The U–Th–He method is a technique to determine the cooling history of minerals. Traditional approaches to U–Th–He dating are time-consuming and require handling strong acids and radioactive solutions. This paper presents an alternative approach in which samples are irradiated with protons and subsequently analysed by laser ablation mass spectrometry. Unlike previous in situ U–Th–He dating attempts, the new method does not require any absolute concentration measurements of U, Th, or He.

We propose using the Wasserstein-2 distance (W₂) as an alternative to the widely used Kolmogorov–Smirnov (KS) statistic for analysing distributional data in geochronology. W₂ measures the horizontal distance between observations, while KS measures vertical differences in cumulative distributions. Using case studies, we find that W₂ is preferable in scenarios where the absolute age differences in observations provide important geological information. W₂ has been added to the R package IsoplotR.

Secondary ion mass spectrometry (SIMS) is the oldest and most sensitive analytical technique for in situ U–Pb geochronology. This paper introduces a new algorithm for SIMS data reduction that treats data as compositional data, which means that the relative abundances of ²⁰⁴Pb, ²⁰⁶Pb, ²⁰⁷Pb, and ²³⁸Pb are processed within a tetrahedral data space or simplex. The new method is implemented in an eponymous computer programme that is compatible with the two dominant types of SIMS instruments.