Canadian Rockies Hot Springs
Natural Wonders & Cultural Treasures
The Nature of Hot Springs
Where does the spring water come from?
Family viewing the outlet of Miette
Hot Springs
© Parks Canada / Brenda Falvey, 2001 |
Most of the rain and snow that falls on the slopes of a mountain
ends up in rivers and streams. Some of it, however, filters down
through the cracks and pores in the mountain rock, pulled by gravity
to a depth of three kilometres below the surface. It is this water
which later returns to the surface in our hot springs.
Why is it warm?
As it seeps into the ground, the water becomes hotter and hotter
— heated by radioactive decay in the earth's core. When
the water boils, pressure forces it upward, just like the water
in a coffee percolator. The speed at which the water rises, and
the degree to which it mixes with cold ground water, causes the
temperature to fluctuate.
Why does it smell?
As the water heats up, it dissolves minerals in the surrounding
rock. When these dissolved minerals break down, they release hydrogen
sulphide gas, which smells like rotten eggs. Pyrite and gypsum
are two common sulphur-bearing minerals dissolved in the Banff
and Miette hot springs. The water at Radium Hot Springs is odorless
because of the type of rock in that area.
What is tufa? (pronounced too-fa)
As the hot springs water bubbles from its underground channel,
it begins to drop the load of minerals it gained on its journey
through the earth. One of these minerals, calcium carbonate, hardens
into a porous grey/brown rock called tufa. The entire hillside
around each springs is composed of tufa.
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