NORTHEASTERN SECTION - Yellowstone Treasures - page 278

Named in the 1960s for the popping sounds from many bubbles are large, hot, opalescent,
blue-green Crackling Lake and its neighbor Crackling Spring, partway up the hill.
To your right as you mount the stairs from the basin is the Milky Complex, whose Teal
Blue Bubbler will sometimes be spouting as you pass.
A few steps and a steep but shady path take you back to the start of this loop.
Porcelain Basin East Loop
From the stairs just below the museum, turn right (east) for the eastern loop around Porcelain
Basin.
NOTE: The eastern loop is partly wheelchair-accessible if you go past Bathtub Spring and around the
museum to avoid the stairs (see map).
First you'll see a solfatara full of steaming and bubbling fumaroles and spouters, lined in
red, orange, or yellow and called Vermilion Springs. The variety in the colors here is due to
different levels of acidity and different oxidation states of iron and sulfur.
Farthest from the walkway is Locomotive Spring (or Springs, since there are a red and a
blue pool—though hard to see from the boardwalk), with occasional eruptions to 6 feet high
(1.8 m).
Congress Pool next to the boardwalk became a geyser in 1891, after beginning life as a
fumarole. The geyser was named for that year's Fifth International Geological Congress, and
also (quipped its namer, geologist Arnold Hague) “because its earliest outbursts were power-
ful eruptions marked by periods of rest.” This congress was held in Washington, D.C., but in-
cluded a Yellowstone field trip. Congress promptly settled down to become a pool, a bubbling
mud pot, or sometimes a weak steam vent.
There's more action on the hillside behind Congress Pool, where in 1929 an experimental
drill hole went 265 feet (81 m) down. The enormous steam pressure had threatened to blow
up the drilling rig. Despite being filled with cement, the Carnegie II Drill Hole (near the tree
line) became a perpetual spouter many years later. The ground around it pulsates, threatening
a future steam explosion.
Along the trail to the north toward the Norris campground is cool Nuphar Lake, which
carries the botanical name for the yellow pond lily, yet harbors grasses and reeds. The lake is
fed by rainwater and small thermal springs and has no outlet.
This section of boardwalk ends at the foot of Porcelain Terrace, where thermal activity is
so intense and unpredictable that boardwalks have to be rebuilt frequently. After the 1959 He-
bgen Lake earthquake, fractures formed on top of the terrace, and pools rich in sulfuric acid
filled the fractures. This is causing the sinter to disintegrate and the hillside to crumble.