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Yellowstone National Park info

Yellowstone National Park

Catastrophic events that formed today’s strange landscape [at Yellowstone have] destroyed most of the [geologic] record. Drawing on [plate] tectonic theory to understand these events, geologists theorize that a gigantic plume of molten matter emerged from the Earth’s mantle below North America about 30 million years ago and rose toward the surface. The plume ascended slowly through the semi-plastic mantle, perhaps six inches a year, but by 15 million years ago it had neared the crust, becoming what is called a "hot spot."

Some 40 such hot spots exist on the planet. Their effects are dramatic. They can cause the Earth’s curst to swell into blister-like domes, giant volcanoes that eventually explode and collapse, forming "calderas," giant bowl-shaped holes. The "vast cinder" of the Yellowstone Plateau is a caldera.

Geologists believe this hot spot left a track of calderas across the West’s Great Basin after it surfaced, although it was not the hot spot that moved. What moved, and still moves, is the North American Plate. It is drifting, southwest, a few millimeters a year. Its track, so to speak, extends from northeastern Nevada across southern Idaho. It includes the remains of successively younger calderas.

By 2 million years ago the hot spot was in the Yellowstone region and apparently caused a volcanic explosion that dwarfs any recent ones. This stupendous explosion ejected 2400 times more ash than Mt. St. Helen’s 1980 blast. The crater it left, Huckleberry Ridge Caldera, extended nearly 50 miles, from Yellowstone’s center to Idaho’s Island Park. Another explosion about 1.3 million years ago ejected more ash than Tambora, the volcano on Indonesia’s Sumbawa Island, which, in 1815, produced the biggest volcanic explosion ever recorded.

Yet another eruption 630,000 years ago- it blasted out the present-day Yellowstone Caldera and rivaled the blast creating the Huckleberry Ridge Caldera- defines today’s Yellowstone Plateau. One can see this well from atop Mt. Washburn on the caldera’s northern rim. All the vast landscape between those distant peaks and Mt. Washburn was part of the ancient volcanic range that exploded and collapsed, perhaps in mere hours. Having blasted away whatever geological deposits had existed above it, the hot spot shaped the strange landscape we know. Its heat and uplift cracked the rocks with many faults, creating steep escarpments like Mt Everts. Within the Lava Creek Caldera, where molten magma remains as close as three miles below the surface, lava emerged from fault lines and accumulated as the massive lava flows that now fill the caldera and the plateau’s valleys. Formed of a volcanic material known as rhyolite, this lava was stiffer than basaltic lava and accumulated in "piles of taffy-like incandescent rock," as geologists have described it. Between the lava flows, thermal fields developed as groundwater drained into the heated bedrock and erupted back to the surface as hot springs or geysers. The hot springs and geysers deposited dissolved minerals in the fantastic shapes we see today. Yellowstone contains more than 300 geysers- approximately 2/3 of the planet’s entire stock of geysers- and there are some 10,000 thermal features in all.

For geysers to occur, there must be heat, water, and a plumbing system. A magma chamber provides the heat, which radiates into surrounding rock. Water from rain and snow works its way underground through fractures in the rock. As the water reaches hot rock it begins to rise back to the surface, passing through the rock rhyolite, which is former volcanic ash or lava rich in silica. The hot water dissolves the silica and carries it upward to line rock crevices. This forms a constriction that holds in the mounting pressure, creating a geyser’s plumbing system.

As superheated water nears the surface, its pressure drops, and the water flashes into steam as a geyser. Hot springs have unconstricted plumbing systems. Fumaroles (steam vents) do, too, but are generally dry. Mudpots form when acid decomposes surrounding rock into clay, which mixes with water to form mud of varying consistency and color.

