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Northwest Africa 6712
Basic information Name: Northwest Africa 6712
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 6712
Observed fall: No
Year found: 2009
Country: (Northwest Africa)
Mass:help 3.76 kg
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 6712 (NWA 6712)

(Northwest Africa)

Purchased: Sept 2009

Classification: HED achondrite (Eucrite)

History: Samples were donated to Cascadia by Mr. Fred Olsen.

Physical characteristics: Two pieces fit together forming an overall faceted shape. Red-brown patina covers much of the surface, although a dark-grey fusion crust is visible in places, and one side shows a light-grey interior. Cut face shows a dominantly fine-grained interior, with clasts, including one large and relatively coarse basalt clast (~2-3 cm). A discolored weathering zone extends 3-4 mm inward from one surface.

Petrography: (A.Ruzicka, Cascadia) Prevalent lithology consists of basalt clasts (0.7-2.4 mm) that grade into a finer grained matrix of pigeonite, plagioclase, and augite clasts (<0.3 mm). Fractured and slightly porous plagioclase largely fills interclast areas. Large, coarse basalt clast has a subophitic texture dominated by twinned plagioclase with undulose-to-mosaic extinction (up to 0.8-1.6 mm long × 0.1-0.2 mm wide) and heavily fractured pigeonite with undulose-to-mosaic extinction (up to 0.6-1.5 mm); this clast is internally brecciated. Clouding by precipitates is ubiquitous in plagioclase and pyroxene but spatially variable. Throughout the section, augite occurs as lamellae in pigeonite or as discrete grains and clasts. Small calcite veins locally fill fractures.

Geochemistry: (A. Ruzicka, M. Hutson, and T.J. Schepker, Cascadia) Major minerals have similar compositions in the largest and smaller basalt clasts and in the clastic matrix: plagioclase (Ab12±1.7An86.7±1.7Or1.3±0.8, n = 41), pigeonite (Wo8.0±2.4En32.2±1.1Fs59.8±2.1, Fe/Mn = 32.3 wt, n = 36), augite (Wo40.±1.6En28.0±0.9Fs31.3±1.2, Fe/Mn = 31.6, n = 20).

Classification: Achondrite (eucrite). Equilibrated, heavily brecciated and moderately deformed, apparently monomict breccia.

Specimens: A total of 20.8 g, 1 thin section, and potted butt 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):3758
Pieces:2
Class:Eucrite
Shock stage:moderate
Weathering grade:low
Ferrosilite (mol%):59.8, 31.3
Wollastonite (mol%):8.0, 40.7
Classifier:A. Ruzicka
Type spec mass (g):20.8
Type spec location:Cascadia
Main mass:Mr. Ronnie McKenzie, Pretoria, South Africa
Comments:Field numbers RM-5 and CML0616.; 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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