Chief Geologist Frank Bradley and
party, a group of the 1872 Hayden Expedition, named Shoshone lake
and geyser basin. However, Osborne Russell, an early explorer
and trapper, may have been the first European to enter the basin
Shoshone Geyser Basin, located
at the west end of Shoshone Lake, requires an 8.5 mile hike from
Lone Star Geyser or a canoe trip across Lewis and Shoshone lakes
to reach these jewel-like thermal features. This geyser basin
is truly pristine. Because of its remote location one can enter
this basin and find little evidence of man. The pools and geysers
still retain most of their original formations of intricate sinter.
No boardwalks exist in the basin and caution should be exercised
while exploring, since one pool has already claimed the life of
a man in 1988.
This small basin contains an estimated
110 thermal features. Union Geyser is the famous feature in the
basin. It was active during the early 1900s, but it has had long
periods of dormancy and has been dormant since the mid 1970s.
The three small mounds, standing three feet tall, show little
activity. Minute Man Geyser is now the main attraction at Shoshone.
It is a regular spouter with intervals of one to three minutes.
Temperature 197°F Interval 9-21 minutes. Duration 1-3 minutes.
Height 4-6 feet. This geyser has a distinctive large crater. Golden
sinter beads line the vent of the four-feet-high cone. It has
regular geyser activity, and an eruption is easy to see. An eruption
begins with water rising in the vent and crater. As water begins
to overflow and boil splashing begins and triggers an eruption.
Most of the activity is splashing but there are bursts which reach
six feet. After an eruption, the crater drains and slowly refills
with boiling water for the next eruption.
Temperature 196°F Interval minutes to hours (irregular).
Duration 15-60 minutes. Height 2-5 feet. An elaborate,
massive basin has been built of sinter by the continuous splashing
of water. The crater, lined with white, beaded sinter and a golden-colored
inside rim, measures ten feet long by eight feet wide. The water
constantly boils and has occasional eruptions. The eruptions are
minor and usually consist of continuous splashing. The activity
of Gourd is cyclic. Because corresponding changes in water level
are apparent, there may be a connection with nearby Shield Geyser.
MINUTE MAN GEYSER
Temperature 180°F Interval 1-3 minutes. Duration 2-10
seconds. Height 10-40 feet. Professor Frank Bradley, Chief
Geologist of the Hayden Expedition in 1872, named Minute Man because
it erupted nearly every minute. It has a large cone five feet
high by 12 feet long built of gray sinter or geyserite. Before
an eruption the vent and crater fill with water. Boiling triggers
a violent eruption as water jets to 10-20 feet high at first,
but declines in force until the water and steam are exhausted.
A series of these eruptions will occur for several hours and then
the geyser enters a quiet period for another few hours until the
cycle is repeated.
Temperature 196°F Dimensions 8.5 feet diameter. Depth 27
feet. Taurus Geyser is a deep blue pool. Orange-colored
cyanobacteria and algae line the edge in contrast with the dark
blue water. The spring is in a constant state of ebullition. It
has erupted in the past, but only during an eruption of nearby
Union Geyser, the largest geyser in the basin which itself has
long periods of dormancy. Taurus has erupted with bursts up to
four feet high, but mostly this geyser boils and splashes.
Temperature 192°F Dimensions 11x13 feet. Depth 6 feet. Knobby
Geyser is a small, spring-like geyser in the North Group. It has
a white shallow pool, square shape, with an intricate sinter or
geyserite border. The ornate rim is composed of white and gray,
rosette-like clusters. Knobby has cyclic eruptions depending on
the activity of nearby Velvet Spring, which has periods of long
dormancy. The eruptive activity will last from one to three hours
with occasional pauses varying in length. The duration and volume
of each eruption have direct effect on the length of the pause.
The eruptions can reach 10-25 feet high.
Temperature 189-199°F This group has the largest collection of
small springs in the basin. Some of the major thermal features
are Glen Spring, Funnel Spring, Yellow Sponge, Knobby Geyser,
Bead Geyser, Velvet Spring and Bronze Geyser. All are alkaline
springs and have colorful basins and run-off channels. Some features
are stained red and orange by iron oxides, and others green, yellow
or brown by cyanobacteria and algae. Intricate sinter borders
have formed around many of the springs. All the thermal features
have high temperatures, and boil constantly.