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A Yellowstone Gallery: Midway Geyser Basin


Grand Prismatic Spring

Yellowstone’s and North America’s largest hot spring, Grand Prismatic Pool is located within Midway Geyser Basin. The warm flowing water and colored bacteria living in it create striking patterns and is simultaneously a mirror for the sky. This intimacy of earth and sky thrilled me more than any other feature of Yellowstone’s astounding landscape.

From MIT’s website, “The fault-fractured rock of the region allows rain, snowmelt, and groundwater to percolate downward, become heated, and rise upward to feed the area's hydrothermal features. At Grand Prismatic Pool the water flows outward from the spring evenly across the low mound formed of broad, low, step-like terraces. The deep blue of the hottest water is reflected in the steam rising above the spring. The orange, yellow, and brown colors in the cooler water of the runoff channels are produced by thermophilic cyanobacteria with different species living at different temperatures.”


Excelsior Geyser and the Firehole River



Yellowstone National Park (U.S. National Park Service)



Next week, Yellowstone’s headquarters at Mammoth Hot Springs
(and an elk named Touchdown).



All chapters of PortMoresby's Yellowstone.



Find more of PortMoresby's contributions here.






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