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Northwest Africa 12646
Basic information Name: Northwest Africa 12646
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12646
Observed fall: No
Year found: 2019
Country: (Northwest Africa)
Mass:help 7.26 kg
Classification
  history:
Recommended:  LL4-7 melt breccia    [explanation]

This is the only approved meteorite classified as LL4-7 melt breccia.
Search for other: LL chondrites, LL chondrites (type 4-7), Melted chondrites, Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 9 Aug 2019
Writeuphelp
Writeup from MB 108:

Northwest Africa 12646 (NWA 12646)

(Northwest Africa)

Purchased: 2019 Jan

Classification: LL4-7 melt breccia

History: Purchased by Bob Falls in January 2019 from a Moroccan dealer.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) The specimen is a breccia composed of clasts of relatively unshocked material (which is itself a breccia) within a much darker melt matrix. The unshocked breccia clasts contain a variety of equilibrated components with a range of textures from type 4 (with well-formed chondrules) to type 7 (recrystallized with no remnant chondrules). The melt matrix is very fine grained and contains numerous small grains of metal and sulfide.

Geochemistry: Type 4 clast: Olivine (Fa30.6), low-Ca pyroxene (Fs25.0Wo2.4), augite (Fs9.0Wo44.4). Type 7 clast: Olivine (Fa30.6-30.9, N =3), orthopyroxene (Fs24.7-24.9Wo3.2-3.9, N = 3), augite (Fs10.7Wo43.2), plagioclase (An7.7-14.0Or2.5-5.1, N = 2). Melt matrix: Olivine (Fa30.8-31.2, N = 2), orthopyroxene (Fs25.2-25.5Wo1.9-1.4, N = 2).

Classification: Ordinary chondrite (LL4-7 melt breccia).

Specimens: 103.6 g including one polished thin section at UWB; remainder with Mr. R. Falls.

Data from:
  MB108
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2019 Jan
Mass (g):7258
Pieces:1
Class:LL4-7 melt breccia
Shock stage:S2
Weathering grade:W1/2
Fayalite (mol%):30.6-31.2
Ferrosilite (mol%):24.7-25.5
Wollastonite (mol%):3.9-1.4
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):103.6
Type spec location:UWB
Main mass:R. Falls
Comments:Work name BF19-26; submitted by A. Irving
Institutions
   and collections
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. 108, in preparation (2019)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7048 approved meteorites from (Northwest Africa) (plus 1998 unapproved names)

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