Geothermal areas of Yellowstone
Encyclopedia
The geothermal areas of Yellowstone include several geyser
basins in Yellowstone National Park
as well as other geothermal features such as hot spring
s, mud pots, and fumarole
s. The number of thermal features in Yellowstone is estimated at 10,000 and 200 to 250 geysers erupt in Yellowstone each year, making it the place with the highest concentration of active geysers in the world, thanks to its location in an ancient active caldera
. Many of these features build up sinter, geyserite
, or travertine
deposits around and within them.
The various geyser basins are located where rainwater and snowmelt can percolate into the ground, get indirectly superheated by the underlying Yellowstone hotspot
, and then erupt at the surface as geysers, hot springs, and fumaroles. Thus flat-bottomed valleys between ancient lava
flows and glacial moraines are where most of the large geothermal areas are located. Smaller geothermal areas can be found where fault lines reach the surface, in places along the circular fracture zone around the caldera, and at the base of slopes that collect excess groundwater. Due to the Yellowstone Plateau
's high elevation the average boiling temperature at Yellowstone's geyser basins is 199 °F (93 °C). When properly confined and close to the surface it can periodically release some of the built-up pressure in eruptions of hot water and steam that can reach up to 390 feet (120 m) into the air (see Steamboat Geyser
, the world’s tallest geyser). Water erupting from Yellowstone's geysers is superheated above that boiling point
to an average of 204 °F (95.5 °C) as it leaves the vent. The water cools significantly while airborne and is no longer scalding hot by the time it strikes the ground, nearby boardwalks, or even spectators. Because of the high temperatures of the water in the features it is important that spectators remain on the boardwalks and designated trails. Several deaths have occurred in the park as a result of falls into hot springs.
Prehistoric Native American
artifacts have been found at Mammoth Hot Springs and other geothermal areas in Yellowstone. Some accounts state that the early people used hot water from the geothermal features for bathing and cooking. In the 19th century Father Pierre-Jean De Smet
reported that natives he interviewed thought that geyser eruptions were "the result of combat between the infernal spirits." The Lewis and Clark Expedition
traveled north of the Yellowstone area in 1806. Local natives that they came upon seldom dared to enter what we now know is the caldera because of frequent loud noises that sounded like thunder
and the belief that the spirits that possessed the area did not like human
intrusion into their realm. The first Caucasian
known to travel into the caldera and see the geothermal features was John Colter
, who had left the Lewis and Clark Expedition. He described what he saw as "hot spring brimstone." Beaver trapper Joseph Meek recounted in 1830 that the steam rising from the various geyser basins reminded him of smoke coming from industrial smokestacks on a cold winter morning in Pittsburgh, Pennsylvania
. In the 1850s famed trapper Jim Bridger
called it "the place where Hell bubbled up."
(salty water) that is 1.5 to 3 miles (2.4 to 4.8 km) below the surface. This is actually below the solid volcanic rock
and sediment
that extends to a depth of 3,000 to 6,000 feet (900 to 1,800 m) and is inside the hot but mostly solid part of the pluton
that contains Yellowstone’s magma chamber
. At that depth the brine is superheated to temperatures that exceed 400°F or 205°C (double the boiling point at the surface) but is able to remain a liquid because it is under great pressure (like a huge pressure cooker).
Convection
of the churning brine and conduction
from surrounding rock transfers heat to an overlaying layer of fresh groundwater
. Movement of the two liquids is facilitated by the highly fractured and porous nature of the rocks under the Yellowstone Plateau. Some silica is dissolved from the fractured rhyolite into the hot water as it travels through the fractured rock. Part of this hard mineral is later redeposited on the walls of the cracks and fissures to make a nearly pressure-tight system. Silica precipitates at the surface to form either geyserite or sinter, creating the massive geyser cones, the scalloped edges of hot springs, and the seemingly barren landscape of geyser basins.
There are at least five types of geothermal features found at Yellowstone:
The Norris Geyser Basin 44°43′43"N 110°42′16"W is the hottest geyser basin in the park and is located near the northwest edge of Yellowstone Caldera
near Norris Junction and on the intersection of three major fault
s. The Norris-Mammoth Corridor is a fault that runs from Norris north through Mammoth to the Gardiner, Montana
, area. The Hebgen Lake fault runs from northwest of West Yellowstone, Montana
, to Norris. This fault experienced an earthquake
in 1959 that measured 7.4 on the Richter scale
(sources vary on exact magnitude between 7.1 and 7.8; see 1959 Yellowstone earthquake
). Norris Geyser Basin is so hot and dynamic because these two faults intersect with the ring fracture zone that resulted from the creation of the Yellowstone Caldera of 640,000 years ago.
The Basin consists of three main areas: Porcelain Basin, Back Basin, and One Hundred Springs Plain. Unlike most of other geyser basins in the park the waters from Norris are acidic rather than alkaline (for example, Echinus Geyser has a pH of ~3.5). The difference in pH allows for a different class of bacteria
l thermophile
s to live at Norris, creating different color patterns in and around the Norris Basin waters.
The Ragged Hills that lie between Back Basin and One Hundred Springs Plain are thermally altered glacial kame
s. As glaciers receded the underlying thermal features began to express themselves once again, melting remnants of the ice and causing masses of debris to be dumped. These debris piles were then altered by steam and hot water flowing through them. Madison lies within the eroded
stream channels cut through lava flows formed after the caldera
eruption. The Gibbon Falls lies on the caldera boundary as does Virginia Cascades.
The tallest active geyser in the world is Steamboat Geyser
and it is located in Norris Basin. Unlike the slightly smaller but much more famous Old Faithful Geyser
located in Upper Geyser Basin, Steamboat has an erratic and lengthy timetable between major eruptions. During major eruptions, which may be separated by intervals of more than a year (the longest recorded span between major eruptions was 50 years), Steamboat erupts over 300 feet (90 m) into the air. Steamboat does not lie dormant between eruptions, instead displaying minor eruptions of approximately 40 feet (12 m).
