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Northwest Africa 12773
Basic information Name: Northwest Africa 12773
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 12773
Observed fall: No
Year found: 2019
Country: Morocco
Mass:help 2.7 kg
Meteoritical Bulletin:  MB 108  (2020)  Eucrite
Recommended:  Eucrite    [explanation]

This is 1 of 588 approved meteorites (plus 1 unapproved name) classified as Eucrite.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 21 Nov 2019
Writeup from MB 108:

Northwest Africa 12773 (NWA 12773)


Find: 2019 Jan

Classification: HED achondrite (Eucrite)

Physical characteristics: In hand specimen, the cut surface shows cm-scale, pale-gray clasts surrounded and cross-cut by abundant dark melt veins.

Petrography: The polished block investigated (P23721), displays a fine to medium-grained texture dominated by sub-rounded basaltic clasts with ophitic and sub-ophitic texture. Prominent melt clasts and veins also observed, which contain abundant vesicles up to a few hundred μm in size. Some smaller clasts display a fine grained, more granoblastic texture.

Geochemistry: Mineral compositions and geochemistry: All analyses by EPMA. Ca-Pyroxene: Fs27.6±1.8Wo42.2±2.0, FeO/MnO = 31.2±1.8 (n=32) Low Ca-Pyroxene: Fs61.2±1.1Wo2.6±0.9, FeO/MnO = 30.3±1.1 (n=31) Plagioclase: Ab10.3±1.4An89.4±1.6Or0.4±0.2 (n=29) Silica: 0.3-0.56 wt% FeO, 0.16-1.69 wt% Al2O3, 0.07-0.76 wt% CaO (n=2). Clast A (granoblastic): Pyroxene: Fs27.2±0.7Wo43.1±0.9, FeO/MnO = 31.5±1.0 (n=5) Silica: 0.3-0.56 wt% FeO, 0.16-1.69 wt% Al2O3, 0.07-0.76 wt% CaO (n=2). Clast B (coarse-grained basaltic): Low Ca-Pyroxene: Fs61.0±1.0Wo3.4±1.6, FeO/MnO = 30.5±1.0 (n=3) Ca-Pyroxene: Fs27.0±1.5Wo43.1±1.0, FeO/MnO = 31.0±1.4 (n=4) Plagioclase: Ab9.6±0.5An73.8±0.5Or0.4±0.3 (n=4) Ilmenite: 0.91-0.93 wt% MnO, 0.35 to 0.44 wt% Cr2O3 (n=2) Silica: 0.34 wt% FeO, 0.03 wt% CaO (n=2) Clast C (granoblastic): Low Ca-Pyroxene: Fs61.7±0.4Wo2.2±0.3, FeO/MnO = 32.6±0.8 (n=3) Ca-Pyroxene: Fs27.6 ±0.9Wo42.4±1.2, FeO/MnO = 31.8±0.3 (n=4) Silica: 0.18 - 0.28 wt% FeO, 0.17 wt % Al2O3, 0.07-0.1 wt% CaO (n=2) Ilmenite: 0.85-0.88 wt% MnO, 0.25-0.43 wt% Cr2O3 (n=3) Clast D (basaltic): Low Ca-Pyroxene: Fs60.9Wo3.2, FeO/MnO = 30.7 (n=1) Ca-Pyroxene: Fs30.8±0.7Wo37.9±0.9, FeO/MnO = 30.3±0.8 (n=6) Silica: 0.15-0.39 wt% FeO, 0.08-0.43 wt % Al2O3, 0.05-0.16 wt% CaO (n=2) Plagioclase: Ab10.3±1.9An89.3±1.8Or0.4±0.0 (n=3)

Classification: HED achondrite (eucrite, breccia)

Specimens: 40.18 g on deposit at the NHM London (BM.2019,M64), including polished block (P23721). M. Goff holds the main mass.

Data from:
  Table 0
  Line 0:
Date:2019 Jan
Mass (g):2700
Ferrosilite (mol%):61.2±1.1 (N=31); 27.6±1.8 (N=32)
Wollastonite (mol%):2.6±0.9 (N=31); 42.2±2.0 (N=32)
Classifier:C. L. Smith and N. V. Almeida, NHM
Type spec mass (g):40.18
Type spec location:NHM
Main mass:Martin Goff
Comments:Submitted by N. V. Almeida
   and collections
NHM: Department of Mineralogy, The Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom; Website (institutional address; updated 9 Dec 2011)
References: Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150
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     This is 1 of 2012 approved meteorites from Morocco (plus 35 unapproved names) (plus 1 impact crater)

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