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Irradiation stratigraphy and depositional history of the Apollo 16 double drive tube 60009/10We report track density frequency distributions, the fraction of high density grains and minimum track densities for 63, 1 mm wide locations in the Apollo 16 double drive tube 60009/10. From these data we conclude that there are seven irradiation strata in the core. Only one buried reworking zone extending from 50-52 cm was found and it was exposed near the surface from 4.5-9 times 10 to the 6th y with a most probable exposure period of 6 times 10 to the 6th y. There is lack of conclusive data that this zone represents a reworking zone in which case the material below 52 cm most probably was exposed in situ for 4.5 times 10 to the 6th y and developed a reworking zone approximately less than 0.5 cm. The present surface of the core has a reworking zone of 12-13 cm which was exposed from 1.3 times 10 to the 7th to 2.5 times 10 to the 8th y. The best estimate for this exposure period remains the value of approximately less than 1.25 times 10 to the 8th y determined by Bogard and Hirsch (1976). The other strata in the core appear to contain mixtures of various soil types and are not related to in situ depositional events.
Document ID
19800039457
Document Type
Conference Proceedings
Authors
Blanford, G. E. (Houston Univ. Clear Lake, TX, United States)
Blanford, J. (Houston Univ. Clear Lake, TX, United States)
Hawkins, J. A. (Houston, University Clear Lake City, Tex., United States)
Date Acquired
August 10, 2013
Publication Date
January 1, 1979
Subject Category
LUNAR AND PLANETARY EXPLORATION
Meeting Information
Lunar and Planetary Science Conference(Houston, TX)
Funding Number(s)
CONTRACT_GRANT: NSG-9043
Distribution Limits
Public
Copyright
Other