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Northwest Africa 2202
Basic information Name: Northwest Africa 2202
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 2202
Observed fall: No
Year found: 2004
Country: (Northwest Africa)
Mass:help 140 g
Meteoritical Bulletin:  MB 101  (2012)  Eucrite-pmict
Recommended:  Eucrite-pmict    [explanation]

This is 1 of 424 approved meteorites classified as Eucrite-pmict.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 23 Aug 2012
Writeup from MB 101:

Northwest Africa 2202 (NWA 2202)

(Northwest Africa)

Purchased: 2004

Classification: HED achondrite (Eucrite, polymict)

History: Purchased by DGregory in 2004 from D. Bessey, who obtained it from Morocco that year.

Physical characteristics: A 140 g individual with a dark fusion crust covering 2/3 of the meteorite and a grey, brecciated interior. Bulk physical properties (P. McCausland, UWO): An 11.2 g slab has a grain density of 3.19 g/cm3, a bulk density of 2.89 g/cm3 (giving calculated porosity of 9.5%) and magnetic susceptibility log χ = 3.20.

Petrography: (P. McCausland and R. Flemming, UWO). A 2.7 cm2 polished thin section shows a variety of subangular brecciated lithic and crystalline clasts ranging up to 3 mm diameter, set in a matrix of sub-0.1 mm plagioclase, Ca-rich pyroxene, Ca-poor pyroxene, accessory Fe-sulphide, chromite, ilmenite and interstitial Fe,Ni metal. Pyroxene commonly exhibit planar deformation features and mottled-to-mosaic extinction in crossed polarizers. Lithic clasts have a dark, fine-grained matrix that by SEM-EDX has a similar composition to the host meteorite matrix. The lithic clasts contain low-Ca, Mg-rich pyroxene megacrysts, one of which is mm-sized and zoned to Fe-rich rims. Carbonate weathering veins to 0.1 mm width are common, lying alongside of and often completely enclosing the lithic clasts, separating them from matrix.

Geochemistry: (R. Flemming, J. Renaud, UWO) Ca-rich pyroxene (Fs38.4±5.4Wo28.4±5.8, n=19; FeO/MnO = 32.4); Ca-poor pyroxene (Fs53.6±1.3Wo6.7±2.2, n=6; FeO/MnO = 30.8); Ca-poor pyroxene in dark clast (Fs31.3Wo6.2, n=2; FeO/MnO = 29.3; Fe-rich rim Fs58.6Wo5.2); feldspar in clasts (An89.3±2.3, n=5); matrix feldspar (An82.5±5.4, n=12).

Classification: (P. McCausland, UWO) Eucrite polymict breccia, moderate shock, low weathering.

Specimens: Type specimens in three fragments totaling 20 g and a polished thin section are on deposit at UWO. Main mass: 118 g, DGregory

Data from:
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2004
Mass (g):140
Shock stage:moderate
Weathering grade:low
Ferrosilite (mol%):54.3 ± 2.2
Wollastonite (mol%):28.4 ± 5.8
Magnetic suscept.:3.20
Classifier:P. McCausland, UWO
Type spec mass (g):20
Type spec location:UWO
Main mass:DGregory
Comments:Submitted by P. McCausland
   and collections
UWO: University of Western Ontario, Department of Earth Sciences, BGS 1030, 1151 Richmond St. N, London, Ontario, Canada N6A 5B7, Canada; Website (institutional address; updated 26 Jun 2024)
Bessey: Dean Bessey ,P.O. Box 40810, Glenfield, Auckland 1310 , New Zealand; Website (private address)
DGregory: David Gregory, 230 First Avenue, Suite 108, St. Thomas, Ontario N5R 4P5, Canada (private address)
References: Published in Meteoritical Bulletin, no. 101, MAPS 50, 1661, September 2015
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     This is 1 of 9790 approved meteorites from (Northwest Africa) (plus 1854 unapproved names)

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