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Northwest Africa 13631
Basic information Name: Northwest Africa 13631
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13631
Observed fall: No
Year found: 2016
Country: (Northwest Africa)
Mass:help 81 g
Classification
  history:
Recommended:  CR2    [explanation]

This is 1 of 177 approved meteorites classified as CR2.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 2), and CR chondrites
Comments: Approved 16 Dec 2020
Writeuphelp
Writeup from MB 109:

Northwest Africa 13631 (NWA 13631)

(Northwest Africa)

Purchased: 2016

Classification: Carbonaceous chondrite (CR2)

History: The meteorite was purchased from a dealer in Morocco.

Physical characteristics: Dark-brownish fragment without fusion crust.

Petrography: Carbonaceous chondrite composed of abundant, mostly rounded, sometimes slightly flattened chondrules with an apparent mean diameter of about 700 µm and about 30% almost black matrix. Chondrules are predominatly of type I; one type II chondrule present. Some chondrules are metal-decorated and contain 150-200 µm sized metal blebs typical of CR. CAIs are sparse; only one has been encountered in the section studied. Low matrix totals suggest presence of hydrous mineral phases.

Geochemistry: olivine in type I chondrules: Fa2.7±0.7, Cr2O3: 0.73±0.12 wt%, n=15; low-Ca pyroxene: Fs3.3±0.8Wo0.8±0.1, n=12; olivine in type II chondrules: Fa19.3±6.8 (Fa13.9-31.0, n=7). Matrix analyses yield an average total of 84.8±1.1 wt% (5 µm defocused beam, N=12) suggesting the presence of hydrous minerals.

Data from:
  MB109
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2016
Mass (g):81
Pieces:4
Class:CR2
Shock stage:S2
Weathering grade:W2
Fayalite (mol%):2.7; 19.3
Ferrosilite (mol%):3.3
Wollastonite (mol%):0.8
Classifier:A. Greshake, MNB
Type spec mass (g):16.5
Type spec location:MNB
Main mass:Philippe Schmitt-Kopplin
Comments:Submitted by Ansgar Greshake
Institutions
   and collections
MNB: Museum f├╝r Naturkunde, Invalidenstra├če 43, D-10115 Berlin, Germany (institutional address; updated 24 Dec 2011)
Catalogs:
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 8025 approved meteorites from (Northwest Africa) (plus 1951 unapproved names)

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