Geology of the Bryce Canyon area

The exposed geology of the Bryce Canyon area in Utah shows a record of deposition that covers the last part of the Cretaceous Period and the first half of the Cenozoic era in that part of North America. The ancient depositional environment of the region around what is now Bryce Canyon National Park varied from the warm shallow sea (called the Cretaceous Seaway) in which the Dakota Sandstone and the Tropic Shale were deposited to the cool streams and lakes that contributed sediment to the colorful Claron Formation that dominates the park's amphitheaters.

Other formations were also formed but were mostly eroded following uplift from the Laramide orogeny which started around 70 million years ago (Mya). This event raised the Rocky Mountains far to the east and caused the retreat of the sea that covered the Bryce Canyon area. After Laramide mountain building came to an end, about 15 mya, a large part of western North America began to be stretched into the nearby Basin and Range topography. The greater Bryce area was uplifted as part of the High Plateaus by the same forces. Uplift of the Colorado Plateaus and the opening of the Gulf of California by 5 mya changed the drainage of the Colorado River and its tributaries, including the Paria River, which is eroding headward between two plateaus adjacent to the park. The uplift caused the formation of vertical joints which were later preferentially eroded to form the free-standing pinnacles called hoodoos, badlands, and monoliths we see today.

The formations exposed in the area of the park are part of the Grand Staircase. The oldest members of this super sequence of rock units are exposed in the Grand Canyon, the intermediate ones in Zion National Park, and its youngest parts are laid bare in Bryce Canyon area. A small amount of overlap occurs in and around each park.