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Northwest Africa 16787
Basic information Name: Northwest Africa 16787
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 16787
Observed fall: No
Year found: 2023
Country: (Northwest Africa)
Mass:help 390 g
Classification
  history:
Recommended:  Eucrite-mmict    [explanation]

This is 1 of 295 approved meteorites classified as Eucrite-mmict.   [show all]
Search for other: Achondrites, Eucrites, and HED achondrites
Comments: Approved 26 Jun 2024
Writeuphelp
Writeup from MB 113:

Northwest Africa 16787 (NWA 16787)

(Northwest Africa)

Purchased: 2023

Classification: HED achondrite (Eucrite, monomict)

History: Purchased in 2023 by Habib Naji Naji.

Physical characteristics: Single stone with slightly weathered exterior and minimal fusion crust.

Petrography: (D. Sheikh, Cascadia) Sample is a monomict breccia composed of mm to cm-sized lithic clasts (e.g. gabbros, anorthosites) and mineral fragments set within a fragmented, fine-grained matrix of the same constituents. Silicate minerals (low and high-Ca pyroxene, plagioclase) are roughly equilibrated and are consistent with cumulate eucrite compositions (Mittlefehldt, 2015). Plagioclase feldspar is observed to be both cracked and smooth; sparse vesicles are observed within the smooth plagioclase. Accessory phases identified include chromite, ilmenite, troilite, silica, and rounded olivine inclusions (<5 μm) within low-Ca pyroxene grains.

Geochemistry: Olivine (Fa50.2±1.1, range Fa49.0-51.8, Fe/Mn = 48±1, n=9), Low-Ca Pyroxene (Fs41.7±1.2Wo3.6±1.0, range Fs39.5-43.4Wo2.0-5.2, Fe/Mn = 29±1, n=14), High-Ca Pyroxene (Fs19.2±2.3Wo41.2±2.7, range Fs16.3-22.9Wo36.8-44.4, Fe/Mn = 27±2, n=12), Calcic Plagioclase (An94.1±0.9, range An92.2-95.1, n=15).

Classification: HED Achondrite (monomict eucrite).

Specimens: 43.6 g at Cascadia, main mass with Habib Naji Naji.

Data from:
  MB113
  Table 0
  Line 0:
Place of purchase:Northwest Africa
Date:P 2023
Mass (g):390
Pieces:1
Class:Eucrite-mmict
Shock stage:high
Weathering grade:moderate
Fayalite (mol%):50.2±1.1
Ferrosilite (mol%):41.7±1.2, 19.2±2.3
Wollastonite (mol%):3.6±1.0, 41.2±2.7
Classifier:D. Sheikh, Cascadia
Type spec mass (g):43.6
Type spec location:Cascadia
Main mass:Habib Naji Naji
Comments:CML 1757; HN6; submitted by Daniel Sheikh
Institutions
   and collections		 Cascadia: Cascadia Meteorite Laboratory, Portland State University, Department of Geology, Room 17 Cramer Hall, 1721 SW Broadway, Portland, OR 97201, United States; Website (institutional address; updated 28 Oct 2011)
Catalogs:
References: Published in Meteoritical Bulletin, no. 113, in preparation (2024)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 9933 approved meteorites from (Northwest Africa) (plus 1837 unapproved names)

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