Meteoritical Bulletin: Entry for Northwest Africa 12678

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Northwest Africa 12678

Basic information

Name: Northwest Africa 12678
This is an OFFICIAL meteorite name.
Abbreviation: NWA 12678
Observed fall: No
Year found: 2018
Country: (Northwest Africa)
Mass: 228 g

Classification
history:

Meteoritical Bulletin:	MB 108	(2020)	H5-melt breccia
Recommended:			H5-melt breccia [explanation]

This is 1 of 27 approved meteorites classified as H5-melt breccia. [show all]
Search for other: H chondrites, H chondrites (type 4-7), Melted chondrites, Ordinary chondrites, and Ordinary chondrites (type 4-7)

Comments:

Approved 27 Jun 2019

Writeup

help

Writeup from MB 108:

Northwest Africa 12678 (NWA 12678)

(Northwest Africa)

Purchased: 2018

Classification: Ordinary chondrite (H5, melt breccia)

History: Purchased by Larry Atkins from Morocco in December 2018.

Physical characteristics: Two identically appearing pieces; saw-cut surfaces reveal a fragmental breccia, large portions of which consist of vesiculated melt rock. Significant oxidation visible.

Petrography: (C. Agee, UNM) Microprobe examination shows many melt rock veins crosscutting H5 chondrite domains with texturally equilibrated chondrules and recrystallized matrix. Plagioclase grain size up to 50 μm in diameter.

Geochemistry: (C. Agee, UNM) Olivine Fa_19.5±0.2, Fe/Mn=40±1, n=10; low-Ca pyroxene Fs_16.9±0.2Wo_1.5±0.4, Fe/Mn=22±2, n=6; plagioclase Ab_85.2±1.3An_11.3±0.2Or_3.5±1.4, n=3; shock melt SiO₂=43.8±3.2, TiO₂=0.13±0.02, Al₂O₃=2.9±0.6, Cr₂O₃=0.58±0.04, MgO=30.7±5.6, FeO=17.0±4.7, Mn=0.35±0.04, NiO=0.07±0.05, CaO=1.9±0.5, Na₂O=1.0±0.2, K₂O=0.21±0.13 (all wt%), n=4.

Classification: H5-melt breccia

Specimens: 27.5 g including a probe mount on deposit at UNM, Larry Atkins holds the main mass.

Data from:
  MB108
  Table 0
  Line 0:

Place of purchase:	Morocco
Date:	P 2018
Mass (g):	228.2
Pieces:	2
Class:	H5-melt breccia
Shock stage:	S4
Weathering grade:	W3
Fayalite (mol%):	19.5±0.2
Ferrosilite (mol%):	16.9±0.2
Wollastonite (mol%):	1.5±0.4
Classifier:	C. Agee, UNM
Type spec mass (g):	27.5
Type spec location:	UNM
Main mass:	Larry Atkins
Comments:	Field name LA-11; submitted by C. Agee, UNM

Institutions
and collections

UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)

Catalogs:

References:

Published in Meteoritical Bulletin, no. 108 (2020) Meteorit. Planet. Sci. 55, 1146-1150

Find references in NASA ADS:
Find references in Google Scholar:

Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 7885 approved meteorites from (Northwest Africa) (plus 1958 unapproved names)

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