Travel Reference
In-Depth Information
fissure ridge.
A linear mound built where hot water has risen through a
fissure
and deposited
travertine
along its centerline.
fountain-type geyser.
A
geyser
that erupts from a broad pool, usually in a series of bursts. Compare
with
cone-type geyser.
fumarole.
A vent from which steam and other gases are emitted; in
hydrothermal areas
they form
where there is insufficient water to form a
geyser
or
hot spring.
geyser.
A
hot spring
that throws forth jets of water and steam intermittently.
geyser eggs; geyserite eggs.
Small round, oval, or scallop-shaped bits of
travertine
or
geyserite
that
accumulate around a
geyser,
either lying loosely in a pool of water or sometimes cemented to the
ground.
geyserite.
The white or pale gray brittle rock precipitated from the water thrown up by a
geyser
or at the
edges of a
hot spring.
Also called
hydrous silicon dioxide,
siliceous sinter, or
silica.
giardia.
A microscopic parasite found in natural waters contaminated by feces from infected humans or
animals. Its outer shell protects it and makes it tolerant to chlorine disinfection.
glacial erratic.
A boulder carried by a glacier and deposited, often many miles from where the glacier
plucked it from the bedrock.
glacial horn.
A steep spire- or pyramid-shaped peak formed by glacial erosion in three or more
cirques
surrounding a mountain.
glass.
In geology, rock that formed when
magma
cooled too quickly for crystals to form.
gneiss.
A
metamorphic rock
having alternating light and dark colored bands.
granite.
A coarse-grained
igneous rock
that crystallized at depth from
magma,
containing a large
amount of
silica.
granite-gneiss.
A
metamorphic rock
formed from preexisting
granite.
hoodoo.
An often odd-shaped column formed by uneven erosion of horizontally layered rock.
hot spring.
A source or pool of water at higher than human body temperature (98°F / 37°C).
hydrogen sulfide.
The poisonous gas with the smell of rotten eggs given of by the water in many
hy-
drothermal areas.
hydrothermal system or area.
An area where very hot water underground, in combination with a sys-
tem of fractures, creates
hot springs
and related features.
hydrothermal explosion crater.
See
explosion crater.
hydrous silicon dioxide.
A chemical compound of
silica
and oxygen that contains water; chemical
name for
sinter
or
geyserite.
hyperthermophile.
A kind of
extremophile
microorganism that lives in environments above 176°F
(80°C).
igneous intrusion. Igneous rock
that was injected as
magma
into older rock.
igneous rock.
Rock that has solidified from
magma,
having cooled either slowly deep within Earth or
quickly on Earth's surface.
iron oxide.
Several chemical compounds containing iron and oxygen in different proportions that can
color rocks shades of yellow, red, or black.
iron sulfide.
The compound of iron and sulfur that can color rocks black.
