The Grand Staircase

Early last summer, I took a photo road trip with an old photographer friend (Bob) to the Grand Canyon, Zion and Bryce Canyon National Parks. If you have read other posts you probably know Bob and some of our previous adventures. Our goal on this trip was to hit these iconic parks hoping for great lighting conditions that would bring out the amazing colors these rocks offer. With only a few days to play, we covered some gound!

North Rim of the Grand Canyon – Evening Glow

As we were driving along, this trip started to take on new meaning. The cobwebs of my distant degree in Geology started getting ruffled. I started asking myself questions like how the rocks of the Grand Canyon are related to the rocks of Zion…and Bryce Canyon? Where do they all fit in the history of our earth? Do we see these rocks in any other areas? While I certainly enjoy the spectacular beauty of the landscape, learning the geology became equally important for me to understand. So, it was off to the internet. The National Park Service website was an amazing resource for learning about the geology of these parks. This combined with some basic internet searches for the geology of the area helped put pieces together to answer my questions and helped me build this picture of the geologic history of the region.

As a disclaimer, there are likely several faults (pun intended) in the data I assembled to build the picture. Depending on the site, dates of various events varied some so I used my best judgment to try to represent a reasonable approximation. In reality, the geology of the area is extremely complex. The amount of detail available far exceeds what I was looking for so this is an extremely simplified diagram. I also was researching the geology of the Rocky Mountain region both for interest and understanding the relationship between this area and the mountain states.

Geology of the Grand Canyon, Zion and Bryce Canyon

How are these rocks related? The simple answer is basically that the Grand Canyon represents the oldest rocks in the stratigraphic column. The rocks of Zion National Park are part of the White Cliffs within the Grand Staircase and Bryce Canyon is the youngster in the crowd. As a side note, rock formations within Zion National Park such as the Navajo Formation sandstones are also represented in Arches National Park.

Where do they all fit within the history of the earth? The timelines on the left indicate the geologic timeline and millions of years ago various events were happening. The hundreds of millions of years of geologic activity is somewhat overwhelming to comprehend. Rocks deposited in coastal environments were largely responsible for laying down the various layers of rocks. The continental movement across the earth surface (plate tectonics) had a significant impact on the region to include the mountain building event (orogeny) that produced the Rocky Mountains we see today.

How does this area relate to other areas? Between about 30-70 million years ago, the rocks that were laid down 250-500 million years ago were uplifted making the rim of the Grand Canyon exceed 6,000’ in elevation. The tectonic activity that caused this uplift also built the Rock Mountains. Much of the erosion that has shaped the present-day Rockies is related to carving the Grand Canyon which started about 5-6 million years ago. It is truly amazing what can happen in a relatively short 6 million years!!