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Northwest Africa 14674
Basic information Name: Northwest Africa 14674
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 14674
Observed fall: No
Year found: 2017
Country: (Northwest Africa)
Mass:help 134.5 g
Classification
  history:
Recommended:  CR2-an    [explanation]

This is 1 of 2 approved meteorites classified as CR2-an.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 2), and CR chondrites
Comments: Approved 16 May 2022
Writeuphelp
Writeup from MB 111:

Northwest Africa 14674 (NWA 14674)

(Northwest Africa)

Purchased: 2017 Oct

Classification: Carbonaceous chondrite (CR2, anomalous)

Physical characteristics: one 80 g stone covered by a fresh fusion crust and many small fragments; ~1 mm chondrules in an abundant, dark matrix.

Petrography: The matrix contains abundant framboidal magnetite and phyllosilicates, plus pentlandite, but no tochilinite or chrondstedtite. Chondrules are mostly >500 μm and the biggest is 2 mm across. Average apparent chondrule diameter is 1.3±1.0 mm (n=83). Olivine is fresh in Type I chondrules and pyroxene is partly altered. Olivine in Type II chondrules is partly serpentinized. Chondrule mesostases are replaced by serpentine and chlorite, but diopside dendrites survive. Large metal grains in the matrix are only partly altered. Some chondrules have thick, complex, fine-grained rims, and dark inclusions are abundant, while refractory inclusions are rare.

Geochemistry: Mineral compositions and Geochemistry: Type I chondrule olivine is Fa1-3 and pyroxene is Fs2-5. Type II chondrules have olivine Fa13-31. Kamacite has 6% Ni. Oxygen isotopic composition (J. Gattacceca, C. Sonzogni, CEREGE) from analysis of one acid-washed 1.5 mg aliquot of a powdered 60 mg bulk sample is δ17O=5.10‰, δ18O=10.78‰ , Δ17O=-0.55‰ (slope 0.52, analytical uncertainties 0.08‰, 0.12‰, 0.03‰ respectively).

Classification: Carbonaceous chondrite (CR2-anomalous). Hydrated matrix and partially serpentinised olivine indicate a type 2 chondrite. No crondstedtite and tochilinite are observed as in CM2 chondrites, and chondrule size is much larger than in CM2 chondrites. Large metal grains, complex fine-grained chondrule rims, and abundant dark inclusions are suggestive of CR chondrites, but oxygen isotopes set this meteorite apart from CR2 chondrites. The oxygen isotopic composition is close to that of Al Rais (CR-an) and GRO 95577 (CR1). In a log χ (× 10-9 m3/kg) vs. δ18O plot, this meteorite is in the C2-ung 1 defined by Hewins et al. (2021) (see their figure 25). 

Specimens: The type specimen (at MNHNP) consists of 20 g taken from the main mass, which remains with Labenne Meteorites.

Bibliography:
  • Hewins R. H., Zanetta P.-M., Zanda B., Le Guillou C., Gattacceca J., Sognzoni C., Pont S., Piani L., Rigaudier T., Leroux H., Brunetto R., Maupin R., Djouadi Z., Bernard S., Deldicque D., Malarewicz V., Dionnet Z., Aléon-Toppani A., King A. and Borondics F. (2021) NORTHWEST AFRICA (NWA) 12563 and ungrouped C2 chondrites: Alteration styles and relationships to asteroids. Geochimica et Cosmochimica Acta 311, 238–273. (link)
Data from:
  MB111
  Table 0
  Line 0:
Place of purchase:Agadir
Date:P 2017 Oct
Mass (g):134.5
Pieces:Many
Class:CR2-an
Fayalite (mol%):1-31
Ferrosilite (mol%):2-5
Wollastonite (mol%):39
Magnetic suscept.:4.78
Classifier:R.H. Hewins, MNHNP
Type spec mass (g):20
Type spec location:MNHNP
Main mass:Luc Labenne
Comments:work name LM AU; submitted by R. Hewins
Plots: O isotopes:  
Institutions
   and collections
CEREGE: CEREGE BP 80 Avenue Philibert, Technopole de l'Arbois 13545 Aix-en-Provence Cedex 4 France, France (institutional address; updated 29 Oct 2018)
MNHNP: Museum National d'Histoire Naturelle, IMPMC-CP52, 57 rue Cuvier, 75005 Paris, France, France; Website (institutional address)
Labenne: 23, rue de Esperance, 75013 Paris, France; Website (private address; updated 29 Aug 2012)
Catalogs:
References: Published in Meteoritical Bulletin, no. 111, in preparation (2022)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 8636 approved meteorites from (Northwest Africa) (plus 1884 unapproved names)

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