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Northwest Africa 15588
Basic information Name: Northwest Africa 15588
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 15588
Observed fall: No
Year found: 2019
Country: (Northwest Africa)
Mass:help 109 g
Recommended:  CL3    [explanation]

This is 1 of 2 approved meteorites classified as CL3.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), and CL chondrites
Comments: Approved 30 Jul 2023
Writeup from MB 112:

Northwest Africa 15588 (NWA 15588)

(Northwest Africa)

Purchased: 2019

Classification: CL3

History: Purchased by David Huffman in 2019 from a Moroccan dealer.

Physical characteristics: A single, irregularly shaped, black stone (109 g) with red-brown weathered exterior surfaces. Cut interior surfaces are mostly black with sparse shiny metal.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) The specimen contains a significant amount of altered kamacite, which caused difficulties with proper petrographic assessment both by optical thin section microscopy and back-scattered electron imagery. The extensive staining by secondary terrestrial Fe hydroxides obscures the primary assemblage to some extent. Well-delineated unequilibrated chondrules (apparent diameter 790±260 µm, N = 20) are evident in thin section, but the proportion of matrix cannot be accurately assessed. Accessory phases include taenite, troilite, calcic plagioclase, pleonaste and Al-Ti-diopside.

Geochemistry: Olivine (Fa10.0±5.4, PMD = 44%, range Fa1.3-16.3, N = 10; Cr2O3 in ferroan olivine 0.02-0.11 wt.%, mean 0.07±0.03 wt.%, N = 8), low-Ca pyroxene (Fs6.7±4.6Wo2.0±1.0, range (Fs1.0-12.4Wo0.9-3.0, N = 4), subcalcic diopside (Fs4.5Wo29.5), diopside (Fs2.5Wo39.5), Al-Ti-diopside (Fs1.8Wo57.1, Al2O3 13.1 wt.%, TiO2 4.9 wt.%). Oxygen isotopes (D. Ibarra, BrownU): analyses of acid-washed subsamples by laser fluorination gave, respectively δ17O -1.370, -2.140; δ18O 2.754, 2.154; Δ17O -2.819, -3.271 per mil (TFL slope value = 0.526). All data were normalized to San Carlos olivine analyzed concurrently. Magnetic susceptibility log χ (× 10-9 m3/kg) = 4.89.

Classification: Carbonaceous chondrite (CL3). Oxygen isotopes plot close to the CCAM line but consistently to slightly higher δ17O values, and lie on an extension of the trend for five specimens established as CL chondrites (Metzler et al., 2021). The presence of relatively calcic plagioclase and mineral phases found in CAI are also consistent with a carbonaceous chondrite affinity, but the significant metal content and elevated magnetic susceptibility are not attributes of carbonaceous chondrites other than CL chondrites. The range in Fa contents of olivine in this specimen (PMD = 44%) is much larger than that found in either of the other two known CL chondrites of subtype 3.9, and the ferroan olivines have Cr2O3 contents of up to 0.1 wt.%. Therefore, this specimen must be of a lower subtype than previous examples, and is estimated to be of subtype 3.5 or 3.6.

Specimens: 25.3 g including one polished thin section and one polished mount at PSF; remainder with Mr. D. Huffman.

  • Metzler K., Hezel D.C., Barosch J., Wölfer E., Schneider J.M., Hellmann J.L., Berndt J., Stracke A., Gattacceca J., Greenwood R.C., Franchi I.A., Burkhardt C., and Kleine T. (2021) The Loongana (CL) group of carbonaceous chondrites. Geochim. Cosmochim. Acta 304, 1–31. (link)
Data from:
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2019
Mass (g):109
Shock stage:S2
Weathering grade:high
Fayalite (mol%):10.0±5.4
Ferrosilite (mol%):6.7±4.6
Wollastonite (mol%):2.0±1.0
Magnetic suscept.:4.89
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):25.3
Type spec location:PSF
Main mass:D. Huffman
Comments:Work name DH-001; submitted by A. Irving
Plots: O isotopes:  
   and collections
PSF: Planetary Studies Foundation,10 Winterwood Lane, Unit B, Galena, Illinois 61036-9283, United States; Website (institutional address; updated 1 Dec 2011)
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)
BrownU: Joseph Boesenberg Brown University Dept of Earth, Environmental and Planetary Sciences (DEEPS) 324 Brook Street Providence, RI 02912 , United States (institutional address; updated 26 Oct 2023)
References: Published in Meteoritical Bulletin, no. 112, in preparation (2023)
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Public domain photographs:
A. Irving      

     This is 1 of 9429 approved meteorites from (Northwest Africa) (plus 1876 unapproved names)

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