Norris Geyser Basin periodically undergoes a large-scale, basin-wide thermal disturbance lasting a few weeks. Water levels fluctuate, and temperatures, pH, colors, and eruptive patterns change throughout the basin. During a disturbance in 1985, Porkchop Geyser continually jetted steam and water; in 1989, the same geyser apparently clogged with silica and blew up, throwing rocks more than 200 feet (61 m). In 2003 a park ranger observed it bubbling heavily, the first such activity seen since 1991. Activity increased dramatically in mid-2003. Because of high ground temperatures and new features beside the trail much of Back Basin was closed until October. In 2004 the boardwalk was routed around the dangerous area and now leads behind Porkchop Geyser.
North of Norris, Roaring Mountain is a large, acidic hydrothermal area (solfatara) with many fumaroles. In the late 19th and early 20th centuries, the number, size, and power of the fumaroles were much greater than today. The fumaroles are most easily seen in the cooler, low-light conditions of morning and evening. Artists' Paintpots is a small hydrothermal area south of Norris Junction that includes colorful hot springs and two large mudpots.
. Scientists hypothesize that this basin's structures formed from a hot water system in a glacially dammed lake during the waning stages of the Pinedale Glaciation. The basin is on a ridge reached by a very steep one-mile (1.6 km) trail south of Artists' Paint Pots.
, as well as four other predictable large geysers. One of these large geysers in the area is Castle Geyser
which is about 1400 feet (426.7 m) northwest of Old Faithful. Castle Geyser has an interval of approximately 13 hours between major eruptions, but is unpredictable after minor eruptions. The other three predictable geysers are Grand Geyser
, Daisy Geyser
, and Riverside Geyser
. Biscuit Basin and Black Sand Basin are also within the boundaries of Upper Geyser Basin.
The hills surrounding Old Faithful and the Upper Geyser Basin are reminders of Quaternary
rhyolitic
lava flows. These flows, occurring long after the catastrophic eruption of 640,000 years ago, flowed across the landscape like stiff mounds of bread dough due to their high silica content.
Evidence of glacial activity is common, and it is one of the keys that allows geysers to exist. Glacier till deposits underlie the geyser basins providing storage areas for the water used in eruptions. Many landforms, such as Porcupine Hills north of Fountain Flats, are made up of glacial gravel and are reminders that 70,000 to 14,000 years ago, this area was buried under ice.
Signs of the forces of erosion can be seen everywhere, from runoff channels carved across the sinter in the geyser basins to the drainage created by the Firehole River. Mountain building is evident on the drive south of Old Faithful, toward Craig Pass. Here the Rocky Mountains
reach a height of 8,262 feet (2,518 m), dividing the country into two distinct watershed
s.
Midway Geyser Basin 44°31′04"N 110°49′56"W is much smaller than the other basins found alongside the Firehole River. Despite its small size, it contains two large features, the 200 by wide Excelsior Geyser
which pours over 4000 U.S.gal per minute into the Firehole River. The largest hot spring in Yellowstone, the 370 feet (112.8 m) wide and 121 feet (36.9 m) deep Grand Prismatic Spring
is also found here.
Further north is the Lower Geyser Basin 44°32′58"N 110°50′09"W, which has a much less concentrated set of geothermal features, including Fountain Paint Pots
. Fountain Paint Pots are mud pots, that is, a hot spring that contains boiling mud instead of water. The mud is produced by a higher acidity in the water which enables the spring to dissolve surrounding minerals to create an opaque, usually grey, mud. Also found in this basin is Great Fountain Geyser
, whose eruptions reach 100 to 200 ft (30.5 to 61 m) in the air, while waves of water cascade down its sinter terraces.
in Oregon
, but much smaller than the great Yellowstone Caldera which last erupted about 640,000 years ago. It is interesting to note that West Thumb is a caldera within a caldera.
West Thumb was created approximately 162,000 years ago when a magma chamber bulged up under the surface of the earth and subsequently cracked it along ring fracture zones. This in turn released the enclosed magma
as lava and caused the surface above the emptied magma chamber to collapse. Water later filled the collapsed area of the caldera, forming an extension of Yellowstone Lake. This created the source of heat and water that feed the West Thumb Geyser Basin today.
The thermal features at West Thumb are not only found on the lake shore, but extend under the surface of the lake as well. Several underwater hydrothermal features were discovered in the early 1990s and can be seen as slick spots or slight bulges in the summer. During the winter, the underwater thermal features are visible as melt holes in the icy surface of the lake. The surrounding ice can reach three feet (one meter) in thickness.
Perhaps the most famous hydrothermal feature at West Thumb is a geyser on the lake shore known as Fishing Cone
. Walter Trumbull
of the 1870 Washburn-Langford-Doane Expedition
described a unique event while a man was fishing adjacent to the cone: "...in swinging a trout ashore, it accidentally got off the hook and fell into the spring. For a moment it darted about with wonderful rapidity, as if seeking an outlet. Then it came to the top, dead, and literally boiled." Fishing Cone erupted frequently to the height of 40 feet (12 m) in 1919 and to lesser heights in 1939. One fisherman was badly burned in Fishing Cone in 1921. Fishing at the geyser is now prohibited.
Early visitors would arrive at West Thumb via stagecoach
from the Old Faithful area. They had a choice of continuing on the stagecoach or boarding the steamship Zillah to continue the journey by water to Lake Hotel. The boat dock was located near the south end of the geyser basin near Lakeside Spring.
The Gibbon 44°41′58"N 110°44′34"W, Heart Lake 44°18′00"N 110°30′56"W, Lone Star
44°24′50"N 110°49′04"W, and Shoshone Geyser Basins 44°21′16"N 110°47′57"W are located away from the heavily traveled portions of the park. Some require several miles of off-trail hiking to reach. These areas also generally lack the boardwalks and other safety features of the developed areas. As falling into geothermal features can be fatal, it is usually advisable to visit these areas with an experienced guide or at the very least, travelers need to ensure they remain on well marked trails.
