Datasets generated for O'Mara et al. (2026), Fire biomarkers in marine sediments record terrestrial fire activity. <i>AGU Advances</i>

Measurements include concentrations and ²³⁰Th_XS-normalized mass accumulation rates of a suite of polycyclic aromatic hydrocarbons (PAHs) and anhydrosugars. Core samples were provided by the Lamont-Doherty Core Repository of Columbia University.<br><br>Compound concentration measurements were made via gas chromatography-mass spectrometry at the Lamont-Doherty Earth Observatory (LDEO) Organic Geochemistry Lab using an Agilent 7890A GC coupled to an Agilent 5975C MS. <br><br><b>File descriptions:</b><br><b>Table S1. </b>Compound info for PAH and anhydrosugar compounds analyzed in this study including name, abbreviation, compound type, molecular weight, ring number, and integration ion.</p><p><br></p><p dir="ltr"><b>Table S2.</b> Sample info including laboratory identification number, latitude (°N), longitude (°E), water depth (m), biomarker concentrations (ng/g), 1 sigma concentration uncertainties, and ²³⁰Th_XS-derived mass accumulation rates (ng cm^-2 kyr^-1) for all compounds analyzed.</p><p><br></p><p dir="ltr"><b>Table S3.</b> Source-area environmental data: annual and monthly climate, vegetation and satellite fire-metric values within each modeled source area (500, 1500 and 3000 m atmospheric back-trajectory sheds and river basins) for every core-top site.</p><p><br></p><p dir="ltr"><b>Table S4.</b> Compositional PCA biomarker loadings.

PCA loadings of the seven biomarker variables (two amount variables and five compositional log-ratios) on PC1 and PC2, internal to the ordination. The ordination is a correlation-matrix PCA of the z-scored variables.<br><br></p><p dir="ltr"><b>Table S5.</b> Fire-metric envfit statistics. R² and permutation p-values for each fire metric fitted as an external vector overlay onto the compositional PCA (envfit, Yeo-Johnson transformed), by source area.</p><p><br></p><p dir="ltr"><b>Table S6.</b> Random Forest validation and out-of-sample skill.