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Studies of K-Ar dating and xenon from extinct radioactivities in breccia 14318; implications for early lunar historyThe lunar breccia 14318 is one of three Apollo-14 breccias containing substantial amounts of parentless xenon from the spontaneous fission of extinct Pu-244. The argon and xenon contained in this breccia were studied by stepwise heating of pristine and neutron-irradiated samples. The isotopic composition of xenon from fission, determined by an improved method, is shown to be from Pu-244. Concentrations of this fissiogenic xenon are in substantial excess (15-fold) of what could be produced by spontaneous fission of U-238. The breccia is found to contain abundant trapped argon with an Ar-40/Ar-36 ratio of roughly 14. Otherwise, the argon is radiogenic and gives a convincing K-Ar age of 3.69 plus or minus 0.09 b.y. by the stepwise Ar-40/Ar-39 method, nearly in agreement with ages for other Apollo-14 breccias.
Document ID
19740041753
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Reynolds, J. H.
Alexander, E. C., Jr.
Davis, P. K.
Srinivasan, B.
(California, University Berkeley, Calif., United States)
Date Acquired
August 7, 2013
Publication Date
March 1, 1974
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 38
Subject Category
Space Sciences
Accession Number
74A24503
Funding Number(s)
CONTRACT_GRANT: NGL-05-003-409
Distribution Limits
Public
Copyright
Other

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