Scientists can now finally explain how the unusual steps at the Mammoth Hot Springs came to be:
Geologists have long been at a loss to explain the rocks’ unusual shapes, but physicists at the University of Illinois at Urbana-Champaign say they have figured out the answer.
Unlike most water-washed surfaces, the primary geological process shaping the Mammoth Hot Springs landscape is not erosion. The rocks there are actually growing — at the rate of one to five millimeters a day — as calcium carbonate in the water precipitates to form the mineral travertine.
I think this can be chalked up to one of those things scientists never explained because it was too obvious to bother asking them. That picture looks exactly like what happens if you leave a pan full of my well water on the woodstove overnight.