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Absolute dating techniques

Wasserburg, G. J. and Huneke, J. C. and Podosek, F. A. and Husain, Liaquat and Schaeffer, O. A. and Sutter, J. F. (1972) Absolute dating techniques. Science, 175 (4023). p. 795. ISSN 0036-8075. doi:10.1126/science.175.4023.795.

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In their report on the ages of crystalline rocks from the Apollo 14 mission, Husain, Sutter, and Schaeffer present some important results using the ^(40)Ar-^(39)Ar method. This technique, which has been used by several other workers, depends critically on the use of mineral or rock standards of precisely known ^(40)Ar/K ratio. The "age" of the standard is not directly relevant. What is required is the 40Ar/K in the standard. These standards should be adequately documented somewhere in the literature. Often the point is missed that the ^(40)Ar-^(39)Ar age is not absolute, but is relative to ^(40)Ar/K of the standard sample. The uncertainty of absolute ages determined by this method must include any uncertainty in the ^(40)Ar/K ratio of the comparison sample. At the present stage of development of argon-potassium dating in particular, and geochronology in general, it is rather surprising to find that workers continue to determine ages on lunar samples, using "standards" (terrestrial or otherwise) which are themselves uncertain to several percent. In the work by Husain et al. it would appear that the actual uncertainty in age due to both analytical error and the error in the hornblende monitor is 3.77 ± 0.15 ± 0.15 eons, or 3.77 ± ~0.30 eons. Analytical techniques which have been available for some years easily permit more definitive measurements to be made, particularly on valuable lunar materials. Since the time interval over which lunar igneous activity is presently observed to occur is rather restricted (4.00 to 3.20 eons from current data), the necessity for adequately precise data is apparent.

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Wasserburg, G. J.0000-0002-7957-8029
Additional Information:© 1972 American Association for the Advancement of Science.
Issue or Number:4023
Record Number:CaltechAUTHORS:20141013-111058583
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Official Citation:Absolute Dating Techniques G. J. Wasserburg, J. C. Huneke, F. A. Podosek, Liaquat Husain, O. A. Schaeffer and J. F. Sutter Science, New Series, Vol. 175, No. 4023 (Feb. 18, 1972), p. 795 Published by: American Association for the Advancement of Science Article Stable URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50352
Deposited On:14 Oct 2014 17:15
Last Modified:10 Nov 2021 18:55

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