Last updated: February 19, 2025
Place
Stop 3: Sulphur Springs
NPS/Dan Kish
Quick Facts
Amenities
1 listed
Scenic View/Photo Spot
You have arrived at Sulphur Springs. You likely smell a “rotten egg” smell. This is hydrogen sulfide gas escaping from the springs, mudpots, and fumaroles. Valles Caldera is a dormant, but not extinct, volcano, and hydrogen sulfide and carbon dioxide gasses escape from the partly crystallized magma that lies about 4 to 6 miles below the surface. You will see bubbles of gas escaping from the water or mud as you walk around the area.
The hydrogen sulfide and carbon dioxide gases react with groundwater and oxygen to form carbonic acid and sulfuric acid. That is how the water becomes acidic. The geologic definition of a spring is where groundwater flows onto the Earth’s surface. Here, rainwater and melted snow sink into the ground, encounter hot rock, are heated and then return to the surface as warm and hot springs. Some of the water at Sulphur Springs does not travel deep enough to warm but still encounters the gas and becomes acidic. The rising water and gas come to the surface where there are pathways between and inside rocks. Here, at Sulphur Springs, the water and gas are coming up along faults, where rocks have been broken apart by tectonic stresses in the earth.
Rocks in the area are altered to clay minerals by the acidic nature of the water. This is what creates the bleached, washed-out colors and the thick muddy material that you will see bubbling in the special, water restricted springs, called mudpots.
This area has been used for many things over the years. Sulphur Springs is located along an ancestral route where indigenous people have long procured medicinal plants and undertaken pilgrimage runs into the healing Jemez Mountains. Maríano Otero and family operated a sulfur mine here from 1900 to 1904. A total of about 200,000 pounds of sulfur was extracted during this time.
Later there was a spa and hotel here. The hotel was built in the early 1900s by the Otero family and burned sometime in the 1970s. Historical photos show that it was likely located partway up the hill to your right.
Other buildings and weathered lumber scattered around are what remains of the spa and of a later settlement of people that occupied the area into the early 2000s.
Sulphur Springs has also been studied for geothermal energy potential. In preparation for the geothermal power plant, several test wells were drilled, an Environmental Impact Statement was written, and permitting was pursued to develop the area. Environmental groups and the Pueblos were against the development because the power plant would have adverse effects on the water supply. Additionally, the Pueblos objected to the adverse impact it would have on their religious sites. Lawsuits and counter lawsuits dragged on for years, and eventually the developers figured out that the area wasn’t suitable for a geothermal site and the whole thing was dropped. It isn’t a good candidate for geothermal energy production because although the water is very hot, especially a few thousand feet down, and would easily flash to steam when brought to the surface, there is not enough of it to maintain the flow needed to drive a turbine for electricity generation. The wells that were drilled as part of the study for geothermal energy potential provided a lot of information about the structure of the rocks in Valles Caldera as well as information about groundwater flow. Additional wells were drilled into the area later as part of the Continental Scientific Drilling Program. The goal of the program was to understand the geologic structure and history better and it was successful.
The National Park Service acquired the Sulphur Springs area in 2020. Many individuals, charitable organizations, and foundations contributed and facilitated the purchase. If you are interested in more information about the acquisition, check out this news release.
To the right (south) of the path where the creek crosses under the road is a cold, bubbling spring commonly called Laxative Spring. It may appear milky blue. There are a few other cold springs nearby, mostly located north (left) of the road. Even though they are cold, with temperatures around 59 degrees F in late May, they are acidic with pH values of around 3. For comparison, drinking water has a pH around 7. They are likely cold because the water source does not go deep in the earth and warm. Future investigations may tell us more about these interesting features.
The hydrogen sulfide and carbon dioxide gases react with groundwater and oxygen to form carbonic acid and sulfuric acid. That is how the water becomes acidic. The geologic definition of a spring is where groundwater flows onto the Earth’s surface. Here, rainwater and melted snow sink into the ground, encounter hot rock, are heated and then return to the surface as warm and hot springs. Some of the water at Sulphur Springs does not travel deep enough to warm but still encounters the gas and becomes acidic. The rising water and gas come to the surface where there are pathways between and inside rocks. Here, at Sulphur Springs, the water and gas are coming up along faults, where rocks have been broken apart by tectonic stresses in the earth.
Rocks in the area are altered to clay minerals by the acidic nature of the water. This is what creates the bleached, washed-out colors and the thick muddy material that you will see bubbling in the special, water restricted springs, called mudpots.
This area has been used for many things over the years. Sulphur Springs is located along an ancestral route where indigenous people have long procured medicinal plants and undertaken pilgrimage runs into the healing Jemez Mountains. Maríano Otero and family operated a sulfur mine here from 1900 to 1904. A total of about 200,000 pounds of sulfur was extracted during this time.
Later there was a spa and hotel here. The hotel was built in the early 1900s by the Otero family and burned sometime in the 1970s. Historical photos show that it was likely located partway up the hill to your right.
Other buildings and weathered lumber scattered around are what remains of the spa and of a later settlement of people that occupied the area into the early 2000s.
Sulphur Springs has also been studied for geothermal energy potential. In preparation for the geothermal power plant, several test wells were drilled, an Environmental Impact Statement was written, and permitting was pursued to develop the area. Environmental groups and the Pueblos were against the development because the power plant would have adverse effects on the water supply. Additionally, the Pueblos objected to the adverse impact it would have on their religious sites. Lawsuits and counter lawsuits dragged on for years, and eventually the developers figured out that the area wasn’t suitable for a geothermal site and the whole thing was dropped. It isn’t a good candidate for geothermal energy production because although the water is very hot, especially a few thousand feet down, and would easily flash to steam when brought to the surface, there is not enough of it to maintain the flow needed to drive a turbine for electricity generation. The wells that were drilled as part of the study for geothermal energy potential provided a lot of information about the structure of the rocks in Valles Caldera as well as information about groundwater flow. Additional wells were drilled into the area later as part of the Continental Scientific Drilling Program. The goal of the program was to understand the geologic structure and history better and it was successful.
The National Park Service acquired the Sulphur Springs area in 2020. Many individuals, charitable organizations, and foundations contributed and facilitated the purchase. If you are interested in more information about the acquisition, check out this news release.
To the right (south) of the path where the creek crosses under the road is a cold, bubbling spring commonly called Laxative Spring. It may appear milky blue. There are a few other cold springs nearby, mostly located north (left) of the road. Even though they are cold, with temperatures around 59 degrees F in late May, they are acidic with pH values of around 3. For comparison, drinking water has a pH around 7. They are likely cold because the water source does not go deep in the earth and warm. Future investigations may tell us more about these interesting features.