Lying in the Snake River
watershed east of Lewis Lake
and south of Yellowstone Lake, Heart Lake was named sometime before 1871 for Hart Hunney, a hunter. Other explorers in the region incorrectly assumed that the lake's name was spelled 'heart' because of its shape. The Heart Lake Geyser Basin begins a couple miles from the lake and descends along Witch Creek to the lakeshore. Five groups of hydrothermal features comprise the basin, and all of them contain geysers, although some are dormant.
The Shoshone Geyser Basin, reached by hiking or by boat, contains one of the highest concentrations of geysers in the world - more than 80 in an area 1,600 by 800 feet (243.8 m). Hot springs and mudpots dot the landscape between the geyser basin and Shoshone Lake
.
Hot Springs Basin is located 15 miles (24 km) north-northeast of Fishing Bridge and has one of Yellowstone's largest collections of hot springs and fumaroles. The geothermal features there release large amounts of sulfur
. This makes water from the springs so acidic that it has dissolved holes in the pants of people who sit on wet ground and causes mounds of sulfur three feet (1 m) high to develop around fumaroles. The very hot acidic water and steam have also created voids in the ground that are only covered by a thin crust.
The thermal features at Mud Volcano and Sulfur cauldron 44°37′29"N 110°26′03"W are primarily mud pots and fumaroles because the area is situated on a perched water system with little water available. Fumaroles or "steam
vents" occur when the ground water boils away faster than it can be recharged. Also, the vapors are rich in sulfuric acid that leaches the rock
, breaking it down into clay
. Because no water washes away the acid or leached rock, it remains as sticky clay to form a mud pot. Hydrogen sulfide
gas is present deep in the earth at Mud Volcano. As this gas combines with water and the sulfur
is metabolized by cyanobacteria, a solution of sulfuric acid is formed that dissolves the surface soils to create pools and cones of clay and mud. Along with hydrogen sulfide, steam, carbon dioxide, and other gas
es explode through the layers of mud
.
A series of shallow earthquakes associated with the volcanic activity in Yellowstone struck this area in 1978. Soil temperatures increased to nearly 200°F (93°C). The slope between Sizzling Basin and Mud Geyser, once covered with green grass
and tree
s, became a barren landscape of fallen trees known as "the cooking hillside."
Geyser
A geyser is a spring characterized by intermittent discharge of water ejected turbulently and accompanied by a vapour phase . The word geyser comes from Geysir, the name of an erupting spring at Haukadalur, Iceland; that name, in turn, comes from the Icelandic verb geysa, "to gush", the verb...
basins in Yellowstone National Park
Yellowstone National Park
Yellowstone National Park, established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872, is a national park located primarily in the U.S. state of Wyoming, although it also extends into Montana and Idaho...
as well as other geothermal features such as hot spring
Hot spring
A hot spring is a spring that is produced by the emergence of geothermally heated groundwater from the Earth's crust. There are geothermal hot springs in many locations all over the crust of the earth.-Definitions:...
s, mud pots, and fumarole
Fumarole
A fumarole is an opening in a planet's crust, often in the neighborhood of volcanoes, which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrochloric acid, and hydrogen sulfide. The steam is created when superheated water turns to steam as its pressure drops when it emerges from...
s. The number of thermal features in Yellowstone is estimated at 10,000 and 200 to 250 geysers erupt in Yellowstone each year, making it the place with the highest concentration of active geysers in the world, thanks to its location in an ancient active caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...
. Many of these features build up sinter, geyserite
Geyserite
Geyserite is a form of opaline silica that is often found around hot springs and geysers. Botryoidal geyserite is known as fiorite. It is sometimes referred to as sinter.-References:*...
, or travertine
Travertine
Travertine is a form of limestone deposited by mineral springs, especially hot springs. Travertine often has a fibrous or concentric appearance and exists in white, tan, and cream-colored varieties. It is formed by a process of rapid precipitation of calcium carbonate, often at the mouth of a hot...
deposits around and within them.
The various geyser basins are located where rainwater and snowmelt can percolate into the ground, get indirectly superheated by the underlying Yellowstone hotspot
Yellowstone hotspot
The Yellowstone hotspot, also referred to as the Snake River Plain-Yellowstone hotspot, is a volcanic hotspot responsible for large scale volcanism in Oregon, Nevada, Idaho, and Wyoming, United States. It created the eastern Snake River Plain through a succession of caldera forming eruptions...
, and then erupt at the surface as geysers, hot springs, and fumaroles. Thus flat-bottomed valleys between ancient lava
Lava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
flows and glacial moraines are where most of the large geothermal areas are located. Smaller geothermal areas can be found where fault lines reach the surface, in places along the circular fracture zone around the caldera, and at the base of slopes that collect excess groundwater. Due to the Yellowstone Plateau
Yellowstone Plateau
The Yellowstone Plateau volcanic field is a geological feature found in the U.S. state of Wyoming. It is a popular site for tourists.The plateau developed through three volcanic cycles spanning two million years that included some of the world's largest known eruptions...
's high elevation the average boiling temperature at Yellowstone's geyser basins is 199 °F (93 °C). When properly confined and close to the surface it can periodically release some of the built-up pressure in eruptions of hot water and steam that can reach up to 390 feet (120 m) into the air (see Steamboat Geyser
Steamboat Geyser
Steamboat Geyser, in Yellowstone National Park's Norris Geyser Basin, is the world's tallest currently-active geyser. During major eruptions, water may be thrown more than 300 feet into the air....
, the world’s tallest geyser). Water erupting from Yellowstone's geysers is superheated above that boiling point
Boiling point
The boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....
to an average of 204 °F (95.5 °C) as it leaves the vent. The water cools significantly while airborne and is no longer scalding hot by the time it strikes the ground, nearby boardwalks, or even spectators. Because of the high temperatures of the water in the features it is important that spectators remain on the boardwalks and designated trails. Several deaths have occurred in the park as a result of falls into hot springs.
