BISCUIT
BASIN (UPPER GEYSER
BASIN, YELLOWSTONE HOTSPOT)
HYDROTHERMAL FEATURES
Sapphire Pool (above & below), Sapphire Group,
Biscuit Basin, far-northwestern Upper Geyser Basin, Yellowstone Hotspot,
northwestern Wyoming, USA on 10 August 2011 (looking ~NNW). This hot spring has an intensely blue color,
the color of a gem-quality sapphire.
This pool’s coloration is the result of very high-temperature water
having an abundance of suspended, extremely small particles of colloidal silica
less than one-half micron in size.
Sapphire Pool, Sapphire Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA on 29 August 2011.
Before the August 1959 Hebgen Lake
Earthquake, Sapphire Pool was surrounded by abundant, relatively large
geyserite nodules that resembled dinner rolls or biscuits. These were destroyed by explosive geyser
eruptions at Sapphire Pool that occurred after the 1959 earthquake. The biscuit-like subrounded nodules of
geyserite (a.k.a. siliceous sinter) shown above are along the margin of
present-day Sapphire Pool.
Sapphire Pool, Sapphire Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA on 10 August 2011 (looking ~W).
This is the runoff channel that drains
Sapphire Pool to the east toward the Firehole River. The yellowish and orangish-brown margins
represent extremophile bacterial mats.
“UNNG-BBG-8” (above & below), Sapphire
Group, Biscuit Basin, far-northwestern Upper Geyser Basin, Yellowstone Hotspot,
northwestern Wyoming, USA on 29 August 2011 (looking ~NW).
This moderately small perpetual spouter
first appeared in 2006. Runoff water
drains into the nearby Firehole River.
“UNNG-BBG-9” (apparently), Sapphire
Group, Biscuit Basin, far-northwestern Upper Geyser Basin, Yellowstone Hotspot,
northwestern Wyoming, USA on 29 August 2011 (looking ~NW).
If this feature is correctly identified,
it first appeared in 2006 and 2007, at about the same time as “UNNG-BBG-8”
shown above.
Black Opal Pool (a.k.a. Black Opal Spring), Sapphire
Group, Biscuit Basin, far-northwestern Upper Geyser Basin, Yellowstone Hotspot,
northwestern Wyoming, USA on 10 August 2011 (looking ~NNE).
Black Diamond Pool, Sapphire Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA on 10 August 2011 (looking ~N).
Wall Pool (above & below), Sapphire Group,
Biscuit Basin, far-northwestern Upper Geyser Basin, Yellowstone Hotspot,
northwestern Wyoming, USA on 10 August 2011 (looking ~NNW).
Jewel Geyser, Sapphire Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA on 10 August 2011 (looking ~NNW).
Jewel Geyser, Sapphire Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA on 29 August 2011 (looking ~NW).
Eruptions at Jewel Geyser on the day of the eruption shown above were
consistently 13 minutes apart.
Jewel Geyser - close-up of the geyserite mounds at
& around the vent.
Shell Spring (above & below), Sapphire Group,
Biscuit Basin, far-northwestern Upper Geyser Basin, Yellowstone Hotspot,
northwestern Wyoming, USA in August 2011.
The complex of irregular, pustulose geyserite knobs here somewhat
resembles the interior of an articulated tridacnid
bivalve shell.
Silver Globe Complex, Sapphire Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA in August 2011 (looking ~SW).
Silver Globe Pool (above & below), Sapphire Group,
Biscuit Basin, far-northwestern Upper Geyser Basin, Yellowstone Hotspot,
northwestern Wyoming, USA in August 2011 (looking ~ENE).
Avoca Spring (above & below), Sapphire Group,
Biscuit Basin, far-northwestern Upper Geyser Basin, Yellowstone Hotspot,
northwestern Wyoming, USA in August 2011 (looking ~NE). This feature has been a splashy perpetual spouter
since 2006. Before then, Avoca Spring
has been an overflowing spring, a geyser, and a dormant feature.
Avoca Spring (above & below, looking ~NNE) - a
finely beaded geyserite arch occurs in the southern part of this hot
spring. Geyserite arches are rare.
Avoca Spring, Sapphire Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA in August 2011 (looking ~E).
West Geyser, Sapphire Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA in August 2011 (looking ~N). Only
rarely has this hot spring erupted as a geyser.
West Mustard Spring (above & below), Sapphire Group,
Biscuit Basin, far-northwestern Upper Geyser Basin, Yellowstone Hotspot,
northwestern Wyoming, USA. This feature
is a quiet pool of relatively cool water.
East Mustard Spring (above & below), Sapphire Group,
Biscuit Basin, far-northwestern Upper Geyser Basin, Yellowstone Hotspot,
northwestern Wyoming, USA in August 2011.
This hot spring didn’t have activity until 1983. Splash-like geyser eruptions occur frequently
here, but water column heights are less than about 10 feet.
Outpost Geyser & Sentry Geyser (above &
below), Sapphire Group, Biscuit Basin, far-northwestern Upper Geyser Basin,
Yellowstone Hotspot, northwestern Wyoming, USA in August 2011.
Outpost Geyser is the erupting geyser at
center in the above photo & the geyserite-lined crater at center in the
below photo.
Sentry Geyser is the small grayish-and-whitish
geyserite feature on the southeastern shoulder of Outpost Geyser (just to the
right-front in the above photo & just in front in the below photo).
Both Outpost Geyser and Sentry Geyser have
small, fairly frequent eruptions.
Coral Geyser, Sapphire Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA in August 2011 (looking ~NE). This
former geyser has been surficially inactive for many decades.
Black Pearl Geyser, Sapphire Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA in August 2011. This former geyser
is close to Coral Geyser (see above) and has been inactive for many decades.
Rusty Geyser (above & below), Old Road Group,
Biscuit Basin, far-northwestern Upper Geyser Basin, Yellowstone Hotspot,
northwestern Wyoming, USA in August 2011.
This geyser has frequent, small eruptions.
Cauliflower Geyser, Old Road Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA in August 2011.
Mirror Pool, Old Road Group, Biscuit Basin,
far-northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming,
USA in August 2011 (looking ~NW).
Sprite Spring (Sprite Pool), Cascade Group,
northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming, USA
in August 2011. This feature’s geyser
eruptions consist only of occasional very small splashes.
Pinto Spring, Cascade Group, northwestern Upper Geyser
Basin, Yellowstone Hotspot, northwestern Wyoming, USA in August 2011.
Gem Pool (above & below), Cascade Group,
northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming, USA
in August 2011 (looking ~W). Gem Pool is
an overflowing hot spring with a sapphire-like color. It does not have geyser eruptions.
Above: looking ~W.
Below: runoff channel for Gem Pool (looking
~SSW).
Artemisia Geyser (above & below), Cascade Group,
northwestern Upper Geyser Basin, Yellowstone Hotspot, northwestern Wyoming, USA
in August 2011. This geyser has a fairly
large crater surrounded by a wide platform of complexly-anastomosing geyserite.
Info. mostly synthesized from:
Bryan, T.S. 2008. The Geysers of Yellowstone, Fourth Edition. Boulder, Colorado. University Press of Colorado. 462 pp.
Ohsawa et al. 2000.
Geothermal blue water colored by colloidal silica. Proceedings
of the World Geothermal Congress, 2000, Kyushu-Tohoku, Japan, May 28-June 10,
2000: 663-668.