Robust interpretation of Pb isotopes

Lead isotopes decode planetary evolution through radiogenic decay (e.g., ²³⁸U→²⁰⁶Pb), offering insights into magma sources and crust-mantle dynamics. They serve dual roles: geochronology (model ages) and provenance studies (initial Pb ratios). U/Th-poor minerals (e.g., K-feldspar) preserve primary Pb, while whole-rock analyses require radiogenic corrections. The paper addresses complexities like open-system mixing and model age discrepancies, emphasizing Pb evolution frameworks (e.g., Stacey-Kramers) for tracing crustal recycling and ore genesis.

The study compares solution-mode (TIMS, MC-ICPMS) and in situ (LA-MC-ICPMS) techniques, emphasizing precision and accuracy. Key challenges include mass bias correction, isobaric interferences (e.g., ²⁰⁴Hg on ²⁰⁴Pb), and low-Pb sample limitations. Data validation protocols—acid leaching, matrix-matched standards, and poly-spike normalization—are detailed to mitigate contamination and instrumental artifacts. The authors stress error correlation (e.g., ²⁰⁶Pb/²⁰⁴Pb–²⁰⁷Pb/²⁰⁴Pb) and advocate error ellipses over cross-plots to visualize uncertainties. These strategies ensure reliable interpretations of geologic processes versus analytical noise.

A reporting checklist ensures transparency, covering methods, U/Th/Pb concentrations, and error correlations. Standardized data aids integration with Hf/Nd systems and supports forensic/archaeologic studies. Linearized Pb diagrams simplify growth curve interpretation, while case studies highlight environmental and crustal mapping uses. The framework bridges geochronology and geodynamics, advancing Pb isotopes in mineralization research and planetary models. The work entitled “Strategies towards robust interpretations of Pb isotopes” was published on Geoscience Frontiers (published on Mar 25, 2025).