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Northwest Africa 16682
Basic information Name: Northwest Africa 16682
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 16682
Observed fall: No
Year found: 2022
Country: Mali
Mass:help 3.4 kg
Recommended:  Eucrite-unbr    [explanation]

This is 1 of 140 approved meteorites classified as Eucrite-unbr.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 10 Jun 2024
Writeup from MB 113:

Northwest Africa 16682 (NWA 16682)


Purchased: 2022 Jan

Classification: HED achondrite (Eucrite, unbrecciated)

History: Purchased jointly by Ahmed Salek and Omar Bourki from a nomad in Sebkhat el Maleh in January 2022.

Petrography: (C. Herd, UAb) Optical and electron backscattered investigation of a polished thin section reveals an ophitic to subophitic texture of pyroxene and plagioclase. Pyroxene and plagioclase are 0.5-2 mm in longest dimension. Nearly all low-Ca pyroxene contains high-Ca exsolution lamellae. Accessory minerals include silica polymorph, ilmenite and chromite. Areas of plagioclase consist of sub-micron domains, and grain boundaries with pyroxene show contact melting of pyroxene. Pyroxene is recrystallized and shows low pleochroism. Melt veins and pockets are pervasive. Only very minor iron staining is present along grain boundaries.

Geochemistry: (C. Herd, A. Locock, and D. Poon-Matsune, UAb) Data obtained by EMP examination of carbon-coated thin section: low-Ca pyroxene: Fs61.6±0.8Wo2.8±0.7 (Fe/Mn = 30.4±0.8; n=13); high-Ca pyroxene lamellae: range Fs51Wo15 - Fs35Wo34 (Fe/Mn ~ 30); plagioclase: An89±2Or0.3±0.2 (n=16). Chromite contains 3-18 wt% TiO2.

Classification: HED achondrite, unbrecciated. Equilibrated non-cumulate basaltic eucrite.

Specimens: Type specimen of 25.2 g at UAb, main mass with Ahmed Salek and Omar Bourki.

Data from:
  Table 0
  Line 0:
Place of purchase:Sebkhat el Maleh
Date:P 2022 Jan
Mass (g):3400
Shock stage:M-S6
Weathering grade:low
Classifier:C. Herd, UAb
Type spec mass (g):25.2
Type spec location:UAb
Main mass:Ahmed Salek, Omar Bourki
Comments:Field number AS-24; submitted by C. Herd
   and collections
UAb: 1-26 Earth Sciences Building, University of Alberta, Edmonton, AB, T6G 2E3, Canada, Canada; Website (institutional address; updated 17 Oct 2011)
References: Published in Meteoritical Bulletin, no. 113, in preparation (2024)
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     This is 1 of 122 approved meteorites from Mali (plus 2 unapproved names)

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