When my daughter, Julie, had our first grandchild, Kylie Jane Dixon, my wife and I ventured out to Provo, Utah, to see the little angel.
My son-in-law, Seth, was between teaching jobs and graduate work then and he and Julie thought we might enjoy visiting Yellowstone National Park while we were out west. Man, we couldn’t wait to go.
Yellowstone National Park sits in the northwest corner of Wyoming, bordered on the north by Montana and on the west by Idaho. The park sits in a giant bowl and is approximately 40 miles square and contains some of the most beautiful and spectacular scenery you can imagine. Pristine rivers full of trout meander through canyons, meadows, forests, hills and wide plains of waving grass. Elk, moose, deer, bison, wolves, coyotes, bald eagles, ospreys and, of course, the notorious grizzly bear roam the area along with many other species of wildlife.
Geysers, hot springs, mountains, gorges, deep canyons, wide, flat, open plains, thick pine, lakes, streams, rivers and spectacular waterfalls all intermingle together in a delightful symphony of beauty that’s difficult — no, impossible — to comprehend in a single visit. It is a magical area, a place where God has revealed himself through spectacular natural scenery.
I marveled that the park could have so many diverse features in such a small area. How did it happen? I had to find out and researched the area’s geological history. The park’s beauty has been formed by cataclysmic forces of unimaginable power over millions of years. Here is a brief history of how it took place:
IF WE were to cut Earth in half we would see a largely molten center called the core, a plasma-like section above called the mantle and the hard outer surface or the crust upon which we stand. The proportions are very close to that of an egg. The yoke is the core, the egg white the mantle and the shell the crust. Geologists believe that Yellowstone Park sits directly over a thermal plume. A thermal plume is like a chimney of magma running from the 5,000-degree core through the mantle to the Earth’s crust — a pipeline, if you will, of liquid rock.
As you might imagine, thermal plumes create the potential for dynamic, catastrophic changes to the earth above it. Approximately 2.1 million years ago, these forces, which make a nuclear bomb look like a firecracker, were at work. The thermal plume was slowly lifting the mountains that covered the park. As the plume melted the mountain’s bedrock, heavier material sank and lighter elements floated upward. Dissolved in this seething, molten brew were gases, and vaporized stone, superheated and under unbelievable pressures.
As the earth’s surface rose and stretched, it began to crack. Imagine a huge soda bottle with the contents under tens of thousands of pounds pressure. Heat it to above 1,800 degrees fahrenheit and shake it as hard as you can. Then pop the lid. The soda will explode outward under tremendous force, the gas and liquid contents foaming outward, expanding to many times their original volume. When the mountain dome burst, white-hot ash, melted rock, imprisoned gases, rhyolite lava and other debris shot outward, foaming like shaken soda in a monstrous explosion.
ASH WAS blown miles into the air, so much and so high that Iowa, 1,000 miles away, was covered in three inches of it. The superheated, liquid, foaming material burst through the fissures at temperatures over 1,500 degrees and shot across the landscape at over 100 miles per hour. vaporizing all life before it.
As it lost speed and settled, in some places hundreds of feet thick, its retained heat fused much of the flow into obsidian, a black, shiny rock found throughout the park. These re-solidified ash flows are called tuffs.Three of these colossal eruptions took place over 1.45 million years to form what we now know as Yellowstone.
In order to get some grasp on just how huge the explosions were, let’s look at Mount St. Helens eruption, which produced about ¼ cubic mile of melted rock. Now, imagine 600 cubic miles of melted rock and gas exploding out of the Earth; that’s a blast 2,400 times bigger than St. Helens and just one of the three eruptions that form Yellowstone Park.
All together, the three explosions expelled 1,600 cubic MILES of molten rock in its various forms. Like I said, atomic bombs can’t hold a candle to these beasts. With miles of bedrock expelled from beneath them the mountains collapsed and sank, creating a giant bowl called a caldera. Yellowstone Park is the direct result of the calderas and the hydrothermal energies underneath them. Lava flows poured out of fissures in the calderas floor over the years, making mounds, canyons and other distinctive features.
Consider this, the Earth’s crust is about 25 miles thick. Seismic studies show that today the magma rises to within one mile of the surface in Yellowstone. If you think of the eggshell that represents the Earth’s crust, only 1/25th of it is between your feet and that molten rock atop that thermal plume when you’re in the park. That makes you think a bit doesn’t it?
No wonder the water temperature in the hot springs is 197 degrees fahrenheit. Anyone care to boil an egg? So, I hope you have enjoyed this very abbreviated history of the park’s violent birth. Powerful forces could only form such great diversity of natural beauty, shape and form. We can’t forget though that two great glaciers have also covered the park during fairly recent times. I will write of that in my next article on Yellowstone.