Monday Walk: Rainbow Bridge National Monument
The world’s largest natural bridge.
On the way to Rainbow Bridge, first we hiked through these majestic mountains, stunning views.
“The vertical, matte black streaks are formed by water and organic material flowing over the sandstone during times of rain. A black horizontal line bisecting the canyon wall represents an ancient wadi, or freshwater stream.” — National Park Service (NPS)
This spring, water level is at all time low. In 1999, Lake Powell water elevation rose to 3,696ft, pushing 42 feet of standing water into the rock channel underneath Rainbow Bridge.
The Bridge was likely first observed by a local Native American inhabitant hundreds if not thousands of years ago. It was first “discovered” and publicized to the outside world by Anglos (Whites) on August 14th, 1909.
The Rainbow Bridge, located in San Juan County, Utah, 275 feet (84 m) across and 290 feet high (88 m), at the top it is 42 feet (13 m) thick and 33 feet (10 m) wide. The base is composed of Kayenta Sandstone, reddish-brown sands and muds laid down by inland seas and shifting winds over 200 million years ago.
Information soure: NPS
The following illustration shows the process of the formation of Rainbow — National Park Service (NPS):
A Rainbow Made of Stone
Initially, water flowing off nearby Navajo Mountain meandered across the sandstone, following a path of least resistance. A drainage known today as Bridge Canyon was carved deep into the rock. At the site of Rainbow Bridge, the Bridge Canyon stream flowed in a tight curve around a thin fin of soft sandstone that jutted into the canyon.
As you can see from the illustration, the force of the stream eventually cut a hole through the fin. Rainbow Bridge was created when the stream altered course and flowed directly through the opening, enlarging it.
This process continues to this day, imperceptibly altering the shape of the Bridge. The same erosional forces which created the bridge will, eventually, cause its demise. Rainbow Bridge, along with the rest of the spectacular landscapes of the Colorado Plateau, will exist for only the blink of an eye in geologic time.
We should consider ourselves fortunate, indeed, to be witness to these awe-inspiring formations. Let us treasure them while we can.
Jo is taking us to CANALSIDE IN NOTTINGHAM for a delightful visit. Beautiful views via her lens, as always!