The NC-CC dichotomy in ruthenium isotopes: Implications for the origin of the late veneerOPEN ACCESS
Jonas Pape, Emily A. Worsham, Thorsten Kleine
Icarus
Available online 28 August 2026
“Highlights
- High-precision Ru isotope data of iron meteorites are presented.
- A novel internal normalization scheme for Ru isotope measurements is introduced.
- Ruthenium isotope data reveal the NC-CC dichotomy.
- The Ru isotope systematics of meteorites and terrestrial samples provide new constraints on an NC origin of the late veneer.”
“High-precision mass-independent Ru isotope data for iron meteorites reveal that in three-isotope diagrams including the p-process Ru nuclides 96Ru or 98Ru, non‑carbonaceous (NC) meteorites plot along an s-process mixing line, while the carbonaceous (CC) type irons plot as a cluster off the NC-line. As previously observed for Mo, this offset can be accounted for by an r-process excess in CC over NC materials. As a highly siderophile element, Ru in the bulk silicate Earth (BSE) is thought to predominantly derive from the late veneer, making the Ru isotope dichotomy a powerful genetic tracer of Earth’s late accretionary epoch. The BSE and the isotopically anomalous Itsaq Gneiss Complex as defined in prior studies plot on the NC-line defined in this study, suggesting a predominantly NC late veneer that may have evolved over time from more s-process-enriched to more s-process-depleted compositions. However, more precise 96Ru and 98Ru measurements of the BSE’s composition are needed to more reliably determine the genetic heritage of the late veneer and to quantify as to whether it contains CC material.”
