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Northwest Africa 2993
Basic information Name: Northwest Africa 2993
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 2993
Observed fall: No
Year found: 2006
Country: (Northwest Africa)
Mass:help 625 g
Classification
  history:
Meteoritical Bulletin:  MB 91  (2007)  Achondrite-ung
Recommended:  Achondrite-ung    [explanation]

This is 1 of 88 approved meteorites classified as Achondrite-ung.   [show all]
Search for other: Achondrites, Ungrouped achondrites
Comments: Approved 28 Mar 2007
Writeuphelp
Writeup from MB 91:

Northwest Africa 2993

Algeria

Find: 2006

Achondrite (ungrouped)

History and physical characteristics: A fully crusted, complete stone of 625 g was recovered from the lower Algerian desert in June 2006 and purchased in Erfoud in August 2006 by A. Aaronson.

Petrography: (T. Bunch and J. Wittke, NAU; A. Irving, UWS) Protogranular texture with a grain size range of 0.3– 3.4 mm (mean = 1.35 mm) for silicates and 0.3–5 mm for metal (mean = 2.4 mm). Modal analyses (6.4 cm2; vol%): orthopyroxene, 37; olivine, 32; metal, 30; sulfide, 1. Several metal grains have taenite cores mantled by kamacite. Taenite grain shape is roughly similar to the outline of the entire metal grain; embryonic plessite is evident in a few taenite cores. No directional fabric was recognized. Fusion crust is lightly to moderately altered and weathering is limited to minor oxidation of kamacite with the presence of minor oxide veining.

Mineral compositions and geochemistry: Olivine (Fa12.3±0.2; FeO/MnO=32), orthopyroxene (Fs11.2±0.02Wo1.2; FeO/MnO = 19), kamacite (Ni = 4.6 wt%). Oxygen isotopes: (D. Rumble, CIW) A cleaned and metal-free sample was analyzed by laser fluorination. Replicate analyses are respectively, δ17O = 1.129, 1.220; δ18O = 2.527, 2.661; Δ17O = −0.2006, −0.1802 (all ‰).

Classification: Achondrite (ungrouped). Petrography and geochemistry are consistent with lodranites; oxygen isotopes are inconsistent with lodranites/acapulcoites and are closest to the IAB irons and winonaite trend.

Type specimen: 20.3 g and one polished thin section are on deposit at NAU. The main mass holder is anonymous.

Data from:
  MB91
  Table 2
  Line 145:
Place of purchase:Erfoud, Morocco
Date:2006
Mass (g):625
Pieces:1
Class:Aung
Weathering grade:minimal
Fayalite (mol%):12.3 ± 0.2
Classifier:T. Bunch and J. Wittke, NAU and A. Irving, UWS
Type spec mass (g):20.3
Type spec location:NAU
Main mass:anonymous
Plots: O isotopes:  
Institutions
   and collections
NAU: Geology, Bldg 12 Knoles Dr Northern Arizona University, Flagstaff, AZ 86011, United States; Website (institutional address; updated 12 Apr 2012)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
Aaronson: Sahara Overland Ltd., Harhora, Temara, 12000, Morocco (private address; updated 3 Jan 2010)
CIW: Carnegie Insitution Washington, Geophysical Laboratory, 5251 Broad Branch Rd., NW, Washington DC 20015, United States (institutional address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 91, MAPS 42, 413-466 (2007)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7035 approved meteorites from (Northwest Africa) (plus 2000 unapproved names)

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