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Northwest Africa 8290
Basic information Name: Northwest Africa 8290
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 8290
Observed fall: No
Year found: 2013
Country: (Northwest Africa)
Mass:help 167.8 g
Classification
  history:
Meteoritical Bulletin:  MB 103  (2014)  CO3.1
Recommended:  CO3.1    [explanation]

This is 1 of 13 approved meteorites classified as CO3.1.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), CM-CO clan chondrites, and CO chondrites
Comments: Approved 14 Mar 2014
Writeuphelp
Writeup from MB 103:

Northwest Africa 8290 (NWA 8290)

(Northwest Africa)

Purchased: 2013

Classification: Carbonaceous chondrite (CO3.1)

History: Purchased by Brahim Tahiri from a Moroccan meteorite hunter and sent to his partner Sean Tutorow for classification, 2013.

Physical characteristics: Single stone, weathered exterior with small chondrules visible through desert patina, saw cut reveals densely packed chondrules in a dark brown matrix, a few small CAIs visible under low magnification.

Petrography: (C. Agee, UNM) Microprobe examination of a polished mount shows numerous unequilibrated chondrules, many are porphyritic, most 5-200 μm, largest observed 400 μm. Abundant opaque matrix, most chondrules with glass or mesostasis, and metal/sulfide blebs.

Geochemistry: (C. Agee and H. Miley, UNM) Olivine range Fa0.3-48.0, n=26; ferroan olivine Fa16.9±15.5, Fe/Mn=71±46, Cr2O3=0.22±0.08 wt%, n=15; olivine in type I chondrules, Fa0.9±0.5, n=11; low-Ca pyroxene Fs7.3±8.0Wo2.0±1.3, Fe/Mn=43±35, n=12. Oxygen isotopes (K. Ziegler, UNM) Oxygen isotope values of 3 acid-washed aliquots of bulk sample, 1.0, 1.2, 1.6 mg, gave δ17O = -5.494, -6.824, -6.784, δ18O = -2.175, -3.510, -3.418, Δ17O = -4.346, -4.971, -4.979 (linearized, all permil).

Classification: Carbonaceous chondrite (CO3.1) based on mean Cr2O3=0.22±0.08 wt% in ferroan olivines, approximately midway between Rainbow (CO3.2) and  Colony (CO3.0), as reported by Grossman and Brearley (2005).  

Specimens: 20.7 g including a probe mount on deposit at UNM, Sean Tutorow holds the main mass.

Bibliography:
  • Grossman J.N. and Brearley A.J. (2005) The onset of metamorphism in ordinary and carbonaceous chondrites. Meteorit. Planet. Sci. 40, 87-122. (link)
Data from:
  MB103
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2013
Mass (g):167.75
Pieces:1
Class:CO3.1
Fayalite (mol%):0.9±0.5; 16.9±15.5
Ferrosilite (mol%):7.3±8.0
Wollastonite (mol%):2.0±1.3
Classifier:C. Agee, UNM
Type spec mass (g):20.7
Type spec location:UNM
Main mass:Sean Tutorow
Comments:Field name G482; submitted by C. Agee, UNM
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)
Catalogs:
References: Published in Meteoritical Bulletin, no. 103, MAPS 52, 1014, May 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12888/full
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6877 approved meteorites from (Northwest Africa) (plus 2037 unapproved names)

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