Boiling, acidic calling cards of Valles Caldera National Preserve's volcanic past, some bearing such whimsical names as Stomach Trouble Spring and Laxitive Spring, should be protected under the Geothermal Steam Act List of Significant Thermal Features, according to the National Park Service.

Through January 27, the agency will be collecting public comment on its proposal that the geothermal features in the preserve are significant and so "must be protected from any geothermal leasing, exploration, development or utilization that might adversely affect those features."

Located in the Jemez Mountains of New Mexico, the 89,000-acre preserve was added to the National Park System in late 2014 via an act of Congress. It stands atop a 1.25-million-year-old dormant volcanic caldera nearly 14 miles wide. The most recent eruption since the caldera formed came about 68,000 years ago, according to the Park Service. 

Evidence of the preserve's volcanic basement are found in the form of hydrothermal features located on about 500 acres of the preserve. While ranchers during the 20th century built a concrete bath near a cabin to capture 101-degree Fahrenheit waters pouring from the San Antonio Warm Spring, elsewhere in the preserve there are hot and cold sulfuric acid fumaroles. Nearly 30 fumaroles have been identified in the Redondo and Alamo canyon areas.

Within the 40-acre private inholding of Sulphur Springs, the Park Service said there are at least seven significant named hot springs, mud pots, and fumaroles. "The springs include such colorful, descriptive names as Kidney and Stomach Trouble Spring, Footbath Spring, Ladies' Bathhouse Spring, Laxitive [sic] Spring, Turkey Spring, Lemonade Spring, and Electric Spring. Some of these were historically referred to as Main Bathhouse Spring, Sour Spring, and Alum Spring," the agency said.

In making a case for the thermal features' protection, the Park Service said that "these springs and fumaroles (some of which take the form of bubbling mudpots in wet seasons) are indicators of subsurface thermal processes, are unique to the region, and are easily accessible for study and research; there are no comparable features in the state of New Mexico. The only other places in the United States that have such systems are Yellowstone National Park in Wyoming, Montana, and Idaho; Lassen Volcano, the Long Valley Caldera, and The Geysers in California, the latter two having thermal regimes degraded by geothermal production; and a very small system at Dixie Valley, Nevada."

After considering all comments received, the NPS will issue a final notice of the Interior Department's determination in the Federal Register.