Atom probe results. a: Reconstruction of atom probe specimen 3263 lifted out from the monazite M13 hosted in quartz. Pb atoms (greenish) and Si atoms (purple) distributions through the specimen are represented. One dot corresponds to one atom. Domains with intense color correspond to Pb and/or Si enrichments and highlight the presence of Pb-bearing nanophases and Si-bearing nanophases respectively. b: Atom probe ²⁰⁸Pb/²³²Th dates (uncertainties are given at 2σ) obtained in monazite located in quartz (blue) and garnet (green) avoiding nanophases. One date has been calculated for each specimen considering a volume of ∼0.0005 μm³ following Fougerouse et al. (2020) recommendations. The average date is 1059 ±129 Ma (2σ).