Data-driven modeling of background and mine-related acidity and metals in river basins

The trained self-organizing map is used to determine upstream hydrothermal alteration (AS - acid sulfate; PROP - propylitic, PROP-V - propylitic veins, QSP - quartz-sericite-pyrite, WSP - weak-sericite-pyrite; Mining activity: MINES) from water-quality measurements in the Animas river basin, Colorado, USA. The white hexagons are sized proportional to the number of water-quality samples associated with that SOM neuron.