Yellowstone :: Mammoth Hot Spring Terraces

Friday, September 2nd - - The temperature was even cooler this morning – a rather brisk 29 degrees! There was some frost on the rear window. I drove down to Yellowstone Lake and found a drive that went along the shoreline for a little ways.

The sun had already risen above the mountain tops and there was a lot of haze in the sky. It was the perfect place for breakfast on this, my last morning in the park!

I decided to revisit the Mammoth Hot Springs Terrace, specifically the Upper Terrace where there was actually a road that wound its way through the area. Driving the “long way” around, going south then west then north, it took me nearly 3 hours to reach the Terraces. Of course, I did stop a few times along the way...

And, wow, what a difference a day makes! With a good nights rest and better lighting conditions, the terraces looked completely different than they did the previous day.

Prospect Spring, which flows into the Highland Terrace, and those microscopic thermophiles that make it so colorful.

Leaves and twigs fall into the shallow waters and are transformed by the minerals in the water.

Thermophiles (those heat-loving microorganisms) create tapestries of color where hot water flows among the terraces. Colorless and yellow thermophiles grow in the hottest water; orange, brown, and green thermophiles thrive in cooler waters. The colors also change with the seasons.

The terraces are formed by a combination of factors: The hot water beneath the surface dissolves carbon dioxide that makes a solution of weak carbonic acid. As the solution rises through rock, it dissolves calcium carbonate, the primary compound in limestone. At the surface, the calcium carbonate is deposited in the form of travertine, the rock that forms the terraces of Mammoth Hot Springs.

There is a constant state of flux as the water moves over the surface and the terraces grow.

Over the years, the terraces grow and expand, encroaching on areas where trees had thrived.

The above photo was taken when I visited the park in July 1979. It is a lower angle and doesn't show as much of the “face” of the terraces but, with the position of the mountains in the background, I think it was taken in the same area as the next two photos.

Of course, 34 years have gone by, and some change was to be expected, but this is a lot of change! The Park Ranger stated that the boardwalk in this area has been moved back twice and will have to be moved again within a few years.

Growth and change, dependent upon the flow of water.

I was enthralled by the various colors of the pools of water in the smaller terraces.

And by what is left behind when the water no longer flows.

This visit to the Mammoth Hot Spring Terraces was the perfect ending to my short stay at Yellowstone National Park!