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Northwest Africa 15307
Basic information Name: Northwest Africa 15307
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 15307
Observed fall: No
Year found: 2022
Country: (Northwest Africa)
Mass:help 67 g
Classification
  history:
Recommended:  Ureilite-an    [explanation]

This is 1 of 7 approved meteorites classified as Ureilite-an.   [show all]
Search for other: Achondrites, Ureilites
Comments: Approved 12 Nov 2022
Writeuphelp
Writeup from MB 111:

Northwest Africa 15307 (NWA 15307)

(Northwest Africa)

Purchased: 2022 Feb

Classification: Ureilite (anomalous)

History: Purchased by Shun-Chung Yang in February 2022 from a dealer in Tindouf, Algeria.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Protogranular aggregate composed predominantly of olivine with subordinate very low-Ca pyroxene and minor clinopyroxene (pigeonite and subcalcic augite) plus accessory kamacite and interstitial graphite. Olivine grains (up to 0.9 mm across) do not exhibit any reduced rims, but are mantled by narrow zones of kamacite plus Fe oxides. Grains of both olivine and orthopyroxene consist internally of multiple, small polygonal subgrains delineated by very thin coatings of Fe oxides. Olivine compositions range widely but are not distributed in any regular pattern.

Geochemistry: Olivine (Fa9.6-21.3, CaO 0.15-0.28 wt.%, Cr2O3 0.29-0.61 wt.%, N = 6), orthopyroxene (Fs3.6-8.8Wo1.0-4.0, Al2O3 0.39-0.90 wt.%, Cr2O3 0.36-0.64 wt.%, TiO2 0,06-0.07 wt.%, N = 3), pigeonite (Fs6.4Wo6.2, Al2O3 0.15 wt.%, Cr2O3 0.83 wt.%, TiO2 0.06 wt.%), subcalcic augite (Fs6.3Wo32.1).

Classification: Ureilite (anomalous). The polycrystalline olivine grains in this specimen, although ranging in composition to relatively magnesian values, do not exhibit the characteristic magnesian reduced rims and associated Fe metal blebs typically present in ureilites. In addition the majority of low-Ca pyroxene is very Ca-poor and is probably orthopyroxene, whereas clinopyroxene (pigeonite and subcalcic augite) is only a minor component.

Specimens: 13.5 g including one polished thick section at UWB; remainder with Mr. S.-C. Yang.

Data from:
  MB111
  Table 0
  Line 0:
Place of purchase:Tindouf
Date:P 2022 Feb
Mass (g):67
Pieces:1
Class:Ureilite-an
Shock stage:high
Weathering grade:moderate
Fayalite (mol%):9.6-21.3
Ferrosilite (mol%):3.6-8.8; 6.3
Wollastonite (mol%):1.0-6.2; 32.1
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):13.5
Type spec location:UWB
Main mass:S.-C. Yang
Comments:Work name SCY-70; submitted by A. Irving
Institutions
   and collections
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
WUSL: Washington Univ., One Brookings Drive, St. Louis, MO 63130, United States (institutional address; updated 17 Oct 2011)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
Catalogs:
References: Published in Meteoritical Bulletin, no. 111, in preparation (2022)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 8746 approved meteorites from (Northwest Africa) (plus 1879 unapproved names)

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