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Northwest Africa 8656
Basic information Name: Northwest Africa 8656
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 8656
Observed fall: No
Year found: 2014
Country: (Northwest Africa)
Mass:help 1656 g
Classification
  history:
Recommended:  Martian (shergottite)    [explanation]

This is 1 of 141 approved meteorites (plus 1 unapproved name) classified as Martian (shergottite).   [show all]
Search for other: Martian meteorites
Comments: Approved 29 Nov 2014
Writeuphelp
Writeup from MB 103:

Northwest Africa 8656 (NWA 8656)

Northwest Africa

Purchased: 2014 Jan

Classification: Martian meteorite (Shergottite)

History: Purchased by Darryl Pitt in January and February 2014 from a group of dealers in Mauritania.

Physical characteristics: Exterior mostly wind-ablated with a few remnant patches of dull black fusion crust. Cut interior surfaces are overall greenish-gray with clear, glassy maskelynite evident, and sporadically-distributed dark glass pockets and veinlets.

Petrography: (A. Irving and S. Kuehner, UWS) Diabasic texture. Complexly zoned, prismatically-twinned clinopyroxene (up to 3.5 mm long) and maskelynite laths (up to 1.6 mm long) are the major constitutents along with accessory ilmenite, ulvöspinel, pyrrhotite, merrillite and vesicular glass, plus very minor barite.

Geochemistry: Subcalcic augite (Fs22.6-26.9Wo34.3-26.0, FeO/MnO = 28-29, N = 4), ferroan subcalcic augite (Fs40.7-42.6Wo29.4-30.6, FeO/MnO = 33-36, N = 2; Fs58.5Wo23.6, FeO/MnO = 37), pigeonite (Fs38.1-45.8Wo13.8-15.5, FeO/MnO = 31-37, N = 2), ferropigeonite rims (Fs63.2-65.9Wo14.0-17.2, FeO/MnO = 35-40, N = 4), plagioclase (maskelynite) (An50.3-56.6Or2.9-1.5, N = 4). Oxygen isotopes (K. Ziegler, UNM): analyses of four acid-washed subsamples by laser fluorination gave, respectively, δ17O 2.772, 2.534, 2.623, 2.480; δ18O 4.692, 4.276, 4.417, 4.075; Δ17O 0.295, 0.276, 0.291, 0.328 (all values in per mil).

Classification: Martian (shergottite, diabasic). Likely paired with NWA 8657.

Specimens: 41.3g including two polished thin sections at UWB. The remaining material is held by DPitt.

Data from:
  MB103
  Table 0
  Line 0:
Place of purchase:Mauritania
Date:P 2014 Jan
Mass (g):1655.8
Pieces:several
Class:Martian (shergottite)
Shock stage:high
Weathering grade:low
Ferrosilite (mol%):22.6-26.9; 38.1-45.8
Wollastonite (mol%):34.3-26.0; 13.8-15.5
Classifier:A. Irving & S. Kuehner
Type spec mass (g):41.3
Type spec location:UWB
Main mass:D. Pitt
Comments:MAC 48; 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 12 Feb 2015)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
DPitt: Darryl Pitt, 225 West 83rd Street, New York, NY 10024, United States; Website (private address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 103, in preparation (2014)
Find references in NASA ADS:
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Photos:
CreditPhotos
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Emanuel Foglietto   
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 5323 approved meteorites from (Northwest Africa) (plus 2130 unapproved names)

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