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Northwest Africa 6588
Basic information Name: Northwest Africa 6588
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 6588
Observed fall: No
Year found: 2008
Country: (Northwest Africa)
Mass:help 2.73 kg
Classification
  history:
Meteoritical Bulletin:  MB 99  (2011)  LL6-an
Recommended:  LL6-an    [explanation]

This is 1 of 3 approved meteorites classified as LL6-an.   [show all]
Search for other: LL chondrites, Ordinary chondrites, and Ordinary chondrites (type 4-7)
Comments: Approved 27 Apr 2011
Writeuphelp
Writeup from MB 99:

Northwest Africa 6588 (NWA 6588)

Northwest Africa

Purchased: 2008

Classification: Ordinary chondrite (LL6, anomalous)

History: Purchased in Erfoud, Morocco, May 2008, by Adam Aaronson.

Physical characteristics: Freshly broken surface is dark gray, polycrystalline. Resembles a fine-grained peridotite. Moderately weathered, some iron-oxide staining.

Petrography: (C. Agee, UNM) Thin section reveals ~65% olivine, 25% low-Ca pyroxene, 5% albitic feldspar, 3% sulfides, 1% chromite, <1% Fe-oxide, <1% phosphate. Silicate grain size is variable (5-300 μm) and indistinct chondrules present. Albitic feldspar grains to 150 μm. Finely disseminated Ni-rich iron sulfides (<1 μm) found throughout, and as larger pockets (>100 μm) in grain boundary contact with each other, often occupying silicate triple junctions. Sulfides show fine lamellae. Fe-Ni metal is rare. Minor amount of low-Ni, Fe-oxides present and these are presumably products of weathering, which has replaced primary metal. A few large (>200 μm) irregularly shaped Ca-phosphates with inclusions and intergrowths.

Geochemistry: (C. Agee and M. Splide, UNM). Olivine Fa33.3±0.2, Fe/Mn=68 ± 3, N=13; orthopyroxene Fs27.0±0.2Wo2.2±0.1, Fe/Mn=40 ± 2, N=8; plagioclase Or6.6Ab84.1An9.3, N=4; chromite Fe# = 0.90, Cr# = 0.87; phosphate composition consistent with whitlockite group, Fe# = 0.27, Na2O = 2.4 wt%.

Classification: Ordinary Chondrite (LL6) with anomalous characteristics. Highly equilibrated, oxidized, ordinary chondrite with uniform olivine, pyroxene, and plagioclase compositions. Fayalite, ferrosilite content and Fe/Mn of olivines are high. Fa and Fs are among the highest ever reported for ordinary chondrites. Chromite/olivine geothermometer (Wlotzka, 2005) gives metamorphic equilibration temperature of 741°C, which is about 50°C above the average for LL6.

Specimens: Aaronson holds the main mass, 20 g on deposit at UNM.

Data from:
  MB99
  Table 0
  Line 0:
Place of purchase:Erfoud, Morocco
Date:P 2008
Mass (g):2730
Pieces:1
Class:LL6-an
Fayalite (mol%):33.3±0.2
Ferrosilite (mol%):27.0±0.2
Wollastonite (mol%):2.2±0.1
Classifier:C. Agee
Type spec mass (g):20
Type spec location:UNM
Main mass:A. Aaronson
Comments:Submitted by C. Agee
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)
Aaronson: Sahara Overland Ltd., Harhora, Temara, 12000, Morocco (private address; updated 3 Jan 2010)
Catalogs:
References: Published in Meteoritical Bulletin, No. 99, April 2012, MAPS 47, E1-E52 (2012) [published online only]
Find references in NASA ADS:
Find references in Google Scholar:
Photos:
CreditPhotos
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Institute of Meteoritics UNM   
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6900 approved meteorites from (Northwest Africa) (plus 2027 unapproved names)

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