Prehistoric Native American
Indigenous peoples of the Americas
The indigenous peoples of the Americas are the pre-Columbian inhabitants of North and South America, their descendants and other ethnic groups who are identified with those peoples. Indigenous peoples are known in Canada as Aboriginal peoples, and in the United States as Native Americans...
artifacts have been found at Mammoth Hot Springs and other geothermal areas in Yellowstone. Some accounts state that the early people used hot water from the geothermal features for bathing and cooking. In the 19th century Father Pierre-Jean De Smet
Pierre-Jean De Smet
Pierre-Jean De Smet , also known as Pieter-Jan De Smet, was a Belgian Roman Catholic priest and member of the Society of Jesus , active in missionary work among the Native Americans of the Midwestern United States in the mid-19th century.His extensive travels as a missionary were said to total...
reported that natives he interviewed thought that geyser eruptions were "the result of combat between the infernal spirits." The Lewis and Clark Expedition
Lewis and Clark Expedition
The Lewis and Clark Expedition, or ″Corps of Discovery Expedition" was the first transcontinental expedition to the Pacific Coast by the United States. Commissioned by President Thomas Jefferson and led by two Virginia-born veterans of Indian wars in the Ohio Valley, Meriwether Lewis and William...
traveled north of the Yellowstone area in 1806. Local natives that they came upon seldom dared to enter what we now know is the caldera because of frequent loud noises that sounded like thunder
Thunder
Thunder is the sound made by lightning. Depending on the nature of the lightning and distance of the listener, thunder can range from a sharp, loud crack to a long, low rumble . The sudden increase in pressure and temperature from lightning produces rapid expansion of the air surrounding and within...
and the belief that the spirits that possessed the area did not like human
Human
Humans are the only living species in the Homo genus...
intrusion into their realm. The first Caucasian
Caucasian race
The term Caucasian race has been used to denote the general physical type of some or all of the populations of Europe, North Africa, the Horn of Africa, Western Asia , Central Asia and South Asia...
known to travel into the caldera and see the geothermal features was John Colter
John Colter
John Colter was a member of the Lewis and Clark Expedition . Though party to one of the more famous expeditions in history, Colter is best remembered for explorations he made during the winter of 1807–1808, when Colter became the first known person of European descent to enter the region now known...
, who had left the Lewis and Clark Expedition. He described what he saw as "hot spring brimstone." Beaver trapper Joseph Meek recounted in 1830 that the steam rising from the various geyser basins reminded him of smoke coming from industrial smokestacks on a cold winter morning in Pittsburgh, Pennsylvania
Pittsburgh, Pennsylvania
Pittsburgh is the second-largest city in the US Commonwealth of Pennsylvania and the county seat of Allegheny County. Regionally, it anchors the largest urban area of Appalachia and the Ohio River Valley, and nationally, it is the 22nd-largest urban area in the United States...
. In the 1850s famed trapper Jim Bridger
Jim Bridger
James Felix "Jim" Bridger was among the foremost mountain men, trappers, scouts and guides who explored and trapped the Western United States during the decades of 1820-1850, as well as mediating between native tribes and encroaching whites...
called it "the place where Hell bubbled up."
Types of features found in the park
The heat that drives geothermal activity in the Yellowstone area comes from brineBrine
Brine is water, saturated or nearly saturated with salt .Brine is used to preserve vegetables, fruit, fish, and meat, in a process known as brining . Brine is also commonly used to age Halloumi and Feta cheeses, or for pickling foodstuffs, as a means of preserving them...
(salty water) that is 1.5 to 3 miles (2.4 to 4.8 km) below the surface. This is actually below the solid volcanic rock
Volcanic rock
Volcanic rock is a rock formed from magma erupted from a volcano. In other words, it is an igneous rock of volcanic origin...
and sediment
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
that extends to a depth of 3,000 to 6,000 feet (900 to 1,800 m) and is inside the hot but mostly solid part of the pluton
Intrusion
An intrusion is liquid rock that forms under Earth's surface. Magma from under the surface is slowly pushed up from deep within the earth into any cracks or spaces it can find, sometimes pushing existing country rock out of the way, a process that can take millions of years. As the rock slowly...
that contains Yellowstone’s magma chamber
Magma chamber
A magma chamber is a large underground pool of molten rock found beneath the surface of the Earth. The molten rock in such a chamber is under great pressure, and given enough time, that pressure can gradually fracture the rock around it creating outlets for the magma...
. At that depth the brine is superheated to temperatures that exceed 400°F or 205°C (double the boiling point at the surface) but is able to remain a liquid because it is under great pressure (like a huge pressure cooker).
Convection
Convection
Convection is the movement of molecules within fluids and rheids. It cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids....
of the churning brine and conduction
Heat conduction
In heat transfer, conduction is a mode of transfer of energy within and between bodies of matter, due to a temperature gradient. Conduction means collisional and diffusive transfer of kinetic energy of particles of ponderable matter . Conduction takes place in all forms of ponderable matter, viz....
from surrounding rock transfers heat to an overlaying layer of fresh groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
. Movement of the two liquids is facilitated by the highly fractured and porous nature of the rocks under the Yellowstone Plateau. Some silica is dissolved from the fractured rhyolite into the hot water as it travels through the fractured rock. Part of this hard mineral is later redeposited on the walls of the cracks and fissures to make a nearly pressure-tight system. Silica precipitates at the surface to form either geyserite or sinter, creating the massive geyser cones, the scalloped edges of hot springs, and the seemingly barren landscape of geyser basins.
There are at least five types of geothermal features found at Yellowstone:
- Fumaroles: FumaroleFumaroleA fumarole is an opening in a planet's crust, often in the neighborhood of volcanoes, which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrochloric acid, and hydrogen sulfide. The steam is created when superheated water turns to steam as its pressure drops when it emerges from...
s or steam vents, are the hottest hydrothermal features in the park. They have so little water that it all flashes into steam before reaching the surface. At places like Roaring MountainRoaring MountainRoaring Mountain is in Yellowstone National Park in the U.S. state of Wyoming. Roaring Mountain was named for the numerous fumaroles on the western slope of the peak which during the early 1900s were loud enough to be heard for several miles. Roaring Mountain is north of Norris Geyser Basin and...
