Meteoritical Bulletin: Entry for Northwest Africa 11561

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Northwest Africa 11561

Basic information

Name: Northwest Africa 11561
This is an OFFICIAL meteorite name.
Abbreviation: NWA 11561
Observed fall: No
Year found: 2016
Country: (Northwest Africa)
Mass: 5.75 kg

Classification
history:

Meteoritical Bulletin:	MB 107	(2018)	CR6
Recommended:			CR6 [explanation]

This is 1 of 3 approved meteorites classified as CR6. [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (equilibrated), and CR chondrites

Comments:

Approved 4 Jul 2018

Writeup

help

Writeup from MB 107:

Northwest Africa 11561 (NWA 11561)

(Northwest Africa)

Purchased: 2016 Dec

Classification: Carbonaceous chondrite (CR6)

History: Purchased in December 2016 by Ben Hoefnagels from a French dealer, who had obtained the stone from a source in Niger.

Petrography: (A. Irving and S. Kuehner, UWS) Metamorphic texture. Larger (up to 3.6 mm) pyroxene poikiloblasts containing numerous rounded olivine chadacrysts are present within a dominant finer-grained, recrystallized matrix exhibiting triple grain junctions. Pyroxene is mostly orthopyroxene, but blebby inclusions of clinopyroxene are present in places. Accessory phases are chromite, kamacite, Ni-poor taenite and troilite.

Geochemistry: Olivine (Fa_29.0-29.8, FeO/MnO = 64-67, N = 3), orthopyroxene host (Fs_23.0-23.6Wo_3.8-3.6, FeO/MnO = 40-42, N = 2), clinopyroxene exsolution lamellae (Fs_10.7-12.0Wo_41.8-39.8, FeO/MnO = 28-31, N = 2), plagioclase (An_42.0-50.3Or_1.6-1.8, N = 2). Oxygen isotopes (K. Ziegler, UNM): analyses of acid-washed subsamples by laser fluorination gave, respectively, δ¹⁷O -0.259, -0.450, -0.344; δ¹⁸O 2.659, 2.297, 2.506; Δ¹⁷O -1.663, -1.663, -1.667 per mil.

Classification: Carbonaceous chondrite (CR6). In terms of textural, mineralogical and isotopic characteristics, this specimen is very similar to Tafassasset and NWA 7531.

Specimens: 53.0 g including one polished thin section at UWB; remainder with Mr. B. Hoefnagels.

Data from:
  MB107
  Table 0
  Line 0:

Place of purchase:	France
Date:	P 2016 Dec
Mass (g):	5746
Pieces:	1
Class:	CR6
Shock stage:	low
Weathering grade:	low
Fayalite (mol%):	29.0-29.8
Ferrosilite (mol%):	23.3-23.6; 10.7-12.0
Wollastonite (mol%):	3.8-3.6; 41.8-39.8
Classifier:	A. Irving and S. Kuehner, UWS
Type spec mass (g):	53.0
Type spec location:	UWB
Main mass:	B. Hoefnagels
Comments:	Work name BH116; submitted by A. Irving

Plots:

O isotopes:

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)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)

Catalogs:

References:

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

Find references in NASA ADS:
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Photos:

Credit	Photos
Public domain photographs:
A. Irving

Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 9092 approved meteorites from (Northwest Africa) (plus 1875 unapproved names)

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