Bryce Canyon National Park in Utah has been described as “Poetry in Stone.” I loved that description. Each of us who visits Bryce has to remember that the landscape is never static. It is always dynamic and changing. Change is the only constant. The forces of weathering never get fatigued and exert a relentless force on the rock. Bryce Canyon consists of a series of deep amphitheaters filled with a variety of colored rock formations. Some of them are called hoodoos and they are what Bryce Canyon is most famous for. Hoodoos are eroded columns of sandstone. They were formed when wind, rain, and ice eroded “fins” of harder rock that eventually being columns and then further eroded into strangely shaped hoodoos. When those windows grow larger, their tops eventually collapse. Everyone wonders why do they appear here and not in many other places of the world, though I have seen them in Alberta. Frank Decourten wrote a book called Shadow of Timeabout Bryce and its hoodoos “the grand icons of erosion.’ He also pointed out that “Hoodoos are ephemeral–new columns form while older ones are destroyed–and erosion is both their creator and, eventually, their executioner.” They are created by differential erosion, the cap is harder and does not erode as fast, protecting the column underneath.
We loved the views at the various look offs. Each was spectacular in its own unique way. The spires of pink, orange, and red spires were breathtaking. The Paiute Indians who used to hunt here described them as “red rocks standing like men in a bowl-shaped recess.” The image above is a panorama. That means I combined a number of photos into one image. If you click on it, I hope it gets bigger.
Of course in the world of geography nothing is forever. As Decourten said, “Inevitably, even the pillars, protected to some degree by dripstone and caprock , succumb to the relentless attack of the elements and the hoodoos begin to crumble.” Bryce really is a phantasmagorical funhouse made of stone. Bryce is one of the few places where people notice–really notice–the rock. That is because it is so strange. There is no place like it. But they are not only beautiful, they are fascinating if you dig into the geology of Bryce. As Decourten pointed out, “The vibrant colors, the intricate patterns of erosion, and the infinite variations in the surface textures of these rocks are both enchanting and mystifying.”
If you look closely at this picture of me you might be able to see Fear.
Bryce was affected by the Cretaceous Period is one of the most interesting periods in the history of our planet. It lasted approximately 79 million years, 145.5 million years ago 65.5 million years ago when the dinosaur disappeared. Decourten said “The Cretaceous was perhaps nature’s greatest excursion into mayhem. It was a time when the gradual, steady, geological processes of the planet went haywire. For example, the slow spreading of the ocean basins which results in continental drift was proceeding at a rate up to three times greater than the rate at which such spreading occurs today! During the Cretaceous, the plates of the Earth’s brittle crust were dashing around the planet at a geologically reckless speed–as much as 8 inches per year–about five times faster than your fingernails grow (the normal speed of the tectonic plates). Partly as a result of the high rate of seafloor spreading, great quantities of magma were produced and volcanoes erupted on an unprecedented scale with astonishing intensity. More igneous rock formed worldwide during Cretaceous time than in any other period of geologic history (except perhaps the period just after the formation of the Earth). Ash and gases erupting from the Cretaceous volcanoes seem to have created a natural “greenhouse effect” which profoundly changed the global climate. It was warm 100 million years ago, very warm. Tropical forests grew as far north as Alaska. The arctic zones disappeared and temperate conditions at eh poles caused the icecaps to melt. Water released during this great thaw lifted the world’s oceans onto the low borderlands of all the Cretaceous continents.
On land and in the swollen seas, a riot of evolution, induced by the rapid and profound environmental changes, produced bizarre life forms: giant seagoing lizards (mosasaurs); flying reptiles the size of small jet aircraft; the horned, armored, and duck-billed types of dinosaurs (not to mention the fearsome predators, such as Tyrannosaurus, which fed on them); tree-sized ferns and other primitive plants. Finally, there is some good evidence the Cretaceous might have been punctuated, 66 million years ago, by a collision between the Earth and an asteroid, an appropriately violent end to a turbulent period. A great extinction followed this event resulting in the extinction of vast amounts of life on earth, including, the dinosaurs. Much of that ancient history is told in the rocks and fossils of Bryce. The story is endlessly fascinating.
