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Northwest Africa 11756
Basic information Name: Northwest Africa 11756
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 11756
Observed fall: No
Year found: 2017
Country: Morocco
Mass:help 840 g
Classification
  history:
Recommended:  Brachinite    [explanation]

This is 1 of 49 approved meteorites classified as Brachinite.   [show all]
Search for other: Brachinites, Primitive achondrites
Comments: Approved 26 May 2018
Writeuphelp
Writeup from MB 107:

Northwest Africa 11756 (NWA 11756)

Morocco

Purchased: 2017 Sep

Classification: Primitive achondrite (Brachinite)

Petrography: (K. Metzler, IfP) Olivine-dominated ultramafic rock with metamorphic texture (~120° triple junctions), consisting of olivine, low-Ca pyroxene, and Ca-pyroxene grains up to ~0.8 mm. Metal is replaced by weathering products which are also concentrated along grain boundaries. Accessories are Cr-Al-spinel (up to 700 µm) and weathered FeS. No plagioclase was found.

Geochemistry: Mineral compositions and geochemistry: Olivine grains (n=12): Fa26.8±0.2, mean Fe/Mn (at.)= 58; Low-Ca pyroxene grains (n=12): Fs22.1±0.4Wo2.1±0.1. Ca-pyroxene grains (n=5): Fs9.1±0.2Wo43.6±0.5. The concentration of Cr2O3 in olivine and pyroxene is <0.1 wt% and 0.3 wt%, respectively. Composition of Cr-spinel (n=2; at.): Cr/(Cr+Al)=0.78; TiO2 1.4-1.5 wt%. SEM analyses of large thin section areas reveal that this sample is nearly devoid of aluminum.

Classification: Brachinite, based on metamorphic texture, grain size, modal composition, absence of plagioclase, and mineral chemistry.

Data from:
  MB107
  Table 0
  Line 0:
Place of purchase:Guelmim, Morocco
Date:P 2017 Sep
Mass (g):840
Pieces:1
Class:Brachinite
Shock stage:low
Weathering grade:high
Fayalite (mol%):26.8
Ferrosilite (mol%):22.1; 9.1
Wollastonite (mol%):2.1; 43.6
Classifier:K. Metzler, IfP
Type spec mass (g):20
Type spec location:IfP, Münster
Main mass:Nourddine Azelmat, Morocco
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. 107, in preparation (2018)
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Geography:

Morocco
Coordinates:Unknown.

Statistics:
     This is 1 of 1402 approved meteorites from Morocco (plus 16 unapproved names) (plus 1 impact crater)

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