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Northwest Africa 2828
Basic information Name: Northwest Africa 2828
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 2828
Observed fall: No
Year found: 2005
Country: (Northwest Africa)
Mass:help 8.67 kg
Classification
  history:
Meteoritical Bulletin:  MB 91  (2007)  Aubrite
Recommended:  Aubrite    [explanation]

This is 1 of 70 approved meteorites classified as Aubrite.   [show all]
Search for other: Achondrites, Aubrites, Enstatite achondrites, and Enstatite-rich meteorites
Comments: Approved 11 Jun 2006
Writeuphelp
Writeup from MB 91:

Northwest Africa 2828

Mauritania or Algeria

Find: December 2005

Achondrite (aubrite)

History: Purchased in December 2005 by Greg Hupé from a Moroccan dealer in Tagounite.

Physical characteristics: Thirty-six pale gray to whitish stones lacking fusion crust with a total weight of 8672 g. Several stones have exterior light orange staining, and two stones contain one or two dark brown cross-cutting veins (1–2 mm wide) of magnetic, fine-grained iron oxide and hydroxide minerals.

Petrography: (A. Irving and S. Kuehner, UWS) Monomict microbreccia, which is mostly fairly uniform but contains sporadic small, rounded clasts (up to 4 mm across). Relatively fine but variable grain size (0.3–1.5 mm), and composed predominantly of bladed grains of essentially pure enstatite (exhibiting lamellar twinning) with ~15 vol% oligoclase, accessory altered troilite with fresh, subparallel exsolution blades of daubreelite, and sporadic rounded to ellipsoidal grains of graphite (up to 1.2 mm across). Small (<0.2 mm) lobate cavities partly filled with fine-grained calcite, silica, and an Fe-bearing mineral are present in the interior of even the freshest stones, and may represent former oldhamite grains. Small grains found as inclusions within enstatite are fresh Ti-free troilite, pure Mn-alabandite, daubreelite, fresh oldhamite (some Mn-bearing), schreibersite, and very rare specks of kamacite and taenite. Minor barite and calcite are present, probably the products of terrestrial weathering.

Mineral compositions and geochemistry: Pyroxene (En99.8Wo1.4; Al2O3 = 0.21 wt%), plagioclase (An13.5–15.3 Or3.0–4.4). Oxygen isotopes: (D. Rumble, CIW) Analyses of two whole-rock fragments by laser fluorination gave, respectively, δ18O = 5.50, 5.56; δ17O = 2.89, 2.90; Δ17O = +0.001, −0.026 (all ‰).

Classification: Achondrite (aubrite). Weathering effects in most stones are limited to alteration of interior troilite and probable oldhamite, and minor orange staining and dissolution on exterior surfaces. This aubrite appears to be completely different in appearance and texture from more metal-rich enstatite-rich meteorites NWA 002, NWA 1067, NWA 2736, and NWA 2965.

Type specimen: A total of 20.1 g and two polished thin sections are on deposit at UWS. GHupé; holds the main mass.

Data from:
  MB91
  Table 2
  Line 117:
Place of purchase:Tagounite, Morocco
Date:2005 Dec
Mass (g):8672
Pieces:6
Class:Aub
Classifier:T. Bunch and J. Wittke, NAU
Type spec mass (g):20
Type spec location:NAU
Main mass:Reed
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)
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)
Reed: Blaine Reed, P.O. Box 1141, Delta, CO 81416, United States; Website (private address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 91, MAPS 42, 413-466 (2007)
Find references in NASA ADS:
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Photos:
CreditPhotos
Photos from the Encyclopedia of Meteorites:
The Hupe Collection      
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
Alessandro Takeda   
David Hardy   
Gerald Armstrong   
Jay Piatek      
Jim K   
Krzysztof Nowak   
Michael S. Scherman   
Mike Markowitz   
Robert Zdancewicz   
Woreczko Jan & Wadi   
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6551 approved meteorites from (Northwest Africa) (plus 2022 unapproved names)

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