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Northwest Africa 13218
Basic information Name: Northwest Africa 13218
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13218
Observed fall: No
Year found: 2014
Country: (Northwest Africa)
Mass:help 368 g
Classification
  history:
Recommended:  LL3.2    [explanation]

This is 1 of 21 approved meteorites classified as LL3.2.   [show all]
Search for other: LL chondrites, LL chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)
Comments: Approved 5 Apr 2020
Writeuphelp
Writeup from MB 109:

Northwest Africa 13218 (NWA 13218)

Northwest Africa

Purchased: 2014

Classification: Ordinary chondrite (LL3.2)

History: Purchased from Morocco November 2014.

Physical characteristics: Seven matching stones, dark brown weathered exterior, no fusion crust, sawn surface reveals densely packed chondrules of variable size.

Petrography: (C. Agee, UNM) Microprobe examination of a polished mount shows numerous unequilibrated chondrules, many are porphyritic, apparent mean diameter 625±330 μm n=24. Abundant opaque matrix, most chondrules with glass or mesostasis. Aluminous augite, Fe,Ni-metal, and sulfide present.

Geochemistry: (C. Agee, UNM) Chondrule olivine Fa17.2±9.2, Fe/Mn=52±19, Cr2O3=0.13±0.13 wt%, range Cr2O3=0.02-0.70 wt%, CaO=0.08±0.07 wt%, n=31; low-Ca pyroxene Fs9.7±8.7Wo0.6±0.4, Fe/Mn=20±19, n=6.

Classification: Ordinary chondrite (LL3.2), transitional between type 3.2 and 3.15 based on ferroan olivine mean Cr2O3 content and sigma from Grossman and Brearley (2005).

Specimens: 20.6 g on deposit at UNM, Larry Atkins 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:
  MB109
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2014
Mass (g):368
Pieces:7
Class:LL3.2
Shock stage:S1
Weathering grade:W2
Fayalite (mol%):17.2±9.2
Ferrosilite (mol%):9.7±8.7; 12.2±7.9
Wollastonite (mol%):0.6±0.4; 33.4±7.3
Classifier:C. Agee, UNM
Type spec mass (g):20.6
Type spec location:UNM
Main mass:Larry Atkins
Comments:Field name LA-103; submitted by C. Agee, UNM
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. 109, in preparation (2020)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7472 approved meteorites from (Northwest Africa) (plus 1988 unapproved names)

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