Supplemental Material: Paleogene loess emerged before the Eocene–Oligocene transition in the western United States

Additional methodological information and supporting analyses, including procedures for grain-size pretreatment, model evaluation, and hyperparameter settings applied for the supervised models, along with Figures S1–S5 illustrating stratigraphic logs, confusion matrices for unsupervised and supervised models, and supervised model applications to the Fan et al. (2020) dataset. Raw grain-size dataset including sample names, depths, full grain-size distributions, statistical parameters, and machine-learning classification results for the White River Formation samples (Data S1).