Summary of semi-quantitative XRD analysis of samples in this study. Outcrop samples are denoted by their location and core samples as “C-depth below ground surface”. Sample “1-DGLS” is a core sample, but was collected from an unspecified depth. Additional information regarding these samples is found in Additional file 1: Table S1. (Top) Example diffraction patterns with major matched peaks for two samples. (Bottom) Heat map of semi-quantitative XRD analyses for samples in this study. Model spectra are referenced in Additional file 1: Table S4.