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Northwest Africa 11638
Basic information Name: Northwest Africa 11638
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 11638
Observed fall: No
Year found: 2017
Country: (Northwest Africa)
Mass:help 9.7 g
Classification
  history:
Recommended:  CM2.0    [explanation]

This is 1 of 2 approved meteorites classified as CM2.0.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 2), CM chondrites, and CM-CO clan chondrites
Comments: Approved 27 Mar 2018
Writeuphelp
Writeup from MB 107:

Northwest Africa 11638 (NWA 11638)

(Northwest Africa)

Purchased: 2017

Classification: CM2.0

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

Physical characteristics: Many small and dark-grayish fragments lacking any fusion crust.

Petrography: The meteorite is a carbonaceous chondrite that is composed of chondrule and CAI pseudomorphs set into a fine-grained Fe-rich matrix dominated by phyllosillicates, carbonates and sulfides. It does not contain any anhydrous silicates. Low totals of defocused matrix analyses attest to porosity and the presence of hydrous phases, i.e., phyllosilicates. Abundant mineral phases are up to 50 μm sized Ca-carbonates, often fibrous phyllosilicates, and Ni-bearing pyrrhotite.

Geochemistry: Mean values of defocused (10 μm beam diameter) matrix analyses (all wt%; N=35): SiO2: 26.5, TiO2: 0.12; Na2O: 0.19; Cr2O3: 0.46, MgO: 20.5, MnO: 0.25, CaO: 0.68, FeO: 29.5, Al2O3: 2.59, NiO: 0.69, P2O5: 0.14, S: 0.38, Total: 82.0; Ca-carbonates contain about 1 wt% FeO.

Classification: CM2.0. Subtype following the classification scheme of Rubin et al. (2007)).

Bibliography:
  • Rubin A.E., Trigo-Rogriguez J.M., Huber H., and Wasson J.T. (2007) Progressive aqueous alteration of CM carbonaceous chondrites. Geochim. Cosmochim. Acta 71, 2361-2382 (link)
Data from:
  MB107
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2017
Mass (g):9.7
Pieces:many
Class:CM2.0
Shock stage:S1
Weathering grade:moderate
Classifier:A. Greshake, MNB
Type spec mass (g):2
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)
Find references in NASA ADS:
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Photos:
CreditPhotos
Photos uploaded by members of the Encyclopedia of Meteorites.
    (Caution, these are of unknown reliability)
METEORITICON   
Public domain photographs:
Ansgar Greshake         
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6900 approved meteorites from (Northwest Africa) (plus 2027 unapproved names)

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