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Thermoluminescence and the shock and reheating history of meteorites. III - The shergottitesThermoluminescence (TL) measurements on Shergotty, ALHA 77005, Zagami, and EETA 79001 (lithology A) have been used to obtain further information on the shock history of these meteorites. The level of TL sensitivity in the shergottites varied by a factor of 10, but was always low, probably reflecting the amount of crystalline material in the maskelynite. There are trends in the TL peak temperature, peak width, and TL sensitivity which are believed to be associated with different proportions of feldspar in high- and low-temperature forms. This interpretation is consistent with the observed changes induced in the TL properties by annealing shergottites at 400-900 C. It is suggested that the observed trends were produced during postshock crystallization at a variety of cooling rates, the increasing order of cooling rate being EETA 79001, Zagami, ALHA 77005, and Shergotty, and that there is high-temperature feldspar present in all the samples. This implies a postshock temperature above 600 C, and a small (less than 10 m) size of the ejecta. Current theories are well able to explain how objects of this size could have been ejected from Mars.
Document ID
19860063602
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Hasan, F. A.
(Arkansas Univ. Fayetteville, AR, United States)
Haq, M.
(Arkansas Univ. Fayetteville, AR, United States)
Sears, D. W. G.
(Arkansas, University Fayetteville, United States)
Date Acquired
August 12, 2013
Publication Date
June 1, 1986
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 50
ISSN: 0016-7037
Subject Category
Lunar And Planetary Exploration
Accession Number
86A48340
Funding Number(s)
CONTRACT_GRANT: NAG9-81
Distribution Limits
Public
Copyright
Other

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