|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: 1656 g
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|
Writeup from MB 103:
Northwest Africa 8656 (NWA 8656)
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.
UNM: Institute of Meteoritics
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)
|References:||Published in Meteoritical Bulletin, no. 103, in preparation (2014)|
This is 1 of 5323 approved meteorites from (Northwest Africa) (plus 2130 unapproved names)
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