The Great Desert


The Sulphur Springs hydrothermal area is on the south flank of Redondo Peak, the resurgent dome inside the Valles Caldera. The area has many boiling acid springs, which were once the attraction at a "spa." People would immerse themselves in the boiling muddy acid in the hopes of improving their skins and love lives. De gustibus non disputandem.

We were not able to visit the Sulphur Springs, though not for lack of trying. They are on a private land inholding within the new Valles Caldera National Preserve, and the current land owner is apparently not very friendly. These photo were taken last December by Ms. Elanor Dixon, to whom copyrights belong.

Boiling Grey Goo

Fumarole Steam vent at Sulphur Springs. The white rock around the vent is Bandelier tuff, extensively altered by sulfurous acid water and vapor to montmorillonite clays. Trees and other vegetation grow poorly on this acidic, nutrient-poor soil.
Boiling Spring The water in this spring is boiling at ~ 92C (boiling temperature at this high elevation), and has a pH of ~ 1 (like battery acid). The gray color is from the clays left by alteration of the Bandelier tuff. The water comes mostly from snow melt on Redondo Peak. So in the late summer, the dry season, these boiling pools become spattering mud-pots or dry fumaroles.
Sulphur and Bugs

Sulphur! The Sulphur Springs (of course) deposit pure sulfur, here the yellow masses coating the rock. Sulfur was mined for a short time from old hot spring deposits on a hill above Sulphur Springs. This sulphur is probably a microbial waste product! Before coming to the surface, the spring waters are rich in sulfide dissolved from the Bandelier tuff and other rocks. Several kinds of 'sulfide oxidizing' microbes can take this sulfide, strip electrons from it for their metabolisms, and deposit the remainder as sulfur. Other bacteria can also oxidize this sulfide or sulfur to sulfate as sulfuric acid (which is why the springs are acid!).
Life, Even Here The slimes at the edge of this boiling pool are live, microbial mats. The brown ish colors closest to the boiling water may be the non-photosynthetic microbe Hydrogenobacter, which thrive in acid waters at temperatures near 60C. The green slimes farther away from the boiling may be the photosynthetic bacteria Cyanidium, which live in similar waters at Yellowstone at ~45C. The brown on the pillars is yet another bacterium, possibly Zygogonium

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