Last updated: December 12, 2024
Place
Stop 8: Final Look

NPS/Dave Krueger
As you explored Sulphur Springs, you may have seen additional fumaroles and springs away from the path. Some have names, many don’t. Sometimes new ones just appear - or old ones disappear! Did you see any fumaroles with bright yellow crystals near the opening? The crystals are pure native sulfur deposited when hydrogen sulfide escapes the fumarole.
There are several areas within Valles Caldera National Preserve where hot springs and fumaroles occur. If you are hiking in the backcountry, you may find others.
Sulphur Springs hydrothermal system at Valles Caldera National Preserve consists of hot springs, cold springs, fumaroles, and mudpots. The hydrothermal system at Yellowstone National Park consists of hot springs, cold springs, fumaroles, mudpots and geysers. Why doesn’t Valles Caldera have geysers? Although many of the hot springs at Yellowstone are acidic, those associated with geysers are the opposite; they are alkaline. This property helps create an impermeable rock lining in the geyser plumbing that allows pressure to build up for the water eruption. All the features at Valles Caldera are acidic; none are alkaline. This, and a smaller supply of water are likely why there are no geysers here.
There are several areas within Valles Caldera National Preserve where hot springs and fumaroles occur. If you are hiking in the backcountry, you may find others.
Sulphur Springs hydrothermal system at Valles Caldera National Preserve consists of hot springs, cold springs, fumaroles, and mudpots. The hydrothermal system at Yellowstone National Park consists of hot springs, cold springs, fumaroles, mudpots and geysers. Why doesn’t Valles Caldera have geysers? Although many of the hot springs at Yellowstone are acidic, those associated with geysers are the opposite; they are alkaline. This property helps create an impermeable rock lining in the geyser plumbing that allows pressure to build up for the water eruption. All the features at Valles Caldera are acidic; none are alkaline. This, and a smaller supply of water are likely why there are no geysers here.
Descriptive Transcript
A hilly landscape of bleached gravel with steam rising from the ground in several places. These are volcanic steam vents or fumaroles.
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- Duration:
- 10.944 seconds
Several plumes of steam emerge from the ground in the Sulphur Springs region of Valles Caldera National Preserve.