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Northwest Africa 13657
Basic information Name: Northwest Africa 13657
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13657
Observed fall: No
Year found: 2009
Country: (Northwest Africa)
Mass:help 321 g
Classification
  history:
Recommended:  Eucrite-melt breccia    [explanation]

This is 1 of 42 approved meteorites classified as Eucrite-melt breccia.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 10 Jan 2021
Writeuphelp
Writeup from MB 110:

Northwest Africa 13657 (NWA 13657)

(Northwest Africa)

Purchased: 2009 June 19

Classification: HED achondrite (Eucrite, melt breccia)

Petrography: (K. Metzler, IfP) Coarse-grained basalt clasts (up to cm-size) with ophitic to subophitic textures and mineral fragments (pyroxene, plagioclase,) are set in small amounts of black matrix (fine-grained crystallized melt). Pyroxene in the clasts shows exsolution lamellae. Accessories are ilmenite, troilite, a silica polymorph, spinel, and zircon.

Geochemistry: Mineral compositions and geochemistry: Low-Ca pyroxene (host): Fs63.3±0.8 Wo2.3±0.3 (Fs61.4-64.5 Wo2.0-2.9); mean Fe/Mn (at.): 34; n=14. Ca-rich pyroxene (exsolution lamellae) Fs28.3±0.7 Wo42.5±0.7 (Fs27.2-29.6 Wo41.2-43.6); n=14. Plagioclase An87.5±2.3 Or0.3±0.4 (An81.7-90.1 Or0.0-0.9); n=11.

Classification: Achondrite (eucrite-melt breccia). Classification based on texture, mineral compositions, and Fe/Mn ratio of low-Ca pyroxene.

Data from:
  MB110
  Table 0
  Line 0:
Place of purchase:Ensisheim, France
Date:P 2009 June 19
Mass (g):321
Pieces:1
Class:Eucrite-melt breccia
Shock stage:M-S2
Weathering grade:low
Ferrosilite (mol%):63.3±0.8, 28.3±0.7
Wollastonite (mol%):2.3±0.3, 42.5±0.7
Classifier:K. Metzler, IfP
Type spec mass (g):20
Type spec location:IfP
Main mass:anonymous
Comments:Submitted by K.Metzler, IfP
Institutions
   and collections		 IfP: Institut für Planetologie, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany (institutional address; updated 23 Jan 2012)
Catalogs:
References: Published in Meteoritical Bulletin, no. 110, in preparation (2021)
Find references in NASA ADS:
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Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7795 approved meteorites from (Northwest Africa) (plus 1971 unapproved names)

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