A shorter 146Sm half-life measured and implications for 146Sm-142Nd chronology in the solar system |
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| Authors: | Kinoshita N Paul M Kashiv Y Collon P Deibel C M DiGiovine B Greene J P Henderson D J Jiang C L Marley S T Nakanishi T Pardo R C Rehm K E Robertson D Scott R Schmitt C Tang X D Vondrasek R Yokoyama A |
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| Institution: | Research Facility Center for Science and Technology, University of Tsukuba, Tsukuba, Japan. |
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| Abstract: | The extinct p-process nuclide (146)Sm serves as an astrophysical and geochemical chronometer through measurements of isotopic anomalies of its α-decay daughter (142)Nd. Based on analyses of (146)Sm/(147)Sm α-activity and atom ratios, we determined the half-life of (146)Sm to be 68 ± 7 (1σ) million years, which is shorter than the currently used value of 103 ± 5 million years. This half-life value implies a higher initial (146)Sm abundance in the early solar system, ((146)Sm/(144)Sm)(0) = 0.0094 ± 0.0005 (2σ), than previously estimated. Terrestrial, lunar, and martian planetary silicate mantle differentiation events dated with (146)Sm-(142)Nd converge to a shorter time span and in general to earlier times, due to the combined effect of the new (146)Sm half-life and ((146)Sm/(144)Sm)(0) values. |
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