A precise ⁸⁷Rb⁸⁷Sr age and initial ⁸⁷Sr⁸⁶Sr for the Colomera iron meteorite
- Creators
- Sanz, H. G.
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Burnett, D. S.
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Wasserburg, G. J.
Abstract
Rb-Sr analyses of silicates from the Colomera iron meteorite show a wide range in Rb/Sr and give ⁸⁷Sr⁸⁶Sr values ranging from 0.699 to 8.45. These analyses define a precise linear array on the Rb-Sr evolution diagram yielding an age of 4.61 ± 0.04 × 10⁹yr. A highprecision analysis of a whitlockite separate having very low Rb/Sr yields an initial (⁸⁷Sr⁸⁶Sr)_I = 0.69940 ± 0.00004. An upper limit of 48 ± 7 million years can be set for the time interval between dispersion of the silicate in the metal phase and final Sr isotopic equilibration, if we assume that Colomera silicate formed from a parent material which had the same initial ⁸⁷Sr⁸⁶Sr as Ca-rich achondrites. The data are consistent with a simple evolutionary history in which Colomera differentiated from a parent material of chondritie RbSr ratio at a time 39 million years after the parent material had the initial ⁸⁷Sr⁸⁶Sr of Ca-rich achondrites and 35 million years before the final Sr equilibration in the Guareña chondrite.
Additional Information
We wish to thank F. HERNANDEZ PACHECO and J. M. FUSTER of the Museo National de Ciencias Naturales of Madrid for giving us the opportunity to work with so extraordinary an object as Colomera. The microprobe analyses reported here were done by A. CHODOS. The photograph of the inclusion was taken by A. L. ALBEE. We were privileged to have valuable discussions with A. L. ALBEE, D. A. PAPANASTASSIOU, and A. E. BENCE. Critical comments by W. COMPSTON were a significant aid to us. This research was carried out while the senior author was an International NASA Fellow sponsored by the Comision National para la Investigation del Espacio de Espana and the National Aeronautics and Space Administration. This research was supported by National Science Foundation Grants GP-15911 and GP-9114.Additional details
- Alternative title
- A precise 87Rb87Sr age and initial 87Sr86Sr for the Colomera iron meteorite
- Eprint ID
- 117878
- Resolver ID
- CaltechAUTHORS:20221115-798018900.2
- NASA Postdoctoral Program
- NSF
- GP-15911
- NSF
- GP-9114
- Comision National para la Investigation del Espacio de Espana
- Created
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2022-11-17Created from EPrint's datestamp field
- Updated
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2022-11-17Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences (GPS)
- Other Numbering System Name
- Caltech Division of Geological Sciences
- Other Numbering System Identifier
- 1846