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Northwest Africa 13764
Basic information Name: Northwest Africa 13764
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13764
Observed fall: No
Year found: 2021
Country: Algeria
Mass:help 692 g
Recommended:  Martian (nakhlite)    [explanation]

This is 1 of 32 approved meteorites classified as Martian (nakhlite).   [show all]
Search for other: Martian meteorites
Comments: Approved 13 Mar 2021
Writeup from MB 110:

Northwest Africa 13764 (NWA 13764)


Purchased: 2021 Jan

Classification: Martian meteorite (Nakhlite)

History: Purportedly found at an unspecified location in Algeria, purchased by Rachid Chaoui in January 2021 and subsequently acquired by Jay Piatek.

Physical characteristics: A single unbroken stone (692 g) with an overall gray-green color and remnant black fusion crust on two exterior surfaces. The interior consists of visible dark green (augite), brown (olivine) and less abundant, small white (plagioclase) grains.

Petrography: (A. Irving, UWS and P. Carpenter, WUSL) Relatively coarse grained cumulate assemblage of predominantly zoned augite (up to 2 mm) and olivine (up to 3 mm) with subordinate plagioclase (up to 0.6 mm) and intercumulus microlite-bearing glass. Accessory phases are low-Ca pyroxene (at some olivine-augite interfaces), exsolved titanomagnetite, pyrrhotite and chlorfluorapatite (as subhedral to euhedral grains up to 100 microns in size, mostly within intercumulus glass). Olivine grains contain partly crystallized melt inclusions (some composed of pyroxenes, titanomagnetite, pyrrhotite and glass), and they also contain irregular veinlets of iddingsite-like material.

Geochemistry: Augite cores (Fs22.6-24.5Wo39.8-40.1, FeO/MnO = 31-38, N =3), augite rims (Fs35.3-37.3Wo36.9-38.1, FeO/MnO = 33-35, N = 3), olivine (Fa67.8-75.7, FeO/MnO = 48-50, N = 5), low-Ca pyroxene (Fs53.2-54.3Wo3.1-3.7, FeO/MnO = 29-32, N = 2), plagioclase (An35.6-36.7Or3.0-3.2, N = 3). Magnetic susceptibility log χ (× 10-9 m3/kg) = 3.84.

Classification: Nakhlite.

Specimens: 30.2 g including one polished thin section and one polished mount at UWB; remainder with Mr. J. Piatek.

Data from:
  Table 0
  Line 0:
Place of purchase:Zagora
Date:P 2021 Jan
Mass (g):692
Class:Martian (nakhlite)
Shock stage:low
Weathering grade:low
Fayalite (mol%):67.8-75.7
Ferrosilite (mol%):22.6-37.3; 53.2-54.3
Wollastonite (mol%):40.8-36.9; 3.1-3.7
Magnetic suscept.:3.84
Classifier:A. Irving, UWS, and P. Carpenter, WUSL
Type spec mass (g):30.2
Type spec location:UWB
Main mass:J. Piatek
Comments:Work name RC144.1; submitted by A. Irving
   and collections
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
WUSL: Washington Univ., One Brookings Drive, St. Louis, MO 63130, United States (institutional address; updated 17 Oct 2011)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
References: Published in Gattacceca J., McCubbin F.M., Grossman J., Bouvier A., Chabot N.L., D'Orazio M., Goodrich C., Greshake A., Gross J., Komatsu M., Miao B., and Schrader D. (2022) The Meteoritical Bulletin, No. 110. Meteorit. Planet. Sci. 1-4
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     This is 1 of 1306 approved meteorites from Algeria (plus 30 unapproved names) (plus 4 impact craters)

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