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Northwest Africa 6960 | |||||||||||||||||||||||||||||||
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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: ![]() | ||||||||||||||||||||||||||||||
Classification history: |
This is 1 of 11 approved meteorites classified as OC3. [show all] Search for other: Ordinary chondrites, Ordinary chondrites (type 3) | ||||||||||||||||||||||||||||||
Comments: | Approved 22 Oct 2013 | ||||||||||||||||||||||||||||||
Writeup![]() |
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: |
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Data from: MB102 Table 0 Line 0: |
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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, Burke Museum of Natural History and Culture, Box 353010 Seattle, WA 98195, United States (institutional address; updated 9 Oct 2023) 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) |
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Catalogs: |
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References: | Published in Meteoritical Bulletin, no. 102, MAPS 50, 1662, September 2015
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Geography: |
Statistics: This is 1 of 9429 approved meteorites from (Northwest Africa) (plus 1876 unapproved names) |