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Northwest Africa 8656 | |||||||||||||||||||||||||||||
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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: ![]() | ||||||||||||||||||||||||||||
Classification history: |
This is 1 of 293 approved meteorites (plus 2 unapproved names) classified as Martian (shergottite). [show all] Search for other: Martian meteorites | ||||||||||||||||||||||||||||
Comments: | Approved 29 Nov 2014 | ||||||||||||||||||||||||||||
Writeup![]() |
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: |
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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) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 103, MAPS 52, 1014, May 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12888/full
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Geography: |
Statistics: This is 1 of 9116 approved meteorites from (Northwest Africa) (plus 1873 unapproved names) |