An inland sea divided North America east to west 90 million years ago (‘mya’). During this time sediments were deposited at the bottom of that sea, forming the oldest rocks in the park. Before the canyon was filled with hoodoos it was filled with water. I am particularly interested for some reason in the fact that much of North America was at one time split by an ocean seaway. How can that possibly be? How weird is that desert regions like the American southwest were at one time inundated by this interior seaway? This has been called the Cretaceous Western Interior Seaway. When this interior seaway covered much of North America, including Manitoba, coal, sandstone, and mudstone accumulated along the western edge of this seaway. If it had accumulated on the eastern edge we might be richer here in Manitoba today. What a pity. During this time what we now call the Gulf of Mexico penetrated north across the low plains of central North America and joined the waters that were advancing from the northern Arctic Ocean. This incredible seaway in time submerged the entire region where the Rocky Mountains are now found (though they were not in existence yet at that time). This great interior seaway divided North America into two island continents!
Between 55 and 40 mya years ago much of Utah was a basin of water encircled by mountains. That seems impossible now because it is so dry. Yet for millions of years rivers deposited sediments –mainly dissolved limestone—into a system of large lakes at the top of the Plateau . 20 mya ago, as the Colorado Plateaubegan to be uplifted the lakes dried up and their mixtures of sediments became the muddy limestone that geologists now refer to as the Claron Formation. Then massive tectonic plate activity from 20 to 15 mya began to push up an incredible part of the Earth’s crust. Eventually this uplifted the region by an astonishing 2 miles, creating the 130,00 sq. mile Colorado Plateau that I have come to know a little bit and love a lot.
If one stand on the rim of one of the amphitheaters in Bryce Canyon and thinks about things like this one’s mind is expanded to near stretching limits. The world is and has been a very strange place and much of that strangeness can be detected right here at Bryce. This ancient world has been recorded in stone. That stone of course was subject to what Decourten called “Water, wind, gravity—nature’s wrecking crew—worked in concert to efface and obscure. He also said, The erosion which removed much of the younger layers created this glorious shrine to the dynamic artistry of geologic processes. Whatever else Bryce Canyon National Park may be, it is certainly a monument to erosion.
What we saw today was the product of massive rock layers that had been uplifted and fractured over millions of years and then submitted to the relentless never-ending forces of erosion. Those forces are not at sleep today. They never sleep. What we see tomorrow will also be the product of those same forces.
I have fallen in love with geology the study of how these forces have shaped our wonderful planet. That is to me an astonishing admission. I would never have dreamed this were possible when I was a liberal arts student as an undergraduate at the University of Manitoba. I despised all science. I was enamoured of the arts and humanities. Science was irrelevant. Now I know how foolish I was. Science is critically important to understanding our world. If we understand it, even if we don’t solve all of its mysteries, we can’t help but love it and if we love it we will try to care for it. That is why science—just like arts and humanities—is vitally important.
Our next stop was one of my favourite—i.e. Natural Bridge formed through the erosion of rock by streams or rivers. This window or arch formed from a combination of processes. First, frost wedging, which is the expanding of cracks in rock as water turns to ice, weakened the rock. Then over time, dissolution occurred as a result of chemical dissolving of the rock by rainwater that cut away at the top and sides of this wall of rock. Over time the relentless force of gravity pulled loose the weakened pieces of rock at the center and that created a hole in the wall that we could clearly see and photograph today. That is why the “bridges” of Bryce Canyon, such as Natural Bridge, are spectacular examples of arches that, like the hoodoos, are constantly at risk of destruction as the never ending forces of erosion chip away at the rock. Nothing stands in the way of time. Everything changes.