, the result is loud hissing of steam and gases. - Geysers: GeyserGeyserA geyser is a spring characterized by intermittent discharge of water ejected turbulently and accompanied by a vapour phase . The word geyser comes from Geysir, the name of an erupting spring at Haukadalur, Iceland; that name, in turn, comes from the Icelandic verb geysa, "to gush", the verb...
s such as Old Faithful are a type of geothermal feature that periodically erupt scalding hot water. Increased pressure exerted by the enormous weight of the overlying rock and water prevents deeper water from boiling. As the hot water rises it is under less pressure and steam bubbles form. They, in turn, expand on their ascent until the bubbles are too big and numerous to pass freely through constrictions. At a critical point the confined bubbles actually lift the water above, causing the geyser to splash or overflow. This decreases the pressure of the system and violent boiling results. Large quantities of water flash into tremendous amounts of steam that force a jet of water out of the vent: an eruption begins. Water (and heat) is expelled faster than the geyser’s recharge rate, gradually decreasing the system’s pressure and eventually ending the eruption. - Hot springs: Hot springHot springA hot spring is a spring that is produced by the emergence of geothermally heated groundwater from the Earth's crust. There are geothermal hot springs in many locations all over the crust of the earth.-Definitions:...
s such as Grand Prismatic SpringGrand Prismatic SpringThe Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world, next to those in New Zealand. It is located in the Midway Geyser Basin....
are the most common hydrothermal features in the park. Their plumbing has no constrictions. Superheated water cools as it reaches the surface, sinks, and is replaced by hotter water from below. This circulation, called convection, prevents water from reaching the temperature needed to set off an eruption. Many hot springs give rise to streams of heated water. - Mudpots: MudpotMudpotA mudpot, mud pool or paint pot is a sort of hot spring or fumarole consisting of a pool of usually bubbling mud. The mud is generally of white to greyish color, but is sometimes stained with reddish or pink spots from iron compounds...
s such as Fountain Paint PotsFountain Paint PotsThe Fountain Paint Pot is a mud pot located in Lower Geyser basin in Yellowstone National Park.The Fountain Paint Pot is named for the reds, yellows and browns of the mud in this area. The differing colors are derived from oxidation states of the iron in the mud. As with all hot springs, the heat...
are acidAcidAn acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
ic hot springs with a limited water supply. Some microorganismMicroorganismA microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...
s use hydrogen sulfideHydrogen sulfideHydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
(rotten egg smell), which rises from deep within the earth, as an energy source. They convert the gas into sulfuric acidSulfuric acidSulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
, which breaks down rock into clay. - Travertine terraces: Travertine terraces, found at Mammoth Hot SpringsMammoth Hot SpringsMammoth Hot Springs is a large complex of hot springs on a hill of travertine in Yellowstone National Park adjacent to Fort Yellowstone and the Mammoth Hot Springs Historic District. It was created over thousands of years as hot water from the spring cooled and deposited calcium carbonate...
, are formed from limestoneLimestoneLimestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
(a rock type made of calcium carbonateCalcium carbonateCalcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
). Thermal waters rise through the limestone, carrying high amounts of dissolved carbonate. Carbon dioxideCarbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
is released at the surface and calcium carbonate deposited as travertineTravertineTravertine is a form of limestone deposited by mineral springs, especially hot springs. Travertine often has a fibrous or concentric appearance and exists in white, tan, and cream-colored varieties. It is formed by a process of rapid precipitation of calcium carbonate, often at the mouth of a hot...
, the chalkChalkChalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores....
y white rock of the terraces. These features constantly and quickly change due to the rapid rate of deposition.
Norris Geyser Basin
Yellowstone Caldera
The Yellowstone Caldera is the volcanic caldera located in Yellowstone National Park in the United States, sometimes referred to as the Yellowstone Supervolcano. The caldera is located in the northwest corner of Wyoming, in which the vast majority of the park is contained. The major features of...
near Norris Junction and on the intersection of three major fault
Geologic fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock, across which there has been significant displacement along the fractures as a result of earth movement. Large faults within the Earth's crust result from the action of tectonic forces...
s. The Norris-Mammoth Corridor is a fault that runs from Norris north through Mammoth to the Gardiner, Montana
Gardiner, Montana
Gardiner is a census-designated place in Park County, Montana, United States, along the 45th parallel. The population was 851 at the 2000 census....
, area. The Hebgen Lake fault runs from northwest of West Yellowstone, Montana
West Yellowstone, Montana
West Yellowstone is a town in Gallatin County, Montana, adjacent to Yellowstone National Park. The population was 1,177 at the 2000 census. The town is served by Yellowstone Airport...
, to Norris. This fault experienced an earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
in 1959 that measured 7.4 on the Richter scale
Richter magnitude scale
The expression Richter magnitude scale refers to a number of ways to assign a single number to quantify the energy contained in an earthquake....
(sources vary on exact magnitude between 7.1 and 7.8; see 1959 Yellowstone earthquake
1959 Yellowstone earthquake
The 1959 Yellowstone earthquake also known as the Hebgen Lake earthquake was a powerful earthquake that occurred on August 17, 1959 at 11:37 pm in southwestern Montana. The earthquake was registered at magnitude 7.3 – 7.5 on the Richter scale...
). Norris Geyser Basin is so hot and dynamic because these two faults intersect with the ring fracture zone that resulted from the creation of the Yellowstone Caldera of 640,000 years ago.
