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Northwest Africa 8154
Basic information Name: Northwest Africa 8154
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 8154
Observed fall: No
Year found: 2005
Country: (Northwest Africa)
Mass:help 5.3 kg
Classification
  history:
Meteoritical Bulletin:  MB 102  (2013)  Iron, ungrouped
MB 104  (2015)  Iron, IAB-ung
Recommended:  Iron, IAB-ung    [explanation]

This is 1 of 56 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
Writeuphelp
Writeup from MB 102:

Northwest Africa 8154 (NWA 8154)

(Northwest Africa)

Purchased: 2005

Classification: Iron meteorite (ungrouped)

History: The iron was purchased from Greg Hupé in 2005.

Petrography: Compositionally anomalous iron with an anomalous structure. Weathering is minor. 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.

Geochemistry: (J. T. Wasson, UCLA) Composition by INAA (Mean of two analyses): 4.74 mg/g Co, 133 mg/g Ni, 52.7 μg/g Ga, 218 μg/g Ge, 16.2 μg/g As, 24.4 μg/g Ir, and 1.57 μg/g Au. Has high Cu (559 μg/g) and Sb (604 ng/g).

Classification: This iron has no close relatives. The seven ungrouped irons with Ga in the range 46 to 57 μg/g have very different Ni and, with two exceptions, very different Co contents. The 15 ungrouped irons with Co contents in the range 4.52 to 4.94 mg/g all have very different Ni contents and, with the exception of Etosha, very different Ga contents.

Specimens: 113 g at UCLA.


Writeup from MB 105:
NWA 8154, 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:
Place of purchase:Greg Hupé
Date:P 2005
Mass (g):5300
Pieces:1
Class:Iron, ungrouped
Weathering grade:low
Classifier:J. T. Wasson, UCLA
Type spec mass (g):113
Type spec location:UCLA
Main mass:JUtas
Comments:Submitted by J. T. Wasson
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)
JUtas: Jason Utas, United States (private address; updated 8 Jun 2010)
Catalogs:
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
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6900 approved meteorites from (Northwest Africa) (plus 2027 unapproved names)

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