Travel Reference
In-Depth Information
water is available. Most derive their water directly from rain, snow and condensation, so
their consistency depends on precipitation and the seasons. Are they really boiling? No,
the bubbling is actually the release of steam and gas. Sulfur and iron content give rise to
the nickname 'paint pots.'
Fumaroles
Essentially dry geysers, fumaroles' water boils away before reaching the surface, where
they burst with heat. These steam vents also give off carbon dioxide and some hydrogen
sulfide (that nice 'rotten egg' smell) with a hiss or roaring sound.
Roaring Mountain (
Click here
)
on the Mammoth−Norris road is a huge collection of
fumaroles.
Travertine Terraces
The limestone rock of the Mammoth region
contrasts with the silica-rich rhyolite found
elsewhere in the park. Here, carbon dioxide in
the hot water forms carbonic acid, which then
dissolves the surrounding limestone (calcium
carbonate). As this watery solution breaks the
surface, some carbon dioxide escapes from the
solution and limestone is deposited as travertine, forming beautiful terraces. They can
grow up to an inch per day and are in constant flux.
For a unique angle on thermal activity, check out
the aerial photographs of Norris Geyser Basin at
ht-
Yellowstone Lake
One of the world's largest alpine lakes, Yellowstone Lake was formed by the collapse of
the Yellowstone caldera and shaped by glacial erosion. Hydrothermal explosions have fur-
ther shaped the shoreline, creating the inlets of West Thumb (a smaller caldera within the
larger one), Mary Bay and nearby Indian Pond. Robotic cameras have revealed underwa-
ter geysers, 20ft-high cones, rows of thermal spires and more than 200 vents and craters,
some the size of football fields, on the lake floor. Mary Bay and the lake floor canyon
west of Stevenson Island are the hottest parts of the lake, due to numerous hot springs and
vents.
Grand Canyon of the Yellowstone
This canyon is one of the park's premier attractions. It was formed as rising magma lifted
the land and the Yellowstone River carved through rhyolite weakened by thermal activity.