The Basin consists of three main areas: Porcelain Basin, Back Basin, and One Hundred Springs Plain. Unlike most of other geyser basins in the park the waters from Norris are acidic rather than alkaline (for example, Echinus Geyser has a pH of ~3.5). The difference in pH allows for a different class of bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
l thermophile
Thermophile
A thermophile is an organism — a type of extremophile — that thrives at relatively high temperatures, between 45 and 122 °C . Many thermophiles are archaea...
s to live at Norris, creating different color patterns in and around the Norris Basin waters.
The Ragged Hills that lie between Back Basin and One Hundred Springs Plain are thermally altered glacial kame
Kame
A kame is a geological feature, an irregularly shaped hill or mound composed of sand, gravel and till that accumulates in a depression on a retreating glacier, and is then deposited on the land surface with further melting of the glacier...
s. As glaciers receded the underlying thermal features began to express themselves once again, melting remnants of the ice and causing masses of debris to be dumped. These debris piles were then altered by steam and hot water flowing through them. Madison lies within the eroded
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
stream channels cut through lava flows formed after the caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...
eruption. The Gibbon Falls lies on the caldera boundary as does Virginia Cascades.
Steamboat Geyser
Steamboat Geyser, in Yellowstone National Park's Norris Geyser Basin, is the world's tallest currently-active geyser. During major eruptions, water may be thrown more than 300 feet into the air....
and it is located in Norris Basin. Unlike the slightly smaller but much more famous Old Faithful Geyser
Old Faithful Geyser
Old Faithful is a cone geyser located in Wyoming, in Yellowstone National Park in the United States. Old Faithful was named in 1870 during the Washburn-Langford-Doane Expedition and was the first geyser in the park to receive a name...
located in Upper Geyser Basin, Steamboat has an erratic and lengthy timetable between major eruptions. During major eruptions, which may be separated by intervals of more than a year (the longest recorded span between major eruptions was 50 years), Steamboat erupts over 300 feet (90 m) into the air. Steamboat does not lie dormant between eruptions, instead displaying minor eruptions of approximately 40 feet (12 m).
Norris Geyser Basin periodically undergoes a large-scale, basin-wide thermal disturbance lasting a few weeks. Water levels fluctuate, and temperatures, pH, colors, and eruptive patterns change throughout the basin. During a disturbance in 1985, Porkchop Geyser continually jetted steam and water; in 1989, the same geyser apparently clogged with silica and blew up, throwing rocks more than 200 feet (61 m). In 2003 a park ranger observed it bubbling heavily, the first such activity seen since 1991. Activity increased dramatically in mid-2003. Because of high ground temperatures and new features beside the trail much of Back Basin was closed until October. In 2004 the boardwalk was routed around the dangerous area and now leads behind Porkchop Geyser.
North of Norris, Roaring Mountain is a large, acidic hydrothermal area (solfatara) with many fumaroles. In the late 19th and early 20th centuries, the number, size, and power of the fumaroles were much greater than today. The fumaroles are most easily seen in the cooler, low-light conditions of morning and evening. Artists' Paintpots is a small hydrothermal area south of Norris Junction that includes colorful hot springs and two large mudpots.
Monument Geyser Basin
The Monument Geyser Basin 44°41′03"N 110°45′14"W has no active geysers, but its 'monuments' are siliceous sinter deposits similar to the siliceous spires discovered on the floor of Yellowstone LakeYellowstone Lake
Yellowstone Lake is the largest body of water in Yellowstone National Park, The lake is 7,732 feet above sea level and covers with 110 miles of shoreline. While the average depth of the lake is 139 feet its deepest spot is at least 390 feet...
. Scientists hypothesize that this basin's structures formed from a hot water system in a glacially dammed lake during the waning stages of the Pinedale Glaciation. The basin is on a ridge reached by a very steep one-mile (1.6 km) trail south of Artists' Paint Pots.
Upper Geyser Basin
South of Norris along the rim of the caldera is the Upper Geyser Basin 44°27′52"N 110°49′45"W, which has the highest concentration of geothermal features in the park. This complement of features includes the most famous geyser in the park, Old Faithful GeyserOld Faithful Geyser
Old Faithful is a cone geyser located in Wyoming, in Yellowstone National Park in the United States. Old Faithful was named in 1870 during the Washburn-Langford-Doane Expedition and was the first geyser in the park to receive a name...
, as well as four other predictable large geysers. One of these large geysers in the area is Castle Geyser
Castle Geyser
Castle Geyser is a cone geyser in the Upper Geyser Basin of Yellowstone National Park. It is noted for the particularly large geyserite sinter deposits, which form its cone...
which is about 1400 feet (426.7 m) northwest of Old Faithful. Castle Geyser has an interval of approximately 13 hours between major eruptions, but is unpredictable after minor eruptions. The other three predictable geysers are Grand Geyser
Grand Geyser
Grand Geyser is a fountain geyser in the Upper Geyser Basin of Yellowstone National Park in the United States. It is the tallest predictable geyser known. It was named by Dr. F.V. Hayden in 1871.-Eruptions:...
, Daisy Geyser
Daisy Geyser
Daisy Geyser is a geyser in the Upper Geyser Basin of Yellowstone National Park in the United States.Daisy Geyser is part of the Daisy Group. It was named prior to 1890 by the Hague Party. It erupts every 110 to 240 minutes for a period of 3 to 5 minutes and is one of the most predictable geysers...
, and Riverside Geyser
Riverside Geyser
Riverside Geyser is a geyser in Yellowstone National Park in the U.S. state of Wyoming.The geyser is located on the Firehole River within the Upper Geyser Basin. The geyser shoots steam and water to heights of 75 feet in an arch over the river, sometimes causing brilliant rainbows. The eruptions...
. Biscuit Basin and Black Sand Basin are also within the boundaries of Upper Geyser Basin.
The hills surrounding Old Faithful and the Upper Geyser Basin are reminders of Quaternary
Quaternary
The Quaternary Period is the most recent of the three periods of the Cenozoic Era in the geologic time scale of the ICS. It follows the Neogene Period, spanning 2.588 ± 0.005 million years ago to the present...
rhyolitic
Rhyolite
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...
lava flows. These flows, occurring long after the catastrophic eruption of 640,000 years ago, flowed across the landscape like stiff mounds of bread dough due to their high silica content.
