Meteoritical Bulletin: Entry for Northwest Africa 12981

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Northwest Africa 12981

Basic information

Name: Northwest Africa 12981
This is an OFFICIAL meteorite name.
Abbreviation: NWA 12981
Observed fall: No
Year found: 2019
Country: (Northwest Africa)
Mass: 88 g

Classification
history:

Meteoritical Bulletin:	MB 108	(2020)	LL3
Recommended:			LL3 [explanation]

This is 1 of 453 approved meteorites classified as LL3. [show all]
Search for other: LL chondrites, LL chondrites (type 3), Ordinary chondrites, and Ordinary chondrites (type 3)

Comments:

Approved 16 Nov 2019

Writeup

help

Writeup from MB 108:

Northwest Africa 12981 (NWA 12981)

(Northwest Africa)

Purchased: 2019 Aug

Classification: Ordinary chondrite (LL3)

Petrography: (K. Metzler, IfP) Ordinary chondrite of low petrologic type consisting of closely packed chondrules (up to 2.9 mm) and some chondrule fragments with low amounts of Fe,Ni metal, troilite, and interchondrule matrix. The mean apparent chondrule size is 670 µm (n=87).

Geochemistry: Mineral compositions and geochemistry: (K. Metzler, IfP; A.Greshake, MNB) The mean olivine composition is Fa_12.9±7.1(1.0-27.8; n=28); the mean low-Ca pyroxene composition is Fs_9.6±8.3Wo_1.0±0.9(Fs_2-32.8Wo_0.1-3.5); n=19. The mean concentration of Cr₂O₃ in ferroan olivine is 0.070±0.042 (n=52), similar to that in St. Mary’s County (LL3.3; Grossman and Brearley 2005).

Classification: LL chondrite based on metal content and apparent chondrule size. Estimated petrologic subtype is 3.3, based on PMD of Fa values and on mean concentration and variability of Cr₂O₃ in ferroan olivine.

Bibliography:

Grossman J.N. and Brearley A.J. (2005) The onset of metamorphism in ordinary and carbonaceous chondrites. Meteorit. Planet. Sci. 40, 87-122. (link)

Data from:
  MB108
  Table 0
  Line 0:

Place of purchase:	Morocco
Date:	P 2019 Aug
Mass (g):	88
Pieces:	1
Class:	LL3
Shock stage:	S1
Weathering grade:	W1
Fayalite (mol%):	12.9±7.1
Ferrosilite (mol%):	9.6±8.3
Wollastonite (mol%):	1.0±0.9
Classifier:	K. Metzler, IfP
Type spec mass (g):	18
Type spec location:	IfP
Main mass:	Mirko Graul, Bernau, Germany
Comments:	Submitted by K. Metzler, IfP

Institutions
and collections

IfP: Institut für Planetologie, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany (institutional address; updated 23 Jan 2012)
MNB: Museum für Naturkunde, Invalidenstraße 43, D-10115 Berlin, Germany (institutional address; updated 24 Dec 2011)

Catalogs:

References:

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

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Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 9128 approved meteorites from (Northwest Africa) (plus 1873 unapproved names)

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