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Northwest Africa 4908
Basic information Name: Northwest Africa 4908
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 4908
Observed fall: No
Year found: unknown
Country: (Northwest Africa)
Mass:help 464 g
Meteoritical Bulletin:  MB 99  (2011)  Eucrite
Recommended:  Eucrite    [explanation]

This is 1 of 598 approved meteorites (plus 1 unapproved name) classified as Eucrite.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 27 Mar 2011
Writeup from MB 99:

Northwest Africa 4908 (NWA 4908)

(Northwest Africa)

Purchased: Prior to 2004

Classification: HED achondrite (Eucrite)

History: Believed by Thompson to have been originally found near Erfoud, Morocco. A portion of the sample was donated to Cascadia on May 3, 2004.

Physical characteristics: The sample is partly covered with a shiny black fusion crust; broken surfaces are gray or have a brown patina that appears to contain brownish-red dust. Cut surfaces show sharply-defined angular to subrounded gray clasts and more diffuse blue-gray clastic areas set in a buff-colored host.

Petrography: (A.Ruzicka and T.J. Schepker, Cascadia) Microscopic inspection reveals the buff areas to be microcrystalline and feldspathic, and the blue-grey areas to be feldspathic and cryptocrystalline to microcrystalline. Larger lithic and mineral clasts (<20% of the sample) are composed mainly of plagioclase and exsolved clinopyroxene, with lithic clasts composed of basalt.

Geochemistry: (A. Ruzicka and T.J. Schepker, Cascadia) Plagioclase has relatively uniform composition (Ab10.8±0.3An88.8±0.3Or0.5±0.1, n = 42) and exsolved pyroxene endmembers include orthopyroxene (Wo4.2±0.4En37.1±0.4Fs58.7±0.4, FeO/MnO = 31.4, n = 21) and augite (Wo41.1±1.1En30.3±0.3Fs28.5±1.0, FeO/MnO = 33.4, n = 5). Oxygen isotopes: (E. Martin and I. Bindeman, UOr) δ18O = 4.025, δ17O = 1.931, Δ17O = -0.183 (mean of two analyses). Replicate analyses of standards suggest ±0.080 per mil error on δ18O and ±0.027 per mil error on Δ17O.

Classification: Achondrite (Eucrite), crystalline melt breccia. Weathering is minor.

Specimens: A total of 22 g and 7 thin sections are on deposit at Cascadia. Thompson holds the main mass.

Data from:
  Table 0
  Line 0:
Place of purchase:Erfoud, Morocco
Date:P Prior to 2004
Mass (g):464
Shock stage:high
Weathering grade:low
Ferrosilite (mol%):58.7, 28.5
Wollastonite (mol%):4.2, 41.1
Classifier:A. Ruzicka, T.J. Schepker
Type spec mass (g):22.0
Type spec location:Cascadia
Main mass:Thompson
Comments:Field number CML0209..; submitted by A. Ruzicka
Plots: O isotopes:  
   and collections
Cascadia: Cascadia Meteorite Laboratory, Portland State University, Department of Geology, Room 17 Cramer Hall, 1721 SW Broadway, Portland, OR 97201, United States; Website (institutional address; updated 28 Oct 2011)
Thompson: Edwin Thompson, 5150 Dawn St., Lake Oswego, OR 97035, United States (private address)
UOr: Department of Geological Sciences, 1272 University of Oregon, Eugene, OR 97403, United States (institutional address; updated 1 Oct 2010)
References: Published in Meteoritical Bulletin, No. 99, April 2012, MAPS 47, E1-E52 (2012) [published online only]
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     This is 1 of 9689 approved meteorites from (Northwest Africa) (plus 1854 unapproved names)

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