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Northwest Africa 6711
Basic information Name: Northwest Africa 6711
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 6711
Observed fall: No
Year found: 2009
Country: (Northwest Africa)
Mass:help 714 g
Classification
  history:
Meteoritical Bulletin:  MB 99  (2011)  Eucrite
Recommended:  Eucrite    [explanation]

This is 1 of 443 approved meteorites (plus 1 unapproved name) classified as Eucrite.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 13 May 2011
Writeuphelp
Writeup from MB 99:

Northwest Africa 6711 (NWA 6711)

(Northwest Africa)

Purchased: Sept 2009

Classification: HED achondrite (Eucrite)

History: Sample donated to Cascadia by Mr. Fred Olsen.

Physical characteristics: Oriented, shiny, vesicular, fusion-crusted individual with flow lines. Many grains from the interior are exposed at the surface in low spots between flow lines and along sharper edges of the specimen. Small patches of orange staining. Interior has basaltic texture. Specimen traversed by 0.3-0.5 mm wide, fine-grained, pinkish vein.

Petrography: (A. Ruzicka, Cascadia) Four holocrystalline lithologies. Lithology A predominates, subophitic basalt (grains ~0.2-2 mm) rich in heavily fractured pigeonite showing strong mosaic extinction, and twinned plagioclase showing undulatory extinction. Variable but not pervasive clouding by precipitates in pigeonite and plagioclase; augite occurs as lamellae in pigeonite and as discrete grains. Lithology A grades into dominantly granular areas (lithologies C, D) composed of a higher proportion of silica, augite, and ilmenite. Lithology C contains fine-grained silica, lithology D contains silica laths (to 2 mm) with undulatory extinction. The veins (Lithology B) consist of fine-grained (<0.3 mm), granular-textured basalt (relatively clear plagioclase, pigeonite, augite, ilmenite, silica mineral), which cross-cuts lithology A and occurs at the edge of lithology D.

Geochemistry: (A. Ruzicka and M. Hutson, Cascadia) Major minerals have relatively uniform compositions: plagioclase (Ab9.6±1.0An90.0±0.9Or0.5±0.3, n=30), low-Ca pyroxene (Wo6.2±0.3En35.6±0.6Fs58.3±0.6, Fe/Mn=31.7, n=21), augite (Wo40.4±1.1En29.7±0.5Fs29.9±1.0, Fe/Mn = 32.5, n = 13).

Classification: Achondrite (eucrite). Equilibrated, moderately deformed, contains late-stage veining.

Specimens: A total of 20.5 g and 1 thin section are on deposit at Cascadia. Mr. McKenzie holds the main mass.

Data from:
  MB99
  Table 0
  Line 0:
Place of purchase:Denver
Date:P Sept 2009
Mass (g):714
Pieces:1
Class:Eucrite
Shock stage:moderate
Weathering grade:low
Ferrosilite (mol%):58.3, 29.9
Wollastonite (mol%):6.2, 40.4
Classifier:A. Ruzicka
Type spec mass (g):20.5
Type spec location:Cascadia
Main mass:Mr. Ronnie McKenzie, Pretoria, South Africa
Comments:Field numbers RM-1 and CML0612.; submitted by A. Ruzicka
Institutions
   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)
Olsen: Unknown person (private address; updated 17 Apr 2009)
Catalogs:
References: Published in Meteoritical Bulletin, No. 99, April 2012, MAPS 47, E1-E52 (2012) [published online only]
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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