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Northwest Africa 3171
Basic information Name: Northwest Africa 3171
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 3171
Observed fall: No
Year found: 2004
Country: Algeria
Mass:help 506 g
Meteoritical Bulletin:  MB 89  (2005)  Martian (shergottite)
MetBase:  v. 7.1  (2006)  Shergottite-basaltic
Recommended:  Martian (shergottite)    [explanation]

This is 1 of 329 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite).   [show all]
Search for other: Martian meteorites
Writeup from MB 89:

Northwest Africa 3171


Purchased 2004 February

Martian meteorite (shergottite)

A 506 g broken, greenish-gray stone, believed to have been found in western Algeria, was purchased by A. Aaronson for DGregory (DGregory).  About half of the stone is coated by black fusion crust with flow orientation, and in addition there are some small, wart-like protrusions on several sides of the stone that appear to be localized concentrations of pyroxene coated with fusion crust.  Classification and mineralogy (A. Irving and S. Kuehner, UWS; C. Herd, UAlberta): The sample consists of subequal amounts of intergrown prismatic, grayish-brown pyroxene and sparkling, glassy maskelynite.  Pyroxenes are zoned from cores of subcalcic augite (Fs19.3Wo33.1, FeO/MnO = 26.4)  and pigeonite (Fs29.9Wo12.1, FeO/MnO = 28.2) to pigeonite rims as ferroan as Fs72.9Wo9.8 (FeO/MnO = 39.9).  Plagioclase has been converted entirely to maskelynite and is compositionally inhomogeneous (An41.5Or3.7 - An54.4Or1.3).  Accessory phases are ulvöspinel, ilmenite, chlorapatite, Na-K-Al-Si-rich glass, silica (formerly stishovite, judging from radial cracks around some grains), merrillite, pyrrhotite and baddeleyite.  Rare barite and calcite probably are products of minor desert weathering.  Minor rusty staining around ulvöspinel grains and along thin, black fractures appears to be a complex mixture of fine-grained iron hydroxide and Si-Al-Ca-Mg-Cl-K-bearing phases, and possibly is a product of pre-terrestrial alteration (Irving et al., 2004a). This specimen is not obviously paired with any of the other four African olivine-free basaltic shergottites (Zagami, NWA 480, NWA 856 or NWA 1669).  Oxygen isotopes (T. Larson and F. Longstaffe, UWO): pyroxene d18O = +4.43 ± 0.06‰, d17O = +2.72 ± 0.0‰, D17O = +0.42 ± 0.03‰; maskelynite d18O = +4.69 ± 0.07‰, d17O = +2.82 ± 0.1‰, D17O = +0.38 ± 0.07‰. Specimens: type specimen, 22 g and four polished thin sections, UWS; main mass, DGregory.

Data from:
  Table 7
  Line 486:
Origin or pseudonym:Algeria
Mass (g):506
Classifier:A. Irving, UWS
Type spec mass (g):22
Main mass:Hupé
Plots: O isotopes:  
   and collections
UWO: University of Western Ontario, Department of Earth Sciences, BGS 1030, 1151 Richmond St. N, London, Ontario, Canada N6A 5B7, Canada; Website (institutional address; updated 26 Jun 2024)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
Aaronson: Sahara Overland Ltd., Harhora, Temara, 12000, Morocco (private address; updated 3 Jan 2010)
DGregory: David Gregory, 230 First Avenue, Suite 108, St. Thomas, Ontario N5R 4P5, Canada (private address)
References: Published in Meteoritical Bulletin, no. 89, MAPS 40, A201-A263 (2005)
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Photos from the Encyclopedia of Meteorites:
David Gregory   
The Hupe Collection   
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Gerald Armstrong   
MeteoriteCollector.org - FCOM - Russ Finney      


     This is 1 of 1376 approved meteorites from Algeria (plus 31 unapproved names) (plus 4 impact craters)

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