Mammoth Hot Springs

On August 15, 1997 I visited Mammoth Hot Springs - the original main entrance and current Park headquarters. Toured the interesting terraces formed here by hot springs. There were elk resting in two areas - apparently enjoying the heated ground.

Mammoth Hot Springs is different from other thermal areas in the area. This is largely because limestone is a relatively soft type of rock, allowing the travertine formations to grow much faster than other sinter formations. It has been described as looking like a cave turned inside out.

Each year, the rain and melted snow seeps into the earth. Cold to begin with, the water is quickly warmed by heat radiating from a partially molten magma chamber deep underground, the remnant of a cataclysmic volcanic explosion that occurred 600,000 years ago.

After moving throughout this underwater "plumbing" system, the now hot water rises up through a system of small fissures. Here it also interacts with hot gases charged with carbon dioxide rising up from the magma chamber. As some of the carbon dioxide is dissolved in the hot water, a weak, carbonic acid solution is formed.

In the Mammoth area, the hot, acidic solution dissolves large quantities of limestone on its way up through the rock layers to the hot springs on the surface. Above ground and exposed to the air, some of the carbon dioxide escapes from the solution. Without it, the dissolved limestone can’t remain in the solution, so it reforms into a solid mineral. This white, chalky mineral is deposited as the travertine that forms the terraces.

Minerva Terrace, Mammoth Hot Springs, Yellowstone National Park

Cupid Spring was firstly observed in 1931 and its last noteworthy period of activity ceased in the 1990s. From 2010 onwards, Cupid Spring showed new discharge, which is getting stronger from year to year.