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Northwest Africa 10784
Basic information Name: Northwest Africa 10784
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 10784
Observed fall: No
Year found: 2015
Country: (Northwest Africa)
Mass:help 1182 g
Classification
  history:
Meteoritical Bulletin:  MB 105  (2016)  Eucrite-br
Recommended:  Eucrite-br    [explanation]

This is 1 of 179 approved meteorites classified as Eucrite-br.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 2 Nov 2016
Writeuphelp
Writeup from MB 105:

Northwest Africa 10784 (NWA 10784)

(Northwest Africa)

Purchased: 2015 May 1

Classification: HED achondrite (Eucrite, brecciated)

History: Found in the region of Er-Rich to the north of Errachidia.

Physical characteristics: One flat stone consisting of breccia, with fusion crust on the lower part protected from ablation by wind.

Petrography: (R. Hewins, S. Pont, B. Zanda, MNHNP) This is a breccia with lithic clasts clasts up to 4 mm in size. The main minerals are othopyroxene, augite and plagioclase, with a silica phase, chromite, ilmenite, zircon and rare kamacite both Ni-free and Ni-bearing. The grain size is up to 1.5 mm in the subophitic clast, with augite lamellae up to 80 μm in width. Plagioclase laths are more elongated in finer grained clasts, but there are also granoblastic clasts containing 50 μm grains with up to 2 μm exsolution lamellae. Exsolution lamellae in orthopyroxene are commonly bent and/or displaced up to 25 μm by fracturing. Large plagioclase grains have crystallographically controlled pyroxene inclusions, whereas much plagioclase in fine grained matrix is smooth and featureless except for vugs. The matrix varies from granoblastic to clasts embedded in smooth plagioclase. A vein of melt crosses the section and invades the matrix. It is a nanophyric intergrowth of 1 μm pyroxene and plagioclase crystals, though locally with plagioclase dendrites, containing clasts mainly of pyroxene, and blobs and schlieren of melted plagioclase. The meteorite contains traces of calcite and barite.

Geochemistry: Mineral compositions and Geochemistry: (R. Hewins and S. Pont, MNHNP) The pyroxene compositions are Fs57.2Wo2.2 to Fs64.9Wo4.9, and Fs25.8Wo41.7 to Fs29.6Wo44.1. Fe and Mn are equilibrated between the two pyroxenes, with atomic ratio 31.2±1.9 (n=13) plotting on the UNM eucrite line. Plagioclase is An89.3-87.8Or0.3-0.6. Chromite has ~49% Cr2O3.

Classification: (R. Hewins MNHN) Basaltic eucrite breccia. The meteorite contains anorthite, and pyroxene with Fe/Mn ratios matching eucrite, plus typical eucrite textures.

Specimens: The type specimen consists of 20.63 and 0.93 g at MNHNP. The main mass (937 g) is held by MHNN. Labenne retains 202.6 g and the rest (in the form of caliche crust, crumbs and saw dust) was discarded.

Data from:
  MB105
  Table 0
  Line 0:
Place of purchase:Agadir
Date:P 2015 May 1
Mass (g):1182
Pieces:1
Class:Eucrite-br
Shock stage:high
Weathering grade:low
Classifier:R. Hewins, MNHNP
Type spec mass (g):21.56
Type spec location:MNHNP
Main mass:MHNN
Comments:Y: Temporary name LM 220515 Y.; submitted by R. Hewins
Institutions
   and collections
MNHNP: Museum National d'Histoire Naturelle, IMPMC-CP52, 57 rue Cuvier, 75005 Paris, France, France; Website (institutional address)
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
Labenne: 23, rue de Esperance, 75013 Paris, France; Website (private address; updated 29 Aug 2012)
MNHN: Museum National d'Histoire Naturelle, IMPMC-CP52, 57 rue Cuvier, 75005 Paris, France, France; Website (institutional address)
MHNN: Museum d'Histoire Naturelle de Nantes 12 Rue Voltaire, 44000 Nantes, France (institutional address; updated 2 Nov 2016)
Catalogs:
References: Published in Meteoritical Bulletin, no. 105, MAPS 52, 2411, September 2017. http://onlinelibrary.wiley.com/doi/10.1111/maps.12944/full
Find references in NASA ADS:
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Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 7385 approved meteorites from (Northwest Africa) (plus 1955 unapproved names)

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