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Helium and neon in lunar ilmenites of different antiquitiesHelium and neon were extracted from individual lunar ilmenite grains, approximately 100 micrometers in diameter, using a pulsed step-heating technique. Grains from lunar samples 71501 and 79035, believed to have been exposed to solar corpuscular radiation at greatly different times, were studied. The results found were consistent with the hypothesis that in addition to solar-wind-implanted gas, a second more deeply implanted component was present in both species of grains. Average isotopic ratios were determined giving equal weight to each of the particles. As found in depth studies employing chemical etching, both the He-3/He-4 and Ne-20/Ne-22 ratios were lower in the more deeply implanted gas than in the solar wind component. The He-3/He-4 ratio in the solar wind component of the more ancient grains was lower than that in the more recently exposed ones, whereas no difference was found for the more deeply embedded He. In the deeply embedded component of the ancient grains, the He-4/Ne-20 ratio was approx. 2x that found in the more recently exposed grains. In the shallowly implanted component, the ratio varied greatly from grain to grain, preventing comparison with the solar wind elemental composition.
Document ID
19950035325
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Nier, A. O.
(Univ. of Minnesota, Minneapolis, MN United States)
Schlutter, D. J.
(Univ. of Minnesota, Minneapolis, MN United States)
Date Acquired
August 16, 2013
Publication Date
September 1, 1994
Publication Information
Publication: Meteoritics
Volume: 29
Issue: 5
ISSN: 0026-1114
Subject Category
Lunar And Planetary Exploration
Accession Number
95A66924
Funding Number(s)
CONTRACT_GRANT: NAG9-110
Distribution Limits
Public
Copyright
Other

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