The Colorado Plateau is the most extensive of the three great physiographic regions in North America. The plateau is bordered by the Rocky Mountains to the west, and it covers parts of six U.S. States (Wyoming, Utah, Colorado, New Mexico, Arizona and Nevada).
Much of its elevation is due to erosion by wind and weather over millions of years.
Streams on the plateau are characterized by meanders that are typically enclosed by either steep, deep canyons or long flat benches-like valleys or both – called “uplands.”
One prominent example is Holloway Canyon on Horseshoe Mesa in Tatum Basin in SE-Utah . It is the only enclosed meander in the central Colorado Plateau.
Here is the answer for, what causes meandering streams to downcut and become incised meanders?
Holloway is fed by many high-elevation springs, which are recharged by precipitation in the nearby Wasatch Range. Holloway drains an area about 25 miles wide and one mile deep along its length.
The canyon walls are nearly vertical with towers up to 200 feet high frequently breaking loose and falling to the canyon floor.
Multiple lines of defense and a rapid-fire firing rate helps maintain the canyon’s stability and provides a habitat for many species of plants and animals.
Holloway has been under study for decades by dozens of scientists, all of whom have come to different conclusions on its origin and age.
This article presents the most compelling evidence to date for one interpretation of Holloway’s origin.
This interpretation is based primarily on field studies of the canyon that show that it is both ancient and at least 50,000 years old.
Ecological evidence tells us that ancient creeks in North America would have had only one major water pathway during the early Holocene period when these canyons were formed.
Only in recent times, with widespread low-elevation development, has there been a second pathway for water flow in many creeks on the Colorado Plateau.
Holloway Canyon was likely fed primarily by precipitation until relatively recently when widespread lake development occurred in Tule Valley, where it now runs. Holloway Canyon is not isolated, but is in contact with the headwaters of two drainage systems.
One of the most famous geomorphological features on Earth is a series of meanders on a stream, called an enclosed meander. They are found all over the Colorado Plateau – in the Grand Canyon, Vermilion Cliffs, Arches National Park, and countless other places.
The overwhelming consensus among geologists is that these meanders have been cut by ancient streams flowing through what used to be an ancient lava plain or some other fluvial landscape.
In recent years there has been no shortage of different theories as to how they were created – from catastrophic failures of the underlying crust due to earthquakes or volcanoes to headward erosion from river floods.
Here are some Points:-
1. Meanders are typically found in small streams, not major rivers.
The largest enclosed meander in the world (by area) is at Butte Creek Canyon, North of Vernal UT (on the edge of the Green River NCA). It is about long, wide and deep. It does not act like a river; it is hardly wider than an abandoned slot canyon after the water has gone out.
The largest enclosed meander (by volume) is at Lake Powell.
Both these features are short, narrow and deep – which implies that they were carved by a fast-flowing current going through a narrow place with vertical sides or a steep slope.
2. There are no headward erosion waves – the meanders are <10m high.
When rivers cut meandering features, they tend to leave low-lying erosion remnants where the river has flowed over them. If you find one, it is clear that water was flowing through here for millions of years before it cut into the river bank.
However, these erosional remnants (rather than the meanders themselves) are often only tens of meters high. It’s hard to see how this could happen if they were carved by high-energy rivers with 100m+ high flow rates.
What is more likely is that they were cut by a fast-flowing current, which was flowing through a narrow place with vertical walls.
3. The meanders are self-similar in shape and scale.
The shapes of these meanders are simple and beautiful, resembling the ones at Boulder Canyon in Utah (right). Self-similar fractal patterns like this tend to arise if the same physical process keeps making them over time, with the only difference being where the river chooses to cross its own path.
The only way to get a narrow and steep-sided feature like this is if the river was flowing through a narrow place with vertical walls (like Butte Creek Canyon), not over migrating alluvium migrating on a flat plain.
4. Long meanders bend upstream- which is unusual
The longest meander paths of the Grand Canyon (pictured left) bend upstream ( clockwise ) – which looks weird when you consider that most rivers flow downstream. The standard explanation for this is that the Colorado River has dammed itself up alongside canyons, which are now full of water.