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Northwest Africa 2999
Basic information Name: Northwest Africa 2999
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 2999
Observed fall: No
Year found: 2004
Country: (Northwest Africa)
Mass:help 392 g
Meteoritical Bulletin:  MB 90  (2006)  Angrite
Recommended:  Angrite    [explanation]

This is 1 of 51 approved meteorites classified as Angrite.   [show all]
Search for other: Achondrites, Angrites
Comments: Approved 16 Jan 2006
Revised 3 Feb 2006: Revised writeup
Writeup from MB 90:

Northwest Africa 2999

Morocco or Algeria

Find: 2004

Achondrite (angrite)

History: Twelve individual dark brown stones totaling 392 g, each with a thin fusion crust, were purchased from a Moroccan dealer in Tagounite by G. Hupé in August 2004.

Physical Characteristics: Grain size is predominantly from 0.1 to 0.5 mm, but all stones have irregularly distributed, larger yellowish plagioclase grains (up to 6 mm across) exhibiting an iridescent luster.

Petrography: (A. Irving and S. Kuehner, UWS; T. Bunch and J. Wittke, NAU) Based upon examination of thin sections of all separate stones, this meteorite is texturally heterogeneous. Terrestrial weathering has resulted in partial replacement of metal and minor grain boundary staining by iron hydroxides. The overall texture is protogranular, but there are large porphyroclasts of anorthite, spinel, and polygranular olivine. Anorthite also occurs as narrow (10–20 µm wide) coronas around spinel grains adjacent to clinopyroxene and both spinel and diopside are compositionally zoned away from the coronas. Texturally, this meteorite is very different from most angrites.

Geochemistry: The major minerals are Ca-rich olivine (Fa39.8–41.0; FeO/MnO = 77–97; CaO = 0.6–1.3 wt%), Al,Ti-bearing diopside (Fs9.6–11.3Wo53–54; FeO/MnO = 55–130; Al2O3 = 5–9, TiO2 = 0.5–2.4 [both wt%]), minor Cr-pleonaste spinel (Mg/(Mg+Fe) = 0.44–0.47, Al2O3 = 55–60, Cr2O3 = 4.7–8.7 [both wt%]), pure anorthite (containing Na2O < 0.02 wt%), and kamacite, troilite, and S-bearing calcium silicophosphate. Oxygen isotopes: (D. Rumble, CIW) Triplicate analyses of acid-washed whole rock samples by laser fluorination gave, respectively, δ18O = 3.839, 4.093, 4.154; δ17O = 1.974, 2.054, 2.095; ∆17O = −0.041, −0.095, −0.086 (all ‰).

Classification: Achondrite (angrite).

Specimens: A 22 g type specimen and one polished thin section are on deposit at NAU. Three polished thin sections are on deposit at UWS. GHupé holds the main mass.

Data from:
  Table 2
  Line 191:
Place of purchase:Tagounite, Morocco
Date:Aug 2004
Mass (g):392
Type spec mass (g):22
Plots: O isotopes:  
   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)
CIW: Carnegie Insitution Washington, Geophysical Laboratory, 5251 Broad Branch Rd., NW, Washington DC 20015, United States (institutional address)
GHupé: Gregory M. Hupé, 9003 Placid Lakes Blvd., Lake Placid, FL 33852, United States; Website (private address)
References: Published in Meteoritical Bulletin, no. 90, MAPS 41, 1383-1418 (2006)
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Photos from the Encyclopedia of Meteorites:
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     This is 1 of 9699 approved meteorites from (Northwest Africa) (plus 1854 unapproved names)

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