Global Volcanism Program | Image GVP-03351
A small mudpot vent in Pocket Basin at the north end of Yellowstone's Lower Geyser Basin produced this intriguing feature that mimics a spatter cone that issued a lava flow. Mudpots form in areas of intense, clay-rich hydrothermal alteration where the thermal system is dominated by gases.
Photo by Dan Dzurisin, 1983 (U.S. Geological Survey).
This image is made available as a Public Domain Work, but proper attribution is appreciated.
Galleries: Geothermal Features