Hot springs are full of unique lie forms that have inhabited Earth nearly 4 billion years. A pool’s many colors mostly derive from light refraction, suspended mineral particles, and large communities of primitive life forms: microscopic algae, bacteria, and Archaea. (The Archaea, once considered bacteria, have completely different DNA.) They grow in water too hot for most kinds of life familiar to us on Earth. Life even occurs in boiling water, but, as the waster cools to about 160 F (72 C), the organisms become rich, thick, living layers of color in many different hues. The chemistry of thermal pools also influences the kinds and abundance of life. The boiling hot springs of Norris, which are more acidic than battery acid, sustain algae, bacteria, and Archaea far different from those living in the alkaline springs in the Old Faithful area. Collectively called thermophiles, these bizarre life forms are still largely a mystery to scientists. How do they thrive in such hostile environments? What can they teach us about present and past life on Earth or elsewhere in the universe? Because of the great scientific interest in thermophiles, studies occasionally lead to the discovery of processes or products that have value in our society. One famous example is the laboratory cloning of a heat-stable enzyme originally produced from a minute sample of the Yellowstone microbe named Thermus aquaticus. This novel enzyme, now known as Taq Polymerase, is mass-produced in laboratories for use in DNA studied throughout the world. A seemingly small discovery in a Yellowstone hot spring ultimately made a major contribution to the scientific revolution in DNA analysis in law enforcement, medicine, and agriculture.

The surest way to experience Yellowstone’s continuity with its past is to encounter its wildlife. Seeing an elk, bison, or moose in the forests and meadows is really not so different from seeing a mammoth. There’s something wonderfully monstrous about them, too. This monstrousness may seem a bit ludicrous at park hotels, as rutting bull elks chase cows across the lawns with wheezy, discordant cries. Yet, out among the canyons, when migrating bluebirds flutter like chips of autumn sky in the aspen trees, these same high-pitched cries sound very different. They echo and reverberate powerfully, thoroughly justifying the impressive term- "bugling"- which is used to describe them.

Next to scenery and geological wonders, Yellowstone’s wildlife has been the park’s greatest attraction, yet this biological resource has proved both harder to understand and more difficult to conserve than geysers and waterfalls. Public attitudes towards wild creatures have undergone profound changes, and wildlife management policies sometimes have been reversed. In fact, many questions still remain as to how park animals relate to their environment, to each other, and to human use of the park.

Persistent poaching in the park reduced bison to fewer than 50 animals by 1898. The park’s big game began to seem secure by 1916 when the bison herd reached 348. Yet, other worries arose. Elk numbers had increased rapidly, particularly in the park’s fertile northern range, and the park’s managers feared the elk would deplete their food supply and starve.

The attempt to restore Yellowstone to its 2000 year-old diversity continues despite such setbacks. In March 1995 wolves were reintroduced after 20 years of controversy as to whether livestock losses outside the park would outweigh the ecological and scientific values of having North America’s greatest wilderness symbol inside the park. Although mountain lions had reinhabited Yellowstone naturally, the closest substantial population of the endangered Rocky Mountain wolf subspecies lived in northern Montana. Biologists thought it was unlikely that the wolves would return to Yellowstone unaided.

As part of a recovery plant o reintroduce them to the West, the US Fish and Wildlife Service and the National Park Service transported 14 wolves captured in central Alberta to holding pens in several parts of the park. Released in April 1995, the animals surprised even experts with their ready adaptation. By May thousands of visitors were treated to the spectacle of big black or gray wolves chasing elk across the Lamar Valley in broad daylight. That sight had been virtually unknown in the West for 150 years.

Seventeen more wolves arrived in 1996, this time from British Columbia. The goal was establishment of a self-sustaining park population of about 10 packs by 2002. Even when this is accomplished, Yellowstone wolves will never be as easy to see as elk or bison- but knowing that these highly social and intelligent creatures are there adds another dimension to the place.

The loudest and most strident controversy over policies concerned the wildfires in 1988, which affected nearly 1/3 of the park. News media emphasized the fires’ danger and destructiveness, and critics charged that the natural burn policy had let the fires get out of control. Yet then-Park Superintendent Robert Barbee had suspended the policy early in the summer and many firefighters doubted the partly human-caused blazes could have been controlled any more than they were, given the year’s unprecedented dry conditions and weather patterns.

Despite apocalyptic newscasts the fires did not damage Yellowstone ecologically. Vegetation began recovering quickly. Wildfire losses from fire or smoke inhalation were surprisingly light. Some 243 elk, five bison, two moose, and four deer were known to have died in the park, although more animals succumbed to a temporary food shortage during the ensuing harsh winter. The fires also provided an unprecedented opportunity to study the effects of such large-scale burning on such a little-disturbed ecosystem.