Water lake and alteration minerals

Left: Kīlauea’s water lake on November 17, 2020 (photo by M. Patrick). The orange and brown colors are caused by the presence of various oxygen- and sulfur-bearing iron minerals in the water. The green at the edges is caused by an influx of iron-bearing groundwater that has not yet had time to react with oxygen in the atmosphere. Right: Alteration minerals near Sulphur Cone on Mauna Loa, September 8, 2022 (photo by T. Elias). Similar minerals at Kīlauea would have been dissolved into the lake to cause the high sulfur concentrations in the water. USGS images.