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Chemical and physical studies of type 3 chondrites. IX - Thermoluminescence and hydrothermal annealing experiments and their relationship to metamorphism and aqueous alteration in type below 3.3 ordinary chondritesThermoluminescence (TL) properties were measured in samples of four type-3.0 chondrites annealed at 400-850 C and 0.77-1 kbar in the presence of various amounts of water and sodium disilicate. Several changes recorded in TL characteristics, such as the lowering of TL sensitivity in certain samples, its increase in other samples, and changes in the peak position and peak width of TL suggested the occurrence of metamorphic processes in these samples. It is suggested that, for the chondrite types above 3.2, the observed changes in TL are consistent with the TL-metamorphism trends, being due to the formation of feldspar by the devitrification of chondrule glass during metamorphism. For types below 3.2, the TL data are consistent with the hypothesis that these chondrules experienced lower levels of metamorphism than the higher types or, alternatively, with the hypothesis that the type 3.0 chondrules are being produced from higher types by aqueous alteration.
Document ID
19880041992
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Guimon, R. Kyle
(Arkansas Univ. Fayetteville, AR, United States)
Sears, Derek W. G.
(Arkansas, University Fayetteville, United States)
Lofgren, Gary E.
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 13, 2013
Publication Date
January 1, 1988
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 52
ISSN: 0016-7037
Subject Category
Lunar And Planetary Exploration
Accession Number
88A29219
Funding Number(s)
CONTRACT_GRANT: NAG9-81
Distribution Limits
Public
Copyright
Other

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