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Northwest Africa 8417
Basic information Name: Northwest Africa 8417
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 8417
Observed fall: No
Year found: 2014
Country: (Northwest Africa)
Mass:help 222 g
Classification
  history:
Meteoritical Bulletin:  MB 103  (2014)  LL7
Recommended:  LL7    [explanation]

This is 1 of 60 approved meteorites classified as LL7.   [show all]
Search for other: LL chondrites, LL chondrites (type 4-7), Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 10 Nov 2014
Writeuphelp
Writeup from MB 103:

Northwest Africa 8417 (NWA 8417)

(Northwest Africa)

Purchased: 2014 Apr

Classification: Ordinary chondrite (LL7)

History: Purchased by Aras Jonikas in April 2014 from a Moroccan dealer.

Physical characteristics: Single stone (221.5 g) partly coated by brownish-black fusion crust. The interior is pale green with sparse black grains and visible specks of metal plus brown stained areas.

Petrography: (A. Irving and S. Kuehner, UWS) Very fresh, metal-poor specimen with a complex texture. Large (up to 5 mm across) oikocrysts of orthopyroxene enclose numerous small chadacrysts of olivine, but there also are regions of about equal size composed mostly of olivine and orthopyroxene exhibiting triple grain junctions. Chondrules are absent. Olivine and orthopyroxene of all textural types are highly equilibrated. Accessory minerals are clinopyroxene, Ti-free chromite, sodic plagioclase, K-feldspar, albite, stained kamacite (<1 vol.%), troilite and taenite.

Geochemistry: Olivine (Fa26.5-26.6; FeO/MnO = 54-63), orthopyroxene (Fs21.6-21.7Wo2.8-3.2; FeO/MnO = 31-32), clinopyroxene (Fs10.5-10.7Wo40.4-39.6). Oxygen isotopes (K. Ziegler, UNM): acid-washed subsamples analyzed by laser fluorination gave the following results, respectively: δ17O 3.789, 3.862, 3.729; δ18O 4.937, 5.020, 4.890; Δ17O 1.182, 1.211, 1.147 (all per mil).

Classification: Ordinary chondrite (LL7). The very low metal content, the large size of the oikocrysts (presumably representing former chondrules), and the FeO/MnO ratios in olivine are features consistent with LL parentage (prior to thermal metamorphism). Oxygen isotope compositions plot within the overlapping fields for LL and L chondrites, and the olivine and pyroxene compositions fall within the gaps between the accepted ranges for L and LL chondrites, but if all the characteristics are considered together then this specimen is best classified as an LL7 chondrite.

Specimens: 21 g including one polished thin section at UWB. The main mass is held by A. Jonikas.

Data from:
  MB103
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2014 Apr
Mass (g):221.5
Pieces:1
Class:LL7
Shock stage:low
Weathering grade:low
Fayalite (mol%):26.5-26.6
Ferrosilite (mol%):21.6-21.7
Wollastonite (mol%):2.8-3.2
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):21
Type spec location:UWB
Main mass:A. Jonikas
Comments:AJ14-7; submitted by A. Irving
Plots: O isotopes:  
Institutions
   and collections
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
Catalogs:
References: Published in Meteoritical Bulletin, no. 103, MAPS 52, 1014, May 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12888/full
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Photos:
CreditPhotos
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Denis gourgues      
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6900 approved meteorites from (Northwest Africa) (plus 2035 unapproved names)

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