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Northwest Africa 12864
Basic information Name: Northwest Africa 12864
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12864
Observed fall: No
Year found: 2011
Country: (Northwest Africa)
Mass:help 105.6 g
Meteoritical Bulletin:  MB 108  (2020)  Eucrite
Recommended:  Eucrite    [explanation]

This is 1 of 565 approved meteorites (plus 1 unapproved name) classified as Eucrite.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 11 Oct 2019
Writeup from MB 108:

Northwest Africa 12864 (NWA 12864)

(Northwest Africa)

Purchased: 2011

Classification: HED achondrite (Eucrite)

History: Catalogued in the ROM collection as LM57449

Physical characteristics: Visible fusion crust present exhibiting low-moderate weathering, evident with minor light orange caliche. Fusion crust quite fractured. Interior of the sample is moderately weathered, showing a coarse grained cumulate texture.

Petrography: (K. Tait, I. Nicklin, ROM) Breccia containing basaltic and gabbroic clasts with abundant mineral fragments set in a finer grained, comminuted matrix.  Dark shock-melt clasts are also present as well as clasts composed of finer-grained, brecciated material.  The largest clast is 4 × 2 mm.  Mineral fragments show a range of shock states from mild undulose extinction to mosaicism.

Geochemistry: Mineral composition and geochemistry: Plagioclase An85.1±6.1 (n = 29). Low-Ca pyroxene composition: Fs51.3±15.8Wo6.3±5.7 (n=25) and Mg#38.7-76.1 (n=25). High-Ca pyroxene composition: Fs36.3±0.6Wo28.9±4.6 (n=2). Mg# 50.3-54.6 (n=2).

Data from:
  Table 0
  Line 0:
Place of purchase:Tucson
Date:P 2011
Mass (g):105.62
Shock stage:low
Weathering grade:low
Ferrosilite (mol%):36.3±0.6, 51.3±15.8
Wollastonite (mol%):6.3±5.7, 28.9±4.6
Classifier:K. Tait, ROM
Type spec mass (g):21.1
Type spec location:ROM
Main mass:DGregory
Comments:Submitted by V. Di Cecco, ROM
   and collections
ROM: Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada (institutional address; updated 18 Oct 2011)
DGregory: David Gregory, 230 First Avenue, Suite 108, St. Thomas, Ontario N5R 4P5, Canada (private address)
References: Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150
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     This is 1 of 8745 approved meteorites from (Northwest Africa) (plus 1880 unapproved names)

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