MetSoc Home            Publications            Contacts  
Search the Meteoritical Bulletin Database
Last update: 19 Mar 2023
Search for: Search type: Search limits: Display: Publication:
Text help
Starts with
Sounds like
Falls  Non-NWAs
What's new
  in the last:
Limit to approved meteorite names
Search text:  
Northwest Africa 8418
Basic information Name: Northwest Africa 8418
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 8418
Observed fall: No
Year found: 2014
Country: (Northwest Africa)
Mass:help 466 g
Meteoritical Bulletin:  MB 104  (2015)  C3
Recommended:  C3    [explanation]

This is 1 of 3 approved meteorites classified as C3.   [show all]
Search for other: Carbonaceous chondrites, Carbonaceous chondrites (type 3), and Ungrouped chondrites
Comments: Approved 27 May 2015
Writeup from MB 104:

Northwest Africa 8418 (NWA 8418)

(Northwest Africa)

Purchased: 2014 Apr

Classification: Carbonaceous chondrite (C3)

History: Purchased by Darryl Pitt in April 2014 from a dealer in Erfoud, Morocco.

Petrography: (A. Irving and S. Kuehner, UWS) Relatively fresh specimen composed of relatively large, separated granular chondrules in a finer grained metal-bearing matrix. Chlorapatite occurs throughout the matrix, along with Ni-poor kamacite, Ni-bearing lawrencite, Si-bearing Fe metal and rare merrillite. Some portions of this specimen contain large (up to 15.5 mm by 12 mm), ellipsoidal CAI consisting of porous aggregates (grainsize ~0.5 mm) of mainly Al-Ti-diopside, olivine and anorthite, with accessory spinel, troilite and taenite, surrounded by complete circumferential rims (~ 1 mm thick) of chlorapatite (each one rimmed in turn by a thin outer band of calcite). Phosphate and carbonate mineralogy was established by a combination of electron microprobe analysis and cathodoluminescence microscopy.

Geochemistry: Olivine (Fa0.3-36.2; FeO/MnO = 130-131, N = 4), orthopyroxene (Fs1.9-2.3Wo1.0-0.9, N = 3), pigeonite (Fs1.7Wo9.5; Fs24.9Wo5.5), augite (Fs5.7Wo48.2), Al-Ti-diopside in CAI (Fs0.1Wo59.7; Al2O3 15.4 wt.%, TiO2 3.5 wt.%). Oxygen isotopes (K. Ziegler, UNM): analyses of three acid-washed subsamples by laser fluorination gave δ17O -3.994, -5.750, -5.299; δ18O 0.444, -1.773, -0.823; Δ17O -4.228, -4.814, -4.864. These values fall on the trend for CV and CK chondrites.

Classification: Carbonaceous chondrite (C3) with affinities to CV chondrites. The abundance of apatite in this specimen is an anomalous feature for carbonaceous chondrites.

Specimens: 22.2 g including one polished thin section at UWB. The remaining material is held by DPitt.

Data from:
  Table 0
  Line 0:
Place of purchase:Erfoud
Date:P 2014 Apr
Mass (g):466
Shock stage:S2
Weathering grade:low
Fayalite (mol%):0.3-36.2
Ferrosilite (mol%):1.9-2.3
Wollastonite (mol%):1.0-0.9
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):22.2
Type spec location:UWB
Main mass:D. Pitt
Comments:MAC 37; submitted by A. Irving
Plots: O isotopes:  
   and collections
UNM: Institute of Meteoritics MSC03 2050 University of New Mexico Albuquerque NM 87131-1126 USA, United States; Website (institutional address; updated 12 Feb 2015)
UWS: University of Washington, Department of Earth and Space Sciences, 70 Johnson Hall, Seattle, WA 98195, United States (institutional address; updated 15 Jan 2012)
UWB: University of Washington, Box 353010 Seattle, WA 98195, United States (institutional address; updated 27 Jul 2012)
DPitt: Darryl Pitt, 225 West 83rd Street, New York, NY 10024, United States; Website (private address)
References: Published in Meteoritical Bulletin, no. 104, MAPS 52, 2284, Octover 2017, http://onlinelibrary.wiley.com/doi/10.1111/maps.12930/full
Find references in NASA ADS:
Find references in Google Scholar:

     This is 1 of 9013 approved meteorites from (Northwest Africa) (plus 1869 unapproved names)

Direct link to this page