Mammoth Hot Springs is a very active geothermal region in the northwestern part of Yellowstone Park.

 

Over many years these mineral-rich hot springs have  deposited thick layers of colored travertine on the Mammoth Terraces.

Terrace Mountain is the world's largest calcium carbonate depositing hot spring.

 

The source of the hot springs is the ever changing Norris Geyser Basin.  From here the water flows through a limestone-rich underground fault to Mammoth.

 

At Mammoth the water temperature has dropped low enough to allow algae growth in the pools that gives the travertine its special colors.

 

A network of boardwalks lets you walk over and up-close to the terraces and pools.

 

We visited Mammoth Hot Springs on a sunny and warm day in June 1990.