Many people have heard of Old Faithful before but Yellowstone is filled with many geological areas. Catastrophic volcanic eruptions that happened 2 million, 1.2 million and 600,000 years ago have left a landscape filled with geysers, hot springs, fumaroles and mud pots.
The last volcanic eruption, 600,000 years ago, happened in the middle of what is now Yellowstone. After erupting the volcano collapsed forming a 28 x 47 mile caldera, or basin. On the west side of the caldera close to midway between the Upper and the Norris Geyser Basin sits the Artist Paint Pots.
The Artist Paint Pots are named for the mud pots which are found in the area. Mud pots are hot springs with a limited water supply. Hydrogen sulfide gas rises up through these springs from deep inside the earth. Microorganisms living in the spring use this gas as a source of energy. In the process the gas is converted into sulfuric acid which breaks down the surrounding rocks and converts it to clay.
The clay is composed of minerals and fine particles of silica. Most of the rock in the area is rhyolite, which is chiefly composed of feldspar and quartz, which breaks up into the clay mineral kaolinite. The Crow tribe that lived in the area many years ago used this kaolinite clay to paint their tipis which is why the mud pots are called the Artists of Fountain Paint Pots.
The density or thickness of the mud is dependent on the season. In spring and early summer the mud is usually thin as it mixes with water from the spring rains and the snow melt. As summer progresses and the amount of rainfall lessens the mud begins to thicken. By late summer and fall the mud is typically quite thick which allows for flying mud as gas bubbles push through. Besides the mud pots there are other volcanic feature in the area. There are geysers, like Twig, Fountain, Morning and Clepsydra, none of which were erupting while I was there. There are also fumaroles and hot springs like Celestine Spring pictured above.