Yellowstone Geology

Yellowstone National Park is rich in history of several kinds. The history of the landscape is a story of geological extremes. The history & prehistory of the people of the park is a story of variety and excitement. The history of the fish is a story of persistence, expansion & caprice.

The natural wonders of America's first national park are so abundant that even several lifetimes would be consumed exploring them all. The most popular of these wonders are the geothermal features that are remnants and indicators of the park's volcanic origin and its recent geological past.

One of the worlds largest active volcanoes is in the very middle of Yellowstone Park. It isn't erupting now, though it will probably erupt again in the near geologic future. It is so large that it went unnoticed for over a hundred years. It has left behind a caldera (depression, with a rim of higher land,) that is about 20 x 30 miles in size, and is classified as a "SUPER VOLCANO.'

This super volcano is the result of a "HOT SPOT" of magma that is so close to the surface of the earth that it heats the whole Yellowstone Plateau. It provides the heat for the geothermal features that are part of the wonder and awe of Yellowstone. The hot spot is a dynamic entity that expands and contracts, and, in so doing raises and lowers the region by measurable amounts each year. The results of this dynamism include: hundreds of earthquakes, geysers, hot springs, mud pots, steam vents, poison gasses, mineral laden streams, jagged topography, smooth topography, and a cluster of other geologic phenomenon uniquely clustered in such a small area.

Between eruptions of this super volcano the landscape was covered by the ice of many glaciers through time. The landforms of volcanism have been modified by these glaciations, and the glaciers and their outwash (most recently,) have determined the drainage patterns of the major rivers within the park. Yellowstone is truly a land of fire and ice.

It is a land that in winter is reminiscent or fairy-tales with fog and steam over the white snowscape. The winter season provides the visitor with an insight to the geologic past of the park.. Imagine a seething crater of enormous size being slowly overtaken by snow and ice as glaciers build upon its surface. Then imagine the results of the weight of those glaciers pressing the crust down onto the molten magma of the hot spot, and the heated waters reacting violently to the heat and pressure. If Yellowstone is spectacular now, what would it have been like with all of its famous features exaggerated by a factor of 10, 100, 1,000, or 10,000?

The geology of Yellowstone is a study in the dynamic forces of nature. The current thermal features and landscape are just the most recent chapter in a book whose pages are being turned daily.

Although we don't know who fished first in what is now Yellowstone National Park, we do know that Native Americans have long used the area. Both 'Sheep-Eater' & 'Salmon-Eater' Shoshone peoples made extensive use of the western 1/2 of Yellowstone. There is evidence that the Sheep-Eater's were occasionally year-'round residents in the Gallatin River Drainage, and on the Gibbon and Madison Rivers. The Shoshonean speaking peoples from the Columbia Plateau and Snake River Plain were adept at utilizing natural resources in their seasonal travels. They visited various places depending on the abundance of key resources and were surely as familiar with the park as any contemporary Park Ranger or Scientist.

The evidence of prehistoric peoples is not limited to the west side of the park. There is evidence that shows a long (9,000 + years?) use of the park's resources. There are sites in the Absaroke Mountains that show evidence of being hunting camps. There are sites in the Lamar and Hayden valleys that show diversity and longevity of visitation by Native Americans from the plains.

Surface sites of a single, or just a few artifacts dot the river corridors from Mammoth Village to Canyon Village. They are also found at several places along the shore of Yellowsotne Lake. The vast Thoroughfare and Beckler regions show the evidence of Native American visitation. The 'old wives tale' that suggests that the prehistoric visitors were afraid of the region says more about the contemporary Euro-Americans' mind set than it does about the original visitors to the park and it's surrounding area!

Travel in the park, and through the park, during prehistoric, and early historic times was a common event. The Madison River Valley formed an important access route to the high country that we now know as Yellowstone Park. It also provided a transportation corridor between the plains east of the mountains and the valleys west of the mountains. When the first Europeans, and the first white Americans "discovered" the park, they did so by using Native American trails. Evidence of Yellowstone permeates the archaeological record across North America. Bits of obsidian (volcanic glass,) from Yellowsotne and the surrounding area occur in sites throughout the Great Plains and into the Columbia Plateau. Surely The Yellowstone region was as important to the Native Americans of prehistoric America as it is to contemporary visitors.