Canary Spring (from the top, showing the hot spring):
When the carbonic acid found in the hot springs water comes into contact with the natural limestone of the surrounding geology, carbon dioxide gas escapes and allows the limestone to be re-deposited as travertine, a chalky white rock. Travertine is also known by the name calcium carbonate, the stuff you find in TUMS. Some estimates are that Mammoth Hot Springs deposits up to two tons of calcium carbonate per day.
CAUTION!: The mists from hot springs and geysers in Yellowstone contain a variety of silica-rich minerals that are hazardous to the optics of all types of cameras. Be sure you are down wind from them, or have taken steps to protect your lenses, when photographing these natural wonders.
Mammoth Hot SpringsCanary SpringTravertineCalcium Carbonate