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Origin of metallic Fe-Ni in Renazzo and related chondritesTo assess the formation of metallic Fe-Ni in Renazzo and related chondrites, Ni and Co zoning profiles in metallic Fe-Ni are determined from different petrographic sites (chondrule interiors, chondrule margins, chondrule rims, and matrix) in Renazzo, Al Rais, and the related chondrite, MacAlpine Hills 87320. Metal from chondrule interiors shows flat Ni and Co concentrations and profiles, moderately large grain-to-grain compositional variations (even with chondrules), and generally high Ni and Co. Nickel concentrations extend above the kamacite stability limit; etching such 'martensite' shows high-Ni domains in some cases, but observed Ni concentrations do not exceed 190 mg/g. Metal from chondrule margins adjacent to matrix shows convex Ni and Co zoning profiles; the highest Ni and Co concentrations are at grain centers, although the mean central Ni and Co concentrations in margin grains are much lower than those from chondrule interiors; the remainder are convex. The low Co and Ni contents at the edge of grains in chondrule margins are interpreted to reflect dilution by Fe produced by FeO reduction.
Document ID
19920062100
Document Type
Reprint (Version printed in journal)
Authors
Lee, Min S. (NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Rubin, Alan E. (NASA Lyndon B. Johnson Space Center Houston, TX, United States)
Wasson, John T. (California, University Los Angeles, United States)
Date Acquired
August 15, 2013
Publication Date
June 1, 1992
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 56
Issue: 6 Ju
ISSN: 0016-7037
Subject Category
LUNAR AND PLANETARY EXPLORATION
Funding Number(s)
CONTRACT_GRANT: NAG9-40
Distribution Limits
Public
Copyright
Other