14970.

Specimens: 36.3 g including one polished thin section at UWB; remainder with DPitt.

Data from:
  Table 0
  Line 0:
Place of purchase:Mauritania
Date:P 2019 Feb
Mass (g):2990
Shock stage:low
Weathering grade:low
Fayalite (mol%):21.4±1.8
Ferrosilite (mol%):21.2±0.3
Wollastonite (mol%):2.8±0.1
Magnetic suscept.:3.44
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):36.3
Type spec location:UWB
Main mass:DPitt
Comments:Work name MVCH 466; submitted by A. Irving
Plots: O isotopes:  
   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, Burke Museum of Natural History and Culture, Box 353010 Seattle, WA 98195, United States (institutional address; updated 9 Oct 2023)
DPitt: Darryl Pitt, 225 West 83rd Street, New York, NY 10024, United States; Website (private address)
References: Published in Meteoritical Bulletin, no. 113, in preparation (2024)
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Public domain photographs:
A. Irving, UWS   

     This is 1 of 9790 approved meteorites from (Northwest Africa) (plus 1854 unapproved names)

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