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Northwest Africa 13455
Basic information Name: Northwest Africa 13455
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 13455
Observed fall: No
Year found: 2019
Country: (Northwest Africa)
Mass:help 150 g
Recommended:  CO3-an    [explanation]

This is 1 of 3 approved meteorites classified as CO3-an.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), CM-CO clan chondrites, and CO chondrites
Comments: Approved 5 Dec 2020
Writeup from MB 109:

Northwest Africa 13455 (NWA 13455)

(Northwest Africa)

Purchased: 2019

Classification: Carbonaceous chondrite (CO3-an)

History: The meteorite was purchased from a meteorite dealer in Morocco, possibly from the same lot as NWA 12957.

Physical characteristics: Many small almost black fragments some of which covered by fusion crust.

Petrography: The meteorite is a brecciated carbonaceous chondrite composed of small chondrules (mean diameter about 250 μm), mineral fragments, and rare CAIs embedded in a fine-grained Fe-rich matrix. Some objects are surrounded by accretionary dust rims. Opaque phases include metal, sulfides, and magnetite. Olivine and low-Ca pyroxene are highly unequilibrated. Phyllosilicates and carbonates appear to be absent.

Geochemistry: Cr2O3 in ferroan olivine: 0.30±0.09 wt%, N=8; mean values of defocused matrix analyses (beam diamter 5 µm; all wt%; N=25): SiO2: 28.7, TiO2: 0.05, Na2O: 0.32, Cr2O3: 0.50, MgO: 14.3, MnO: 0.17, FeO: 36.4, Al2O3: 2.86, NiO: 2.16, P2O5: 0.65, S: 2.37, Total: 88.48; Oxygen isotopes (K. Ziegler, UNM): 3 acid-washed fragments analyzed by laser fluorination gave: δ18O=-7.200, -8.292, -5.533; δ17O=-8.959, -9.822, -8.533; Δ17O= -5.157, -5.444, .5.612 (all per mil)

Classification: Carbonaceous chondrite (CO3-an). The type 3 due to highly unequilibrated silicates and the absence of phyllosilicates and carbonates. Anomalous designation is from the oxygen isotopic composition. Pairing with NWA 12957 seems likely.

Data from:
  Table 0
  Line 0:
Place of purchase:Morocco
Date:P 2019
Mass (g):150
Shock stage:S1
Weathering grade:low
Fayalite (mol%):14.4±16.3 (1.1-40.1, n=20)
Ferrosilite (mol%):1.4±0.6 (0.8-2.9, n=16)
Wollastonite (mol%):1.0±0.1 (0.9-1.2, n=16)
Magnetic suscept.:4.28
Classifier:A. Greshake, MNB
Type spec mass (g):20.3
Type spec location:MNB
Main mass:Philippe Schmitt-Kopplin
Comments:Submitted by Ansgar Greshake
Plots: O isotopes:  
   and collections
MNB: Museum für Naturkunde, Invalidenstraße 43, D-10115 Berlin, Germany (institutional address; updated 24 Dec 2011)
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
References: Published in Meteoritical Bulletin, no. 109, in preparation (2020)
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Public domain photographs:
Ansgar Greshake         

     This is 1 of 8777 approved meteorites from (Northwest Africa) (plus 1879 unapproved names)

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