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Northwest Africa 11444
Basic information Name: Northwest Africa 11444
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 11444
Observed fall: No
Year found: 2017
Country: Mauritania
Mass:help 1323 g
Classification
  history:
Meteoritical Bulletin:  MB 106  (2018)  Lunar (melt breccia)
Recommended:  Lunar (melt breccia)    [explanation]

This is the only approved meteorite classified as Lunar (melt breccia).
Search for other: Lunar meteorites
Comments: Approved 13 Oct 2017
Writeuphelp
Writeup from MB 106:

Northwest Africa 11444 (NWA 11444)

Mauritania

Find: 2017

Classification: Lunar, melt breccia

History: Sample was collected at an unknown locality, with hearsay evidence suggesting that this was somewhere in Mauritania. The sample material was purchased by Graham Ensor from Ali El Wali. A large number of fragments collected in the same area. Some fragments were found on the surface, which have a dark, pitted surface colouration due to desert weathering. Other pieces were recovered from within the soil layer and are lighter in color with patches of reddish soil and relatively unpitted.

Physical characteristics: The sample comprises approximately 200 pieces, with a total mass of 1323 g. Some of these pieces have a dark appearance, possibly the result of wind abrasion. Fragments with a lighter-colored outer surface are also present and these often have variable amounts of adhering sand. It is presumed that these were at least partially buried at the time of recovery. In hand specimen, all the pieces display prominent angular to sub-rounded, feldspar-rich, clasts, up to 1.5 cm in diameter, enclosed in a dark matrix, laden with smaller, angular fragments.

Petrography (R. Greenwood, OU): The sample is a complex breccia, containing a wide variety of fragments and variable amounts of flow-banded glass. Fragments are generally angular and include coarse-grained to aphanitic gabbros and basalts and a wide range of single-crystal types. There are many examples of clasts consisting of brown, devitrified basaltic glass with acicular plagioclase microlites. Angular, crystal fragments can be up to 0.5 mm in diameter and consist predominantly of plagioclase, pyroxene (often displaying well-developed exsolution lamellae), and olivine. Both high and low Ca pyroxenes are present in the gabbroic clasts, with both often showing prominent exsolution lamellae. The specimen contains a few percent of anhedral Fe,Ni metal grains (kamacite), up to 150 μm in diameter. The glass is often highly vesicular, flow-banded and contains a diverse range of crystals and lithic fragments.

Geochemistry: Mineral compositions and geochemistry: Pyroxenes show wide compositional variation, with both high and low Ca varieties present. Average composition: Fs35.1±11.4Wo16.1±14.2 (N=15, range Fs30Wo4 to Fs18Wo42). Olivine, average composition: Fa37.1±16.9 (N = 21, range Fa7-67). Well-developed exsolution lamallae are commonly present. Plagioclase shows limited compositional variation: An96.5±0.5 (N=11). Fe, Ni Metal grains (up to 150 microns in diameter) are kamacite (7 to 8 wt.% Ni) (N = 6). All mineral compositions determined by EDS analysis. Oxygen isotopes: δ17O 3.28 per mil; δ18O 6.28 per mil; Δ17O 0.01 per mil (using standard formula: Δ17O = δ17O - 0.52 δ18O) (Analysis is consistent with the oxygen isotopic composition of other lunar meteorites).

Classification: Lunar, melt breccia. Moderate weathering

Specimens: Main mass with Graham Ensor

Data from:
  MB106
  Table 0
  Line 0:
Place of purchase:Morocco
Date:2017
Mass (g):1323
Pieces:about 200
Class:Lunar (melt breccia)
Weathering grade:Mod
Fayalite (mol%):37.1±16.9 (N= 21)
Ferrosilite (mol%):35.1±11.4 (N=15)
Wollastonite (mol%):16.1±14.2 (N=15)
Classifier:Richard Greenwood
Type spec mass (g):44.82
Type spec location:OU
Main mass:Graham Ensor
Finder:Ali El Wali
Comments:Submitted by Richard Greenwood
Plots: O isotopes:  
Institutions
   and collections
OU: Planetary and Space Sciences Department of Physical Sciences The Open University Walton Hall Milton Keynes MK7 6AA United Kingdom, United Kingdom (institutional address; updated 8 Dec 2011)
Catalogs:
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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Geography:

Mauritania
Coordinates:Unknown.

Statistics:
     This is 1 of 100 approved meteorites from Mauritania (plus 1 unapproved name) (plus 2 impact craters)

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