Silica sinter breccia field along the Imperial Meadows Trail in the Lower Geyser Basin of Yellowstone National Park

Extensive silica sinter breccia field along the Imperial Meadows Trail in the Lower Geyser Basin of Yellowstone National Park looking southwest towards Twin Buttes. The inset image shows a place where a passing hiker’s footstep brushed away the white surface sinter, revealing bright green phototrophic microorganisms underneath (boot toe for scale). Photo by Jeff Having, University of Minnesota, in August 2022.