Meteoritical Bulletin: Entry for Northwest Africa 8631

header

MetSoc Home Publications Contacts

Search the Meteoritical Bulletin Database
Last update: 15 Apr 2024
Search for:	Search type:	Search limits:	Display:	Publication:
Names Text Places Classes Years	Contains Starts with Exact Sounds like	NonAntarctic Falls Non-NWAs Has strewnfield		What's new in the last:
Include past classifications in search		Has photo	Limit to approved meteorite names
Search text:

Northwest Africa 8631

Basic information

Name: Northwest Africa 8631
This is an OFFICIAL meteorite name.
Abbreviation: NWA 8631
Observed fall: No
Year found: 2012
Country: (Northwest Africa)
Mass: 37 g

Classification
history:

Meteoritical Bulletin:	MB 103	(2014)	CO3.0
Recommended:			CO3.0 [explanation]

This is 1 of 22 approved meteorites classified as CO3.0. [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), CM-CO clan chondrites, and CO chondrites

Comments:

Approved 25 Nov 2014

Writeup

help

Writeup from MB 103:

Northwest Africa 8631 (NWA 8631)

(Northwest Africa)

Purchased: 2012

Classification: Carbonaceous chondrite (CO3.0)

History: Purchased in Erfoud in 2012

Physical characteristics: A single stone partly covered with fusion crust. Cut surface reveals a dark brown interior with small brown-orange chondrules.

Petrography: Chondrules and mineral fragments in a fine grained Fe-rich matrix. Chondrules are mostly of type I, some armored by opaques. Sulfides and metal are found in chondrules and matrix including blebs in the matrix (to 200 μm for metal, to 50 μm for sulfides). Modal abundances (by point counting N=448): matrix 53%, chondrules and mineral fragments 40%, opaques and their weathering products 7% (including ~2% metal, in agreement with magnetic susceptibility). Average chondrule size 240±130 μm (N=67).

Geochemistry: Olivine Fa_13.2±17.0(PMD=118%, Fa_0.4-46.9, N=22). Type I chondrules olivine Fa_1.0±0.4(N=14), type II chondrules olivine Fa_34.5±9.0(N=8). Cr₂O₃ in ferroan olivine is 0.35±0.06 (N=8). Orthopyroxene Fs_2.0±0.8Wo_1.6±0.9(Fs_1.2-3.3, PMD-FeO=34%, N=5). Magnetic susceptibility log χ =4.65 (χ in 10^-9 m³/kg).

Classification: Carbonaceous chondrite (CO3.0). Sub-type from Cr₂O₃ content of ferroan olivine and olivine Fa range. Matrix abundance is higher and chondrules larger than the usual CO chondrite. Moderate weathering.

Specimens: 7.5 g and a polished section in CEREGE. Main mass with Jean Redelsperger

Data from:
  MB103
  Table 0
  Line 0:

Place of purchase:	Erfoud
Date:	P 2012
Mass (g):	37
Pieces:	1
Class:	CO3.0
Weathering grade:	moderate
Fayalite (mol%):	13.2±17.0 (PMD=118%, N=22)
Ferrosilite (mol%):	2.0±0.8 (PMD=34%, N=5)
Wollastonite (mol%):	1.6±0.9
Magnetic suscept.:	4.65
Classifier:	J. Gattacceca, CEREGE
Type spec mass (g):	7.5
Type spec location:	CEREGE
Main mass:	Jean Redelsperger
Comments:	Submitted by J. Gattacceca

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)

Catalogs:

References:

Published in Meteoritical Bulletin, no. 103, MAPS 52, 1014, May 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12888/full

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)
Allmeteorite.com
Denis gourgues

Geography:

Coordinates:

Unknown.

Statistics:
This is 1 of 9699 approved meteorites from (Northwest Africa) (plus 1854 unapproved names)

Also see:

This lists the most popular meteorites among people who looked up this meteorite.

Revision
history:

This lists important revisions made to data for this record.

Direct link to this page