Fig. 2.

Parent PAH concentrations across the K–Pg boundary interval for sites M0077, 1262, and 738. K–Pg boundary deposits are highlighted in gray, and samples are colored by the pyrene APDI index (67). Warm colors represent more pyrogenic inputs, cool colors represent more petrogenic inputs, and white represents mixed inputs. Black rectangles on core photographs denote intervals with charcoal observations (26, 31). Vertical green bars represent intervals with elevated (>0.25 ppb) Ir concentrations, and purple bars represent intervals with peak (>1 ppb) Ir concentrations. Vertical blue bars represent intervals with low, extraterrestrial ¹⁸⁷Os/¹⁸⁸Os ratios (57, 59, 63). Sites M0077 and 1262 are displayed on a 0 to 1.1 × 10⁵ ng/g axis; site 738 is displayed on a 0 to 4 × 10⁵ ng/g axis.