Initial strontium isotopic abundances and the resolution of small time differences in the formation of planetary objects
- Creators
- Papanastassiou, D. A.
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Wasserburg, G. J.
Abstract
It is shown that differences in the ⁸⁷Sr/⁸⁶Sr ratio corresponding to about 10⁻² % are clearly resolvable using improved instrumental techniques. Several basaltic achondrites having a total spread of 0.2% in ⁸⁷Sr/⁸⁶Sr were studied and appear to define an identical initial ⁸⁷Sr/⁸⁶Sr abundance corresponding to 0.698976 ± 0.000055 (maximum uncertainties). These samples are found to lie on a well defined isochron with a slope of 0.0629 ∓ 0.0037 and an age 4.39 ∓ 0.26 × 10⁹ yr. for λ = 1.39 × 10⁻¹¹ yr⁻¹. The maximum deviation of a data point from the best fit line is 6 × 10⁻³ %. This shows that if the samples were derived from material with chondritic or solar Rb/Sr abundance ratios, they were formed within a time period of 4 m.y. or 1.6 m.y. respectively. The application of such measurements to establish a refined early solar system chronology is discussed.
Additional Information
© 1968 Published by Elsevier B.V. Received 26 February 1969. The samples studied were obtained through the generous cooperation of several institutions: G. Kurat, Naturhistorisches Museum, Vienna (Jonzae, Stannern); C.B. Moore, Ninninger Collection, Arizona State University (Juvinas, Moore County, Pasamonte, Sioux County); L.T. Silver, California Institute of Technology (Nuevo Laredo); and P. Pellas and F. Kraut, Musé National d'Histoire Naturelle, Paris (St. Séverin). This work was supported by grants from the National Science Foundation (GP-7976, GP-9114), and in part by a contract from the National Aeronautics and Space Administration (NRG-05-002-044). We were privileged to have the benefit of frequent discussions with D.S. Burnett, and constructive criticisms from W.A. Fowler, P. Gast and G. Wetherill. We would like to thank Pai Young and Uwe Derksen for their efforts in maintaining the Lunatic I spectrometer in the operating condition necessary for this work. Both of us would like, to thank Professor T. Lauritsen for having directed one of us (D.A.P.) into this field.Additional details
- Eprint ID
- 115129
- Resolver ID
- CaltechAUTHORS:20220610-395899300
- GP-7976
- NSF
- GP-9114
- NSF
- NRG-05-002-044
- NASA
- Created
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2022-06-10Created from EPrint's datestamp field
- Updated
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2022-06-13Created from EPrint's last_modified field
- Other Numbering System Name
- Caltech Division of Geological Sciences
- Other Numbering System Identifier
- 1603