⁴⁰Ar-³⁹Ar ages and cosmic ray exposure ages of Apollo 14 samples
Abstract
We have used the ⁴⁰Ar-³⁹Ar dating technique on eight samples of Apollo 14 rocks (14053, 14310), breccia fragments (14321), and soil fragments (14001, 14167). The large basalt fragments give reasonable ⁴⁰Ar/³⁹Ar release patterns and yield well defined crystallization ages between 3.89–3.95 aeons. Correlation of the ⁴⁰Ar/39Ar release patterns with ³⁹Ar/³⁷Ar patterns showed that the low temperature fractions with high radiogenic argon loss came from K-rich phases. A highly shocked sample and fragments included in the breccia yield complex release patterns with a low temperature peak. The total argon age of these fragments is 3.95 AE. Cosmic ray exposure ages on these samples are obtained from the ratio of spallogenic ³⁸Ar to reactor induced37Ar and show a distinct grouping of low exposure ages of ∼ 26 my correlated with Cone crater. Other samples have exposure ages of more than 260 my and identify material with a more complex integrated cosmic age exposure history.
Additional Information
We wish to acknowledge the skillful support of P. Young and A. Massey who designed, built and maintained the programmable system used in these analyses. T. Wen and D.A. Papanastassiou provided the precise K analyses of the irradiation monitor. Jennifer Wenner provided one of the better figures. This work was supported by NASA contract NAS-9-8074 and NSF grant GP-19887.Additional details
- Alternative title
- 40Ar-39Ar ages and cosmic ray exposure ages of Apollo 14 samples
- Eprint ID
- 117921
- Resolver ID
- CaltechAUTHORS:20221121-280779900.7
- NAS-9-8074
- NASA
- GP-19887
- NSF
- Created
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2022-11-29Created from EPrint's datestamp field
- Updated
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2022-11-29Created from EPrint's last_modified field
- Other Numbering System Name
- Caltech Division of Geological and Planetary Sciences
- Other Numbering System Identifier
- 2050