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Northwest Africa 8155 | |||||||||||||||||||||||
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Basic information | Name: Northwest Africa 8155 This is an OFFICIAL meteorite name. Abbreviation: NWA 8155 Observed fall: No Year found: 2011 Country: (Northwest Africa) Mass: 208 g | ||||||||||||||||||||||
Classification history: |
This is 1 of 68 approved meteorites classified as Iron, IAB-ung. [show all] Search for other: IAB complex irons, Iron meteorites, and Metal-rich meteorites | ||||||||||||||||||||||
Comments: |
Approved 2 Jan 2014 Revised 21 May 2016: Reclassification | ||||||||||||||||||||||
Writeup |
Writeup from MB 102:
Northwest Africa 8155 (NWA 8155) (Northwest Africa) Purchased: 2011 Classification: Iron meteorite (ungrouped) History: The iron was purchased from Greg Hupé in 2005. Petrography: This compositionally anomalous iron also has an anomalous structure. Metal consists of tiny crystals, ~0.2 × 0.05 mm in size. There is no recognizable octahedral structure. A striking feature are the grape-like clusters of graphite ellipsoids ("graphite flowers") with long axes of 1.0 to 0.4 mm. In the ~13 cm2 section are two circular troilites (0.8 and 1.0 mm long axis), a schreibersite needle 1.8 × 0.25 mm surrounded by thin kamacite and schreibersite around a cavity, probably originally filled with troilite. Weathering is minor. Geochemistry: (J. T. Wasson, UCLA) Composition by INAA: 4.75 mg/g Co, 133 mg/g Ni, 52.0 μg/g Ga, 218 μg/g Ge, 16.2 μg/g As, 24.4 μg/g Ir, and 1.57 μg/g Au. Has very high Cu (598 mg/g) and Sb (650 ng/g). Single analysis. Classification: This iron is likely paired with NWA 8154. The structural and compositional properties are the same within the uncertainties. Specimens: 27.2 g at UCLA. Writeup from MB 105: NWA 8155, reclassification
(J.T. Wasson, UCLA): Based on their high contents of Au, As and Sb, NWA 8154, NWA 8155, and their paired siblings (e.g., NWA 8539) are reclassified as ungrouped members of the IAB complex; non-IAB ungrouped irons have lower contents of these elements (especially Sb). They are ungrouped members of the IAB complex because they do not consistently plot in the Ni-Au, As-Au, Co-Au and Ga-Au fields of the IAB main group or of the five IAB subgroups | ||||||||||||||||||||||
Data from: MB102 Table 0 Line 0: |
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Institutions and collections |
UCLA: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA 90095-1567, United States (institutional address; updated 17 Oct 2011) Labenne: 23, rue de Esperance, 75013 Paris, France; Website (private address; updated 29 Aug 2012) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015 Published in Meteoritical Bulletin, no. 105, MAPS 52, 2411, September 2017. http://onlinelibrary.wiley.com/doi/10.1111/maps.12944/full
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Geography: |
Statistics: This is 1 of 9589 approved meteorites from (Northwest Africa) (plus 1869 unapproved names) | ||||||||||||||||||||||
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Revision history: |
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