Geology of Yellowstone Essay

2754 Words Feb 6th, 2012 12 Pages
Introduction
It is believed that Native Americans inhabited the lands of what is now Yellowstone National Park for more than 11,000 years, until approximately 200 years ago, when European settlers began to drive many of them from their homelands. In 1872 Yellowstone was declared the world’s first national park as a way to preserve and protect the land for the “benefit and enjoyment of future generations.” (National Park Service) Yellowstone National Park covers a vast area in the Northwestern United States. Its landscape is very complex and ever changing thanks to the many geological forces that are found there. In fact, the unique geological features such as the geysers, hot springs, steam vents, among many others, are what lead to
…show more content…
The third eruption happened about 640,000 years ago, and spewed 240 cubic miles of material. This third eruption created the third and largest of Yellowstone’s calderas, Yellowstone Caldera, which is 30 by 45 miles in size. The pyroclastic lava flows from this eruption formed the north wall of the caldera and are visible from the south-facing cliffs east of Madison. (Solcomhouse) This third eruption is said to have vaporized an entire mountain range. Smaller eruptions have also helped to shape Today’s Yellowstone, such as one that occurred 174,000 years ago and created what is now the “West Thumb” of Yellowstone Lake. (National Park Service) Many sources say that a catastrophic eruption, such as those that have formed the three calderas at Yellowstone, is unlikely during the next several hundred years, but if one such eruption did occur it would devastate much of the United States and would have the potential to alter the global climate.
Lava flows of rhyolite and basalt have flowed through parts of Yellowstone as recently as 70,000 years ago. These lava flows destroyed everything in their paths while moving slowly at a rate of a few hundred feet per day, flowing months, or sometimes even several years. They are thick and cover as much as 130 square miles. They have nearly filled the Yellowstone Caldera, and spilled beyond the caldera’s border. These lava flows are responsible for forming four of the nine named plateaus in…