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Northwest Africa 8257 | |||||||||||||||||||||||||||||||||
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Basic information | Name: Northwest Africa 8257 This is an OFFICIAL meteorite name. Abbreviation: NWA 8257 Observed fall: No Year found: 2013 Country: (Northwest Africa) Mass: ![]() | ||||||||||||||||||||||||||||||||
Classification history: |
This is 1 of 9 approved meteorites classified as L3.15. [show all] Search for other: L chondrites, L chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3) | ||||||||||||||||||||||||||||||||
Comments: |
Approved 10 Dec 2015 Revised 23 Jun 2019: subtype added | ||||||||||||||||||||||||||||||||
Writeup![]() |
Writeup from MB 104:
Northwest Africa 8257 (NWA 8257) (Northwest Africa) Purchased: 2013 Dec Classification: Ordinary chondrite (L3) History: Purchased by Darryl Pitt in December 2013 from a dealer in Erfoud, Morocco. Petrography: (A. Irving and S. Kuehner, UWS) Closely packed, well-formed, glass-bearing chondrules are set in a sparse finer grained matrix. Geochemistry: Olivine (Fa0.5-72.9; Cr2O3 in ferroan examples ranges from 0.06-0.52 wt.%, mean 0.18±0.17 wt.%, N = 13), orthopyroxene (Fs2.2-19.9Wo0.3-4.9, N = 3), subcalcic augite (Fs10.9Wo35.9; Fs22.3Wo24.9). Oxygen isotopes (K. Ziegler, UNM): analyses of three acid-washed subsamples by laser fluorination gave, respectively, δ17O 2.950, 3.615, 3.246; δ18O 4.356, 4.840, 4.723; Δ17O 0.650, 1.059, 0.752 per mil. Classification: Ordinary chondrite (L3). The wide range in Fa content in olivine coupled with the range of Cr content in ferroan olivine imply a very low subtype <3.2. Specimens: 38 g including one polished thin section at UWB; the remainder is held by DPitt. Writeup from MB 108: NWA 8257: petrologic subtype
J. Boesenberg, Brown, and S. Kuehner, UWS, find that NWA 8257 has a Cr2O3 content of ferroan olivine of 0.04-1.02 wt.%, mean 0.22±0.24 wt.%, N = 30. The range and mean of Cr content in ferroan olivine is consistent with a subtype of 3.15 (per Grossman and Brearley, 2005, Fig. 15a). | ||||||||||||||||||||||||||||||||
Bibliography: |
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Data from: MB104 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. 104, MAPS 52, 2284, Octover 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12930/full Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150
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Geography: |
Statistics: This is 1 of 9305 approved meteorites from (Northwest Africa) (plus 1873 unapproved names) |