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The origin and history of the metal and sulfide components of chondrulesInstrumental and radiochemical neutron activation analysis is used to determine the concentrations of 14 siderophile and other nonlithophilic elements in 31 chondrules from the extremely unequilibrated chondrite Semarkona. The results are presented in tables and graphs, characterized in detail, and compared with the results obtained for lithophile elements in the same samples by Grossman and Wasson (1983). The elements studied are found to be significantly more fractionated than the lithophile elements, with variations in chondrule/whole-rock abundances of up to a factor of 1000, a mean ratio of 0.2, and differences between Ni-rich and Ni-depleted chondrules. It is argued that the metal and sulfides in the chondrules represent the composition of the solar nebula before chondrule formation and already contained the siderophile and chalcophile elements, although some Fe was contained in silicates along with Ni, Co, Au, Ge and Se. The segregation of metals during a molten stage is considered of minor importance.
Document ID
19850054070
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Grossman, J. N.
(U.S. Geological Survey, Reston, VA; California, University Los Angeles, CA, United States)
Wasson, J. T.
(California, University Los Angeles, CA, United States)
Date Acquired
August 12, 2013
Publication Date
April 1, 1985
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 49
ISSN: 0016-7037
Subject Category
Lunar And Planetary Exploration
Accession Number
85A36221
Funding Number(s)
CONTRACT_GRANT: NAG9-40
Distribution Limits
Public
Copyright
Other

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