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Northwest Africa 10931
Basic information Name: Northwest Africa 10931
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 10931
Observed fall: No
Year found: 2013
Country: (Northwest Africa)
Mass:help 615 g
Classification
  history:
Meteoritical Bulletin:  MB 105  (2016)  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 10 Dec 2016
Writeuphelp
Writeup from MB 105:

Northwest Africa 10931 (NWA 10931)

(Northwest Africa)

Purchased: 2013

Classification: Carbonaceous chondrite (CO3.1)

History: Purchased by Aziz Habibi in Gulomim from a nomad.

Physical characteristics: Smooth fusion crust exterior with numerous sub-millimeter chondrule outlines. A saw cut reveals many very small chondrules and a few small CAIs set in a dark-brown matrix.

Petrography: (C. Agee, UNM) Microprobe examination of a polished mount shows numerous chondrules, many fragmental or irregular, most in the size range 50-200 μm. Scattered matrix olivines and CAIs were observed throughout. Fine grained matrix makes up approximately 50% of this meteorite.

Geochemistry: (C. Agee and N. Muttik, UNM) All olivine Fa25.7±18.2, Fe/Mn=98±41, n=38; ferroan chondrule olivine Fa28.5±17.0, Fe/Mn=105±37, Cr2O3=0.14±0.15 (wt%), n=34; enstatite Fs4.5±3.9Wo2.4±1.5, n=10; diopside Fs3.1±3.8Wo38.6±8.6, n=6

Classification: Carbonaceous chondrite (CO3.1), type 3.1 based on mean value and sigma of Cr2O3 in ferroan olivine (Grossman and Brearley, 2005), the values are midway between Colony (CO3.0) and Rainbow (CO3.2).

Specimens: 25.0 g including a probe mount on deposit at UNM, Aziz Habibi 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:
  MB105
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2013
Mass (g):614.6
Pieces:1
Class:CO3.1
Shock stage:low
Weathering grade:low
Fayalite (mol%):25.7±18.2
Ferrosilite (mol%):4.5±3.9
Wollastonite (mol%):2.4±1.5
Classifier:C. Agee, UNM
Type spec mass (g):25
Type spec location:UNM
Main mass:Aziz Habibi
Comments:Field name AH120; 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)
Catalogs:
References: Published in Meteoritical Bulletin, no. 105, MAPS 52, 2411, September 2017. http://onlinelibrary.wiley.com/doi/10.1111/maps.12944/full
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7328 approved meteorites from (Northwest Africa) (plus 1973 unapproved names)

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