English: Conceptual diagram of Yellowstone hot spring dissolved organic matter (YDOM) transformation in Yellowstone hot springs as derived from drill core studies.

(1) Depth and temperature are determined from geothermal gradients published in White et al. (1975).

(2) Calculated from the amorphous silica geothermometer equation. A temperature probe Iowered into nearby Cinder Pool reached 91 °C; Fournier (1977).

(3) Maximum temperature observed in the subsurface at Norris and consistent with estimates calculated with silica, Na-K, and Na-K-Ca geothermometers; White et al. (1975).

(4) Actual temperature from Y-2 (Firehole Lake) drill hole data reported in White et al. (1975), and consistent with the temperature calculated with the quartz adiabatic geothermometer equation, Fournier (1977).

(5) Actual temperature from Y-10 (Mammoth) drill hole data reported in White et al. (1975)

(6) Estimated by Fournier (1989) using chemical geothermometer equations.