Images

This mountain meadow inhabiting species is generally distinctive in its long copious stem and leaf hairs and inflorescences with congested white to pinkish or light purplish flowering heads that are surrounded by very long stem leaves.

Alpine meadow near Two Ocean Pass on the Continental Divide just south of Yellowstone National Park.

Image of the north part of Yellowstone Lake with the smoke plume from the Brimstone Fire in the distance, acquired by the YVO webcam on September 2, 2019, at 2:05 PM MDT.

The Parting of the Waters, looking southeast. North Two Ocean Creek splits into Atlantic Creek, flowing to the left in the photo, and Pacific Creek, flowing to the right. The wooden sign indicates that it is 3,488 miles to the Atlantic Ocean and 1,353 miles to the Pacific Ocean.

Aerial view of the new thermal area, in the center left. The existing Tern Lake thermal area is the bright white patch of ground in the upper middle part of the image. West Tern Lake is in the lower right. Research conducted under NPS Geology Programs Milestones Permit 2016-9.

View from the ground of the new thermal area near Tern Lake in Yellowstone National Park. Research conducted under NPS Geology Programs Milestones Permit 2016-9.

Lower Falls of the Yellowstone River and the Grand Canyon of the Yellowstone, photographed during a helicopter flyover on August 19, 2019.

Old Faithful Geyser, as well as Old Faithful Inn and the Yellowstone National Park visitor center, as viewed from the lookout on Observation Point trail.

Old Faithful geyser visitor center, and visitor facilities as viewed from Observation point on August 18, 2019.

Map of Yellowstone National Park showing locations of thermal basins that host hot springs, geysers, and mudpots.  Dark green areas host alkaline-chloride fluids.  Yellowstone Caldera margin shown as bold dashed line.

View of the Cirque of the Towers in the Wind River Range, with Pingora Peak in the center. The Bull Lake and Pinedale glaciations carved this valley by steepening and smoothing its granite walls. Image captured while descending from Texas Pass. Image view is toward the southwest. USGS photo by Stanley Mordensky, August 2019.

A closeup of the head and mouthparts of the wetsalts tiger beetle, a voracious predator in Yellowstone. Photo by Robert K. D. Peterson, 2019.

Example of how the same rock type can look very different due to hydrothermal alteration. Left image is of the Lava Creek Tuff, which erupted during the formation of Yellowstone caldera 631,000 years ago, near Tower Junction.

Closeup of a wall of the Grand Canyon of the Yellowstone showing red, orange, and yellow mineral alternation, as well as white veins of silica, in the subsurface alteration zone of a former thermal basin.

Alteration associated with mud pots in Yellowstone National Park. Left image is an overview of Artist Paint Pots. Note the white kaolinite alteration in the lower right and the red/pink mud pots near the boardwalk. Right image is charcoal-gray mud from Mud Volcano consisting of kaolinite with fine-grained pyrite and other iron sulfide minerals.

Steamboat Geyser erupts in the golden light of sunrise on July 18th, 2019. The water-dominated part of a Steamboat eruption usually lasts anywhere from 3 to 90 minutes. Afterwards, a steam-dominated phase continues for many hours.

Dead lodgepole pine trees near the parking lot of Fountain Paint Pots in the Lower Geyser Basin. The trees look as if they are wearing white socks; hence, the name, “bobby socks trees.” The dead trees soak up the silica-rich water, turning the lower portion of the trees white.

Schematic model showing a cross section of Old Faithful's plumbing system as determined from seismic studies. The red circles (t0-t3) show the location of the tremor source over time, and how the tremor source migrates upward prior to an Old Faithful eruption. Times between red circles are based on a 93-minute eruption interval.

Images of snow algae and snow cyanobacteria on snow fields in the Beartooth Mountains near the Beartooth Pass Summit (elevation 10,947 ft/3,368 m) on Highway 212. Top left shows a typical pink snow algae bloom on a patch of snow, and top right shows the snow algae bloom scraped off the snow surface with a rock hammer.

Schematic diagram of Yellowstone's current magmatic system. A silicic crystal-mush (gray region with white crystals) is thought to underlie the caldera at a depth of ~5 km to 15 km, with more mafic basalt (in black) underneath.

Sections of a zircon crystal, only 100 micrometers across, showing stages of the crystal's growth. Upper panel shows the outer surface of the crystal, which is 131,000 years old based on 238U-230Th dating. This is when the crystal stopped growing. Lower panel shows the interior of the same zircon crystal.