Geology of the Bryce Canyon area

The disrupted geology of Bryce Canyon is a series of deposits which cover the last part of the Cretaceous period and the first half of the Cenozoic era in this part of North America. The former sedimentation of the current Bryce Canyon National Park extends from the warm shallow sea in which the Dakota Sandstone and the Tropic Shale were deposited, up to cold rivers and lakes of the now colorful Claron Formation, which the amphitheater -like semicircle of the Parks dominated.

It still formed more layers that have been removed but again for the most part, there are two periods of uplift followed an approximately 70 million years ago, the cause of the formation of the Rocky Mountains, and the other in front of 10 to 15 million years, which spawned the Colorado Plateau. The uplift produced vertical fractures that were much eroded and later strengthened by free-standing pinnacles, Badlands and monoliths formed. These particular formations of the park include the Grand Staircase ( " Grand Staircase ").

The Grand Staircase

The outcropping of rocks in Bryce Canyon are about 100 million years younger than the neighboring Zion National Park, and in turn are younger than those in the more southern Grand Canyon. However, all three locations belong to a common rock series - a long sequence, known by geologists as the Grand Staircase. Overall, the Grand Staircase documented nearly two billion years of Earth's history. The Bryce Canyon formations are the youngest known stages of the Grand Staircase. If there should have been ever younger rocks, they have been removed by erosion.

Sedimentation of the disrupted rocks

Cretaceous ocean passage and later

The base of the Dakota Sandstone consists of conglomerate and fossil- rich sandstone. This sequence was probably later to Cretaceous in a shallow sea - geologists call Cretaceous ocean passage ( Cretaceous Seaway ) - deposited, which divided North America in north-south direction. The Dakota Sandstone is the oldest formation that is open in Bryce Canyon, but in lying to the southwest Zion area, the youngest. In the area of Bryce Canyon this formation in the Paria Valley is seen as fossilized sand ceiling that probably in the transgression (sea attacks on the country over ) the Cretaceous ocean passage in this area of beaches, was deposited in lagoons, and coal swamps.

The Tropic Shale was deposited as mud and silt in the same sea as this was lower and thus quieter. This rock series can be found in the deeper sections of the park. It contains fossilized ammonites.

Sandy and clayey sediments as the formations Straight Cliffs, Wahweap and Kaiparowits were deposited on the Cretaceous, later raised and partly eroded away at the end of the geological era again, so that they are available now discordant. These rocks occur in the southern part of the park at lower altitudes to day.

The improvement process was carried out during a mountain building, the so-called lara mix orogeny, which lasted from the late Cretaceous to early Paleocene. She squeezed single crustal sections upward while lower altitudes pelvic areas further absenkten gradually.

Claron formation

A wide network of shallow lakes that has taken thousands of square kilometers covered during the Eocene large parts of eastern and central Utah and southwestern Montana. Large amounts of lake sediments were deposited in this system in the 20 million years of its existence, million years ago, about 63-40. In the course of climate change these lakes changes with time, their dimensions - in high rainfall periods, they spread out in low rainfall periods and shrank. These processes have left deposits of various thickness and composition, stacked to the Bryce Canyon:

Pure lime slurries were deposited in greatest depth. In less deep water then was the transition to lime-rich mud to lime- mud towards the shore and at different sands and gravel deposits near the shore.

These sediments were later to a heterogeneous mixture of fossil- poor limestone, marl, sandstone and conglomerates petrified, now the Claron Formation (? ): Form (formerly Wasatch Formation). The geologist Clarence Dutton described the iron-oxide- rich deeper part of the Claron because of its colorful appearance as Pink riffs series. The fragile tips for Bryce Canyon is famous, called hoodoos ( jinx ), made almost entirely of these Claron layers. The elements of the Whitecliff form monoliths. Most natural arches and bridges, including the famous Natural Bridge were ground out of sandstone deposits in the Claron.

Colorado Plateau and erosion

There were even younger rocks formed by sedimentation, but for the most part eliminated by subsequent accelerated erosion of uplift. These formations show in the northern part of the park and at some points of the plateau edge. Among the 15 to 30 meter thick Boat Mesa Conglomerate from the Oligocene, which is formed from detritus of the Claron, and, from the Pliocene to early Pleistocene, the Sevier River Formation of gray - brownish sandstone with some conglomerate. Located

In the Miocene, around 16 million years ago the Colorado Plateau was uplifted from almost sea level to over a kilometer. With this uplift tensile forces are generated, which decomposed in the region different plateaus, such as the Paunsaugunt. The voltages of Nevada heading west were so strong that the earth's crust was stretched and a sequence of pools and mountain chains arose, the Basin and Range Province. Consequently, the stress -induced transformation of the Colorado Plateau was strongest on the western edge. It emerged at the same time long, running in a north-south direction distortions, such as Sevier and Paunsaugunt.

As North America drifted slowly to the north, the climate cooled and it was humid. Maybe ablations of the Paunsaugunt plateau have created from the top of the late Tertiary and early Quaternary the " amphitheater " of Bryce Canyon. However, certain types of erosion and frost damage groomed out the so-called hoodoos. During the ice ages during the Pleistocene was in the higher regions year-round ice and snow.

Swell

Geology of National Parks: Fifth Edition, Ann G. Harris, Esther Tuttle, Sherwood D., Tuttle (Iowa, Kendall / Hunt Publishing, 1997) ISBN 0-7872-5353-7
Secrets in The Grand Canyon, Zion and Bryce Canyon National Parks: Third Edition, Lorraine Salem Tufts ( North Palm Beach, Florida; National Photographic Collections, 1998) ISBN 0-9620255-3-4