Evidence of glacial activity is common, and it is one of the keys that allows geysers to exist. Glacier till deposits underlie the geyser basins providing storage areas for the water used in eruptions. Many landforms, such as Porcupine Hills north of Fountain Flats, are made up of glacial gravel and are reminders that 70,000 to 14,000 years ago, this area was buried under ice.
Signs of the forces of erosion can be seen everywhere, from runoff channels carved across the sinter in the geyser basins to the drainage created by the Firehole River. Mountain building is evident on the drive south of Old Faithful, toward Craig Pass. Here the Rocky Mountains
Rocky Mountains
The Rocky Mountains are a major mountain range in western North America. The Rocky Mountains stretch more than from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States...
reach a height of 8,262 feet (2,518 m), dividing the country into two distinct watershed
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
s.
Midway Geyser Basin
Midway Geyser Basin 44°31′04"N 110°49′56"W is much smaller than the other basins found alongside the Firehole River. Despite its small size, it contains two large features, the 200 by wide Excelsior Geyser
Excelsior Geyser
Excelsior Geyser Crater, formerly known as Excelsior Geyser, is a hot spring in the Midway Geyser Basin of Yellowstone National Park in the United States. Excelsior was named by the Hayden Geological Survey of 1871...
which pours over 4000 U.S.gal per minute into the Firehole River. The largest hot spring in Yellowstone, the 370 feet (112.8 m) wide and 121 feet (36.9 m) deep Grand Prismatic Spring
Grand Prismatic Spring
The Grand Prismatic Spring in Yellowstone National Park is the largest hot spring in the United States, and the third largest in the world, next to those in New Zealand. It is located in the Midway Geyser Basin....
is also found here.
Lower Geyser Basin
Further north is the Lower Geyser Basin 44°32′58"N 110°50′09"W, which has a much less concentrated set of geothermal features, including Fountain Paint Pots
Fountain Paint Pots
The Fountain Paint Pot is a mud pot located in Lower Geyser basin in Yellowstone National Park.The Fountain Paint Pot is named for the reds, yellows and browns of the mud in this area. The differing colors are derived from oxidation states of the iron in the mud. As with all hot springs, the heat...
. Fountain Paint Pots are mud pots, that is, a hot spring that contains boiling mud instead of water. The mud is produced by a higher acidity in the water which enables the spring to dissolve surrounding minerals to create an opaque, usually grey, mud. Also found in this basin is Great Fountain Geyser
Great Fountain Geyser
The Great Fountain Geyser is a fountain-type geyser located in the Firehole Lake area of Lower Geyser Basin of Yellowstone National Park, Wyoming. It is the only predicted geyser in the Lower Geyser Basin.-Eruption:...
, whose eruptions reach 100 to 200 ft (30.5 to 61 m) in the air, while waves of water cascade down its sinter terraces.
West Thumb Geyser Basin
The West Thumb Geyser Basin 44°25′07"N 110°34′23"W, including Potts Basin to the north, is the largest geyser basin on the shores of Yellowstone Lake. The heat source of the thermal features in this location is thought to be relatively close to the surface, only 10,000 feet (3,000 m) down. West Thumb is about the same size as another famous volcanic caldera, Crater LakeCrater Lake
Crater Lake is a caldera lake located in the south-central region of the U.S. state of Oregon. It is the main feature of Crater Lake National Park and famous for its deep blue color and water clarity. The lake partly fills a nearly deep caldera that was formed around 7,700 years agoby the...
in Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...
, but much smaller than the great Yellowstone Caldera which last erupted about 640,000 years ago. It is interesting to note that West Thumb is a caldera within a caldera.
West Thumb was created approximately 162,000 years ago when a magma chamber bulged up under the surface of the earth and subsequently cracked it along ring fracture zones. This in turn released the enclosed magma
Magma
Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...
as lava and caused the surface above the emptied magma chamber to collapse. Water later filled the collapsed area of the caldera, forming an extension of Yellowstone Lake. This created the source of heat and water that feed the West Thumb Geyser Basin today.
The thermal features at West Thumb are not only found on the lake shore, but extend under the surface of the lake as well. Several underwater hydrothermal features were discovered in the early 1990s and can be seen as slick spots or slight bulges in the summer. During the winter, the underwater thermal features are visible as melt holes in the icy surface of the lake. The surrounding ice can reach three feet (one meter) in thickness.
Perhaps the most famous hydrothermal feature at West Thumb is a geyser on the lake shore known as Fishing Cone
Fishing Cone
Fishing Cone is a geyser in the West Thumb Geyser Basin of Yellowstone National Park in the United States.In the earlier part of the 20th century, this cone had eruptions as high as 40 feet...
. Walter Trumbull
Walter Trumbull
Walter H. Trumbull, Jr. was an American football player. He attended Middlesex School in Concord, Massachusetts before enrolling at Harvard University. He played at the tackle and center positions for Percy Haughton's Harvard Crimson football from 1912 to 1914...
of the 1870 Washburn-Langford-Doane Expedition
Washburn-Langford-Doane Expedition
The Washburn Expedition of 1870, explored the region of northwestern Wyoming that a couple years later became Yellowstone National Park. Led by Henry Washburn, Nathaniel P. Langford and under U.S. Army escort led by Lt. Gustavus C...
described a unique event while a man was fishing adjacent to the cone: "...in swinging a trout ashore, it accidentally got off the hook and fell into the spring. For a moment it darted about with wonderful rapidity, as if seeking an outlet. Then it came to the top, dead, and literally boiled." Fishing Cone erupted frequently to the height of 40 feet (12 m) in 1919 and to lesser heights in 1939. One fisherman was badly burned in Fishing Cone in 1921. Fishing at the geyser is now prohibited.
