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Chemical composition of HAL, an isotopically-unusual Allende inclusionSamples of hibonite, black rim, and portions of friable rim from an unusual Allende inclusion, named HAL, were analyzed by INAA and RNAA for 37 major, minor, and trace elements. An unusually low amount of Ce was found in HAL, although it otherwise was highly enriched in REE compared to C1 chondrites. HAL is also depleted in Sr, Ba, U, V, Ru, Os, and Ir relative to other refractory elements. It is concluded that the distribution of REE between hibonite and rims was established when hibonite and other refractory minerals were removed at slightly different temperatures from a hot, oxidizing gas in which they previously coexisted as separate grains. Possible locations for the chemical and mass dependent isotopic fractionation are considered to be in ejecta from the low temperature helium-burning zone of a supernova and in the locally oxidizing environment generated by evaporation of interstellar grains of near-chondritic chemical composition.
Document ID
19820062339
Document Type
Reprint (Version printed in journal)
Authors
Davis, A. M. (Chicago Univ. Chicago, IL, United States)
Tanaka, T. (Chicago Univ. Chicago, IL, United States)
Grossman, L. (Chicago, University Chicago, IL, United States)
Lee, T. (Carnegie Institution of Washington, Washington, DC; Chicago, University Chicago, IL, United States)
Wasserburg, G. J. (California Institute of Technology Pasadena, CA, United States)
Date Acquired
August 10, 2013
Publication Date
September 1, 1982
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 46
Subject Category
LUNAR AND PLANETARY EXPLORATION
Funding Number(s)
CONTRACT_GRANT: NGL-05-002-188
CONTRACT_GRANT: NGR-14-001-249
Distribution Limits
Public
Copyright
Other