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Northwest Africa 15923
Basic information Name: Northwest Africa 15923
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 15923
Observed fall: No
Year found: 2022
Country: (Northwest Africa)
Mass:help 105 kg
Meteoritical Bulletin:  MB 112  (2023)  Eucrite-melt breccia
Recommended:  Eucrite-melt breccia    [explanation]

This is 1 of 106 approved meteorites classified as Eucrite-melt breccia.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 7 May 2023
Writeup from MB 112:

Northwest Africa 15923 (NWA 15923)

(Northwest Africa)

Find: 2022

Classification: HED achondrite (Eucrite, melt breccia)

History: Mark Lyon purchased 105 kg of similar looking fusion crusted achondritic meteorites from a meteorite dealer in Mauritania in 2022/2023. The largest stone is 12 kg. A 433.7 g stone was donated to the Buseck Center for Meteorite Studies at ASU.

Physical characteristics: A fresh, fusion crusted angular stone with poorly developed regmaglypts. Fusion crust is locally glossy with well developed flow patterns. Sawn surface (7 × 5 cm) shows coarse breccia of light-colored rounded breccia clasts separated by dark vesicular melt veins with a matte-black appearance. Clasts are poorly sorted and range considerably in size, many measuring several centimeters.

Petrography: (E. Mares, S. Ravikumar, L. Garvie, A. Wittmann, ASU) Eucrite-melt breccia with clasts to 5 cm with a distinct boundary to the black melt veins. Predominant minerals are up to 1-mm-sized exsolved pyroxenes and calcic plagioclase that exhibit gabbroic cumulate textures. All clasts appear similar in their modal mineralogies, suggesting the sample is a monomict breccia. Accessory phases include ilmenite, chromite, troilite, silica, F-rich Ca phosphate, Ca-Fe-Mg phosphate, and zircon. Small grains of ilmenite and chromite are present as inclusions within the pyroxene-plagioclase clasts. Troilite is primarily encountered as small rounded blebs within the melt veins. No metallic Fe-Ni detected.

Geochemistry: Low-Ca pyroxene: Fs 61.9±1.1Wo2.6±0.9, FeO/MnO=31.71±0.89, n=10; augite: Fs27.7±0.9Wo42.9±0.9, FeO/MnO=33.33±1.35, n=10; Calcic plagioclase: An96.2±1.0Ab3.1±0.2, n=10. Silica contains 0.11±0.01 wt% Al, 0.24±0.12 wt% Fe and up to 0.1 wt% K (n=10). Chromite has variable Ti content (ranges from 1.3-9.1 wt% Ti; n = 4). Ilmenite is close to stoichiometric FeTiO3 with trace Mg, Mn, and Cr.

Classification: This meteorite is a gabbroic monomict eucrite impact breccia.

Specimens: One specimen (433.7 g) in the ASU Buseck Center for Meteorite Studies.

Data from:
  Table 0
  Line 0:
Place of purchase:Mauritania
Mass (g):105000
Class:Eucrite-melt breccia
Shock stage:high
Weathering grade:low
Classifier:E. Mares, S. Ravikumar, L. Garvie, A. Wittmann
Type spec mass (g):433.7
Type spec location:ASU
Main mass:ASU
Comments:ASU#2198; submitted by L. Garvie
   and collections
ASU: Center for Meteorite Studies, Arizona State University, Tempe, Arizona 85287-1404, United States; Website (institutional address; updated 14 Jan 2012)
References: Published in Meteoritical Bulletin, no. 112, in preparation (2023)
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Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Ryan Upchurch   
Public domain photographs:
Laurence Garvie   

     This is 1 of 9746 approved meteorites from (Northwest Africa) (plus 1866 unapproved names)

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