Early visitors would arrive at West Thumb via stagecoach
Stagecoach
A stagecoach is a type of covered wagon for passengers and goods, strongly sprung and drawn by four horses, usually four-in-hand. Widely used before the introduction of railway transport, it made regular trips between stages or stations, which were places of rest provided for stagecoach travelers...
from the Old Faithful area. They had a choice of continuing on the stagecoach or boarding the steamship Zillah to continue the journey by water to Lake Hotel. The boat dock was located near the south end of the geyser basin near Lakeside Spring.
Backcountry Geyser Basins
; ; ;The Gibbon 44°41′58"N 110°44′34"W, Heart Lake 44°18′00"N 110°30′56"W, Lone Star
Lone Star Geyser
Lone Star Geyser is a cone type geyser located in the Lone Star Geyser Basin of Yellowstone National Park. The basin is a backcountry geyser basin located southeast of Old Faithful Geyser and the Upper Geyser Basin...
44°24′50"N 110°49′04"W, and Shoshone Geyser Basins 44°21′16"N 110°47′57"W are located away from the heavily traveled portions of the park. Some require several miles of off-trail hiking to reach. These areas also generally lack the boardwalks and other safety features of the developed areas. As falling into geothermal features can be fatal, it is usually advisable to visit these areas with an experienced guide or at the very least, travelers need to ensure they remain on well marked trails.
Lying in the Snake River
Snake River
The Snake is a major river of the greater Pacific Northwest in the United States. At long, it is the largest tributary of the Columbia River, the largest North American river that empties into the Pacific Ocean...
watershed east of Lewis Lake
Lewis Lake (Wyoming)
Lewis Lake is located in the U. S. state of Wyoming in the southern part of Yellowstone National Park, about southeast of Shoshone Lake, and approximately southwest of Yellowstone Lake. Lewis Lake and Shoshone Lake are both located a few miles northeast of the Pitchstone Plateau.The Lewis River...
and south of Yellowstone Lake, Heart Lake was named sometime before 1871 for Hart Hunney, a hunter. Other explorers in the region incorrectly assumed that the lake's name was spelled 'heart' because of its shape. The Heart Lake Geyser Basin begins a couple miles from the lake and descends along Witch Creek to the lakeshore. Five groups of hydrothermal features comprise the basin, and all of them contain geysers, although some are dormant.
The Shoshone Geyser Basin, reached by hiking or by boat, contains one of the highest concentrations of geysers in the world - more than 80 in an area 1,600 by 800 feet (243.8 m). Hot springs and mudpots dot the landscape between the geyser basin and Shoshone Lake
Shoshone Lake
Shoshone Lake is a backcountry lake with the area of elevated at in the southwest section of Yellowstone National Park, Wyoming, US. It lies at the headwaters of the Lewis River a tributary of the Snake River. The U.S...
.
Hot Springs Basin is located 15 miles (24 km) north-northeast of Fishing Bridge and has one of Yellowstone's largest collections of hot springs and fumaroles. The geothermal features there release large amounts of sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
. This makes water from the springs so acidic that it has dissolved holes in the pants of people who sit on wet ground and causes mounds of sulfur three feet (1 m) high to develop around fumaroles. The very hot acidic water and steam have also created voids in the ground that are only covered by a thin crust.
Mud Volcano and Sulfur cauldron
Steam
Steam is the technical term for water vapor, the gaseous phase of water, which is formed when water boils. In common language it is often used to refer to the visible mist of water droplets formed as this water vapor condenses in the presence of cooler air...
vents" occur when the ground water boils away faster than it can be recharged. Also, the vapors are rich in sulfuric acid that leaches the rock
Rock (geology)
In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...
, breaking it down into clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
. Because no water washes away the acid or leached rock, it remains as sticky clay to form a mud pot. Hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
gas is present deep in the earth at Mud Volcano. As this gas combines with water and the sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
is metabolized by cyanobacteria, a solution of sulfuric acid is formed that dissolves the surface soils to create pools and cones of clay and mud. Along with hydrogen sulfide, steam, carbon dioxide, and other gas
Gas
Gas is one of the three classical states of matter . Near absolute zero, a substance exists as a solid. As heat is added to this substance it melts into a liquid at its melting point , boils into a gas at its boiling point, and if heated high enough would enter a plasma state in which the electrons...
es explode through the layers of mud
Mud
Mud is a mixture of water and some combination of soil, silt, and clay. Ancient mud deposits harden over geological time to form sedimentary rock such as shale or mudstone . When geological deposits of mud are formed in estuaries the resultant layers are termed bay muds...
.
A series of shallow earthquakes associated with the volcanic activity in Yellowstone struck this area in 1978. Soil temperatures increased to nearly 200°F (93°C). The slope between Sizzling Basin and Mud Geyser, once covered with green grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
and tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s, became a barren landscape of fallen trees known as "the cooking hillside."
Video
- Old Faithful
- Castle GeyserCastle GeyserCastle Geyser is a cone geyser in the Upper Geyser Basin of Yellowstone National Park. It is noted for the particularly large geyserite sinter deposits, which form its cone...
- Fountain Paint PotsFountain Paint PotsThe Fountain Paint Pot is a mud pot located in Lower Geyser basin in Yellowstone National Park.The Fountain Paint Pot is named for the reds, yellows and browns of the mud in this area. The differing colors are derived from oxidation states of the iron in the mud. As with all hot springs, the heat...
See also
- Mud volcanoMud volcanoThe term mud volcano or mud dome are used to refer to formations created by geo-excreted liquids and gases, although there are several different processes which may cause such activity. Hot water mixes with mud and surface deposits. Mud volcanoes are associated with subduction zones and about 700...
- List of Yellowstone geothermal features
- Hydrothermal explosionHydrothermal explosionHydrothermal explosions occur when superheated water trapped below the surface of the earth rapidly converts from liquid to steam, violently disrupting the confining rock. Boiling water, steam, mud, and rock fragments called breccia are ejected over an area of a few meters up to several kilometers...