Published February 7, 2025 | Published
Journal Article Open

Enrichment of moderately volatile elements in first-generation planetesimals of the inner Solar System

  • 1. ROR icon Arizona State University
  • 2. ROR icon California Institute of Technology
  • 3. ROR icon Rice University
  • 4. ROR icon Massachusetts Institute of Technology

Abstract

The depletion of moderately volatile elements (MVEs) in terrestrial planets remains poorly understood, with explanations including partial nebular condensation and MVE loss during planetesimal differentiation or collisions. In this study, we use magmatic iron meteorites to reconstruct the MVE inventory of the earliest inner [noncarbonaceous (NC)] and outer [carbonaceous (CC)] Solar System planetesimals. We show that several NC and CC iron meteorite parent bodies (IMPBs) exhibit chondrite-like MVE abundances, indicating that "first-generation" inner Solar System planetesimals were remarkably MVE rich. Consistent with isotopic signatures of MVEs in Earth and Mars, these planetesimals made a substantial contribution to the MVE inventories of terrestrial planets. Variations in MVE abundances among IMPBs, particularly the two volatile-depleted NC and CC IMPBs (IVA and IVB), reflect secondary volatile loss after disruption of their parent bodies. Consequently, MVE depletion in terrestrial planets is more closely linked to the protracted history of MVE loss during planetesimal collisions rather than incomplete condensation or MVE loss during planetesimal differentiation.

Copyright and License

© 2025 the Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a creative commons Attribution NonCommercial License 4.0 (CC BY-NC).

Acknowledgement

We thank A. P. Vyas for helping to improve the clarity of communication.

Funding

This study was supported by startup funds from ASU to D.S.G.

Contributions

D.S.G. conceived the project and compiled the data. D.S.G. performed the numerical calculations with S.B. and B.Z. All authors interpreted the data. D.S.G. wrote the manuscript with inputs from all authors.

Data Availability

All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials.

Supplemental Material

Figs. S1-S3; Tables S1-S4 (PDF)

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Additional details

Created:
February 10, 2025
Modified:
February 10, 2025