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Northwest Africa 12273
Basic information Name: Northwest Africa 12273
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12273
Observed fall: No
Year found: 2018
Country: (Northwest Africa)
Mass:help 280 g
Meteoritical Bulletin:  MB 107  (2018)  Chondrite-ung
Recommended:  Chondrite-ung    [explanation]

This is 1 of 22 approved meteorites classified as Chondrite-ung.   [show all]
Search for other: Ungrouped chondrites
Comments: Approved 11 Dec 2018
Writeup from MB 107:

Northwest Africa 12273 (NWA 12273)

(Northwest Africa)

Purchased: 2018

Classification: Ungrouped chondrite

History: Purchased by Jay Piatek from a Moroccan meteorite dealer on October 25, 2018.

Physical characteristics: Dense, single individual. Fusion crust absent; abundant bright metal; scattered small chondrules are visible.

Petrography: (C. Agee, UNM) This meteorite consists of approximately 75% metal in the form of kamacite (~90%) and taenite (~10%) grains, diameters ranging from 50-500 μm. Minor troilite was observed throughout. Silicates occur primarily in the form of chondrules, most are porphyritic, diameters in the range 100-500 μm, making up approximately 20% of this meteorite.

Geochemistry: (C. Agee) Olivine Fa26.2±3.3, Fe/Mn=55±5, n=29; low-Ca pyroxene Fs15.3±1.8Wo0.7.±0.2, Fe/Mn=23±2, n=11. Oxygen isotopes (K. Ziegler, UNM): 3 acid-washed fragments analyzed by laser fluorination gave δ18O= 5.258, 5.613, 7.249; δ17O= 3.939, 3.971, 4.786; Δ17O= 1.163, 1.007, 0.959 (linearized, all per mil, TFL slope=0.528).

Classification: Ungrouped chondrite. This is a metal-rich chondrite with oxygen isotopes that overlap with LL-chondrites. The olivine Fa content is consistent with L3, however the low-Ca pyroxene Fs is consistent with H4. The high metal content is inconsistent with ordinary chondrite. Texturally, this meteorite resembles a CB-b, however the oxygen isotopes and Fa and Fs are unlike CB chondrites.

Specimens: 23.2 g including a probe mount on deposit at UNM, Jay Piatek holds the main mass of 240 g.

Data from:
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2018
Mass (g):280
Shock stage:low
Weathering grade:low
Fayalite (mol%):26.2±3.3
Ferrosilite (mol%):15.3±1.8
Wollastonite (mol%):0.7±0.2
Classifier:C. Agee, UNM
Type spec mass (g):23.2
Type spec location:UNM
Main mass:Jay Piatek
Comments:Field name ZF-1; submitted by C. Agee
Plots: O isotopes:  
   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)
References: Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462
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Public domain photographs:
Carl Agee         

     This is 1 of 9765 approved meteorites from (Northwest Africa) (plus 1865 unapproved names)

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