Zion
National Park Geology
Zion National Park is located somewhere in the middle of the Grand Staircase National Monument. For many people, the name Grand Staircase seemed an odd name for this part of the southwest, but from a geological view point it is the perfect name.
The Grand Staircase encompasses the area from Bryce Canyon to the Grand Canyon. The area is a build up of more than 10,000 feet of sedimentary material. The sedimentary layers are made up of sand, gravel and mud that have eroded from surrounding mountains and were then brought to the valley by rivers and streams. The sediment build up began more than 240 million years ago. The differing elevation of the area is what gives the appearance of a staircase. For example, the bottom layer of rock at Bryce Canyon is the top layer at Zion National Park, and the bottom layer at Zion National Park is the top layer at the Grand Canyon.
Over time the sediment began to erode creating the beautiful canyons found in the area, including Bryce, Zion and the Grand Canyon. Erosion is cause by wind, water and time. As the canyons are carved through the sandstone and other deposited sediment geologist are able to determine the layers content and age. This provides a wealth of knowledge concerning the creation of this amazing area.
Throughout the Grand Staircase National Monument are examples of sediment layering and erosion. This is most visible to visitor in the many slot canyons found within the monument. The most famous of these slot canyons is the “Narrows” located Zion National Park. The Narrows is a 16-mile slot carved by the Virgin River through the Markagunt Plateau. The canyon itself is more than 2000 feet deep and at times only 20 feet wide. The sedimentary rock layers are easy to spot in the canyon. Erosion of the Narrows is on going and is sure to provide interesting discoveries for future generations.
