Meteoritical Bulletin: Entry for Northwest Africa 11811

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Northwest Africa 11811

Basic information

Name: Northwest Africa 11811
This is an OFFICIAL meteorite name.
Abbreviation: NWA 11811
Observed fall: No
Year found: 2017
Country: (Northwest Africa)
Mass: 182.4 g

Classification
history:

Meteoritical Bulletin:	MB 107	(2018)	LL5-an
Recommended:			LL5-an [explanation]

This is the only approved meteorite classified as LL5-an.
Search for other: LL chondrites, Ordinary chondrites, and Ordinary chondrites (type 4-7)

Comments:

Approved 9 Nov 2018

Writeup

help

Writeup from MB 107:

Northwest Africa 11811 (NWA 11811)

(Northwest Africa)

Purchased: 2017

Classification: LL5-an

Physical characteristics: Dark stone. Cut surface reveals a gray interior with chondritic texture.

Petrography: (J. Gattacceca, H. Pourkhorsandi, CEREGE) Chondrite with recrystallized texture. Main minerals are olivine, pyroxene, and interstitial plagioclase with typical size about 25 μm. Presence of merrilite. Opaque minerals are sulfides (including pentlandite), chromite, and rare FeNi metal.

Geochemistry: Olivine Fa_33.5±0.9, PMD=3%, NiO 0.17 wt% (N=8). Orthopyroxene Fs_26.4±0.2Ws1.6±0.1 (N=5). Ca-pyroxene Fs_25.1Wo_17.4(N=1). Plagioclase An_11.9Ab_80.2Or_7.9(N=2). Chromite Cr# = 0.91, TiO₂ 3.6 wt% (N=1). FeNi metal Fe32.3±0.3Ni66.2±0.3Co1.35±0.06 (N=7). Magnetic susceptibility log χ (× 10^-9 m³/kg) = 3.42. Oxygen isotopic composition (J. Gattacceca, C. Sonzogni, CEREGE) from analysis of one acid-washed 1.5 mg aliquot of a powdered 475 mg bulk sample is δ¹⁷O=4.38‰, δ¹⁸O=5.85‰ , Δ¹⁷O=1.31‰ (linearized, slope 0.5247, analytical uncertainties 0.08‰, 0.12‰, 0.03‰ respectively).

Classification: LL5-anomalous. The anomalous designation comes from the high Fa content of olivine compared to other equilibrated LL chondrites, and the presence of metal in the form of FeNi2 exclusively.

Specimens: Type specimen at CEREGE. Main mass with Kuntz.

Data from:
  MB107
  Table 0
  Line 0:

Place of purchase:	Erfoud
Date:	P 2017
Mass (g):	182.4
Pieces:	1
Class:	LL5-an
Weathering grade:	moderate
Fayalite (mol%):	33.5±0.9 (N=8)
Ferrosilite (mol%):	26.4±0.2 (N=5)
Wollastonite (mol%):	1.6±0.1
Magnetic suscept.:	3.42
Classifier:	J. Gattacceca, H. Pourkhorsandi, CEREGE
Type spec mass (g):	20.07
Type spec location:	CEREGE
Main mass:	Kuntz
Comments:	work name K331; submitted by J. Gattacceca

Plots:

O isotopes:

Institutions
and collections

CEREGE: CEREGE BP 80 Avenue Philibert, Technopole de l'Arbois 13545 Aix-en-Provence Cedex 4 France, France (institutional address; updated 10 Jun 2023)
Kuntz: Fabien Kuntz, France; Website (private address)

Catalogs:

References:

Published in Meteoritical Bulletin, no. 107, MAPS 55, 460-462

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

Photos:

Credit	Photos
Photos uploaded by members of the Encyclopedia of Meteorites. (Caution, these are of unknown reliability)
Wojciech Moscinski

Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 9921 approved meteorites from (Northwest Africa) (plus 1838 unapproved names)

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