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Northwest Africa 12922
Basic information Name: Northwest Africa 12922
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12922
Observed fall: No
Year found: 2019
Country: (Northwest Africa)
Mass:help 20.3 g
Classification
  history:
Recommended:  CK6    [explanation]

This is 1 of 58 approved meteorites classified as CK6.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (equilibrated), CK chondrites, CK chondrites (type 4-6), and CV-CK clan chondrites
Comments: Approved 21 Nov 2019
Writeuphelp
Writeup from MB 108:

Northwest Africa 12922 (NWA 12922)

(Northwest Africa)

Purchased: 2019

Classification: Carbonaceous chondrite (CK6)

History: A single stone weighing 20.3 g was found in Western Sahara prior to 2019. The sample was purchased by John Sinclair and J. Donald Cline at the Tucson Gem and Mineral show in 2019.

Physical characteristics: Sample is dark grayish-black in color, and has a weakly tabular shape. The sample is partially covered in a weathered black fusion crust with contraction cracks. A cut face shows the interior is composed of a dark brownish assemblage of rounded chondrules set within a dark matrix.

Petrography: Description and classification (A. Love, App): Sample shows a recrystallized chondritic texture composed of indistinct chondrules set within a recrystallized, olivine-dominated, opaque-rich matrix. Porphyritic and granular olivine chondrules have an average diameter of 672 μm Additional minerals are: low-Ca pyroxene, pigeonite, Ca-pyroxene, Cr-bearing magnetite, zoned plagioclase feldspar, rare troilite and rare alkali feldspar.

Geochemistry: (A. Love, App): Olivine (Fa30.5±0.3, Fe/Mn=93.1±2.6, NiO=0.4±0.0, n=10); low Ca pyroxene (Fs26.7±1.4Wo1.7±1.6 (Fs24.5-3.2Wo0.5-4.8), Fe/Mn=61.9±4.2, n=6); pigeonite (Fs22.1±0.7Wo12.9±2.7 (Fs21.3-22.7Wo9.8-14.8), Fe/Mn=58.2±2.2, n=3); Ca pyroxene (Fs10.6Wo42.1, n=1); plagioclase: (An43.9±10.4Or3.2±2.2, n=5); Cr-Magnetite contains 4.2Wt% Cr2O3.

Classification: Carbonaceous Chondrite (CK6 C-S2 W3). Chondrule size, magnetic susceptibility, Cr-bearing magnetite and Fe/Mn of olivine and pyroxene are consistent with CK. Equilibrated compositions of olivine, indistinct, yet visible chondrules and size of plagioclase grains (>100µm) characterize this sample as CK6.

Specimens: PARI holds the main mass. A polished thin section and endcut weighing 4.1 g are on deposit at App.

Data from:
  MB108
  Table 0
  Line 0:
Place of purchase:Tucson Gem and Mineral Show
Date:P 2019
Mass (g):20.3
Pieces:1
Class:CK6
Shock stage:C-S2
Weathering grade:W3
Fayalite (mol%):30.5±0.3
Ferrosilite (mol%):26.7±1.4; 22.1±0.7; 10.6
Wollastonite (mol%):1.7±1.6; 12.9±2.7; 42.1
Magnetic suscept.:4.59
Classifier:A. Love, App
Type spec mass (g):4.1
Type spec location:App
Main mass:PARI
Finder:Unknown
Comments:Submitted by Anthony Love
Institutions
   and collections
App: Department of Geology, 572 Rivers St., Appalachian State University, Boone, NC 28608, United States (institutional address; updated 7 Mar 2013)
PARI: Pisgah Astronomical Research Institute 1 Pari Dr Rosman, NC 28772, United States (institutional address; updated 13 Sep 2016)
Catalogs:
References: Published in Meteoritical Bulletin, no. 108, in preparation (2019)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7048 approved meteorites from (Northwest Africa) (plus 1998 unapproved names)

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