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Northwest Africa 11840
Basic information Name: Northwest Africa 11840
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 11840
Observed fall: No
Year found: 2018
Country: (Northwest Africa)
Mass:help 1.8 g
Classification
  history:
Recommended:  CM2    [explanation]

This is 1 of 504 approved meteorites classified as CM2.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 2), CM chondrites, and CM-CO clan chondrites
Comments: Approved 4 Jul 2018
Writeuphelp
Writeup from MB 107:

Northwest Africa 11840 (NWA 11840)

(Northwest Africa)

Purchased: 2018

Classification: Carbonaceous chondrite (CM2)

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

Physical characteristics: Many small almost black fragments partially covered with fusion crust.

Petrography: Brecciated carbonaceous chondrite with abundant Fe-rich matrix, chondrules (mean diameter 280 μm), chondrule pseudomorphs, CAIs, and mineral fragments. Many components are surrounded by fine-grained dust rims. Matrix consists of abundant carbonates, sulfides and phyllosilicates. No pyroxene has been detected in the thin section studied. Absence of pyroxene and presence of Fe-Mg-rich carbonates attest to a high degree of alteration.

Geochemistry: Carbonates contain up to 1.3 wt% MgO and 1.0 wt% FeO

Data from:
  MB107
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2018
Mass (g):1.8
Pieces:1
Class:CM2
Shock stage:S1
Weathering grade:moderate
Fayalite (mol%):16.5±17.3 (0.6-48.8, n=19)
Classifier:A. Greshake, MNB
Type spec mass (g):0.36
Type spec location:MNB
Main mass:Vincent Gira
Comments:Submitted by Ansgar Greshake
Institutions
   and collections
MNB: Museum für Naturkunde, Invalidenstrasse 43, D-10115 Berlin, Germany (institutional address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 107, in preparation (2018)
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Photos:
CreditPhotos
Public domain photographs:
Ansgar Greshake         
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6505 approved meteorites from (Northwest Africa) (plus 2021 unapproved names)

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