I've finally made it to Yellowstone National Park after seeing photos of the geysers, reading about them, watching videos and talking to people throughout the years. Today we're going to see firsthand how this unique part of the world is a manifestation of a hotspot below the earth's crust. Let's do it!
I'll admit that I didn't know much about geology before I started researching this area. Nevertheless, I've discovered that Yellowstone formed over the last 17 million years as the North American Plate was transported by a process known as plate tectonics across a stationary mantle magma chamber.
Part of the largest volcanic system in North America, the Yellowstone Caldera is a supervolcano that is estimated to have erupted 640,000 years ago. At the time of this event, more ash, rock and pyroclastic material was spewed out than more than 1,000 Mt. St. Helens of 1980. From this and 2 other eruptions, tremendous amounts of ash were deposited over the central part of the continent that eventuated in the extinction of several animal species.
Our first stop is Old Faithful. This is an iconic image that I had heard about and had seen pictures of for as long as I can remember. This geyser is one of the most spectacular sites in all of America's parks. It is incredible to register the fact that Yellowstone has more than 10,000 hydrothermal features with more than 300 active geysers. Old Faithful is the prototype, erupting according to schedule every 90 minutes. I found out that Yellowstone has half the world's geysers making it the largest concentration of this phenomenon on earth.
My geologic curiosity has now been piqued. We head to the colorful Grand Prismatic Spring. These springs are up to 330 feet in diameter and about 121 feet in depth. There is an otherworldly appearance of these steaming bodies of water that emit bright hues caused by algae and bacteria. These microorganisms thrive in different water temperatures.
We now hit the trail and head to the northern boundary of Yellowstone where we reach the Mammoth Hot Springs. This unique area was created through a process that has taken place over thousands of years. Water heats due to the underlying magma chamber and subsequently cools, leaving calcium carbonate in its wake. Up to two tons flow into the springs each day in solution. This results in an ever-changing landscape, measured in days to decades. Due to extensive geothermal vents, the travertine that is produced is allowed to flourish. Algae live in pools of hot water, the results of which are unique shades of brown, orange, red and green that give this gem its distinct appearance. Our guide tells us that if he comes back to Mammoth in a few weeks this area's appearance will have changed.
There is another phenomenon that occurs in Yellowstone, about which I was unaware-earthquakes. Thousands of small earthquakes affect this region every year. These are generally not perceptible to people; however, a 7.5 magnitude earthquake occurred outside the northwest boundary of the park in 1959. This resulted in a landslide that induced a partial dam collapse on Hebgen Lake. The sediment that was produced dammed the river downstream, resulting in the formation of a new body of water, Earthquake Lake. In 1985, there were 3,000 minor earthquakes in the northwest section of the park. This apparently has been attributed to the subsidence of the Yellowstone Caldera, and is referred to as the earthquake swarm.
The bottom line for me after touring this area is that Yellowstone is a geothermal wonder. Research by the U.S. Geologic Survey and the University of Utah has been ongoing so as to monitor the processes of the Yellowstone Plateau volcanic field. The geology of the park demonstrates the dynamic nature of this hydrothermal system. What a world!