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Northwest Africa 6960
Basic information Name: Northwest Africa 6960
     This is an OFFICIAL meteorite name.
Abbreviation: NWA 6960
Observed fall: No
Year found: 2011
Country: (Northwest Africa)
Mass:help 441 g
Classification
  history:
Meteoritical Bulletin:  MB 102  (2013)  OC3
Recommended:  OC3    [explanation]

This is 1 of 10 approved meteorites classified as OC3.   [show all]
Search for other: Ordinary chondrites, Ordinary chondrites (type 3)
Comments: Approved 22 Oct 2013
Writeuphelp
Writeup from MB 102:

Northwest Africa 6960 (NWA 6960)

(Northwest Africa)

Purchased: 2011 Jun

Classification: Ordinary chondrite (type 3)

History: Purchased by GHupé in June 2011 from a Moroccan dealer at the St. Marie-aux-Mines Mineral Show.

Physical characteristics: Very fresh dark gray stone (441 g) with white to beige (and some dark) chondrules, pale angular grains and low amounts of fresh metal.

Petrography: (A. Irving and S. Kuehner, UWS) Well-formed chondrules of varying sizes (some in the size range for LL chondrites, others much smaller). Some chondrules have pyrrhotite-rich rims and others have fine grained dust rims. Large angular olivine grains also are present, and one unusual clast composed of pigeonite+anorthite was found. Olivine (Fa0.5-49.5; Cr2O3 in ferroan olivine ranges from 0.03-0.20 wt.%, mean 0.14, s.d. 0.05, N = 9), orthopyroxene (Fs1.0-16.9Wo0.6-3.2), pigeonite (Fs22.2-35.4Wo8.0-5.9). Pyrrhotite occurs as an accessory mineral in the matrix, but kamacite and taenite are both minor constituents.

Geochemistry: Olivine (Fa0.5-49.5; Cr2O3 in ferroan olivine ranges from 0.03-0.20 wt.%, mean 0.14, s.d. 0.05, N = 9), orthopyroxene (Fs1.0-16.9Wo0.6-3.2), pigeonite (Fs22.2-35.4Wo8.0-5.9). Oxygen isotopes (R. Tanaka, OkaU): analyses of acid-washed subsamples by laser fluorination gave δ18O 5.236, 4.596; δ17O 3.330, 2.935; Δ17O 0.572, 0.514 per mil.

Classification: Chondrite (OC3, Type 3.4). Although oxygen isotopic compositions plot near the field for L chondrites, this very fresh specimen has far too little metal (around 2 vol.%), and some of the chondrules are too large, for this to be an L chondrite. Subtype estimated to be 3.4 based on Cr2O3 range in ferroan olivine. Estimation of subtype based on histograms (Fig. 4) in Grossman and Brearley (2005).

Bibliography:
  • Grossman J.N. and Brearley A.J. (2005) The onset of metamorphism in ordinary and carbonaceous chondrites. Meteorit. Planet. Sci. 40, 87-122. (link)
Data from:
  MB102
  Table 0
  Line 0:
Place of purchase:St. Marie
Date:P 2011 Jun
Mass (g):441
Pieces:1
Class:OC3
Shock stage:S2
Weathering grade:W1
Fayalite (mol%):0.5-49.5 (n=11)
Ferrosilite (mol%):1.0-16.9
Wollastonite (mol%):0.6-3.2
Classifier:A. Irving and S. Kuehner, UWS
Type spec mass (g):21
Type spec location:UWB
Main mass:GHupé
Comments:GH-417; submitted by A. Irving
Plots: O isotopes:  
Institutions
   and collections
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)
GHupé: Gregory M. Hupé, 9003 Placid Lakes Blvd., Lake Placid, FL 33852, United States; Website (private address)
OkaU: Institute for Study of the Earth's Interior, Okayama University, Misasa Tottori 682-0193, Japan (institutional address)
Catalogs:
References: Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015
Find references in NASA ADS:
Find references in Google Scholar:
Geography: 
Coordinates:Unknown.

Statistics:
     This is 1 of 6916 approved meteorites from (Northwest Africa) (plus 2027 unapproved names)

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