Uploaded March 2026 | Updated September 2026, 2 weeks ago
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Mudpots south-southeast of Emerald Spring
Hydrothermal features at Yellowstone, Wyoming include hot springs, geysers, fumaroles, and mudpots. Mudpots, or paintpots, are hot springs having thin to thick muddy material consisting of clay-sized grains of clay minerals mixed with varying amounts of water. Rising gases result in bursting bubbles of mud at the surface. The clay forms by chemical weathering of rhyolite, a common lava type at Yellowstone. When rising hydrogen sulfide gas (H2S), exsolved from subsurface magma, reaches the top of the water table, oxidation occurs and sulfuric acid forms (H2SO4). The sulfuric acid reacts with rhyolite and forms various clay minerals. Yellowstone's mudpots tend to have thin, watery mud in boreal spring and early summer with boiling-type bubbles appearing at the surface. In boreal late summer and autumn, the mud is thicker, which alters the bubble surfacing and bubble bursting behavior of rising gases.
Seen here are mudpots in the Back Basin of Yellowstone’s Norris Geyser Basin. They are located about 70 to 90 meters south-southeast of Emerald Spring. Some have called this area “Doctor Allen’s Paint Pots”, but others have pointed out that the name refers to features east of this. It is unclear what these mudpots are named, if at all.
In 1998, researchers measured the temperature of these mudpots at 77 degrees Celsius, with a pH of about 2.7 (= acidic). Acid hot springs and geysers are common in the Norris Geyser Basin.
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Norris Geyser Basin videos:
youtube.com/playlist?list=PL8dL6UmmXTBUBbNdHNDEMBc4U7Y9zUu22
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Filmed from the Norris Back Basin boardwalk.
Clips 1-10 - mudpots in the late afternoon of 24 June 2018.
Clips 11-14 - runoff channels from mudpots area in the late afternoon of 24 June 2018. (time stamp 4:09)
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Mudpots south-southeast of Emerald Spring
Hydrothermal features at Yellowstone, Wyoming include hot springs, geysers, fumaroles, and mudpots. Mudpots, or paintpots, are hot springs having thin to thick muddy material consisting of clay-sized grains of clay minerals mixed with varying amounts of water. Rising gases result in bursting bubbles of mud at the surface. The clay forms by chemical weathering of rhyolite, a common lava type at Yellowstone. When rising hydrogen sulfide gas (H2S), exsolved from subsurface magma, reaches the top of the water table, oxidation occurs and sulfuric acid forms (H2SO4). The sulfuric acid reacts with rhyolite and forms various clay minerals. Yellowstone's mudpots tend to have thin, watery mud in boreal spring and early summer with boiling-type bubbles appearing at the surface. In boreal late summer and autumn, the mud is thicker, which alters the bubble surfacing and bubble bursting behavior of rising gases.
Seen here are mudpots in the Back Basin of Yellowstone’s Norris Geyser Basin. They are located about 70 to 90 meters south-southeast of Emerald Spring. Some have called this area “Doctor Allen’s Paint Pots”, but others have pointed out that the name refers to features east of this. It is unclear what these mudpots are named, if at all.
In 1998, researchers measured the temperature of these mudpots at 77 degrees Celsius, with a pH of about 2.7 (= acidic). Acid hot springs and geysers are common in the Norris Geyser Basin.
-------------------
Norris Geyser Basin videos:
youtube.com/playlist?list=PL8dL6UmmXTBUBbNdHNDEMBc4U7Y9zUu22
-------------------
Filmed from the Norris Back Basin boardwalk.
Clips 1-10 - mudpots in the late afternoon of 24 June 2018.
Clips 11-14 - runoff channels from mudpots area in the late afternoon of 24 June 2018. (time stamp 4:09)
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