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Ag Isotopic Evolution of the Mantle During Accretion: New Constraints from Pd and Ag Metal-Silicate Partitioning Decay of (sup 107) Pd to (sup 107) Ag has a half-life of 6.5 times 10 (sup 6) mega-annums. Because these elements are siderophile but also volatile, they offer potential constraints on the timing of core formation as well as volatile addition. Initial modelling has shown that the Ag isotopic composition of the bulk silicate Earth (BSE) can be explained if accretion occurs with late volatile addition. These arguments were tested for sensitivity for pre-cursor Pd/Ag contents, and for a fixed Pd/Ag ratio of the BSE of 0.1. New Ag and Pd partitioning data has allowed a better understanding of the partitioning behavior of Pd and Ag during core formation. The effects of S, C and Si, and the effect of high temperature and pressure has been evaluated. We can now calculate D(Ag) and D(Pd) over the wide range of PT conditions and variable metallic liquid compositions that are known during accretion. We then use this new partitioning information to revisit the Ag isotopic composition of the BSE during accretion.
Document ID
20180002991
Document Type
Conference Paper
Authors
Righter, K.
(NASA Johnson Space Center Houston, TX, United States)
Schonbachler, M.
(Eidgenossische Technische Hochschule Zurich, Switzerland)
Date Acquired
May 21, 2018
Publication Date
May 7, 2018
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
JSC-E-DAA-TN54987
LPI Contrib. No. 2084
Meeting Information
Meeting: Differentiation: Building the Internal Architecture of Planets
Location: Pasadena, CA
Country: United States
Start Date: May 7, 2018
End Date: May 10, 2018
Sponsors: Universities Space Research Association, Lunar and Planetary Inst.
Distribution Limits
Public
Copyright
Public Use Permitted.
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