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Northwest Africa 11549
Basic information Name: Northwest Africa 11549
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 11549
Observed fall: No
Year found: 2013
Country: (Northwest Africa)
Mass:help 24.6 g
Meteoritical Bulletin:  MB 106  (2018)  Eucrite
Recommended:  Eucrite    [explanation]

This is 1 of 608 approved meteorites (plus 1 unapproved name) classified as Eucrite.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 29 Dec 2017
Writeup from MB 106:

Northwest Africa 11549 (NWA 11549)

(Northwest Africa)

Purchased: 2013

Classification: HED achondrite (Eucrite)

History: Donated to Cascadia by Mr. John A. Shea, who purchased the sample in 2013 from Mr. Steve Witt who in turn had acquired the specimen in a lot of NWA meteorites from an unknown trader.

Physical characteristics: Remnant fusion crust and broken surfaces with light orange weathering patina visible on two pieces. Cut surfaces reveal light-gray interior with minimal weathering staining, including coarser portions and finer portions. Coarser areas are dominated by grey pyroxene and lighter colored plagioclase up to ~1 mm across

Petrography: Contains clasts rich in plagioclase and pyroxene with textures that range from ophitic to subpohitic to granular. Pyroxene grains sometimes show micron-scale exsolution lamellae. Minor weathering product.

Geochemistry: Bulk pigeonite Fs55.1±5.8Wo12.0±6.7, taken as average of all pyroxene with Wo5.5-35 (N=150), low-Ca pyroxene in fusion crust Fs48.4±3.0Wo4.3±0.6 (N=4); augite Fs37.1Wo35.3 (N=1); plagioclase An85.2±2.3Ab14.4±2.0 (N=91). Fusion crust glass (average of 14 analyses, wt. %): SiO2 47.4±0.6, TiO2 1.0±0.2, Al2O3 11.0±0.3, Cr2O3 0.25, FeO 20.6±0.4, MnO 0.69±0.1, MgO 6.8±0.1, CaO 9.9±0.4, Na2O 0.53±0.04, total 98.1±0.7.

Classification: Monomict eucrite based on texture and mineral composition. Composition of fusion crust glass, proxy for bulk rock composition, is similar to non-cumulate eucrites such as Juvinas

Specimens: Cascadia holds 2 pieces (5.7 g, 1.7 g), a polished thin section, and a potted butt. Mr. John A. Shea (201 East Rose Valley Rd, Wallingford PA, 19086) holds the main mass

Data from:
  Table 0
  Line 0:
Place of purchase:internet
Date:P 2013
Mass (g):24.6
Weathering grade:minor
Ferrosilite (mol%):55.1±5.8, 48.4±3.0, 37.1
Wollastonite (mol%):12.0±6.7, 4.3±0.6, 35.3
Classifier:A. Ruzicka, K. Bocian, N. Mishra, Cascadia
Type spec mass (g):7.4
Type spec location:Cascadia
Main mass:John A. Shea
Comments:Lab number CML0810; submitted by A. Ruzicka
   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)
References: Published in Gattacceca J., Bouvier A., Grossman J., Metzler K., and Uehara M. (2019) Meteoritical Bulletin, no. 106. Meteorit. Planet. Sci. 54 in press.
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     This is 1 of 9825 approved meteorites from (Northwest Africa) (plus 1851 unapproved names)

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