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Northwest Africa 7325
Basic information Name: Northwest Africa 7325
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 7325
Observed fall: No
Year found: 2012
Country: (Northwest Africa)
Mass:help 345 g
Classification
  history:
Recommended:  Achondrite-ung    [explanation]

This is 1 of 64 approved meteorites classified as Achondrite-ung.   [show all]
Search for other: Achondrites, Ungrouped achondrites
Comments: Approved 18 Dec 2012
Writeuphelp
Writeup from MB 101:

Northwest Africa 7325 (NWA 7325)

(Northwest Africa)

Purchased: 2012 Apr

Classification: Ungrouped achondrite

History: Purchased by Stefan Ralew in April 2012 from a dealer in Erfoud, Morocco. The material was found reportedly in southern Morocco in early 2012.

Physical characteristics: A group of 35 very fresh, dark greenish stones (total 345 g), several of which have partial remnant chartreuse-colored fusion crust. This material is notable for the characteristic "frosty" luster of the plagioclase and bright green color of the clinopyroxene.

Petrography: (A. Irving and S. Kuehner, UWS): The studied specimen has an overall plutonic igneous (possibly cumulate) texture. It is a medium-grained aggregate of Al-Cr-bearing diopside, calcic plagioclase and lobate (possibly resorbed) grains of forsterite, with accessory Cr-bearing iron sulfide (probably troilite), very sparse ferrochromite, kamacite and taenite, and rare eskolaite (associated with Cr-Fe sulfide). In thin section the untwinned plagioclase is birefringent, but the levels of birefringence are less than normal and variable on a fine scale (suggesting the existence of compositional and/or structural microdomains); there also are sparse vesicles (suggesting at least partial melting). The pyroxene exhibits at least two sets of polysynthetic twin lamellae, which resemble those produced by moderately high shock.

Geochemistry: Clinopyroxene (Fs1.1-2.6 Wo45.1-44.5, FeO/MnO = 12-21, Al2O3 = 2.6-2.8 wt.%, Cr2O3 = 1.0 wt.%), plagioclase (An88.1-89.2Or0.0), olivine (Fa2.7-2.8, FeO/MnO = 30-36, CaO = 0.27-0.32 wt.%, Cr2O3 = 0.32-0.35 wt.%). Bulk composition (G. Chen, UAb): analyses of representative bulk wire-saw cutting dust by ICP-MS gave: (in ppm) La 0.15, Ce 0.34, Nd 0.16, Sm 0.05, Eu 0.58, Gd 0.05, Hf 0.44, Th 0.27. Oxygen isotopes (K. Zeigler, UNM): laser fluorination analyses of acid-washed subsamples gave, respectively δ17O = 3.214, 3.670, 3.249; δ18O = 7.566, 8.204, 7.957; Δ17O = -0.781, -0.662, -0.952 per mil [for TFL slope of 0.528].

Classification: Achondrite (ungrouped). The combination of highly magnesian mafic silicates and highly calcic plagioclase with chromium-bearing sulfides is unique among achondrites, and the specimen is highly depleted in most trace elements.

Specimens: A total of 21 g of type material and one polished thin section are on deposit at UWB. The remaining material is held by Ralew.

Data from:
  MB101
  Table 0
  Line 0:
Place of purchase:Erfoud
Date:P 2012 Apr
Mass (g):345
Pieces:35
Class:Achondrite-ung
Shock stage:medium
Weathering grade:low
Fayalite (mol%):2.7-6.0
Ferrosilite (mol%):2.6
Wollastonite (mol%):44.5
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):21
Type spec location:UWB
Main mass:S. Ralew
Comments:Submitted by A. Irving
Plots: O isotopes:  
Institutions
   and collections
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 26 Dec 2011)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
UAb: 1-26 Earth Sciences Building, University of Alberta, Edmonton, AB, T6G 2E3, Canada, Canada; Website (institutional address; updated 17 Oct 2011)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
Ralew: Stefan Ralew, Kunibertstraße 29, 12524 Berlin, Germany; Website (private address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 101, MAPS 47, in preparation (2013)
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Find references in Google Scholar:
Photos:
CreditPhotos
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Denis gourgues         
Dominik Stoeckli   
Francois Pacaud   
Gregor H.   
Piotr gural100   
Steve Witt   
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 4403 approved meteorites from (Northwest Africa) (plus 2382 unapproved names)

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