|Orange Spring Mound, Mammoth Hot Springs, Yellowstone National Park, Wyoming|
The National Park Service tells us:
Bacteria and algae create the streaks of color on Orange Spring Mound. It is noticeably different from many of the other terrace formations nearby. Its large mounded shape is the result of very slow water flow and mineral deposition.You can learn more about Yellowstone's Mammoth Hot Springs and see photos of many of the geologic formations there by visiting the Mammoth Hot Springs Terraces Tour.