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Northwest Africa 6342
Basic information Name: Northwest Africa 6342
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 6342
Observed fall: No
Year found: 2010
Country: Algeria
Mass:help 72.2 g
Meteoritical Bulletin:  MB 99  (2011)  Martian (shergottite)
Recommended:  Martian (shergottite)    [explanation]

This is 1 of 326 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite).   [show all]
Search for other: Martian meteorites
Comments: Approved 30 Dec 2010
Writeup from MB 99:

Northwest Africa 6342 (NWA 6342)


Purchased: Apr 2010

Classification: Shergottite

History: A small stone was found in Algeria in April 2010 and purchased by Darryl Pitt.

Physical characteristics: A single, dense, unweathered stone (72.2 g), with patches of black fusion crust. The interior is mostly dark grey-green with irregular pale green patches and minor interstitial areas containing microvesicles.

Petrography: (A. Irving and S. Kuehner, UWS; T. Bunch and J. Wittke, NAU): The specimen is texturally heterogeneous. Some domains exhibit poikilitic texture whereas others do not. Poikilitic domains consist of oikocrysts of pyroxene (mostly pigeonite with some augite) enclosing olivine chadacrysts, with accessory Mg-bearing merrillite, feldspathic intercumulus material, Ti-bearing chromite, ilmenite, pentlandite and pyrrhotite. Feldspathic material (~5 vol.%) occurs in pockets interstitial to mafic silicates, and consists of vesicular glass of intermediate plagioclase composition containing thin, subparallel to fanning, acicular crystals of pigeonite, ilmenite, merrillite, olivine and sulfides (indicative of rapid quenching).

Geochemistry: Olivine (Fa31.4-34.6, FeO/MnO = 42.0-56.1), pigeonite (Fs17.4Wo5.5 to Fs25.6Wo9.0, FeO/MnO = 24.6-31.7), subcalcic augite (Fs15.4-26.1Wo32.3-31.2, FeO/MnO = 24.0), plagioclase glass (An48.3-55.2Or1.5-0.6), chromite (Cr/(Cr+Al) = 0.86-0.91). Oxygen isotopes (D. Rumble, CIW): acid-washed material analyzed in replicate by laser fluorination gave, respectively δ18O = 4.08, 3.97; δ17O = 2.44, 2.38; Δ17O = 0.292, 0.288 per mil. Bulk composition (C. Herd, ICPMS, UAb): duplicate analyses of representative powder prepared from clean wire-saw cutting dust gave the following elemental abundances (in ppm): Cr 3940, Ni 4030, La 0.77, Ce 1.89, Nd 1.50, Sm 0.66, Yb 0.62, Lu 0.09, Hf 0.69.

Classification: Achondrite (Martian, shergottite, ultramafic).

Specimens: 14.5 g of type material, one polished thin section and one polished thick section are on deposit at UWS. The main mass is held by DPitt.

Data from:
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P Apr 2010
Mass (g):72.2
Fayalite (mol%):31.3-34.6
Ferrosilite (mol%):17.4-25.6; 15.4-26.1
Wollastonite (mol%):5.5-9.0; 32.3-31.2
Classifier:A. Irving and S. Kuehner; T. Bunch and J. Wittke
Type spec mass (g):14.5
Type spec location:UWS
Main mass:DPitt
Comments:Submitted by A. Irving
Plots: O isotopes:  
   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)
UAb: 1-26 Earth Sciences Building, University of Alberta, Edmonton, AB, T6G 2E3, Canada, Canada; Website (institutional address; updated 17 Oct 2011)
CIW: Carnegie Insitution Washington, Geophysical Laboratory, 5251 Broad Branch Rd., NW, Washington DC 20015, United States (institutional address)
DPitt: Darryl Pitt, 225 West 83rd Street, New York, NY 10024, United States; Website (private address)
NAU: Geology, Bldg 12 Knoles Dr Northern Arizona University, Flagstaff, AZ 86011, United States (institutional address; updated 12 Apr 2012)
References: Published in Meteoritical Bulletin, No. 99, April 2012, MAPS 47, E1-E52 (2012) [published online only]
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     This is 1 of 1374 approved meteorites from Algeria (plus 31 unapproved names) (plus 4 impact craters)

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